title: Battle of Huế

text: On 28 January, the PAVN/VC units tasked with attacking the new city began moving into position 48 hours earlier than the northern wing tasked with attacking the Citadel, because it had a longer distance to march and more difficult terrain to cross. The 804th Battalion, 4th Regiment, began marching from Phú Lộc to a mountain camp south of Huế where the majority of the southern wing was gathered. Also on 28 January, the 810th Battalion, 4th Regiment and the 2nd Sapper Battalion began marching toward the city from locations along the coast east of Huế. On the afternoon of 29 January, the main body of the southern wing, the 804th Battalion, the 1st Sapper Battalion, the 815th and 818th Battalions of the 5th Regiment, the southern wing command group, and various supporting units descended from their mountain staging area and headed for the Tả Trạch River, which stood between the attacking force and Huế. The units intended to use a ferry station south of the city to cross the river. The lead elements of the southern wing, the 1st Sapper Battalion and part of the 804th Battalion, arrived two hours ahead of schedule, which meant that they reached the crossing well before the sun had set. An allied aircraft spotted the units and reported their position. Artillery shells began raining down near the ferry landing and fighter-bombers soon joined the attack, which killed at least 12 PAVN-VC and scattered the rest. The Allied bombardment lasted intermittently from 17:30 until 03:30 the next day, forcing the entire southern wing to postpone the ferry crossing. The Allies did not send ground forces to investigate the incident, and no evidence exists that it generated much concern in any of the allied headquarters. The PAVN/VC crossed the river without incident on the evening of 30 January, but the delay meant that only the 1st and 2nd Sapper Battalions and an 82mm mortar company would be in their forward positions when the offensive began.


title: Battle of Huế

text: Premature Tet Offensive attacks at Nha Trang and Qui Nhơn on the morning of 30 January led to the cancellation of the Tết ceasefire, but many ARVN soldiers were already away on leave, meaning that defenses in and around Huế were undermanned. On learning of the cancellation of the ceasefire, Trưởng ordered his headquarters staff to remain at the Mang Ca compound that night, he sent three platoons from the "Hac Bao" Reconnaissance Company to guard the provincial headquarters, the power station and the prison in the new city. He split up two more platoons to reinforce security at the various gates leading into the Citadel. His remaining "Hac Bao" platoon, made up of the most experienced soldiers, took up position at the centrally located Tây Lộc Airfield to act as a rapid-reaction force. News of the cancelled cease-fire never reached the MACV Compound.


title: Battle of Huế

text: On the afternoon of 30 January Trưởng dispatched a "Hac Bao" platoon and an Australian Army adviser to scout the north bank of the Perfume River which provided the simplest route from Base Area 114 into the city. After marching southwest approximately , the team concealed itself in some bushes near the river and waited. That evening, the PAVN-VC northern attack wing began moving towards Huế from base camps in the western hills. A VC company armed with 82mm mortars and 57mm recoilless rifles veered north and took up a position near PK–17 outpost to shell the ARVN airborne and armored units stationed there once the offensive began. to the northwest, an engineer unit moved within sight of its target, the An Lo Bridge that spanned the Bo River, as it did, the 806th Battalion, one company from the 800th Battalion and a sapper platoon of forty men, all from the 6th Regiment, quietly occupied a forward staging area in a graveyard northwest of the Citadel. Around that time, the 802nd Battalion from the 6th Regiment, the remainder of the 800th Battalion, the 12th Sapper Battalion, and several heavy weapons companies marched down from the mountains to a spot on the Perfume River several kilometers west of Huế before turning toward the Citadel. At 22:00, South Vietnamese Regional Force (RF) troops stationed in a village a few hundred meters north of the An Hoa Bridge observed what appeared to be enemy figures moving past them in the dark. RF soldiers opened fire and radioed a warning to Trưởng's headquarters. ARVN troops in the Citadel fired flares over the village to help the RF troops there assess the situation. The enemy force, the forty sappers and an infantry company from the 800th Battalion that had been waiting in the graveyard northwest of An Hoa, did not return fire but crept away before they could be illuminated by the descending flares. The sappers’ mission was to scale the Citadel's wall near the Mang Ca compound, open and hold the Hau and An Hoa Gates and assist the infantry company with its attack on Trưởng's headquarters. The PAVN-VC could not afford to engage in a firefight at this point, and they succeeded in sneaking away without raising further alarms. After a few minutes, the RF soldiers stopped shooting, and some began to wonder whether they had seen enemy troops or had been firing at shadows. Shortly before midnight, the reconnaissance team hiding in the bushes on the north bank of the Perfume River saw a long column of PAVN soldiers emerge from the darkness. The allied platoon stayed out of sight as the 800th, 802nd and 12th Sapper Battalions marched past its position, heading east along the river toward the city. The patrol commander reported by radio what he had seen, Trưởng immediately dispatched a light observation airplane from the Tây Lộc Airfield to look for the enemy force. Flying through overcast skies, the aircraft returned two hours later, its pilot having seen nothing out of the ordinary.


title: Battle of Huế

text: On the night of 30 January it started to rain; from 2 February onwards this rain, low cloud and foggy weather (known locally as the "crachin") would last through much of the battle and severely hamper Allied air and artillery support.


title: Battle of Huế

text: In the early morning hours of 31 January 1968, a division-sized force of PAVN-VC soldiers launched a coordinated attack on the city of Huế. At 02:33, a signal flare lit up the night sky, and two battalions from the PAVN 6th Regiment attacked the western wall of the Citadel. Their objective was to capture the Mang Ca Garrison. Other objectives included the Tây Lộc Airfield and the Imperial Palace.


title: Battle of Huế

text: At the Chanh Tay gate () on the west wall of the Citadel, a six-man PAVN sapper team dressed in ARVN uniforms killed the guards and opened the gate. Upon their flashlight signals, the 800th Battalion and several teams from the 12th Sapper Battalion rushed through the gate and headed northwest towards Tây Lộc Airfield. A 40-man assault team that was tasked with attacking Mang Ca through a sewer found the entrance blocked and moved around to assault the Huu Gate () at the southwest corner of the Citadel; they were engaged by an ARVN machine gun and lost 24 men before seizing their objective. The 802nd


title: Battle of Huế

text: Battalion and a heavy weapons company had some trouble crossing the canal outside the southeastern wall, but entered shortly thereafter. The 806th Battalion, which was dug into a cemetery along Highway 1 near the western corner of the Citadel, dispatched a group of soldiers to capture the An Hoa Bridge, driving off the RF detachment guarding the bridge and opening a line of communication with the other PAVN-VC in the Citadel. Meanwhile, the team of thirty sappers who had scaled the northwestern wall overpowered the guards standing watch at the An Hoa and Hau Gates, then opened their doors to the infantry company waiting outside. The combined force then headed for the Mang Ca compound with the goal of neutralizing Trưởng's headquarters before it had time to organize the city's defenders.


title: Battle of Huế

text: At 03:40, ten minutes behind schedule, elements of the PAVN 164th Artillery Regiment fired a barrage of 122mm rockets into the new city from firing positions in the southwestern hills. PAVN soldiers also fired 130 82mm mortar rounds into the Mang Ca Compound the opening minutes of the battle. Meanwhile, 4 km to the west of the city the PAVN 416th Battalion, 5th Regiment, as well as a local force company and a recoilless rifle company, swarmed into the villages of Thon Que Chu and Thon La Chu (). At Thon La Chu a South Vietnamese official who was a VC agent had earlier used aid money to build a three-story concrete and steel bomb shelter for local villagers and the command group of the Huế City Front used this as its headquarters. Meanwhile, the 416th Battalion began fortifying the twin villages with spider holes, trenches and camouflaged fighting positions.


title: Battle of Huế

text: At 04:00 the PAVN reached the Tây Lộc Airfield, where 50 men of the "Hac Bao" reconnaissance company, reinforced by the 1st Division's 1st Ordnance Company, stopped the PAVN 800th Battalion. Although one battle account stated that the South Vietnamese "offered no strong resistance", the PAVN report acknowledged "the heavy enemy ARVN fire enveloped the entire airfield. By dawn, our troops were still unable to advance". The fighting for the airfield continued to seesaw, with first the ARVN having the upper hand and then the PAVN. Meanwhile, the PAVN 802nd Battalion moved north of Tây Lộc to attack Mang Ca. Although the PAVN battalion penetrated the division compound, an ad hoc 200-man defensive force of staff officers and clerks staved off the assaults. Trưởng called back most of the "Hac Bao" Company from the airfield to bolster the headquarters' defenses, which kept division headquarters secure. At 04:40 sappers captured the Huu Gate and the command group of the PAVN 6th Regiment entered the Citadel. Outside the Citadel walls sapper teams failed to destroy the Bach Ho and Trường Tiền Bridges after being ambushed by RF troops. The 150 ARVN at Tây Lộc Airfield withdrew east through the city, avoiding PAVN forces and sneaked into the Mang Ca compound shortly after 07:00, just in time to help repulse another major assault from the 802nd Battalion. The reconnaissance platoon, having made its way back into the city, defended the Imperial Palace but eventually had to retreat to Mang Ca. At 08:00, PAVN troops raised a liberation flag over the Citadel flag tower.


title: Battle of Huế

text: South of the river a reinforced company of the 2nd Sapper Battalion launched a simultaneous attack on the MACV Compound in the new city. The attackers were engaged by a machine gunner in a guard tower and troops in a bunker who were able to hold off the attack for long enough to allow others in the compound to form a cohesive defense. At 05:00 a reinforced company from the 1st Sapper Battalion


title: Battle of Huế

text: attacked the compound from the east, but failed to penetrate the compound. After failing to take Mang Ca and the MACV Compound in their initial assaults, the PAVN-VC did not attempt to seize them again, instead keeping them under fire and generally adopting a defensive posture, this tactical mistake allowed the ARVN and U.S. to bring in the reinforcements that would eventually clear the city. East of the MACV Compound, a heavy weapons team from the 2nd Sapper Battalion attempted to destroy the communications facility. Firing at long range, they missed their target and made no further effort to take the position.


title: Battle of Huế

text: A company each from the 815th and 818th Battalions entered the western edge of the new city around 04:50, eighty minutes behind schedule. The 815th Battalion had been delayed because South Vietnamese paramilitaries had ambushed the battalion at a river crossing three kilometers south of the city. The main body of the 818th Battalion had left camp later than planned and had gotten lost on its way to the city. After battling RF troops who were guarding a series of four bridges over the canal, some of the PAVN troops crossed into the city and headed for a list of targets that included the Montagnard military school, the Civil Operations and Revolutionary Development Support (CORDS) center, the Le Loi transportation camp, the provincial administration complex and prison and the Thừa Thiên Provincial Headquarters (). Other PAVN troops split off and attacked the Huế railway station and a police headquarters facility near the Bach Ho Railroad Bridge. PAVN troops also seized the Tu Dam Pagoda, just south of the canal, which they soon converted to the main command post for the southern wing.


