Pollock Conservation Cooperative Research Center
2007 Awarded Research Projects
Combining genetics and population dynamics to improve management of Pacific ocean perch (Sebastes alutus)
Anthony Gharrett and Terrance Quinn
Abstract:
Pacific ocean perch (POP) are the most abundant Sebastes rockfish species in Alaskan
waters in both biomass and catch. They are distributed broadly along the Gulf of Alaska (GOA)
and Bering Sea (BS) continental slopes. As for most rockfish species, POP do not mature at an
early age; and they can live to very old ages. Rockfishes are viviparous; after POP larvae are
released they may spend several months in the water column before they settle into more
demersal habitats. An assumption made for many marine species, which have pelagic larvae and
apparently mobile adults, is that their population structures extend over very broad reaches,
possibly including much of the natural range. Recently, genetic studies of POP population
structure have demonstrated that relatively strong divergence occurs between collections that
were sampled at locations spaced about 200 km apart along the GGOAOA and BSBS continental
slopes. The degree of divergence suggests that, although population structure is not defined by
geographic or oceanographic boundaries, the limited net dispersion that occurs in both pelagic
larvae and adults results in restricting the spatial scale of POP production to areas that are related
to the average distance moved between birth and reproduction called neighborhoods. The spatial
scale of neighborhoods (productivity units) is the geographic scale on which management should
focus. We have nearly completed a large scale genetics study of adult POP samples (Palof, thesis
research); and a genetics study of young-of-the-year POP juveniles is in progress (L. Kamin,
thesis research). From those results we will be able to address questions about the extent of
dispersion, and should be able to make preliminary estimates of neighborhood size. The
questions we address here are the effects that harvest patterns exert on production and genetic
structure of POP and, by extension, other species for which limited dispersion results in a
neighborhood model of population structure, and the neighborhoods are much smaller than the
management areas. To evaluate these effects, we will develop quantitative models that include
information about dispersal, population dynamics, and exploitation and test the effects of
different harvesting strategies, which will range from harvesting over the entire management
area to harvests in a few limited areas with in the area.
Back to 2007 PCCRC Funded Projects
2007 PCCRC awards press release
Research projects
Contact PCCRC
Denis Wiesenburg, PCCRC Director
School of Fisheries and Ocean Sciences
University of Alaska Fairbanks
P.O. Box 757220
Fairbanks, AK 99775-7220
Phone: (907) 474-7210
Fax: (907) 474-7204
Email: wiesenburg@sfos.uaf.edu