Maddie Reifsteck, Eckerd College, Marine Science Discipline

Elizabeth Phillips, Northwest Fisheries Science Center

Steve De Blois, Northwest Fisheries Science Center

Julia Clemons, Northwest Fisheries Science Center 

Pacific hake, hereafter hake, the most abundant groundfish in the California Current Ecosystem, are assessed and monitored biennially by the US/Canada PHEAT survey. This survey is conducted after the hake population’s seasonal migration concludes to obtain a synoptic overview of hake distribution and biomass. However, because the survey progresses from south to north, June through August, resulting data cannot be used to assess intraseasonal movements of hake. If hake move substantially within a season, estimates of total biomass and distribution may need to be adjusted. To that end, acoustic data from the 2019 PHEAT survey were compared to acoustic data collected by the 2019 CPS survey, which uses similar methods to collect data but was run north to south along the same geographic range later in the summer. By comparing estimated relative abundance of hake, evidence of modest differences in distribution and abundance across the latitudinal range of each survey was found, with total abundance shifting north towards Monterey Bay after 50 days. Average abundance data appear more evenly spread across the latitudinal range as the summer progressed. Hake also showed greater abundance closer to shelf break, especially in August. The results indicate a more thorough comparison over the entire geographic range of both surveys should be conducted. Further study into intraseasonal movements of different year classes of hake, shifts in prey availability, and changing ocean conditions may clarify what drives these short-term shifts in distribution and abundance.

For more information, please contact: mfreifst@eckerd.edu

You can also read more about my time at sea on the NMFS blog: https://www.fisheries.noaa.gov/science-blog/hollings-scholar-takes-high-seas

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