S. C. Swan, J. D. M. Gordon, and T. Shimmield

Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Argyll, PA37 1QA, Scotland, UK

Source - Journal of Northwest Atlantic Fishery Science, Volume 31: 221-231
ISSN-0250-6408

Swan, S.C. Gordon, J.D.M., and Shimmield, T. 2003. Preliminary Investigations on the Uses of Otolith Microchemistry for Stock Discrimination of the Deep-water Black Scabbardfish (Aphanopus carbo) in the Northeast Atlantic. J. Northw. Atl. Fish. Sci., 31: 221-231. https://doi.org/10.2960/J.v31.a17

Abstract 

The black scabbardfish (Aphanopus carbo: family Trichiuridae) is widely distributed in the North Atlantic at depths between about 700 and 1 000 m. There is a long-established longline fishery off the island of Madeira, and another that began off mainland Portugal in 1983. It is an important species in the landings from the mixed bottom trawl fishery that developed in the Rockall Trough in the 1990s. The stock composition of this species is unknown, as are the eggs, larvae and smallest juveniles. Length composition and reproductive maturity vary between areas and these were among the criteria that led the ICES Deep-water Study Group to carry out preliminary assessments on tentative southern and northern stocks. An objective of the BASBLACK Project (EC DG Fisheries 97/0084) was to investigate stock discrimination in this species. The hypothesis to be tested was that there is one stock of black scabbardfish, which has a main spawning area in the south and a sub-adult feeding area in the north. One method used was otolith microchemistry and this paper describes the methodology and some of the results. The elemental composition of the otoliths was determined using solution-based ICP-MS. The method used to minimize suppression or enhancement effects of the otolith matrix is described. Multivariate analysis was used to compare the results between areas, after taking into account possible differences in element concentration associated with fish length. Although the results are inconclusive, they suggest that this could be a useful technique for this species.

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Language - English
Publisher - Northwest Atlantic Fisheries Organization (NAFO), Dartmouth, N.S., Canada
Publication Date - 2003
Publication Type - Journal Article
Descriptors - Aphanopus carbo, ICP-MS, microchemistry, otolith, stock identification

Citation: Swan, S.C. Gordon, J.D.M., and Shimmield, T. 2003. Preliminary Investigations on the Uses of Otolith Microchemistry for Stock Discrimination of the Deep-water Black Scabbardfish (Aphanopus carbo) in the Northeast Atlantic. J. Northw. Atl. Fish. Sci., 31: 221-231. https://doi.org/10.2960/J.v31.a17