Atlantic Puffin (Fratercula arctica) Foraging Ecology During Marine Heatwave Conditions

• Main Author: Kennerley, William L.
• Other Authors: Lyons, Donald E., Clucas, Gemma V., Orben, Rachael O., Fisheries, Wildlife, and Conservation Sciences
• Format: Master Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Atlantic puffin; fratercula; Fratercula arctica; North Atlantic
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/1z40m230m

Marine heatwaves (“MHWs”) are discrete periods of anomalously warm ocean conditions that can lead to shifts in the distribution and abundance of marine organisms. Low-trophic level, pelagic forage species are frequently among those affected by MHWs, often resulting in considerable impacts upon their predators. In the North Atlantic Ocean, Atlantic puffins (Fratercula arctica, “puffins”) are a charismatic mesopredator and are particularly vulnerable to changes in local forage fish communities when breeding and thus restricted to central place foraging. Increasingly frequent MHWs in the Gulf of Maine - the southern extent of the puffins’ breeding range - have led to depressed reproductive success and lowered chick body condition at fledging. Using miniaturized biologging devices (global positioning system units and time-depth recorders) and fecal DNA metabarcoding, I assessed the foraging ecology of some of the world’s southernmost breeding Atlantic puffins during two years of anomalously warm conditions. Puffins regularly foraged up to 28 km from the breeding colony and performed more than 300 dives per day, with higher foraging effort associated with warmer and more stratified ocean conditions. Despite differing environmental conditions and reproductive success rates between years, overall foraging effort did not differ significantly. Although puffins responded to changing environmental conditions, my results indicate there were limits to how much puffins could adjust their dive behavior and space use around the Matinicus Rock colony. Puffins displayed remarkable dietary flexibility, however. I assessed the diet of breeding puffins via fecal DNA metabarcoding, allowing us to determine the forage fish species consumed by chicks, provisioning adults, and – for the first time – incubating adult puffins. Across two years, 28 unique fish taxa were present in puffin diet and the relative proportions of these prey differed between years, suggesting dietary adaptability. The diet of puffin chicks and adults differed and ...