title: Battle of Huế

text: Just before dawn the 804th Battalion reached the eastern outskirts of the new city, three hours behind schedule. Some elements of the battalion had been delayed by South Vietnamese paramilitary troops while others had gotten lost. With the city finally in sight, the three companies that made up the 804th Battalion headed off in different directions. One company occupied a six-way intersection on Highway 1 a few blocks southeast of the MACV Compound to prevent Allied mechanized forces from entering the city. The company also helped a group of sappers seize the Treasury Building (), the post office and a radio station a few blocks to the north. The second company from the 804th Battalion seized the An Cuu Bridge while the third company stormed a smaller bridge over the canal a short distance to the west. At dawn the only areas of the new city still under Allied control were the prison defended by a "Hac Bao" platoon; the Le Loi transportation camp; the Huang Giang Hotel; the MACV Compound; the communications facility; and the Navy loading dock.


title: Battle of Huế

text: In the early morning a U.S. Army helicopter was shot down over the city; the crew sought refuge with a group of ARVN in a small compound. A U.S. Army UH-1 Huey piloted by Chief Warrant Officer Frederick Ferguson landed in the compound and rescued the crew under fire. For his actions Ferguson was subsequently awarded the Medal of Honor.


title: Battle of Huế

text: The embattled Trưởng called in reinforcements ordering all four battalions of the 3rd Regiment in the countryside to return to the Citadel, he also instructed two armored units, the 3rd Troop, 7th Cavalry, stationed at PK–17, and the tank-equipped 1st Troop, 7th Cavalry, at the Tam Thai camp southeast of new city to proceed to Mang Ca. Trưởng obtained permission from I Corps commander, General Hoàng Xuân Lãm, to take control of the 1st Airborne Task Force. Although the South Vietnamese 9th Airborne Battalion was caught up in the battle for Quảng Trị, the 2nd and 7th Airborne Battalions were available at PK–17. The armored troop at Tam Thai was first to respond to Trưởng's order. Shortly after 04:30, a column of M41 tanks and M113 armored personnel carriers (APCs) left the compound and headed up Highway 1. Shortly after the column crossed over the An Cuu Bridge over the Phu Cam Canal (), however, soldiers from the 1st Sapper Battalion and the 818th Battalion, hiding in and around buildings near the road, opened fire at close range with rocket-propelled grenades, heavy machine guns and at least four 75mm recoilless rifles. The ambush destroyed several vehicles and threw the 1st Troop, 7th Cavalry, into confusion. Several M41 crews abandoned their undamaged tanks when they found their escape route blocked by burning hulks.


title: Battle of Huế

text: Responding to the call at PK-17, at 09:00 the 3rd Troop and the 7th Battalion of the Airborne task force rolled out of their base area in an armored convoy onto Highway 1. A PAVN blocking force from the 806th Battalion in the graveyard stopped the ARVN relief force about 400 meters short of the Citadel wall destroying two M113s. The Airborne attempted a frontal assault on the graveyard but were unable to force their way through the PAVN positions and found themselves unable to advance or retreat and called for assistance. The 2nd Airborne Battalion reinforced the convoy and conducted a flanking attack. In the early morning hours of 1 February the PAVN withdrew and at midday a "Hac Bao" unit led the Airborne force into Mang Ca. The cost had been heavy: the ARVN suffered 131 casualties including 40 dead, and lost four of the 12 armored personnel carriers in the convoy. The ARVN claimed to have killed 250 PAVN, captured five prisoners and recovered 71 individual and 25 crew-served weapons.


title: Battle of Huế

text: The ARVN 3rd Regiment had an even more difficult time. On the 31st, two of its battalions, the 2nd and 3rd, advanced east from encampments southwest of the city along the northern bank of the Perfume River, but PAVN defensive fire forced them to fall back. Unable to enter the Citadel, the two battalions established their night positions outside the southeast wall of the Citadel. PAVN forces blocked the 1st and 4th Battalions of the regiment, operating to the southeast, as they attempted to reinforce the units in Huế. The 1st Battalion encountered the 810th Battalion which had been deployed to block the eastern approaches to the new city, running low on ammunition Captain Phan Ngoc Luong, the commander of the 1st Battalion, retreated with his unit to the coastal Ba Long outpost, arriving there with only three eight-round clips per man for their World War II vintage M1 Garand rifles. At Ba Long, the battalion then embarked upon motorized junks and reached the Citadel the following day. The 4th Battalion ran into a blocking force from the 2nd Sapper Battalion and a company from the 810th Battalion. The government troops tried to fight their way through but lacked the strength or the firepower to do so. Four days would pass before they were at last able to punch a hole in the PAVN-VC lines and reach the MACV compound.


title: Battle of Huế

text: South of the city, on 31 January Lieutenant Colonel Phan Hữu Chí, the commander of the ARVN 7th Armored Cavalry Squadron, attempted to break the PAVN-VC stranglehold. He led an armored column toward Huế, but like the other South Vietnamese units, found it impossible to break through. With the promise of U.S. Marine reinforcements, Chi's column, with three tanks in the lead, tried once more. This time they crossed the An Cuu Bridge into the new city. Coming upon the central police headquarters in southern Huế, the tanks attempted to relieve the police defenders, but a B-40 rocket made a direct hit on Chi's tank, killing him instantly. The South Vietnamese armor pulled back.


title: Battle of Huế

text: Three USMC battalions were protecting Phu Bai Combat Base, Highway 1 and all western approaches to Huế. This was an operational area that actually required two complete regiments to secure.


title: Battle of Huế

text: On the night of 30/31 January, the Marines faced rocket and mortar fire at the Phu Bai Combat Base and PAVN-VC infantry units hit Marine combined action platoons (CAP) and local Popular Force and RF units in the region, including the Truoi River and Phú Lộc sectors. At about 04:00 a PAVN company attacked the ARVN security detachment defending the Highway 1 bridge over the Truoi River () and the nearby CAP H-8. 1st Marine Regiment commander Colonel Stanley S. Hughes, ordered Captain George R. Christmas, commander of Company H, 2nd Battalion 5th Marines to relieve the CAP unit and Company H engaged the PAVN-VC as they withdrew from the CAP position. Seeing an opportunity to trap the PAVN-VC, Lieutenant Colonel Ernie Cheatham reinforced Company H with his Command Group and Company F. With his other companies in blocking positions, Cheatham hoped to pin the PAVN-VC against the Truoi River. However at 10:30, 31 January Company G was ordered to Phu Bai as the Task Force reserve and Company F was removed from Hughes' operational control later that afternoon. With the departure of Company F about 16:30, the PAVN-VC successfully disengaged and Companies H and E took up night defensive positions. 2/5 Marines killed 18 PAVN or VC and captured one, at a cost of three Marines killed and 13 wounded.


title: Battle of Huế

text: While the fighting continued in the Truoi River and the Phú Lộc sectors, the 1st Battalion, 1st Marines had begun to move into Huế. In the early morning of 31 January, after the rocket bombardment of the airfield and the initial attack on the Truoi River Bridge, Task Force X-Ray received reports of strikes all along Highway 1 between the Hải Vân Pass and Huế. All told, the PAVN-VC hit some 18 targets from bridges, CAP units, and company defensive positions. With Company A, 1/1 Marines as the Phu Bai reserve, Hughes directed Lieutenant Colonel Marcus Gravel to prepare the company for any contingency. At 06:30, Hughes ordered the company to reinforce the Truoi River Bridge. Captain Gordon Batcheller later recalled that "we were rousted up about 04:00 on the 31st and launched south on trucks to rendezvous with and reinforce ARVN forces about a map sheet and a half south of Phu Bai." The convoy was then turned around and sent towards Huế.


title: Battle of Huế

text: Up to this point the fighting for Huế had been entirely a South Vietnamese affair. Brigadier General Foster LaHue, the Task Force X-Ray commander, actually had very little reliable intelligence on the situation. All he knew was that Trưởng's headquarters had been under attack, as was the MACV Compound. Because of enemy mortaring of the LCU ramp in southern Huế, the allies had stopped all river traffic to the city. As LaHue later wrote: "Initial deployment of forces was made with limited information."


title: Battle of Huế

text: As the Marines approached the southern suburbs of the city they came under increasing fire from the PAVN 804th Battalion. In one village, the troops dismounted and cleared the houses on either side of the main street before proceeding. During this fighting Company A, 1/1 Marines commander Captain Batchellor was wounded and Gunnery Sergeant John L. Canley assumed command of the Company. He and Sergeant Alfredo Cantu Gonzalez led the Marines in the defense of the convoy, actions for which both men would later be awarded the Medal of Honor. The Marine convoy stopped several times to eliminate resistance in heavy house-to-house fighting before proceeding again. At about 15:15 the Marines managed to make their way toward the MACV Compound. By this time, the PAVN-VC attackers had pulled back their forces from the immediate vicinity of the Compound. Gravel met with Army Colonel George O. Adkisson, the senior U.S. advisor to the ARVN 1st Division.


title: Battle of Huế

text: Leaving Company A behind to secure the MACV Compound, Gravel took Company G, reinforced by the three M48 tanks from the 3rd Tank Battalion and a few ARVN M24 light tanks from the 7th Armored Cavalry Squadron, and attempted to cross the Trường Tiền Bridge, the main bridge over the Perfume River. Gravel left the armor behind on the southern bank to provide direct fire support. As he later remembered, the American M48s were too heavy for the bridge and the ARVN tankers "refused to go." As the Marine infantry started across, a machine gun on the other end of the bridge opened fire, killing and wounding several Marines. One Marine, Lance corporal Lester A. Tully, later awarded the Silver Star for his action, ran forward, threw a grenade, and silenced the gun. Two platoons successfully made their way to the other side. They turned left and immediately came under automatic weapons and recoilless rifle fire from the Citadel wall. The Marines decided to withdraw. This was easier said than done as the PAVN-VC were well dug-in and firing from virtually every building in the Citadel. With the number of wounded rising, the Marines commandeered some abandoned Vietnamese civilian vehicles and used them as makeshift ambulances to carry out the wounded. Among the casualties on the bridge was Major Walter M. Murphy, the 1st Battalion S-3, or operations officer, who later died of his wounds.


title: Battle of Huế

text: By 20:00, the 1/1 Marines had established defensive positions near the MACV Compound and a helicopter landing zone in a field just west of the Navy LCU Ramp in southern Huế. On that first day, the two Marine companies in Huế had sustained casualties of 10 killed and 56 wounded. During the night, the battalion called helicopter into the landing zone to take out the most badly wounded. The American command still had little realization of the situation in Huế.


