Diet composition and foraging habitats of Adélie and gentoo penguins in three different stages of their annual cycle

Abstract

new knowledge on the feeding ecology and foraging habitats of pygoscelid penguins. They confirm the importance of Antarctic krill during the annual cycle and improve the understanding of life strategies and predator-prey interactions essentially out of the reproductive period, in which the information is very limited. These results can help to establish new management strategies, particularly considering the potential overlap between predators and fisheries.

Seasonal consistency and individual variation in foraging strategies differ among and within Pygoscelis penguin species in the Antarctic Peninsula region

“…These findings are similar to those of Juáres et al (2016) at Stranger Point, King George Island, which suggested Adélie penguins had a greater variation in body feather δ 13 C values than gentoo penguins. These results also agree with tracking studies indicating that Adélie and chinstrap penguins disperse broadly during the post-breeding period while gentoo penguins remain close to their breeding colonies and forage in open-water, near-shore habitats (Wilson 2010;Hinke et al 2015).…”

“…These results differ from those of Juáres et al (2016), which found no differences in the δ 15 N values of gentoo penguins between these two time periods at Stranger Point on King George Island, South Shetland Islands. The δ 13 C values and SEA b of gentoo penguins in our study indicated that foraging habitat use did not differ seasonally.…”

“…This agrees with similar findings by Negrete et al (2016) as gentoo penguins often remain close to their breeding colonies outside the breeding season (Wilson et al 1998). While Juáres et al (2016) and Negrete et al (2016) did not examine individual consistency, our results indicate that individual gentoo penguins were consistent relative to each other in their foraging habitat use (δ 13 C) and diets (δ 15 N) between seasons. In addition, similar to Adélie and chinstrap penguins, δ 13 C values in gentoo penguins revealed a slight truncation during the breeding season, suggesting foraging range restriction due to incubation responsibilities.…”

“…In addition, vertical and temporal differences in foraging habitat use aid in differentiating the foraging niches of the three species when they occur in sympatry (Wilson 2010). However, very few studies have investigated inter-individual foraging variation within populations of Pygoscelis species Handley et al 2017) or temporal consistency at the population and individual level (e.g., Polito et al 2015;Juáres et al 2016;Negrete et al 2016). Our results suggest that Pygoscelis penguins can differ in foraging ecology not only at the population level among species, sites and seasons, but also in the level of individual variation within populations, and in the degree of foraging consistency within individuals.…”

“…In addition to dietary differences among species, studies focused on foraging habitat demonstrate that, in general, gentoo penguins forage in deeper benthic, inshore habitats while chinstrap and Adélie penguins forage further offshore in shallower, pelagic areas (Trivelpiece et al 1987;Miller et al 2010). However, the majority of past studies have focused primarily on the breeding season and only a few have focused on diet or foraging habitat during the postbreeding or non-breeding period (Miller et al 2009(Miller et al , 2010Gorman et al 2014;Juáres et al 2016;Negrete et al 2016). Even so, existing studies do indicate that gentoo penguin populations exhibit a generalist diet with substantial variation in their foraging ecology across breeding locations (Pütz et al 2001;Pütz 2002, 2003;Miller et al 2009;Polito et al 2015;Handley et al 2017).…”