A Bayesian state-space model for mixed-stock migrations, with application to Northeast Atlantic mackerel Scomber scombrus

  • CL Cunningham 1 Department of Environmental Science and Technology, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BP, UK; current address: Marine Resource Assessment and Management Group, Department of Mathematics and Applied Ma
  • DG Reid FRS Marine Laboratory Aberdeen, PO Box 101, Victoria Road, Aberdeen, AB11 9DB, UK
  • MK McAllister Division of Biology, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BP, UK
  • GP Kirkwood&#8224 Division of Biology, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BP, UK
  • CD Darby Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK

Abstract

Management of fisheries that exploit mixed-stock populations relies on assumptions made concerning stock structure and mixing in different areas. To address the problems of accounting for uncertainty when formulating scientific advice for the management of highly migratory fish stocks, management decisions need to be based upon assessment models that represent plausible alternative hypotheses for stock structure and migration patterns of the exploited populations. We present a multi-stock, multi-fleet, multi-area, seasonally structured Bayesian state-space model in which different stocks spawn in spatially different areas and the mixing of these stocks is explicitly accounted for in the absence of sufficient tagging data with which to estimate migration rates. The model is applied to the Northeast Atlantic mackerel Scomber scombrus population, accounting for the annual spawning-feeding-overwintering migration patterns of the three spawning components, together with uncertainty in the extent to which the southern component migrates north to feed and overwinter, and consequently the extent to which it mixes with the other components and is subject to exploitation. The model allows the effect of exploitation on the individual components to be assessed, and the results suggest that the fishing mortality of southern spawning adults was insensitive to the extent to which they migrated north.

Keywords: Bayesian state-space model, mackerel, migration, mixed stocks, uncertainty

African Journal of Marine Science 2007, 29(3): 347–367
Published
2008-02-07
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X