title: Battle of Huế

text: North of the Perfume River, on 1 February, the ARVN 1st Division enjoyed some limited success. Although the 2nd and 3rd Battalions of the 3rd Regiment remained outside of the Citadel walls, unable to penetrate the PAVN defenses; the 2nd and 7th Airborne Battalions, supported by armored personnel carriers and the "Hac Bao" Company, recaptured the Tây Lộc airfield.


title: Battle of Huế

text: At about 15:00, the ARVN 1st Battalion, 3rd Regiment reached the 1st Division command post at the Mang Ca compound. Later that day, U.S. Marine helicopters from HMM-165 brought part of the ARVN 4th Battalion, 2nd Regiment from Đông Hà Combat Base into the Citadel. Eight CH-46 Sea Knight helicopters made the flight in marginal weather with a ceiling and visibility, arriving at an improvised landing zone under enemy mortar fire. The deteriorating weather forced the squadron to cancel the remaining lifts with about half of the battalion in the Citadel.


title: Battle of Huế

text: Shortly after 15:00, Company F, 2/5 Marines made a helicopter landing into southern Huế. They were to relieve a MACV Microwave/Tropo communications facility approximately 2.5 km southeast of the MACV Compound surrounded by a VC force. Operated by the United States Army Signal Corps 513th Signal Detachment, 337th Signal Company, 37th Signal Battalion, it was the main communications link for the Huế area, the DMZ and for the besieged Khe Sanh Combat Base. The company spent the better part of the afternoon trying to reach the isolated communications site. They were unsuccessful and Company F sustained casualties of three dead and 13 wounded.


title: Battle of Huế

text: On 20 January, the 1st Cavalry Division began moving from Landing Zone English in Bình Định Province 350 km north to Camp Evans as part of Operation Checkers. While the helicopters and men of the Division were soon in position, most of their heavy and support equipment was loaded on trucks that would have to proceed by convoy up Highway 1. While a new supply port was being constructed on the coast, the Division relied on the Marine supply base at Tân Mỹ and supply convoys along Highway 1 from Da Nang. On the night of 31 January, the PAVN-VC launched a mortar attack on Camp Evans which caused an ammunition dump to explode, disabling most of the helicopters of the 229th Assault Helicopter Battalion. Other attacks along Highway 1 damaged or destroyed 20 bridges and 26 culverts between the Hải Vân Pass and Phu Bai and Highway 1 was closed to convoy traffic until early March.


title: Battle of Huế

text: On 1 February, III Marine Amphibious Force (III MAF) Commander Lieutenant General Robert Cushman alerted the 1st Cavalry Division commander, Major General John J. Tolson, to be ready to deploy his 3rd Brigade into a sector west of Huế. By 22:15 that night, Tolson's command had agreed with III MAF on its designated area of operations in the Huế sector. Tolson's plan called for an air assault by two battalions of the 3rd Brigade northwest of Huế. The 2nd Battalion, 12th Cavalry was to arrive in the landing zone first, followed by the 5th Battalion, 7th Cavalry to be inserted near PK-17. Attacking in a southeasterly direction, the two battalions would then attempt to close the PAVN-VC supply line into Huế.


title: Battle of Huế

text: During the mid-afternoon of 2 February, the 2/12th Cavalry arrived in a landing zone about northwest of Huế. The Cavalry force soon encountered two dug-in PAVN Battalions around the villages of Thon Que Chu and Thon La Chu which they were unable to overcome as fog prevented their usual gunship support. The 2/12th Cavalry withdrew to a night defensive perimeter, but at dawn on 3 February following a mortar barrage the PAVN attacked their position. This was only beaten back with heavy artillery fire. Losses continued to mount throughout the day from mortar and small arms fire and that night the Battalion commander decided to breakout from the encirclement by a night march to an ARVN position on Nha Nanh hill () from where they could be resupplied and the casualties medevaced. On reaching the ARVN base, the 2/12th Cavalry dug in there for the next 4 days.


title: Battle of Huế

text: On 8 February 5/7th Cavalry began moving southwest from PK-17 towards La Chu while 2/12th Cavalry were ordered to retrace their route to form the southern pincer for an attack on the PAVN stronghold. As the 5/7th Cavalry approached Que Chu the command and control helicopter was shot down by anti-aircraft fire, the crew was rescued by a dustoff helicopter. Company B then walked into an ambush north of Que Chu and was pinned down in the open with little cover, they were only able to withdraw after calling in close artillery support. Company D was also engaged by PAVN in the village of Lieu Coc and forced to withdraw. 1/7th Cavalry then dug in to night defensive positions. On 9 February 5/7th Cavalry resumed their advance with artillery support from PK-17 and naval gunfire; they overran Lieu Coc finding PAVN bodies and fighting positions. As they moved closer to La Chu, PAVN resistance increased and it was obvious that this was a major PAVN base. 5/7th Cavalry would be stalled north of La Chu for 2 weeks, probing but failing to penetrate the PAVN defenses.


title: Battle of Huế

text: On 16 February deputy COMUSMACV General Creighton Abrams flew into PK-17 for a meeting with Tolson where Abrams expressed his displeasure at the Cavalry's slow progress. Following this visit two more cavalry battalions (1st Battalion, 7th Cavalry Regiment and 2nd Battalion, 501st Infantry Regiment) and additional air and artillery support were committed to the attack on La Chu.


title: Battle of Huế

text: On 21 February following intensive radar-guided airstrikes and artillery strikes, the four Cavalry battalions launched a four-pronged attack from the north, west and south on Que Chu and La Chu. The PAVN strongly defended the perimeter, but once the Cavalry forces broke through with the support of two newly arrived M42 Dusters, they found that the base had been largely abandoned while the Cavalry had been building up their forces for the attack. The Cavalry had finally captured the PAVN's main support base, but were still 8 km from the Citadel. Sergeant Joe Hooper of the 2/501st would subsequently be awarded the Medal of Honor for his actions in this engagement.


title: Battle of Huế

text: On the morning of 22 February, the 1/7th Cavalry, remained in Thon Que Chu and Thon La Chu to mop up pockets of resistance while the remaining units under 3rd Brigade control began marching toward the Citadel. They advanced along parallel tracks, with the 5/7th Cavalry, following the course of Highway 1; the 2/501st Infantry, searching the central route; and the 2/12th Cavalry, sweeping the area to the south. In mid-morning the 5/7th Cavalry, came under heavy fire from an estimated company-size force who occupied the hamlet of Thon An, approximately one kilometer from the An Hoa Bridge. Helicopter gunships and artillery and the pair of Dusters systematically leveled any structure that appeared to serve as a strong point. The supporting fire continued throughout the day, but the PAVN did not abandon their positions. With darkness approaching the attack was postponed until the next morning. Meanwhile, several kilometers to the south, the 2/12th Cavalry, made contact with another PAVN force just before noon. Several companies of PAVN armed with mortars, machine guns, recoilless rifles and RPGs were strongly entrenched along the south side of the Sau Canal, a deep waterway that ran toward the Citadel perpendicular to the Perfume River. On 23 February, the 2/12th Cavalry and the 2/501st Infantry, resumed their battle at the Sau Canal. The PAVN occupied a rectangular slice of land between the canal and the Perfume River that was approximately fifteen hundred meters wide and less than a kilometer deep, however U.S. efforts to overrun this position were repeatedly repulsed as the PAVN fought to keep open their escape route from the Citadel.


title: Battle of Huế

text: The 3rd Brigade would not reach the west wall of the Citadel until 25 February by which time the PAVN-VC had successfully withdrawn from the battlefield. It was estimated that it would have taken at least 16 battalions to establish an effective cordon around Huế, at this time there were only 30 battalions available in all of I Corps.


title: Battle of Huế

text: On the night of 1/2 February PAVN sappers successfully brought down the Bach Ho (railroad) bridge across the Perfume River, restricting movement from the south towards the Citadel, but failed to destroy the An Cuu Bridge over the Phu Cam Canal.


title: Battle of Huế

text: On 2 February, the Marines made some minor headway and brought in further reinforcements. A company from the 2/5th Marines finally relieved the MACV communications facility that morning. Gravel launched a two-company assault supported by tanks towards the Provincial Headquarters and Thua Thien Prison, seven blocks west of the MACV Compound where the ARVN were believed to still be holding out. The Marines did not progress further than one block before their advance was halted by troops from the PAVN 815th Battalion and after three hours of room to room fighting, the Marines captured the Huế University building at the base of the Trường Tiền Bridge two blocks northwest of the MACV Compound, so reducing enemy fire towards the LCU ramp. The Marines then tried to assault the Treasury Building in the next block, but were stopped by fire from the 100 plus PAVN defenders and flanking fire from the Le Loi Elementary School. The battalion consolidated its night defensive positions and waited to renew its attack the following day.


title: Battle of Huế

text: About 11:00, Company H, 2/5 Marines, crossed the An Cuu Bridge in an armed convoy. As the convoy, accompanied by Army trucks equipped with quad .50 machine guns and two M50 Ontos, entered the city, enemy snipers opened up on the Marine reinforcements. Near the MACV Compound, the Marines came under heavy machine gun and rocket fire. The Army gunners and the Marine Ontos quickly responded. In the resulting confusion, the convoy exchanged fire with a Marine unit already in the city. About mid-day, the PAVN continued to block any advance to the south. A 75 mm recoilless rifle knocked out one of the supporting tanks. By the end of the day, the Marines had sustained two dead and 34 wounded and claimed to have killed nearly 140 PAVN-VC. That night the PAVN 815th Battalion overran the ARVN defenders at the Thua Thien Prison releasing the 2,500 prisoners, including 350 VC who were soon armed with captured ARVN weapons and joined the fighting.


title: Battle of Huế

text: Back at Phu Bai, Cheatham was reviewing Marine urban fighting doctrine which recommended staying off the streets and moving forward by blasting through walls and buildings. He proceeded to gather the necessary equipment including M20 Bazookas, M40 106 mm recoilless rifles mounted on M274 Mules, C-4 explosive, flamethrowers, tear gas and gas masks. This equipment was loaded onto a convoy which arrived at the MACV Compound at 13:00 on 3 February. Cheatham then joined his company commanders in Huế University and they proceeded to develop the tactics to be used in recapturing southern Huế.


