Population structure of beaked redfish, Sebastes mentella: evidence of divergence associated with different habitats

Abstract

Cadrin, S. X., Bernreuther, M., Daníelsdóttir, A. K., Hjörleifsson, E., Johansen, T., Kerr, L., Kristinsson, K., Mariani, S., Nedreaas, K., Pampoulie, C., Planque, B., Reinert, J., Saborido-Rey, F., Sigurðsson, T., and Stransky, C. 2010. Population structure of beaked redfish, Sebastes mentella: evidence of divergence associated with different habitats. – ICES Journal of Marine Science, 67: 1617–1630. Throughout their range, Sebastes spp. are adapted to a diversity of ecological niches, with overlapping spatial distributions of different species that have little or no morphological differences. Divergence of behavioural groups into depth-defined adult habitats has led to reproductive isolation, adaptive radiation, and speciation in the genus Sebastes. Recent genetic research, supported by life-history information, indicates four biological stocks of Sebastes mentella in the Irminger Sea and adjacent waters: a western stock, a deep-pelagic stock, a shallow-pelagic stock, and an Iceland slope stock. Congruent differences in fatty acids and parasites suggest that these genetically distinct populations are adapted to disparate trophic habitats in pelagic waters (shallower and deeper than the deep-scattering layer) and in demersal habitats on the continental slope. Morphology of pelagic forms is also more streamlined than demersal forms. Although genetic differences and evidence for reproductive isolation are clear, these populations appear to share common nursery habitats on the Greenland shelf. We propose a redefinition of practical management units near the Irminger Sea based on geographic proxies for biological stocks and minimizing mixed-stock catches according to the spatial patterns of the recent fishery.

Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus)

“…This introduces uncertainty when assigning samples of unknown origin to their parent stock. Combining information from different sources in a holistic approach to stock identification can improve the accuracy of stock discrimination and provide greater insight into stock structure and the mechanisms that underlie it (Begg and Waldman 1999;Cadrin et al 2010;Baldwin et al 2012). Proper integration of the information provided by multiple stock markers requires careful consideration and coordination of sampling strategies (Abaunza et al 2008).…”

Understanding the Size Selectivity of Redfish (Sebastes spp.) in North Atlantic Trawl Codends

“…in the North Atlantic have been collected using diamond mesh codends (e.g. Bohl, 1961;Thorsteinsson et al, 1979;Konstantinov et al, 1982;Gorchinsky et al, 1993;Hickey et al, 1995;Lisovsky et al, 1995;Lisovsky et al, 2006) and have recently been reviewed by an ICES Topic Group (ICES, 2011c). Data are available from the early 1960s and onwards for S. marinus, S. mentella and S. fasciatus (Table 1).…”

“…Most of the available Sebastes selectivity data have been collected by Russian research institutes and are summarized by Lisovsky (2001), Lisovsky et al (1995; and Pavlenko (2009). German and Icelandic data, presented by Bohl (1961) and Thorsteinsson et al, (1979) respectively, are also available in the literature. A study carried out by Hickey et al (1995) in Canada that examined the effect of lastridge ropes on the selectivity properties on redfish for three different mesh size codends completes the list of studies that to our knowledge are available on redfish diamond mesh codend selectivity (Table 1).…”

“…stocks in the North Atlantic evidences close connection between these stocks (Cadrin et al, 2010). Thus, because of the delicate situation of some of these stocks (especially in the Northeast Atlantic) the responsible management authorities are obliged to implement effective measures to maintain or restore stocks to MSY levels (i.e.…”

Otolith geochemistry indicates life-long spatial population structuring in a deep-sea fish, Coryphaenoides rupestris

“…As such, it is hoped that the management process will start to recognize the existence of stock discontinuities in this currently overexploited deep-sea species. Additionally, efforts should be made to improve our perception of stocks that possess an important vertical dimension to their structuring and/or life history (Cadrin et al 2010). …”