Use of at-sea distribution data to derive potential foraging ranges of macaroni penguins during the breeding season

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 169:263-275 (1998) - doi:10.3354/meps169263 Use of at-sea distribution data to derive potential foraging ranges of macaroni penguins during the breeding season P. N. Trathan*, E. J. Murphy, J. P. Croxall, I. Everson British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom *E-mail: p.trathan@bas.ac.uk ABSTRACT: Macaroni penguins are the main avian consumer of Antarctic krill in the vicinity of South Georgia. The largest breeding colonies occur on small offshore islands to the northwest of the main island. To delimit the foraging range of penguins from these colonies during the chick-rearing period, we used a series of ship-based survey transects to estimate their distribution and abundance. The survey transects were positioned so as to radiate from a point close to those islands with the largest colonies. Spatial and temporal variations within the data are examined. Penguins were mostly over the continental shelf in water less than 350 m depth and with more than 70% of birds at distances less than 40 km from the main breeding site. To model the observed distribution of penguins, a theoretical at-sea distribution is developed together with a 'potential foraging footprint'. The results are compared with those from previous models based solely on the use of foraging trip duration and at-sea activity budgets. The foraging 'footprint' is probably the best basis currently available for assessing the nature of interactions between macaroni penguins and the commercial fisheries for krill. KEY WORDS: Macaroni penguin · Foraging · At-sea · Colony counts · Eudyptes chrysolophus Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 169. Publication date: August 06, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.