title: Battle of Huế

text: Many of the Marines of Task Force X-Ray had little or no urban combat experience and the U.S. troops were not trained for urban close-quarters combat, so this battle was especially tough for them. Due to Huế's religious and cultural status, Allied forces were ordered not to bomb or shell the city, for fear of destroying the historic structures. Also, since it was still monsoon season with heavy rain and low clouds on many days during the battle, it was virtually impossible for the U.S. forces to use air support. But as the intensity of the battle increased, the policy was eliminated. PAVN tactics were to hold the Marines close, negating the use of artillery and air support. A forward fighting line was maintained directly opposite the Marines with a secondary line two blocks back. Each building on the fighting lines was defended by snipers and machine guns, while spider holes were dug in gardens and streets, creating cross-fire between all buildings and streets. If the Marines penetrated the forward line the PAVN moved to the secondary line and then reoccupied the abandoned positions at night.


title: Battle of Huế

text: On the night of 3 February, the PAVN commander, seeing the buildup of Marines at Huế University, thinned out his frontline forces leaving just a platoon to defend the Treasury building and adjacent Post Office. On the morning of 4 February the Marines launched their attack on the Treasury. The initial assault was on the left flank by Company A, 1/1 Marines which was tasked with securing a Catholic chapel and the Jeanne d'Arc High School (). The Marines secured the chapel and the east school building, but were pinned down for hours by interlocking fire from the west building. During this action Sergeant Gonzalez was killed while firing on PAVN machine gun positions. The Marines eventually broke into the west building and cleared it room by room. Due to the delays on the left flank, the main assault in the center by Company F, 2/5 Marines was delayed until mid-afternoon. The Treasury building was hit by M-48 and 106 mm fire and tear gas, while a M274 Mule-mounted 106mm recoilless rifle engaged the machine gun in the Le Loi Elementary School. Under cover of the tear gas and the 106mm backblast the Marines crossed the street and blew holes in the wall using C-4 and Bazookas. The Marines then pushed into the Treasury building which the PAVN had hastily abandoned. The Post Office also seemed abandoned until the Marines located a vault inside the building, they proceeded to gas out the PAVN inside killing more than 24 of them as they emerged. After securing the Jeanne d'Arc High School, Company A, 1/1 Marines recaptured the Le Loi Elementary School. More than half the company's 147 men had been wounded or killed in that day's fighting. That evening VC sappers succeeded in blowing up the An Cuu bridge, cutting the road link to Phu Bai.


title: Battle of Huế

text: Following the capture of the Treasury, Cheatham continued his methodical advance to the west leading with tear gas, M-48s and Ontos, followed by Mules and Marines, while PAVN-VC resistance lessened as its manpower and ammunition was depleted. The PAVN-VC no longer tenaciously defended each building, relying more on sniper fire, mortars and rockets. On 5 February the Marines recaptured the Huế Central Hospital complex (), rescuing Lieutenant Colonel Pham Van Khoa (the Mayor of Huế and Thua Thien Province chief), who had been hiding in the grounds.


title: Battle of Huế

text: On 6 February the Marines attacked the Provincial Headquarters which served as the command post of the PAVN 4th Regiment. While the Marines seized the surrounding wall easily, the area between the wall and the building was covered by fire from every window and from spider-holes in the grounds. An Ontos was brought forward to blast an entry into the building, but was disabled by a B-40 rocket. A Mule was brought forward to blow a hole in the building and the Marines advanced under cover of tear gas. Entering the building the Marines fought room by room, clearing the building, but many of the PAVN slipped away. With the building secured the Marines then methodically cleared out the spider-holes, shooting their occupants. The Marines raised an American flag to celebrate their victory, but shortly thereafter were ordered to lower it, as according to South Vietnamese law, no American flag was permitted to be flown without an accompanying South Vietnamese flag. After resting his men at the Provincial Headquarters, Cheatham resumed his advance west towards the Phu Cam Canal, then swung south and east to clear the area with the canal to his right.


title: Battle of Huế

text: On 7 February the PAVN twice ambushed a 25 vehicle supply convoy supported by two Ontos going along Route 547 () from Phu Bai to the 11th Marines Firebase Rockcrusher () which provided artillery support to Allied forces fighting in and around Huế. These ambushes killed 20 Marines and wounded 39. PAVN sappers finally destroyed the Trường Tiền bridge restricting movement between the old and new cities. The PAVN forces in the new city, worn down by more than a week of incessant combat and effectively cut off from their comrades on the other side of the river, began to slowly abandon the city, the 815th and 2nd Sapper Battalions moved to the southern side of the Phu Cam Canal, where the 818th Battalion was already in place. The 804th Battalion and the 1st Sapper Battalion remained south of the canal near the An Cuu Bridge while the 810th Battalion began preparing to sneak west across the Perfume River by raft and boat to Gia Hoi Island.


title: Battle of Huế

text: Gravel's 1/1 Marines had been clearing the area to the east and south of the MACV Compound and on 10 February they captured the soccer stadium (), providing a second, safer helicopter landing zone. A pontoon bridge had been built across the Phu Cam Canal, restoring the road access that had been lost when the An Cuu Bridge was blown up.


title: Battle of Huế

text: On 11 February Company H, 2/5 Marines secured a bridge over the Phu Cam Canal () and the block on the opposite side of the canal. The next day Company F swept the west bank of the canal, fighting through houses and the Huế Railway Station that had been sheltering PAVN snipers, before withdrawing back across the bridge. On 13 February Companies F and H crossed the bridge again with the aim of securing the entire area. As the Marines advanced into the open countryside towards the Từ Đàm Pagoda they located fresh PAVN graves and then were hit by a barrage of mortar fire, forcing them to withdraw. The Marines had inadvertently located the PAVN headquarters for the battle. On 13 February, Abrams established MACV Forward at Phu Bai, effectively replacing Cushman and assuming overall control of all U.S. forces in I Corps.


title: Battle of Huế

text: Within the ARVN 1st Battalion, 3rd Regiment and 2nd and 7th Airborne Battalions cleared out the north and western parts of the Citadel including the Chanh Tay Gate, while the 4th Battalion, 2nd Regiment moved south from Mang Ca towards the Imperial Palace, killing over 700 PAVN-VC by 4 February. On 5 February Trưởng exchanged the Airborne with the 4th Battalion, which had become stalled. The 4th Battalion, 3rd Regiment, south of the river, crossed the river and assaulted the Thuong Tu Gate near the eastern corner of the Citadel. When seven successive attempts to breach the gate failed, the battalion joined the 2nd and 3rd Battalions, 3rd Regiment, near the southern corner of the Citadel. On 6 February, the 1st Battalion captured the An Hoa Gate on the northwest corner of the Citadel and the 4th Battalion captured the southwest wall. On the night of the 6th, the PAVN counterattacked, with a battalion from the 29th Regiment scaling the southwest wall and pushing the 4th Battalion back to Tây Lộc. On the 7th the 3rd Regiment, which had been futilely trying to break into the southeast corner of the Citadel, was moved by Mike boats to Mang Ca to reinforce his units inside the Citadel. The ARVN 2nd Troop, 7th Cavalry, equipped with fifteen M113s arrived at Mang Ca from Quảng Trị to relieve the 3rd Troop. To avoid ambushes it turned off Highway 1 a few kilometers north of the city, traveled east cross-country, and swung around the rear of Mang Ca through the Trai Gate.


title: Battle of Huế

text: Also on 7 February, the North Vietnamese tried to bring their own air support into the battle, sending four Vietnam People's Air Force Il-14 transport aircraft from an airfield near Hanoi. Two of the aircraft carrying explosives, antitank ammunition and field telephone cables managed to find an opening in the cloud layer about north of Huế. They dropped their cargoes in a large lagoon for local forces to retrieve. One of the aircraft returned safely; but the other, flying through dense fog, crashed into a mountain, losing all on board. Meanwhile, the other two IL−14s, which had been modified to drop bombs, had orders to bomb Mang Ca. Neither flight crew could find the city in the fog, however, and both aircraft returned to North Vietnam without dropping their bombs. They tried again five days later, but once again, bad weather prevented them from locating Mang Ca. The two aircraft radioed that they were scrubbing the mission, then headed out to sea to jettison their bombs. A short time later, their transmissions went dead and they were never heard from again.


title: Battle of Huế

text: On 10 February two forward observers from the Marines' 1st Field Artillery Group were flown into Tây Lộc to help coordinate artillery and naval gunfire to support the fighting within the Citadel, however Trưởng instructed them that the Imperial Palace was not to be fired on. On 11 February the Vietnamese Marines Task Force A comprising the 1st and 5th Battalions, began to be lifted by helicopter into Mang Ca to replace the Airborne, however due to poor weather this deployment would not be completed until 13 February. At 10:45 on 11 February Company B, 1st Battalion, 5th Marines was airlifted aboard Marine CH-46s into Mang Ca, but enemy fire forced several of the helicopters to return to Phu Bai. The Marines together with five M48s from the 1st Tank Battalion would later be loaded onto Mike boats at the LCU ramp in southern Huế and ferried across to Mang Ca.


title: Battle of Huế

text: On 13 February Companies A and C, 1/5 Marines left Mang Ca and moved south along the eastern wall of the Citadel, while Company B remained in reserve. Unknown to the Marines, the ARVN Airborne had withdrawn from the area two days previously when the Vietnamese Marines began to arrive at Mang Ca and the PAVN defenders had used this opportunity to reoccupy several blocks and reinforce their defenses, Company A was engaged by the PAVN and quickly suffered 35 casualties. The 1/5 Marines commander Major Robert Thompson ordered Company B up to relieve Company A and the advance continued slowly until it was halted by PAVN flanking fire from the Dong Ba Gate (). On 14 February the Marines resumed their attack supported by Marine and Navy gun fire and Marine close air support. Despite this they made little progress, as they had to withdraw when supporting fire was called in and the PAVN quickly reoccupied abandoned positions. After a day of attacks the Marines withdrew to their night defensive positions. Company D, 1/5 Marines arrived in the Citadel on the evening of 14 February after taking fire while crossing the Perfume River. On 15 February Company D led the renewed attack against the Dong Ba Gate with Company C defending its flank. Company B joined the assault and after six hours the Marines had secured the base of the gate and later the entire gate, at a cost of six Marines killed and 50 wounded and 20 PAVN killed. Overnight the PAVN counterattacked and briefly regained control of the gate before being forced out by Company D.


title: Battle of Huế

text: Also on 14 February the South Vietnamese Marine Task Force A joined the battle. The operational plan was for the Marines to move west from Tây Lộc and then turn south. However, they were soon stopped by strong PAVN defenses; after two days the Vietnamese Marines had only advanced 400 meters. Meanwhile, the ARVN 3rd Regiment fought off a PAVN counterattack in the northwest corner of the Citadel.


