Assessment of the East Greenland-Iceland fin whale population using a four-area model


Show simple item record Branch, Trevor A Butterworth, Doug S 2016-03-09T06:53:44Z 2016-03-09T06:53:44Z 2006
dc.identifier.citation Branch, T. A., & Butterworth, D. S. (2006). Assessment of the East Greenland-Iceland fin whale population using a four-area model. In Joint NAMMCO/IWC Scientific Workshop on the catch history, stock structure and abundance of North Atlantic fin whales. en_ZA
dc.description.abstract The East Greenland-Iceland (EGI) fin whale population is modeled as four subpopulations with movement between the following areas: East Greenland (area 1), West Iceland (area 2), East Iceland (area 3) and the Far East (area 4). The model is sex- and age-structured, and is fitted to CPUE, sightings survey abundance, and mark-recapture data using both maximum likelihood and Bayesian approaches. Movement parameters are not differentiated by sex since the inclusion of sex-specific movement parameters did not improve the AIC. For the base case assessment scenario, best fits to the data were obtained when West Iceland and East Iceland are effectively fully mixed with a low level of interchange with East Greenland and little interchange with the Far East region. For the base case and all sensitivity tests, the overall recruited population is increasing and above 74% (base case 84%) of pre-exploitation abundance (K), and subpopulations in all areas are above 68% (base case 78%) of the individual K values. MSYR for the recruited population is 0.020 for the base case and 0.014 to 0.036 for the sensitivity tests. Projections for annual catches of 0, 100, and 200 whales taken from West Iceland indicate that only the last would result in abundance decreases compared to current levels. Under catch levels of 200 whales the probability of the total EGI population falling below 60% of pre-exploitation levels within the next 30 years was 5.7%, 7.3% and 11.5% for the 1+, recruited and mature components of the population, although there was a 51% probability of this occurring for the West Iceland mature component. en_ZA
dc.language eng en_ZA
dc.publisher International Whaling Commission
dc.subject East Greenland-Iceland fin whale en_ZA
dc.subject fin whale population en_ZA
dc.subject four-area model en_ZA
dc.title Assessment of the East Greenland-Iceland fin whale population using a four-area model en_ZA
dc.type Working Paper en_ZA 2016-03-08T09:29:41Z
uct.type.publication Research en_ZA
uct.type.resource Research paper en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Marine Resource Assessment and Management Group en_ZA
uct.type.filetype Text
uct.type.filetype Image

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