Year: 2026
Type: article
Abstract: Despite extensive dietary studies of the subantarctic fur seal Arctocephalus tropicalis at subantarctic localities, little is known about the diet of colonies inhabiting subtropical regions. Since Amsterdam Island hosts one of the largest colonies of subantarctic fur seal, we aimed to detail its diet using a combination of scat and regurgitate analysis together with stable isotopes. A total of 8125 prey items were identified from 560 scats, with an 80% predominance of fish by numerical abundance. Myctophid fishes were the most diverse (23 species) and numerous (66%) prey items with 2 main taxa: Symbolophorus barnardi/boops (21%) and Electrona paucirastra (11%). Noticeably, fresh mass analysis of 225 seal regurgitates pointed out a cephalopod-based diet (85%). A total of 1584 prey items were counted from regurgitates, with again a predominance of fish (57%) over cephalopods (35%). The main prey items from regurgitates were the fish Scomberesox scombroides (21%), Ctenoscopelus phengodes (15%), and the squid Ommastrephes cylindraceus (11%). Blood isotopic values of lactating females indicated that they foraged all year long in subtropical waters (δ13C) where they are top predators, sharing the same trophic position (δ15N) as the Indian yellow-nosed albatross Thalassarche carteri. The high percentage by mass of cephalopods in seal regurgitates together with the relatively high percentage by numerical abundance of cephalopods in scats (20%) suggest that subantarctic fur seals from Amsterdam Island consume more cephalopods than elsewhere, and probably more cephalopods than any fur seal species (Arctocephalus spp.) so far investigated.
Source: Marine Ecology Progress Series
DOI: 10.3354/meps15311
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life below water
Open Access status: green
OpenAlex ID: W7204991240