title: Battle of Huế

text: Despite their reducing hold on the city the PAVN seemed determined to prolong the battle for the Citadel. The 6th Battalion, 24th Regiment, 304th Division, originally located near Khe Sanh, reached the Citadel after following a route that took it through Base Area 101, Base Area 114 and Thon La Chu and the 7th Battalion, 90th Regiment, 324B Division, was due to arrive a few days later after a forced march from the DMZ. On 16 February two companies from the 1st Battalion, 8th Cavalry Regiment, fought elements of the 803rd Regiment, 324B Division, about northeast of Huế, killing 29 PAVN before they broke contact the following day.


title: Battle of Huế

text: On 16 February the 1/5 Marines advanced approximately 140 meters for a cost of seven Marines killed and 47 wounded and 63 PAVN killed. That day at a meeting at Phu Bai between Generals Abrams, LaHue, Trưởng and South Vietnamese Vice President Nguyễn Cao Kỳ, Kỳ approved the use of all necessary force to clear the PAVN-VC forces from the Citadel, regardless of damage to historic structures. On the night of 16 February a radio intercept indicated that a battalion-size PAVN force was about to launch a counterattack over the west wall of the Citadel. Artillery and naval gunfire was called in and a later radio intercept indicated that a senior PAVN officer had been killed in the barrage. Later that night a radio message from the commander of PAVN forces in the Citadel was intercepted, he stated that his predecessor had been killed and requested permission to withdraw from the city, but this was denied and he was told to stand and fight. On 17 February the Vietnamese Marines and ARVN 3rd Regiment resumed their attacks south, while the "Hac Bao" Company was moved to support the right flank of the 1/5 Marines. Over the next three days these forces would slowly reduce the PAVN's perimeter. On 18 February the 1/8th Cavalry was attacked by elements of the 803rd Regiment northeast of Huế, this second clash apparently convinced the PAVN command that the Regiment could not reach the Citadel.


title: Battle of Huế

text: By 20 February the 1/5 Marines advance had stalled and after conferring with his commanders Thompson decided to launch a night attack against three PAVN strongpoints that were blocking further movement with the entire battalion attacking at daybreak. At 03:00 on 21 February, three ten-man teams from 2nd Platoon of Company A launched their assault, quickly capturing the sparsely defended strongpoints which the PAVN had withdrawn from overnight. As the PAVN moved to reoccupy the strongpoints at dawn they were caught in the open by the Marines, 16 PAVN were killed for the loss of three Marines. The Marines were now only 100 meters from the south wall of the Citadel. That evening Company B was replaced by Company L, 3rd Battalion, 5th Marines. Unknown to the ARVN and the U.S., on the night of 20 February the PAVN had begun a phased withdrawal from the Citadel, leaving through the Huu and Nha Do () Gates and making their way southwest to return to their bases in the hills.


title: Battle of Huế

text: At 09:30 on 22 February, Company A, 1/5 Marines led the day's attack to find that the PAVN had largely disappeared and the south wall was soon secured. Company L, 3/5 Marines was then tasked with clearing the area to the Thuong Tu Gate and out to the Trường Tiền Bridge. Advancing with tank and air support they completed the mission meeting little resistance.


title: Battle of Huế

text: To the west, the South Vietnamese forces continued to meet stubborn resistance. On 22 February after a barrage of 122 mm rockets the PAVN counterattacked the Vietnamese Marines, who pushed them back with the support of the "Hac Bao" Company. 23 February saw little progress, prompting a frustrated Abrams to suggest that the Vietnamese Marine Corps should be dissolved. On the night of 23 February the PAVN attempted another counterattack, but were forced back by artillery fire. The ARVN 3rd Regiment launched a night attack along the southern wall of the Citadel. At 05:00 on 24 February they raised the South Vietnamese flag on the Citadel flag tower and proceeded to secure the southern wall by 10:25. Trưởng then ordered the 2nd Battalion, 3rd Regiment and the "Hac Bao" Company to recapture the Imperial Palace and this was achieved against minimal resistance by late afternoon. The last pocket of PAVN at the southwest corner of the Citadel was eliminated in an attack by the 4th Vietnamese Marine Battalion in the early hours of 25 February.


title: Battle of Huế

text: On 22 February the ARVN 21st and the 39th Ranger Battalions boarded junks and traveled to Gia Hoi Island (), between the east wall of the Citadel and the Perfume River where the Communist provisional government had been headquartered since the start of the offensive. The Rangers swept the island as thousands of local residents came out of hiding and ran through their ranks to escape the battle. The toughest fight of the day centered on a pagoda that contained a PAVN battalion headquarters. The sweep continued until 25 February. The three-day operation netted hundreds of VC cadre, many of whom were university students who, according to local residents, had played a key role in rounding up government officials and intellectuals the PAVN/VC regarded as threats to their new regime.


title: Battle of Huế

text: On 23 February a company from the 5/7th Cavalry, boarded helicopters and flew to the docks near Mang Ca, where it joined a platoon of armored personnel carriers from Troop A, 3rd Squadron, 5th Cavalry Regiment, on loan from the 9th Infantry Division which had just arrived in the Phu Bai–Huế region after redeploying from Long Khánh Province to northern I Corps by sea. The mechanized task force swept along the northwestern wall toward the An Hoa Bridge, flushing out a number of PAVN soldiers who had taken refuge in the grasses and weeds. Meanwhile, two kilometers to the northwest, the remainder of the 5/7th Cavalry, resumed its advance toward Thon An. The cavalrymen fought their way into the PAVN-occupied hamlet and found beneath its shattered remains a honeycomb of tunnels and bunkers and spent the rest of the day searching the ruins for survivors and combing through the adjacent cemetery, where the 806th Battalion had ambushed the ARVN 7th Airborne Battalion on 31 January. On 24 February, the 5/7th Cavalry, rejoined its detached company and the armored cavalry platoon from the 3/5th Cavalry, near the western corner of the Citadel. The combined force then swept toward the Bach Ho Railroad Bridge along the southwestern face of the Citadel, where a few PAVN still held out in a narrow band of trees between the moat and the wall.


title: Battle of Huế

text: While 1/1 Marines conducted mopping-up operations in southern Huế, 2/5 Marines had been conducting patrols south of the Phu Cam Canal. On 24 February 2/5 Marines launched an operation to the southwest of Huế to relieve the ARVN 101st Engineering Company compound which had been under siege by the PAVN since the start of the battle. As the Marines approached the base at 07:00 they were met by PAVN mortar and machine-gun fire; artillery fire was called in on the PAVN positions and the Marines entered the base at 08:50. The base remained under fire from PAVN positions in a Buddhist temple to the south and from a ridgeline to the west and at 07:00 on 25 February Companies F and G began to attack the ridgeline, but were met by intense mortar fire. Under cover of supporting fire the Marines secured part of the ridgeline, killing three PAVN for the loss of one Marine killed. The attack resumed the following morning and the ridge was secured with 20 PAVN and two Marines killed. Company H attacked a nearby hill meeting a stubborn defense, losing one dead and killing six PAVN. Company H withdrew so that air strikes could be launched and these knocked out mortar and machine gun positions killing 20 PAVN; however, one bomb fell short killing four Marines. On 27 February the entire battalion attacked the hill but the PAVN had withdrawn during the night, leaving behind 14 dead.


title: Battle of Huế

text: On 28 February 1/5 Marines and 2/5 Marines launched an operation to the east of Huế to try to cut off any PAVN forces moving from Huế towards the coast. While the Marines encountered few PAVN in their sweeps they located various abandoned infrastructure that had been used to support the battle, including a 3 km trench system with over 600 fighting holes. On 2 March 1968 the Marines concluded Operation Huế City.


title: Battle of Huế

text: The fighting in other parts of South Vietnam during Tet was generally confined to a week or sometimes less; the battle for Huế was the longest, lasting from 31 January through 2 March 1968.


title: Battle of Huế

text: ARVN losses were 452 killed and 2,123 wounded, while U.S. losses were 216 killed and 1,584 wounded. PAVN-VC losses are a matter of debate. The PAVN's Department of Warfare gives figures of 2,400 killed and 3,000 wounded from 30 January until 28 March. A PAVN document captured by the ARVN stated that 1,042 troops had been killed in the city proper and that several times that number had been wounded. MACV gave figures of 5,133 PAVN-VC killed at Huế.


title: Battle of Huế

text: 844 civilians were killed and 1,900 wounded during the battle. 4,856 civilians and captured ARVN personnel were executed by the PAVN-VC or went missing during the battle according to the South Vietnamese Government.


title: Battle of Huế

text: In addition to the significant civilian casualties inflicted in the battle, eighty percent of the city was destroyed and 116,000 civilians out of the pre-battle population of 140,000 were made homeless.


title: Battle of Huế

text: The PAVN-VC were generally greeted with little enthusiasm by the population of Huế. Power and water supply into the city had been cut off, and people were aware that the ARVN and U.S. forces would soon counterattack. While a few joined the PAVN-VC and others supported them by digging fortifications and preparing food, most of the population either tried to flee behind the ARVN-U.S. lines or took shelter in their homes or in churches and pagodas, which they hoped would be safe.


title: Battle of Huế

text: The PAVN set up provisional authorities shortly after capturing Huế, charged with removing the existing Republic of Vietnam administration from power within the city and replacing it with a "revolutionary administration". Working from lists of "cruel tyrants and reactionary elements" previously developed by VC intelligence officers, many people were to be rounded up during the initial hours of the attack. These included ARVN soldiers, civil servants, political party members, local religious leaders, schoolteachers, American civilians and other expatriates. Cadres called out the names on their lists over loudspeakers, ordering them to report to a local school. Those not reporting voluntarily were hunted down.


title: Battle of Huế

text: The PAVN-VC's actions were based on a series of orders issued by the PAVN High Command and the Provisional Revolutionary Government of the Republic of South Vietnam (PRG). In a 3500-page document issued on 26 January 1968 by the Trị-Thiên-Huế Political Directorate, the political cadres were given specific instructions: Operating in close support of the regular military and guerrilla elements, the political cadre were to: destroy and disorganize the Republic of Vietnam's administrative machinery "from province and district levels to the city wards, streets, and wharves; motivate the people of Huế to take up arms, pursue the enemy, seize power, and establish a revolutionary government; motivate (recruit) local citizens for military and "security" forces ... transportation and supply activities, and to serve wounded soldiers... pursue to the end (and) punish spies, reactionaries, and tyrants and maintain order and security in the city."


