the 1970s the NOAA Fisheries, Southwest Fisheries Science Center (SWFSC) has collaborated with American Fishermen's Research Foundation (AFRF) in tagging studies of albacore in the North Pacific. Through these studies we have learned that juvenile albacore (to 2 years of age) make trans-Pacific migrations in their younger years between Japan and the West coast of North America. To date over 24,000 albacore have been tagged with conventional dart tags and 1,245 of these have been recovered. In Spring of 2001 AFRF and the SWFSC began a pilot project to learn more about the migration habits of North Pacific albacore, Thunnus alalunga in an effort to allow the incorporation of detailed migration movements into stock assessment models. Archival tags are a recent technical innovation that are being used to collect daily locations (through light level data recorded by the tag), internal temperature of the fish's abdomen, ambient water temperature, and depth. Genetic research using ddRAD sequencing indicates that albacore migrate between the North and South Pacific oceans across the equator. Biology and ecology The albacore is a powerful, hard-hitting predator that forms mixed schools with skipjack tuna, yellowfin tuna, and bluefin tuna, sometimes around floating objects like sargassum weeds. Schools of albacore are highly migratory within bodies of water and segregated by maturity, with older fish tending to form more compact groups. Of those caught by humans, immature albacore have a 1:1 sex ratio while older albacore are mostly male. In the Atlantic Ocean, older fish are found in cooler waters. The opposite is true for the Pacific Ocean, where fish are found more abundantly along thermal discontinuities. Depth range also varies by location: Atlantic fish dive as deep as where Pacific fish reach only in depth. In the northeast Atlantic, feeding migrations to productive areas occur during the summer. Due to climate changes over the last 40 years, the timing and spatial distribution of the albacore have also changed. Albacore show a broad range of behavioral differences by region. In Baja California, albacore make frequent dives to depths exceeding during the day and stay near the surface at night, while off the coast of Washington and Oregon they stay near the surface the entire day. Albacore never really rest; their need for oxygen means they must always be on the move. Feeding Albacore tuna are pelagic predators - open-sea hunters. Their diets vary very little from season to season. Unlike