Climate shifts and global spatio-temporal variation in albacore tuna (Thunnus alalunga) diets

Cindy Matuch, Hopkins Marine Station of Stanford University, Monterey, CA, United States, Natasha Hardy, University of Alberta, Edmonton, AB, Canada, Stephanie Green, University of Alberta, AB, Canada and Larry Crowder, Hopkins Marine Station of Stanford University, Department of Biology, Pacific Grove, CA, United States
Albacore tuna (Thunnus alalunga) are a highly-migratory, cosmopolitan marine predator using large portions of ocean basins throughout their life and consuming a very wide range of prey. Research on albacore diet has grown since the early 1900s alongside other fundamental biological studies seeking to expand our knowledge of this commercially important species. These studies are patchy in time and space, with only a very few syntheses of regional to global scale patterns. The distributions of albacore and their food webs are changing due to climate change. Therefore, understanding their historical diets is key to understanding potential shifts in their diets in the future. Here, we performed a global meta-analysis of albacore diets from published papers from 1880–2010 and explored differences in the diets of albacore tuna across the Pacific, Atlantic, and Indian Oceans, as well as the Mediterranean Sea. We found albacore tuna diets to be highly variable across spatial and temporal scales. Key prey groups include clupeiform, myctophiform and perciform fishes, squids, octopus, shrimp and krill. The global patterns in albacore diets identified in this study will contribute to a broader study focusing on predicting future variability in albacore diets in the California Current System, as they expand their range to higher latitudes.