Dolphins now enjoying life in Navesink River

on August 08, 2008 at 11:08 AM, updated August 08, 2008 at 11:30 AM

A pod of bottlenose dolphins that ventured into the Shrewsbury River two months ago haven't lost their taste for Monmouth County.

Still feeding on a bounty of menhaden--a herring-like, large-headed fish averaging a foot in length--about a dozen of the dolphins have stayed behind, moving to the nearby Navesink River while a few returned to the Atlantic Ocean.

Dolphins still in Navesink
Dolphins still in Navesink A pod of dolphins that was in the Shrewsbury River in June has been living and feeding in the Navesink River. Officials from the National Oceanic and Atmospheric Administration think the dolphins will stay in the area until their food runs out or the weather gets colder. Boaters are encouraged to keep a safe distance from the pod. (Video by Scott Lituchy /The Star-Ledger)

The National Oceanic and Atmospheric Administration said Thursday they believe 16 of the marine mammals initially wriggled into the Shrewsbury in mid-June, about the same time summertime boat traffic increased and tourist flocked to the area. They arrived at the Navesink weeks ago.

The possibility that one or more of the remaining dolphins could be hit or injured by the boat traffic has been a constant concern.

"We're still worried about it. Traffic is increasing," said Sheila Dean of the Marine Mammal Stranding Center in Brigantine. "We don't like seeing them stay in there."

That concern prompted state and federal authorities to issue warnings, and eventually tickets, to boaters who they claim harassed the dolphins by moving too close to them during and just after the July 4 weekend. Boats of observers continue to surround the animals.

Authorities are hoping humans and dolphins can keep a safe distance until the marine visitors decide to return to the open sea--which they hope will happen by fall.

"For now, we're monitoring their condition," said Teri Frady of the NOAA. "By fall, their prey should move and hopefully they will move. We're trying to plan for all contingencies. By fall, if they are still there, we'll be thinking about whether there is anything we need to do."

Trying to push or move the dolphins out of the river is a difficult task that can do as much harm as good, according to NOAA authorities. The animals become stressed when humans attempt to move them or even guide them out of a river.

Relying on volunteers to report on dolphin sightings and any problems, the non-profit Marine Mammal Stranding Center plans to inspect the pod in a few days to determine whether any dolphin is having difficulty.

"Just by looking at their backs, as they come up to the top, we can see of they are round--which is healthy--or concave. Concave would indicate they are losing weight," said Dean.

But the dolphins appear to be finding a lot of menhaden, also known as mossbunker, pogy or fat back, to munch on. Scientists contend it is not unusual for coastal bottlenose dolphins to enter high-saline rivers, like the Shrewsbury, to pursue prey--or for the animals to remain behind as long as the food is plentiful.