Increases in Adelie penguins in the Ross Sea: Could the fish
Details of Research
TitleIncreases in Adelie penguins in the Ross Sea: Could the fishery for Antarctic toothfish be responsible?AbstractThe Ross Sea is home to about a third of the world population of Adelie penguins (Pygoscelis adeliae). Between 2001 and 2013 the number of breeding pairs of Adelie penguins at colonies in the southwestern Ross Sea more than doubled. It has been suggested that this increase was caused by the fishery for Antarctic toothfish (Dissostichus mawsoni) leading to mesopredator release of Antarctic silverfish (Pleuragramma antarctica), a shared prey of toothfish and Adelie penguins. Cases of mesopredator release in marine systems have been widely reported, but limited information on marine predators often hinders quantitative investigation of these changes. The present study has brought together information from multiple models to estimate the biomass of silverfish that could be released from predation through the effects of the toothfish fishery. New diet data for toothfish are presented which show that Antarctic toothfish and Adelie penguins do not have significantly overlapping diets in the southwestern Ross Sea. The mass of silverfish released from predation due to the effects of fishing was estimated to be 128 tonnes wet-weight per year (tWW/y; 5th-95th estimation interval of 46-358 tWW/y) in 2013, equivalent to less than 2 percent of the biomass of silverfish estimated to be consumed annually by Adelie penguins. Even if toothfish consumed only silverfish, the predicted predation release effect would still not be sufficient to explain the observed increase in the number of Adelie penguins in the southern Ross Sea. The results of the modelling are hence inconsistent with predation release of silverfish due to the toothfish fishery being responsible for recent increases in the number of Adelie penguins breeding in the southwestern Ross Sea. Copyright 2016 Elsevier B.V.AcknowledgementsThis work was funded by the New Zealand Ministry for Primary Industries (MPI) project ANT2014-02 "Establishing a Marine Ecosystem and Monitoring Programme for the Ross Sea Region" and MBIE project C01X1226 Ross Sea Climate and Ecosystems. We thank the members of the New Zealand Antarctic Fisheries Working Group for helpful discussions and input into this paper, and Steve Parker (NIWA) for help with CCAMLR data. All penguin survey, capture and handling for this study were approved under permits approved and issued by New Zealand's Ministry of Foreign Affairs and Trade under the Antarctic (Environmental Protection) Act 1994 and Landcare Research's Animal Ethics Committee 2005 and 2010 (0509/01 and 10/09/01). Fish analysed for metabolisable energy content were sampled by scientific bottom trawl on the New Zealand IPY-CAML (International Polar Year, Census of Antarctic Marine Life) voyage TAN0802, under Antarctic Marine Living Resources Act 1981, Permit number: AMLR 07/005/Tangaroa/ZMFR.
1st AuthorPinkerton, M.AuthorPinkerton, M.Lyver, P.Stevens, D.Forman, J.Eisert, R.Mormede, S.Year2016JournalEcological ModellingVolume337Pages262-271DOI10.1016/j.ecolmodel.2016.07.007URLhttps://www.scopus.com/inward/recor.....89a7110f772ab9ed5d7930a55KeywordsFisheries, CCAMLREcosystem approach to fisheriesNichePredation releaseSouthern oceanTrophic overlap, Birds, Spheniscidae, rank3Author KeywordsCCAMLREcosystem approach to fisheriesNichePredation releaseSouthern OceanTrophic overlap
TypeArticleCitationPinkerton, M., Lyver, P., Stevens, D., Forman, J., Eisert, R. and Mormede, S. (2016). Increases in Adelie penguins in the Ross Sea: Could the fishery for Antarctic toothfish be responsible? Ecological Modelling, 337: 262-271
Antarctica NZ (29th Nov 2018). Increases in Adelie penguins in the Ross Sea: Could the fish . In Website Antarctica NZ. Retrieved 5th Mar 2021 06:58, from https://adam.antarcticanz.govt.nz/nodes/view/63718