August 6, 2020 — The following was released by NOAA Fisheries:
Scientists in the Pacific Islands region published new research that can help predict catch rates in the Hawaiʻi longline fishery. Drs. Phoebe Woodworth-Jefcoats and Johanna Wren found that information about phytoplankton (microscopic algae) can be used to forecast catch rates for bigeye tuna. They used the size of phytoplankton to forecast catch rates for up to 4 years. This information could help advance ecosystem-based fisheries management in the Pacific Islands region.
Woodworth-Jefcoats and Wren hypothesize that the size of phytoplankton is an indicator of the quality of food for larval and juvenile bigeye tuna. While bigeye tuna don’t actually eat phytoplankton, they do eat zooplankton that eat phytoplankton. Zooplankton are tiny animals that drift with the ocean currents and are prey to many oceanic species. When there is more large phytoplankton, there is likely more large zooplankton and more high-quality food for young bigeye tuna. And when young bigeye tuna have better food, more of them survive to reach adulthood. These fish are then available for capture by the Hawaiʻi fishery.