Twelve Years of Cold-Stunned Sea Turtles on Cape Cod

A new paper co-authored by CFF's Samir Patel is out now in Marine Biology, digging into how immature sea turtles feed in the waters off Cape Cod and where they sit in the local food web.

The work draws on twelve years of sampling. Each fall, immature loggerhead, Kemp's ridley, and green sea turtles strand on Cape Cod beaches after cold stunning. About 25% of these cold-stunned sea turtles are deceased when they strand, and the team conducts necropsies (animal autopsies) on these carcasses. All work involving these sea turtles is conducted under U.S. Fish & Wildlife Service permit ES60415D. The team collected blood and muscle tissue, then compared the stable isotope signatures across those tissues and across species. Those signatures reveal each turtle's foraging history and its trophic position, or where it falls in the food web.

From the collected data, green turtles held the lowest trophic position, Kemp's ridleys sat in the middle, and loggerheads the highest. Larger turtles of all three species carried higher nitrogen values, a sign that these animals shift from feeding in the open ocean toward feeding closer to shore and at a higher trophic position as they grow.

The broad patterns don't capture everything, though. Individual turtles still varied widely, which suggests animals within the same species follow their own migratory and foraging strategies. Where these juveniles head next is the natural next question. 

Further research on their movement patterns will give important context on how they use Massachusetts waters.

Read the full paper 

This work was carried out in collaboration with NOAA Fisheries, Mass Audubon's Wellfleet Bay Wildlife Sanctuary, and the Massachusetts Division of Marine Fisheries.