title: Battle of Huế

text: Those identified by the PAVN-VC were initially marched out of the city for "reeducation". Few returned. Those deemed guilty of the most serious "crimes" were speedily tried and executed. As the PAVN-VC area of control within Huế shrank, the pace of executions increased to prevent the "enemies of the people" being freed by ARVN or U.S. forces or identifying the VC who had revealed themselves. Mark Bowden suggests that PAVN-VC anger at the lack of enthusiasm among the population of Huế may have fuelled the purges, particularly as defeat loomed closer. Estimates of Vietnamese civilians killed by the PAVN-VC at Huế range from 2,800 (based on bodies exhumed from mass graves) to almost 6,000. Bowden conservatively estimates that 2,000 people were executed.


title: Battle of Huế

text: Foreign civilians captured in the city received varying treatment. Some were marched north into captivity, while others were executed, including three West German doctors, two French Benedictine monks and two U.S. government employees. French journalists Catherine Leroy and Francois Mazure were captured by the PAVN, but were allowed to return to U.S. lines bringing photos of the PAVN side of the battle which were subsequently published in "Life" Magazine.


title: Battle of Huế

text: The initial press statements by MACV played down the events in Huế, claiming that only a part of the city had fallen to a small enemy force, that the city would soon be fully restored to South Vietnamese Government control and that the main attack would be directed against Khe Sanh. This and subsequent optimistic reports were soon contradicted by press reports as journalists made their way into the city and reported on the extent of PAVN-VC control and the bitter house-to-house fighting that was underway.


title: Battle of Huế

text: On 10 February 1968, CBS News anchorman Walter Cronkite visited southern Huế to film footage for a special report on the Vietnam War. The "Report from Vietnam: Who, What, When, Where, Why?" screened on 27 February 1968, Cronkite closed the report with the editorial comments:


title: Battle of Huế

text: After watching Cronkite's editorial report, President Lyndon Johnson is purported to have said, "If I've lost Cronkite, I've lost Middle America." This account has been questioned in a book on journalistic accuracy.


title: Battle of Huế

text: Militarily, Huế and the entire Tet Offensive were Allied victories. However, the shock of the Tet Offensive, coming so soon after General William Westmoreland's "End in view" tour of the U.S. in November 1967, undermined the credibility of Westmoreland and his strategy within the Johnson Administration. Over the coming months U.S. public opinion turned decisively against the war.


title: Battle of Huế

text: Throughout the entire battle, the U.S. command consistently underestimated the size of the PAVN-VC forces engaged and the Allied forces necessary to deal with them. Initially forces were identified as coming from the PAVN 4th, 5th and 6th Regiments. Additional battalions were later identified as coming from the 29th Regiment of the 325C Division, the 90th and 803rd Regiments of the 324B Division and the 24th Regiment of the 304th Division. Three of these regiments were believed to be involved in the siege of Khe Sanh. Allied intelligence estimated that 16–18 PAVN battalions, totaling 8–11,000 soldiers, were engaged in the battle. Allied air and artillery support was restricted by the poor weather, supply difficulties and, initially, by restrictions intended to limit damage to Huế's historic structures.


title: Battle of Huế

text: While PAVN-VC defeat was inevitable in the face of U.S. firepower, the failure to sever the PAVN-VC supply lines and isolate the battlefield meant that the battle lasted longer and was more costly to the ARVN and U.S. than was necessary. Until the last week of the battle, the ARVN, U.S. Marines and 1st Cavalry each fought separate, largely uncoordinated battles without a unified command structure, no overall strategy and competing demands for logistics, air and artillery support. Delaying the counterattack until a clear strategy was developed and the necessary forces assembled might have reduced casualties among the ARVN, U.S. forces and civilians and shortened the battle.


title: Battle of Huế

text: The battle was an ARVN-U.S. victory in only the narrowest sense in that they had evicted the PAVN-VC from the city at heavy cost, but failed to annihilate them. The PAVN-VC failed to hold the city or spark a general uprising, but they had undermined confidence in the Thiệu-Kỳ government and the prospect of victory. Unplanned by the North Vietnamese, their greatest success was the shock and negative impact of the battle and the entire Tet Offensive on U.S. public opinion.


title: Battle of Huế

text: PAVN General Trần Văn Trà later wrote of the Tet Offensive, "We did not correctly evaluate the specific balance of forces between ourselves and the enemy... [its objectives] were beyond our actual strength...in part an illusion based on our subjective desires."


title: Battle of Huế

text: The November 2004 anti-insurgent Marine operation in the city of Fallujah, which took place during the Iraq War, has been compared to the Battle of Huế. Both battles were fought in close quarters in an urban setting where the enemy ensconced itself in the midst of civilians. In Fallujah, Sunni insurgents turned mosques into fortresses, in a similar way to how PAVN-VC forces utilized Buddhist temples in Huế. Both battles also had insurgents and other forces utilizing snipers, significantly increasing the combat potential of the combatants, while the Marines also constituted the advanced fighting elements of the US forces deployed in both Huế and Fallujah. In his analysis of the Battle of Fallujah, Jonathan F. Keiler, a military historian and former officer in the Judge Advocate General's Corps wrote:


title: Battle of Huế

text: The Marine Corps' military operations in urban terrain doctrine recognizes that tactical success does not necessarily translate to strategic victory... the Battle of Huế in the Vietnam War, when Marines defeated an enemy that sought to put up a good fight but never expected to win. Much the same can be said of Fallujah's defenders. In spite of the beating they took in November, they will continue to assert they repelled the initial attack and fought well thereafter.


title: Battle of Huế

text: The U.S. Navy "Ticonderoga" class-guided-missile cruiser , commissioned in 1991, is named after the battle. To date it is the only U.S. Navy ship named after a battle in the Vietnam War.


title: Ctenophora

text: Ctenophora (; ctenophore ; ) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and they are the largest animals to swim with the help of cilia.


title: Ctenophora

text: Depending on the species, adult ctenophores range from a few millimeters to in size. Only 100 to 150 species have been validated, and possibly another 25 have not been fully described and named. The textbook examples are cydippids with egg-shaped bodies and a pair of retractable tentacles fringed with tentilla ("little tentacles") that are covered with colloblasts, sticky cells that capture prey.


title: Ctenophora

text: Their bodies consist of a mass of jelly, with a layer two cells thick on the outside, and another lining the internal cavity. The phylum has a wide range of body forms, including the egg-shaped cydippids with retractable tentacles that capture prey, the flat generally combless platyctenids, and the large-mouthed beroids, which prey on other ctenophores.


title: Ctenophora

text: Almost all ctenophores function as predators, taking prey ranging from microscopic larvae and rotifers to the adults of small crustaceans; the exceptions are juveniles of two species, which live as parasites on the salps on which adults of their species feed.


title: Ctenophora

text: Despite their soft, gelatinous bodies, fossils thought to represent ctenophores appear in lagerstätten dating as far back as the early Cambrian, about 525 million years ago. The position of the ctenophores in the "tree of life" has long been debated in molecular phylogenetics studies. Biologists proposed that ctenophores constitute the second-earliest branching animal lineage, with sponges being the sister-group to all other multicellular animals (Porifera Sister Hypothesis). Other biologists contend that ctenophores were emerging earlier than sponges (Ctenophora Sister Hypothesis), which themselves appeared before the split between cnidarians and bilaterians. Pisani et al. reanalyzed of the data and suggest that the computer algorithms used for analysis were misled by the presence of specific ctenophore genes that were markedly different from those of other species. Follow up analysis by Whelan et al. (2017) yielded further support for the Ctenophora Sister hypothesis, and the issue remains a matter of taxonomic dispute.


title: Ctenophora

text: Among animal phyla, the Ctenophores are more complex than sponges, about as complex as cnidarians (jellyfish, sea anemones, etc.), and less complex than bilaterians (which include almost all other animals). Unlike sponges, both ctenophores and cnidarians have: cells bound by inter-cell connections and carpet-like basement membranes; muscles; nervous systems; and some have sensory organs. Ctenophores are distinguished from all other animals by having colloblasts, which are sticky and adhere to prey, although a few ctenophore species lack them.


title: Ctenophora

text: Like sponges and cnidarians, ctenophores have two main layers of cells that sandwich a middle layer of jelly-like material, which is called the mesoglea in cnidarians and ctenophores; more complex animals have three main cell layers and no intermediate jelly-like layer. Hence ctenophores and cnidarians have traditionally been labelled diploblastic, along with sponges. Both ctenophores and cnidarians have a type of muscle that, in more complex animals, arises from the middle cell layer, and as a result some recent text books classify ctenophores as triploblastic, while others still regard them as diploblastic. The comb jellies have more than 80 different cell types, exceeding the numbers from other groups like placozoans, sponges, cnidarians, and some deep-branching bilaterians.


title: Ctenophora

text: Ranging from about to in size, ctenophores are the largest non-colonial animals that use cilia ("hairs") as their main method of locomotion. Most species have eight strips, called comb rows, that run the length of their bodies and bear comb-like bands of cilia, called "ctenes", stacked along the comb rows so that when the cilia beat, those of each comb touch the comb below. The name "ctenophora" means "comb-bearing", from the Greek "κτείς" (stem-form κτεν-) meaning "comb" and the Greek suffix "-φορος" meaning "carrying".


title: Ctenophora

text: For a phylum with relatively few species, ctenophores have a wide range of body plans. Coastal species need to be tough enough to withstand waves and swirling sediment particles, while some oceanic species are so fragile that it is very difficult to capture them intact for study. In addition, oceanic species do not preserve well, and are known mainly from photographs and from observers' notes. Hence most attention has until recently concentrated on three coastal genera – "Pleurobrachia", "Beroe" and "Mnemiopsis". At least two textbooks base their descriptions of ctenophores on the cydippid "Pleurobrachia".


title: Ctenophora

text: Since the body of many species is "almost" radially symmetrical, the main axis is oral to aboral (from the mouth to the opposite end). However, since only two of the canals near the statocyst terminate in anal pores, ctenophores have no mirror-symmetry, although many have rotational symmetry. In other words, if the animal rotates in a half-circle it looks the same as when it started.


title: Ctenophora

text: The Ctenophore phylum has a wide range of body forms, including the flattened, deep-sea platyctenids, in which the adults of most species lack combs, and the coastal beroids, which lack tentacles and prey on other ctenophores by using huge mouths armed with groups of large, stiffened cilia that act as teeth.


title: Ctenophora

text: Like those of cnidarians, (jellyfish, sea anemones, etc.), ctenophores' bodies consist of a relatively thick, jelly-like mesoglea sandwiched between two epithelia, layers of cells bound by inter-cell connections and by a fibrous basement membrane that they secrete. The epithelia of ctenophores have two layers of cells rather than one, and some of the cells in the upper layer have several cilia per cell.


