Dynamic Habitat Use of Albacore and Their Primary Prey Species in the California Current System

Contributors: Barbara Muhling, Stephanie Brodie, Owyn Snodgrass, Desiree Tommasi, Heidi Dewar, John Childers, Michael Jacox, Christopher A. Edwards, Yi Xu, Stephanie Snyder

Organizations: University of California, Santa Cruz Institute for Marine Science, Santa Cruz, CA • NOAA Southwest Fisheries Science Center, San Diego, CA • NOAA Southwest Fisheries Science Center, Monterey, CA • NOAA Earth System Research Laboratory, Boulder, CO • Ocean Sciences Department, University of California, Santa Cruz, CA • Department of Fisheries and Oceans Delta, British Columbia, Canada • Thomas More University, Crestview Hills, KY

Summary: Juvenile north Pacific albacore (Thunnus alalunga) forage in the California Current System (CCS), supporting fisheries between Baja California and British Columbia.

Within the CCS, their distribution, abundance, and foraging behaviors are strongly variable interannually. Here,we use catch logbook data and trawl survey records to investigate how juvenile albacore in the CCS use their oceanographic environment, and how their distributions overlap with the habitats of four key forage species. We show that northern anchovy (Engraulis mordax) and hake (Merluccius productus) habitat is associated with productive coastal waters found more inshore of core juvenile albacore habitat, whereas Pacific sardine (Sardinops sagax) and boreal clubhook squid (Onychoteuthis borealijaponica) habitat overlaps more consistently with that of albacore.

Our results can improve understanding of how albacore movements relate to foraging strategies, and why prey-switching behavior occurs. This has relevance for the development of ecosystem models for the CCS, and for the eventual implementation of ecosystem-based fishery management.