Slope Rockfish - Thornyheads

Longspine thornyheads (Sebastolobus altivelis) and shortspine thornyheads (S. alascanus) are increasingly important commercial species since the early 1980s in the British Columbia trawl fishery. The largest catches are taken in deep waters off the southwest coast of Vancouver Island. The two species overlap in distribution and have similar appearances. Unlike many other rockfish species, thornyheads are not found in aggregated schools, but instead exhibit a more uniform distribution over soft sediments. They are often found near rocks or other high relief structures.

Longspine thornyheads occur from the southern tip of Baja California to the Aleutian Islands at depths of 370 to 1600 m. Shortspine thornyheads are found from northern Baja to the Bering Sea, and as far as the Commander Islands, north of Japan, at depths of 90 to 1460 m. Shortspine thornyheads migrate into deeper water as they increase in size, but this behaviour has not been observed for longspines.

Graphic

Longspine thornyhead (Sebastolobus altivelis) and Shortspine thornyhead (Sebastolobus alascanus)

Publications

Below are selected publications relating to the Thornyhead program. For more information or for a copy of any of these publications, please contact Rowan Haigh.

Schnute, J., Haigh, R., Krishka, B., Sinclair, A., Starr, P. 2004. The British Columbia longspine thornyhead fishery: analysis of survey and commercial data (1996-2003). Can. Sci. Ad. Sec. Res. Doc. 2004/59.Complete Document (PDF).

Haigh, R. and J.T. Schnute. 2003. The longspine thornyhead fishery along the west coast of Vancouver Island, British Columbia, Canada: portrait of a developing fishery. North American Journal of Fisheries Management. 23: 120-140. Complete Document (PDF).

Jacobson, L.D., and R.D. Vetter. 1996. Bathymetric demography and niche separation of thornyhead rockfish: Sebastolobus alascanus and Sebastolobus altivelis. Canadian Journal of Fisheries and Aquatic Sciences 53:600-609.

Starr, P.J., B.A. Krishka, and E. M. Choromanski. 2002. Trawl survey for thornyhead biomass estimation off the west coast of Vancouver Island, September 15 to October 2, 2001. Canadian Technical Report of Fisheries and Aquatic Sciences 2421, Nanaimo, British Columbia.

Starr, P.J. 2001. Assessment of the Canadian longspine thornyhead (Sebastolobus altivelis) for 2001. Can. Sci. Ad. Sec. Res. Doc. 2001/136. 57 p.Complete Document (PDF).

Looking for more information?

For more information about thornyheads please see the Stock Status Report (*.pdf file).

For more information about ongoing work on thornyheads at the Pacific Biological Station, please contact Dr. Jon Schnute. For information about groundfish fisheries management or the stock assessment review process in the Pacific Region, please visit the Groundfish Management Unit homepage.