Diets of eight Northern Pacific seabirds, including of the Laysan Albatross, used to study marine changes

Tyler Gagne (Monterey Bay Aquarium, California, USA) and colleagues have published open access in the journal Science Advances on utilizing seabird diet information to track changes in the marine environment. The Laysan Albatross Thalassarche immutabilis is one of the eight species studied.

The paper’s abstract follows

“Pelagic ecosystems are dynamic ocean regions whose immense natural capital is affected by climate change, pollution, and commercial fisheries. Trophic level–based indicators derived from fishery catch data may reveal the food web status of these systems, but the utility of these metrics has been debated because of targeting bias in fisheries catch. We analyze a unique, fishery-independent data set of North Pacific seabird tissues to inform ecosystem trends over 13 decades (1890s to 2010s). Trophic position declined broadly in five of eight species sampled, indicating a long-term shift from higher–trophic level to lower–trophic level prey. No species increased their trophic position. Given species prey preferences, Bayesian diet reconstructions suggest a shift from fishes to squids, a result consistent with both catch reports and ecosystem models. Machine learning models further reveal that trophic position trends have a complex set of drivers including climate, commercial fisheries, and ecomorphology. Our results show that multiple species of fish-consuming seabirds may track the complex changes occurring in marine ecosystems.”

A Laysan Albatross and its downy chick, photograph by Pete Leary

Reference:

Gagne, T.O., Hyrenbach, K.D., Hagemann, M.E. & Van Houtan, K.S. 2018. Trophic signatures of seabirds suggest shifts in oceanic ecosystems. Science Advances 4(2). DOI: 10.1126/sciadv.aao3946.

John Cooper, ACAP Information Officer, 12 March 2017