Diving patterns in relation to diet of Gentoo and Macaroni penguins at South Georgia

Croxall, J.P.; Davis, R.W.; O'Connell, M.J.. 1988 Diving patterns in relation to diet of Gentoo and Macaroni penguins at South Georgia. The Condor, 90 (1). 157-167.

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Abstract/Summary

The depthsa ttainedo n 1,444d ivesb y 14 GentooP enguins(P ygosceliPs apua) and 6,352d ivesb y eightM acaroniP enguins(E udyptesc hrysolophusw)e re recordedt,o gether with the timing and durationo f the foragingt rip and the amounta nd type of prey caught. MacaroniP enguinsa te only Antarctick rill Euphausias uperba.W hen feedingo nly at night they maden o divesd eepert han 20 m; on all-day trips 36% of divesw ereb etween2 0 to 80 m. GentooP enguinsfe dd uringt he day.W hen theyc aughkt rill, 77%o f divesw eres hallower than 54 m; when fish were taken, 59% of dives were 54 to 136 m, which is consistent with the benthic-demersahla bit of thej uvenile Nototheniaa nd Champsocephalufsis ht hey eat. The patterno f predationo n krill by both penguins peciesis consistenwt ith its vertical migrationt o the surfacea t night and dispersatlh rought he water column during the day. The food requirements of chick-rearing Macaroni Penguins would be met by catching at least six adult krill per dive (or 150 juvenile krill or amphipods). For similar Gentoo Penguins, a minimum of 15 adult krill per dive (one every 8 set), or one fish every third dive, is needed. Recorded interannual variations in krill size can treble these rates, which would also be doubled if half the dives were for travelling, not feeding.

Item Type:	Publication - Article
Additional Keywords:	Gentoo penguin, Macaroni penguin, Pygoscelis papua, Eudyptes chrysolophus, Antarctic krill, Euphausia superba, fish, diving, diet, foraging, prey capture rate
Date made live:	15 Nov 2018 10:11 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/521545

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