Reef Fish Sustainability Off West Hawaiʻi Island

Jennifer Wong-Ala, a 2017 spring graduate from the University of Hawaiʻi at Mānoa’s Global Environmental Science (GES) degree program, conducted original research to determine how biological and physical factors affect the number of fish surviving to sustain populations of reef fish off West Hawaiʻi Island.

Jennifer Wong-Ala

Adult reef fish, like yellow tang, release eggs strategically—in places where the eggs can be swept into the open ocean to live out their free-floating larval stage and develop until they are ready to come back to the reef. This process of successfully returning home, termed recruitment, can be influenced by many physical factors including ocean currents, as well as biological strategies such as when and where fish larvae are born and how long the fish remain in the free-floating larval stage.

To explore the influence of these factors, Wong-Ala and her mentor, oceanography assistant professor Anna Neuheimer, developed a computer model which accounted for date of birth, location of birth, movement of larvae, duration of the free-floating larval stage, development, settlement and death of larval reef fish off of Hawaiʻi Island.

Their study found that recruitment changed depending on the fish’s birthdate due to influences of the currents, eddies and moon phase (i.e. tides). Additionally, location of birth mattered, with individuals born in shallow and sheltered bays having higher rates of recruitment compared to individuals born in unsheltered locations under certain conditions.

“This study provides a baseline understanding of how biophysical factors interact to impact recruitment in western Hawaiʻi Island,” said Wong-Ala.

The information can be used to explain species-specific variation in recruitment from year to year and predict possible changes in the future. Understanding the amount of fish that make it back to the reef is important for maintaining sustainable reef fish populations.

Following her passion with supportive mentors

“I chose GES because it is an interdisciplinary major that allows us to learn about the changes in the environment, gain valuable computer skills, and focus on what we are truly interested [in],” said Wong-Ala, who was born and raised in Waimānalo, Oʻahu. “My favorite aspect of my thesis experience is the relationship that developed with my mentor. I have worked in her lab for three years and it has been an experience that has taught me so much. I hope to be a mentor like her in the future.”

A graduate of Kapiʻolani Community College, Wong-Ala became interested in environmental science through the KCC-School of Ocean, Earth, Science and Technology summer bridge program. She was invited to participate in UH Mānoa’s School of Ocean, Earth, Science and Technology. Anela Choy, Wong-Ala’s mentor, co-founded the Maile program along with Barbara Bruno and Keolani Noa. The program helps student thrive through individualized mentoring and peer support.

Having graduated last Saturday, Wong-Ala is preparing to enter a graduate program at Oregon State University in Ocean, Earth and Atmospheric Sciences.

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