title: Ctenophora

text: The outer layer of the epidermis (outer skin) consists of: sensory cells; cells that secrete mucus, which protects the body; and interstitial cells, which can transform into other types of cell. In specialized parts of the body, the outer layer also contains colloblasts, found along the surface of tentacles and used in capturing prey, or cells bearing multiple large cilia, for locomotion. The inner layer of the epidermis contains a nerve net, and myoepithelial cells that act as muscles.


title: Ctenophora

text: The internal cavity forms: a mouth that can usually be closed by muscles; a pharynx ("throat"); a wider area in the center that acts as a stomach; and a system of internal canals. These branch through the mesoglea to the most active parts of the animal: the mouth and pharynx; the roots of the tentacles, if present; all along the underside of each comb row; and four branches around the sensory complex at the far end from the mouth – two of these four branches terminate in anal pores. The inner surface of the cavity is lined with an epithelium, the gastrodermis. The mouth and pharynx have both cilia and well-developed muscles. In other parts of the canal system, the gastrodermis is different on the sides nearest to and furthest from the organ that it supplies. The nearer side is composed of tall nutritive cells that store nutrients in vacuoles (internal compartments), germ cells that produce eggs or sperm, and photocytes that produce bioluminescence. The side furthest from the organ is covered with ciliated cells that circulate water through the canals, punctuated by ciliary rosettes, pores that are surrounded by double whorls of cilia and connect to the mesoglea.


title: Ctenophora

text: When prey is swallowed, it is liquefied in the pharynx by enzymes and by muscular contractions of the pharynx. The resulting slurry is wafted through the canal system by the beating of the cilia, and digested by the nutritive cells. The ciliary rosettes in the canals may help to transport nutrients to muscles in the mesoglea. The anal pores may eject unwanted small particles, but most unwanted matter is regurgitated via the mouth.


title: Ctenophora

text: Little is known about how ctenophores get rid of waste products produced by the cells. The ciliary rosettes in the gastrodermis may help to remove wastes from the mesoglea, and may also help to adjust the animal's buoyancy by pumping water into or out of the mesoglea.


title: Ctenophora

text: The outer surface bears usually eight comb rows, called swimming-plates, which are used for swimming. The rows are oriented to run from near the mouth (the "oral pole") to the opposite end (the "aboral pole"), and are spaced more or less evenly around the body, although spacing patterns vary by species and in most species the comb rows extend only part of the distance from the aboral pole towards the mouth. The "combs" (also called "ctenes" or "comb plates") run across each row, and each consists of thousands of unusually long cilia, up to . Unlike conventional cilia and flagella, which has a filament structure arranged in a 9 + 2 pattern, these cilia are arranged in a 9 + 3 pattern, where the extra compact filament is suspected to have a supporting function. These normally beat so that the propulsion stroke is away from the mouth, although they can also reverse direction. Hence ctenophores usually swim in the direction in which the mouth is eating, unlike jellyfish. When trying to escape predators, one species can accelerate to six times its normal speed; some other species reverse direction as part of their escape behavior, by reversing the power stroke of the comb plate cilia.


title: Ctenophora

text: It is uncertain how ctenophores control their buoyancy, but experiments have shown that some species rely on osmotic pressure to adapt to the water of different densities. Their body fluids are normally as concentrated as seawater. If they enter less dense brackish water, the ciliary rosettes in the body cavity may pump this into the mesoglea to increase its bulk and decrease its density, to avoid sinking. Conversely, if they move from brackish to full-strength seawater, the rosettes may pump water out of the mesoglea to reduce its volume and increase its density.


title: Ctenophora

text: Ctenophores have no brain or central nervous system, but instead have a nerve net (rather like a cobweb) that forms a ring round the mouth and is densest near structures such as the comb rows, pharynx, tentacles (if present) and the sensory complex furthest from the mouth. Fossils shows that Cambrian species had a more complex nervous system, with long nerves which connected with a ring around the mouth. The only known ctenophores with long nerves today is "Euplokamis" in the order Cydippida. Their nerve cells arise from the same progenitor cells as the colloblasts.


title: Ctenophora

text: The largest single sensory feature is the aboral organ (at the opposite end from the mouth). Its main component is a statocyst, a balance sensor consisting of a statolith, a tiny grain of calcium carbonate, supported on four bundles of cilia, called "balancers", that sense its orientation. The statocyst is protected by a transparent dome made of long, immobile cilia. A ctenophore does not automatically try to keep the statolith resting equally on all the balancers. Instead, its response is determined by the animal's "mood", in other words, the overall state of the nervous system. For example, if a ctenophore with trailing tentacles captures prey, it will often put some comb rows into reverse, spinning the mouth towards the prey.


title: Ctenophora

text: Research supports the hypothesis that the ciliated larvae in cnidarians and bilaterians share an ancient and common origin. The larvae's apical organ is involved in the formation of the nervous system. The aboral organ of comb jellies is not homologous with the apical organ in other animals, and the formation of their nervous system has therefore a different embryonic origin.


title: Ctenophora

text: Ctenophore nerve cells and nervous system have different biochemistry as compared to other animals. For instance, they lack the genes and enzymes required to manufacture neurotransmitters like serotonin, dopamine, nitric oxide, octopamine, noradrenaline, and others, otherwise seen in all other animals with a nervous system, with the genes coding for the receptors for each of these neurotransmitters missing. They have been found to use L-glutamate as a neurotransmitter, and have an unusually high variety of ionotropic glutamate receptors and genes for glutamate synthesis and transport compared to other metazoans. The genomic content of the nervous system genes is the smallest known of any animal, and could represent the minimum genetic requirements for a functional nervous system. Therefore, if ctenophores are the sister group to all other metazoans, nervous systems may have either been lost in sponges and placozoans, or arisen more than once among metazoans.


title: Ctenophora

text: Cydippid ctenophores have bodies that are more or less rounded, sometimes nearly spherical and other times more cylindrical or egg-shaped; the common coastal "sea gooseberry", "Pleurobrachia", sometimes has an egg-shaped body with the mouth at the narrow end, although some individuals are more uniformly round. From opposite sides of the body extends a pair of long, slender tentacles, each housed in a sheath into which it can be withdrawn. Some species of cydippids have bodies that are flattened to various extents so that they are wider in the plane of the tentacles.


title: Ctenophora

text: The tentacles of cydippid ctenophores are typically fringed with tentilla ("little tentacles"), although a few genera have simple tentacles without these sidebranches. The tentacles and tentilla are densely covered with microscopic colloblasts that capture prey by sticking to it. Colloblasts are specialized mushroom-shaped cells in the outer layer of the epidermis, and have three main components: a domed head with vesicles (chambers) that contain adhesive; a stalk that anchors the cell in the lower layer of the epidermis or in the mesoglea; and a spiral thread that coils round the stalk and is attached to the head and to the root of the stalk. The function of the spiral thread is uncertain, but it may absorb stress when prey tries to escape, and thus prevent the collobast from being torn apart.


title: Ctenophora

text: In addition to colloblasts, members of the genus "Haeckelia", which feed mainly on jellyfish, incorporate their victims' stinging nematocytes into their own tentacles – some cnidaria-eating nudibranchs similarly incorporate nematocytes into their bodies for defense. The tentilla of "Euplokamis" differ significantly from those of other cydippids: they contain striated muscle, a cell type otherwise unknown in the phylum Ctenophora; and they are coiled when relaxed, while the tentilla of all other known ctenophores elongate when relaxed. "Euplokamis"' tentilla have three types of movement that are used in capturing prey: they may flick out very quickly (in 40 to 60 milliseconds); they can wriggle, which may lure prey by behaving like small planktonic worms; and they coil round prey. The unique flicking is an uncoiling movement powered by contraction of the striated muscle. The wriggling motion is produced by smooth muscles, but of a highly specialized type. Coiling around prey is accomplished largely by the return of the tentilla to their inactive state, but the coils may be tightened by smooth muscle.


title: Ctenophora

text: There are eight rows of combs that run from near the mouth to the opposite end, and are spaced evenly round the body. The "combs" beat in a metachronal rhythm rather like that of a Mexican wave. From each balancer in the statocyst a ciliary groove runs out under the dome and then splits to connect with two adjacent comb rows, and in some species runs along the comb rows. This forms a "mechanical" system for transmitting the beat rhythm from the combs to the balancers, via water disturbances created by the cilia.


title: Ctenophora

text: The Lobata has a pair of lobes, which are muscular, cuplike extensions of the body that project beyond the mouth. Their inconspicuous tentacles originate from the corners of the mouth, running in convoluted grooves and spreading out over the inner surface of the lobes (rather than trailing far behind, as in the Cydippida). Between the lobes on either side of the mouth, many species of lobates have four auricles, gelatinous projections edged with cilia that produce water currents that help direct microscopic prey toward the mouth. This combination of structures enables lobates to feed continuously on suspended planktonic prey.


title: Ctenophora

text: Lobates have eight comb-rows, originating at the aboral pole and usually not extending beyond the body to the lobes; in species with (four) auricles, the cilia edging the auricles are extensions of cilia in four of the comb rows. Most lobates are quite passive when moving through the water, using the cilia on their comb rows for propulsion, although "Leucothea" has long and active auricles whose movements also contribute to propulsion. Members of the lobate genera "Bathocyroe" and "Ocyropsis" can escape from danger by clapping their lobes, so that the jet of expelled water drives them back very quickly. Unlike cydippids, the movements of lobates' combs are coordinated by nerves rather than by water disturbances created by the cilia, yet combs on the same row beat in the same Mexican wave style as the mechanically coordinated comb rows of cydippids and beroids. This may have enabled lobates to grow larger than cydippids and to have less egg-like shapes.


title: Ctenophora

text: An unusual species first described in 2000, "Lobatolampea tetragona", has been classified as a lobate, although the lobes are "primitive" and the body is medusa-like when floating and disk-like when resting on the sea-bed.


title: Ctenophora

text: The Beroida, also known as Nuda, have no feeding appendages, but their large pharynx, just inside the large mouth and filling most of the saclike body, bears "macrocilia" at the oral end. These fused bundles of several thousand large cilia are able to "bite" off pieces of prey that are too large to swallow whole – almost always other ctenophores. In front of the field of macrocilia, on the mouth "lips" in some species of "Beroe", is a pair of narrow strips of adhesive epithelial cells on the stomach wall that "zip" the mouth shut when the animal is not feeding, by forming intercellular connections with the opposite adhesive strip. This tight closure streamlines the front of the animal when it is pursuing prey.


title: Ctenophora

text: The Ganeshida has a pair of small oral lobes and a pair of tentacles. The body is circular rather than oval in cross-section, and the pharynx extends over the inner surfaces of the lobes.


title: Ctenophora

text: The Thalassocalycida, only discovered in 1978 and known from only one species, are medusa-like, with bodies that are shortened in the oral-aboral direction, and short comb-rows on the surface furthest from the mouth, originating from near the aboral pole. They capture prey by movements of the bell and possibly by using two short tentacles.


