UH Study Finds Adult Fish ‘Predict’ Food Availability for Young

Atlantic cod. UH Manoa courtesy photo.

A new study led by a University of Hawai‘i at Mānoa researcher has revealed that fish parents are able to anticipate beneficial environments for their young to feed and grow in.

Oceanographer Anna Neuheimer, an associate professor at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), led the study which examined the reproduction times of Atlantic cod, an economically important fish. The findings showed a variance of 86 days across the species’ range in the north Atlantic Ocean. This pattern is unexplained by temperature variation but researchers suspected that it provided an advantage to the fish.

Observing this phenomena has been difficult since these life stages are typically not observed directly in the field. To overcome this challenge, Neuheimer led co-authors in Denmark to develop new tools that combined data on the timing of observed stages, temperatures across the North Atlantic and temperature-dependent development rates to estimate timing of the targeted stages of young fish and their food.

The team found evidence indicating that Atlantic cod reproduce at specific times to match the birth of their young with the seasonal availability of food.

“This timing match is a challenge for the parents, as eggs take weeks to develop before the young fish need to feed—that is, they must “predict” when their young’s food will occur weeks in advance,” said Neuheimer.

While the study results were predicted by a century-old hypothesis called the Match-Mismatch Hypothesis, Neuheimer’s work presents the first hard evidence. The new tools developed in the study can be used to help predict fishery catch changes in the future.

“Additionally, life history studies on wide-ranging marine organisms can give an early indication of what might occur for organisms in other habitats,” said Neuheimer. “Identifying the factors shaping adaptive variability is key to determining how biology will respond to climate forcing now and in the future.”

As part of a fellowship at the Aarhus Institute of Advanced Studies, Neuheimer will continue to explore how the relative match between young fish and their prey results in fishery catch changes from year to year, and how timing of fish reproduction and food availability may shift in the future. The research is also being used to create new models of reef fish timing around the Hawaiian Islands to explain and predict shifts in young reef fish populations.