18th Biennial Conference of the Society for Marine Mammalogy, Quebec City, Canada, October 12-16, 2009
The Hawaiian monk seal (Monachus schauinslandi) is an endangered species only found within the Hawaiian Archipelago. The majority of the breeding population for this seal is located around six islands in the Northwest Hawaiian Island chain (NWHI). Overall, both juvenile and adult seals have a wide range in δ13C and δ15N from 1912-2006 (δ13C: -12.5‰; δ15N: 12.6‰). Seals in the northern NWHI were enriched in δ13C by nearly 2‰ and depleted in δ15N by nearly 6‰ during the 96 years. Meanwhile, seals within the middle and southern extent of the NWHI showed little to very slight decreases in δ13C and δ15N. Preliminary comparison of modern monk seals with selected potential prey in the southern NWHI indicate possible trophic reliance on a mix of reef fish, eels, and lobster. Commercial fishery data post-WWII indicate an overlap between fisheries and monk seal diets in lobster, squirrelfish, and goatfish.
Thompson, Nina M.; Hirons, Amy; Potter, Charles W.; and Littnan, Charles, "Trophic Structure of the Northwest Hawaiian Islands and Resident Monk Seals (Monachus schaundslandi) During the Twentieth Century" (2009). Oceanography Faculty Proceedings, Presentations, Speeches, Lectures. 430.