title: Ctenophora

text: The Cestida ("belt animals") are ribbon-shaped planktonic animals, with the mouth and aboral organ aligned in the middle of opposite edges of the ribbon. There is a pair of comb-rows along each aboral edge, and tentilla emerging from a groove all along the oral edge, which stream back across most of the wing-like body surface. Cestids can swim by undulating their bodies as well as by the beating of their comb-rows. There are two known species, with worldwide distribution in warm, and warm-temperate waters: "Cestum veneris" ("Venus' girdle") is among the largest ctenophores – up to long, and can undulate slowly or quite rapidly. "Velamen parallelum", which is typically less than long, can move much faster in what has been described as a "darting motion".


title: Ctenophora

text: Most Platyctenida have oval bodies that are flattened in the oral-aboral direction, with a pair of tentilla-bearing tentacles on the aboral surface. They cling to and creep on surfaces by everting the pharynx and using it as a muscular "foot". All but one of the known platyctenid species lack comb-rows. Platyctenids are usually cryptically colored, live on rocks, algae, or the body surfaces of other invertebrates, and are often revealed by their long tentacles with many side branches, seen streaming off the back of the ctenophore into the current.


title: Ctenophora

text: Adults of most species can regenerate tissues that are damaged or removed, although only platyctenids reproduce by cloning, splitting off from the edges of their flat bodies fragments that develop into new individuals.


title: Ctenophora

text: The last common ancestor (LCA) of the ctenophores was hermaphroditic. Some are simultaneous hermaphrodites, which can produce both eggs and sperm at the same time, while others are sequential hermaphrodites, in which the eggs and sperm mature at different times. There is no metamorphosis. At least three species are known to have evolved separate sexes (dioecy); "Ocyropsis crystallina" and "Ocyropsis maculata" in the genus Ocyropsis and "Bathocyroe fosteri" in the genus Bathocyroe. The gonads are located in the parts of the internal canal network under the comb rows, and eggs and sperm are released via pores in the epidermis. Fertilization is generally external, but platyctenids use internal fertilization and keep the eggs in brood chambers until they hatch. Self-fertilization has occasionally been seen in species of the genus "Mnemiopsis", and it is thought that most of the hermaphroditic species are self-fertile.


title: Ctenophora

text: Development of the fertilized eggs is direct; there is no distinctive larval form. Juveniles of all groups are generally planktonic, and most species resemble miniature adult cydippids, gradually developing their adult body forms as they grow. In the genus "Beroe", however, the juveniles have large mouths and, like the adults, lack both tentacles and tentacle sheaths. In some groups, such as the flat, bottom-dwelling platyctenids, the juveniles behave more like true larvae. They live among the plankton and thus occupy a different ecological niche from their parents, only attaining the adult form by a more radical ontogeny. after dropping to the sea-floor.


title: Ctenophora

text: At least in some species, juvenile ctenophores appear capable of producing small quantities of eggs and sperm while they are well below adult size, and adults produce eggs and sperm for as long as they have sufficient food. If they run short of food, they first stop producing eggs and sperm, and then shrink in size. When the food supply improves, they grow back to normal size and then resume reproduction. These features make ctenophores capable of increasing their populations very quickly. Members of the Lobata and Cydippida also have a reproduction form called dissogeny; two sexually mature stages, first as larva and later as juveniles and adults. During their time as larva they are capable of releasing gametes periodically. After their first reproductive period is over they will not produce more gametes again until later. A population of "Mertensia ovum" in the central Baltic Sea have become paedogenetic, and consist solely of sexually mature larvae less than 1.6 mm.


title: Ctenophora

text: Most ctenophores that live near the surface are mostly colorless and almost transparent. However some deeper-living species are strongly pigmented, for example the species known as "Tortugas red" (see illustration here), which has not yet been formally described. Platyctenids generally live attached to other sea-bottom organisms, and often have similar colors to these host organisms. The gut of the deep-sea genus "Bathocyroe" is red, which hides the bioluminescence of copepods it has swallowed.


title: Ctenophora

text: The comb rows of most planktonic ctenophores produce a rainbow effect, which is not caused by bioluminescence but by the scattering of light as the combs move. Most species are also bioluminescent, but the light is usually blue or green and can only be seen in darkness. However some significant groups, including all known platyctenids and the cydippid genus "Pleurobrachia", are incapable of bioluminescence.


title: Ctenophora

text: When some species, including "Bathyctena chuni", "Euplokamis stationis" and "Eurhamphaea vexilligera", are disturbed, they produce secretions (ink) that luminesce at much the same wavelengths as their bodies. Juveniles will luminesce more brightly in relation to their body size than adults, whose luminescence is diffused over their bodies. Detailed statistical investigation has not suggested the function of ctenophores' bioluminescence nor produced any correlation between its exact color and any aspect of the animals' environments, such as depth or whether they live in coastal or mid-ocean waters.


title: Ctenophora

text: In ctenophores, bioluminescence is caused by the activation of calcium-activated proteins named photoproteins in cells called photocytes, which are often confined to the meridional canals that underlie the eight comb rows. In the genome of "Mnemiopsis leidyi" ten genes encode photoproteins. These genes are co-expressed with opsin genes in the developing photocytes of "Mnemiopsis leidyi", raising the possibility that light production and light detection may be working together in these animals.


title: Ctenophora

text: Ctenophores are found in most marine environments: from polar waters to the tropics; near coasts and in mid-ocean; from the surface waters to the ocean depths. The best-understood are the genera "Pleurobrachia", "Beroe" and "Mnemiopsis", as these planktonic coastal forms are among the most likely to be collected near shore. No ctenophores have been found in fresh water.


title: Ctenophora

text: In 2013, the marine ctenophore "Mnemiopsis leidyi" was recorded in a lake in Egypt, accidentally introduced by the transport of fish (mullet) fry; this was the first record from a true lake, though other species are found in the brackish water of coastal lagoons and estuaries.


title: Ctenophora

text: Ctenophores may be abundant during the summer months in some coastal locations, but in other places, they are uncommon and difficult to find.


title: Ctenophora

text: In bays where they occur in very high numbers, predation by ctenophores may control the populations of small zooplanktonic organisms such as copepods, which might otherwise wipe out the phytoplankton (planktonic plants), which are a vital part of marine food chains.


title: Ctenophora

text: Almost all ctenophores are predators – there are no vegetarians and only one genus that is partly parasitic. If food is plentiful, they can eat 10 times their own weight per day. While "Beroe" preys mainly on other ctenophores, other surface-water species prey on zooplankton (planktonic animals) ranging in size from the microscopic, including mollusc and fish larvae, to small adult crustaceans such as copepods, amphipods, and even krill. Members of the genus "Haeckelia" prey on jellyfish and incorporate their prey's nematocysts (stinging cells) into their own tentacles instead of colloblasts. Ctenophores have been compared to spiders in their wide range of techniques for capturing prey – some hang motionless in the water using their tentacles as "webs", some are ambush predators like Salticid jumping spiders, and some dangle a sticky droplet at the end of a fine thread, as bolas spiders do. This variety explains the wide range of body forms in a phylum with rather few species. The two-tentacled "cydippid" "Lampea" feeds exclusively on salps, close relatives of sea-squirts that form large chain-like floating colonies, and juveniles of "Lampea" attach themselves like parasites to salps that are too large for them to swallow. Members of the cydippid genus "Pleurobrachia" and the lobate "Bolinopsis" often reach high population densities at the same place and time because they specialize in different types of prey: "Pleurobrachia"'s long tentacles mainly capture relatively strong swimmers such as adult copepods, while "Bolinopsis" generally feeds on smaller, weaker swimmers such as rotifers and mollusc and crustacean larvae.


title: Ctenophora

text: Ctenophores used to be regarded as "dead ends" in marine food chains because it was thought their low ratio of organic matter to salt and water made them a poor diet for other animals. It is also often difficult to identify the remains of ctenophores in the guts of possible predators, although the combs sometimes remain intact long enough to provide a clue. Detailed investigation of chum salmon, "Oncorhynchus keta", showed that these fish digest ctenophores 20 times as fast as an equal weight of shrimps, and that ctenophores can provide a good diet if there are enough of them around. Beroids prey mainly on other ctenophores. Some jellyfish and turtles eat large quantities of ctenophores, and jellyfish may temporarily wipe out ctenophore populations. Since ctenophores and jellyfish often have large seasonal variations in population, most fish that prey on them are generalists and may have a greater effect on populations than the specialist jelly-eaters. This is underlined by an observation of herbivorous fishes deliberately feeding on gelatinous zooplankton during blooms in the Red Sea. The larvae of some sea anemones are parasites on ctenophores, as are the larvae of some flatworms that parasitize fish when they reach adulthood.


title: Ctenophora

text: Most species are hermaphrodites, and juveniles of at least some species are capable of reproduction before reaching the adult size and shape. This combination of hermaphroditism and early reproduction enables small populations to grow at an explosive rate.


title: Ctenophora

text: Ctenophores may balance marine ecosystems by preventing an over-abundance of copepods from eating all the phytoplankton (planktonic plants), which are the dominant marine producers of organic matter from non-organic ingredients.


title: Ctenophora

text: On the other hand, in the late 1980s the Western Atlantic ctenophore "Mnemiopsis leidyi" was accidentally introduced into the Black Sea and Sea of Azov via the ballast tanks of ships, and has been blamed for causing sharp drops in fish catches by eating both fish larvae and small crustaceans that would otherwise feed the adult fish. "Mnemiopsis" is well equipped to invade new territories (although this was not predicted until after it so successfully colonized the Black Sea), as it can breed very rapidly and tolerate a wide range of water temperatures and salinities. The impact was increased by chronic overfishing, and by eutrophication that gave the entire ecosystem a short-term boost, causing the "Mnemiopsis" population to increase even faster than normal – and above all by the absence of efficient predators on these introduced ctenophores. "Mnemiopsis" populations in those areas were eventually brought under control by the accidental introduction of the "Mnemiopsis"-eating North American ctenophore "Beroe ovata", and by a cooling of the local climate from 1991 to 1993, which significantly slowed the animal's metabolism. However the abundance of plankton in the area seems unlikely to be restored to pre-"Mnemiopsis" levels.


title: Ctenophora

text: In the late 1990s "Mnemiopsis" appeared in the Caspian Sea. "Beroe ovata" arrived shortly after, and is expected to reduce but not eliminate the impact of "Mnemiopsis" there. "Mnemiopsis" also reached the eastern Mediterranean in the late 1990s and now appears to be thriving in the North Sea and Baltic Sea.