Present address: Institute of Marine Research, PO Box 1870, Nordnes, N-5817 Bergen, Norway.
The role of environmental conditions and exploitation in determining dynamics of redfish (Sebastes species) in the Northwest Atlantic
Article first published online: 9 DEC 2010
© 2010 Blackwell Publishing Ltd
Volume 20, Issue 1, pages 66–81, January 2011
How to Cite
DEVINE, J. A. and HAEDRICH, R. L. (2011), The role of environmental conditions and exploitation in determining dynamics of redfish (Sebastes species) in the Northwest Atlantic. Fisheries Oceanography, 20: 66–81. doi: 10.1111/j.1365-2419.2010.00566.x
- Issue published online: 9 DEC 2010
- Article first published online: 9 DEC 2010
- Received 22 November 2009 Revised version accepted 13 June 2010
- Northwest Atlantic;
- population dynamics;
- Sebastes fasciatus;
- Sebastes mentella
The six stocks of redfish (Sebastes spp.) in the Northwest Atlantic have been fished for the past 60 years, during which time they have also experienced considerable variability in environmental conditions. Despite their close proximity and with life-history features characteristic of many deep-sea fishes (long-lived, slow-growing, late-maturing, relatively low fecundity), each redfish stock has displayed quite different dynamics. Some have been able to support apparently sustainable fisheries, whereas others have been forced to close. The causes of such differences are unclear. We used dynamic factor analysis to determine the relative impacts of exploitation (days fishing for redfish, days fishing for shrimp, days fished by all fisheries, catch in the redfish fishery, total redfish catch) and environment (North Atlantic Oscillation, surface temperature, salinity, shallow, middle, and deep bottom temperatures) on trends of abundance in each stock over the years 1960–2004. The results showed that a mix of exploitation and environmental variability, with various and different lag times, accounted for observed trends. The Gulf of St. Lawrence stock was affected most by exploitation. Flemish Cap and northern Newfoundland-Labrador stocks were mostly affected by environmental factors with longer time lags than more southerly stocks. We conclude that management of redfish must take into account individual responses to exploitation and environment over the time periods during which such factors operate, often decades or more, as opposed to the usual practice of reviewing only dynamics of the past few years. Deep-sea populations cannot be managed on the same scales as shelf fisheries.