Post-fledging survival of Adélie penguins at multiple colonies: chicks raised on fish do well

Marine ecology progress series

Katie M. Dugger^2¹  David G. Ainley^1²  Grant Ballard^4³  Scott Jennings^2,4,6⁴  Kerry J. Barton^5⁵  Brian J. Karl^5⁶  Mario La Mesa^3⁷ 

[1] Associates Ecological Consultants, Los Gatos, CA 95032, USA^1;H. T. Harvey &ISMAR-CNR, Istituto di Scienze Marine, UOS di Ancona, 60125 Ancona, Italy^3;Landcare Research, Lincoln 7640, New Zealand^5;Point Blue Conservation Science, Petaluma, CA 94954, USA^4;Present address: ACR, Cypress Grove Research Center, Marshall, CA 94940, USA^6;US Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA^2

关键词: Adélie penguin;    Antarctic silverfish;    Anvers Island;    Central-place foraging;    Ross Island;    Intraspecific trophic competition;   

DOI  :  10.3354/meps12687

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

We assessed whether the mass of Adélie penguin Pygoscelis adeliae fledglings at 3 colonies of markedly disparate size on Ross Island, Ross Sea, correlated with their eventual return as subadults. We compared our results with those from Anvers Island, Bellingshausen Sea. Colony sizes at Ross Island have been increasing, contrary to decreasing size at Anvers Island. At Ross Island, during the month prior to fledging, chick diet consisted equally of energy-dense Antarctic silverfish Pleuragramma antarctica and less-caloric crystal krill Euphausia crystallorophias, while at Anvers Island the diet was principally Antarctic krill E. superba. At Ross Island, the mass of fledglings who subsequently returned (mean ± SE: 3.4 ± 0.0411 kg) exceeded that of those not seen again (3.2 ± 0.0251 kg), compared to Anvers Island (3.2 vs. 3.0 kg, respectively). At Ross Island, fledging mass was inversely related to colony size and, at the largest colony, fledging mass decreased as the colony grew. Average mass of returnees at the largest colony was less than the mass at Anvers Island for those fledglings that did not return. The mean proportion of fish in the chicks’ diet decreased at the largest Ross Island colony over time, as did fledging mass. We hypothesize that intraspecific competition increased along with colony size, decreasing the availability of fish. We further hypothesize that at the large Ross Island colony, post-fledging penguins must be finding adequate prey, and more energy-dense fish, just outside the colony’s foraging area to explain opposing trends in colony trajectories.

【 授权许可】

Unknown