TY - JOUR

T1 - Contrasting life-history traits of two toothfish (Dissostichus spp.) species at their range edge around the South Sandwich Islands

AU - Soeffker, Marta

AU - Hollyman, Philip R.

AU - Collins, Martin A.

AU - Hogg, Oliver T.

AU - Riley, Ainsley

AU - Laptikhovsky, Vladimir

AU - Earl, Timothy

AU - Roberts, Jim

AU - MacLeod, Eleanor

AU - Belchier, Mark

AU - Darby, Chris

PY - 2022/7/1

Y1 - 2022/7/1

N2 - The South Sandwich Islands (SSI), a chain of volcanic islands in the Atlantic sector of the Southern Ocean, are home to two large notothenoid species: the Patagonian toothfish Dissostichus eleginoides and the Antarctic toothfish Dissostichus mawsoni. Both species support valuable fisheries throughout the Southern Ocean under management of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). The SSI region, which is located south of the Southern Antarctic Circumpolar Current Front, has a diverse and distinct biodiversity and it represents a range edge for the distribution of both toothfish species. In this paper we have updated and expanded previous biological analyses with recent data, explored the stock hypotheses and links of these species to other regions, and investigated the role of the SSI archipelago in the life cycles of both toothfish species, where they overlap in their distribution. We conclude that Patagonian toothfish around the SSI are linked to the adjacent South Georgia population, but have some unique characteristics, including faster growth and better somatic condition, possibly reflecting ‘Bergmann's rule’ which states that body size increases with decreasing temperature and increasing latitude. By comparison, the Antarctic toothfish at the SSI appear to be the northern extent of a larger stock connecting further south towards the Antarctic continent. Finally, we consider the relative importance of the SSI in the life cycle of both species, including in the context of climatic changes to this region.

AB - The South Sandwich Islands (SSI), a chain of volcanic islands in the Atlantic sector of the Southern Ocean, are home to two large notothenoid species: the Patagonian toothfish Dissostichus eleginoides and the Antarctic toothfish Dissostichus mawsoni. Both species support valuable fisheries throughout the Southern Ocean under management of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). The SSI region, which is located south of the Southern Antarctic Circumpolar Current Front, has a diverse and distinct biodiversity and it represents a range edge for the distribution of both toothfish species. In this paper we have updated and expanded previous biological analyses with recent data, explored the stock hypotheses and links of these species to other regions, and investigated the role of the SSI archipelago in the life cycles of both toothfish species, where they overlap in their distribution. We conclude that Patagonian toothfish around the SSI are linked to the adjacent South Georgia population, but have some unique characteristics, including faster growth and better somatic condition, possibly reflecting ‘Bergmann's rule’ which states that body size increases with decreasing temperature and increasing latitude. By comparison, the Antarctic toothfish at the SSI appear to be the northern extent of a larger stock connecting further south towards the Antarctic continent. Finally, we consider the relative importance of the SSI in the life cycle of both species, including in the context of climatic changes to this region.

KW - Antarctic toothfish

KW - Dissostichus spp.

KW - Life history

KW - Patagonian toothfish

KW - Range edge distribution

KW - South Sandwich Islands

U2 - 10.1016/j.dsr2.2022.105098

DO - 10.1016/j.dsr2.2022.105098

M3 - Article

VL - 201

JO - Deep-Sea Research Part II: Topical Studies in Oceanography

JF - Deep-Sea Research Part II: Topical Studies in Oceanography

M1 - 105098

ER -