MEPS 526:183-197 (2015)  -  DOI: https://doi.org/10.3354/meps11182

ABSTRACT: Quantifying prey consumption by top predators is a crucial component of ecosystem-based management in the Southern Ocean. In this study, we developed a bioenergetics model to estimate prey consumption by a top predator, the Adélie penguin Pygoscelis adeliae. Our model predicts prey consumption throughout the breeding season and incorporates uncertainty in model parameters using Monte Carlo simulation. The model was parameterized with data obtained at Béchervaise Island, the site of a long-term monitoring program in East Antarctica. We parameterized the model (1) using 13 yr of penguin population data, (2) for a year in which penguins successfully reared their chicks (2001-2002) and (3) for a year with low breeding success (1998-1999). Daily per capita energy consumption during the breeding season averaged 4269 kJ d^-1 (95% CI: 4187-4352 kJ d^–1) and 4684 kJ d^-1 (95% CI: 4596-4771 kJ d^–1) for males and females, respectively. Over the entire breeding season a male breeder consumes 470 MJ (95% CI: 461-479 MJ) compared to 515 MJ (95% CI: 506-525 MJ) for a female. On average, the Béchervaise Island population of 1836 breeding pairs consumes 16447 MJ d^-1 which amounts to 1809224 MJ during the breeding season. On the basis of variable breeding success and the proportion of krill and fish in their diet, we estimate that this population consumes 78 to 406 t of krill and 4 to 46 t of fish each breeding season. Our results demonstrate clear periods of peak consumption associated with the penguins’ breeding cycle.

KEY WORDS: Southern Ocean · Predator–prey · Uncertainty · Krill · Harvesting · Fisheries