Species Profile

Longspine Thornyhead

Scientific Name: Sebastolobus altivelis
Taxonomy Group: Fishes
Range: Pacific Ocean
Last COSEWIC Assessment: April 2007
Last COSEWIC Designation: Special Concern
SARA Status: Schedule 1, Special Concern


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Quick Links: | Description | Habitat | Biology | Threats | Protection | National Recovery Program | Documents

Image of Longspine Thornyhead

Description

Longspine thornyhead, a rockfish species belonging to the scorpionfish family, is a slow growing fish that is adapted for survival in deep waters where oxygen concentrations are minimal and water pressure is high. In Canada’s Pacific waters, longspine thornyheads dominate the fish species that live in deep benthic waters (> 800 metres below the surface), and likely play a significant ecological role within this environment. This species has a reddish body and some black on its fins, grows to 35 cm in length, and features large eyes and strong, sharp head spines.

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Distribution and Population

Longspine thornyhead lives in the Pacific Ocean where it ranges from the southern tip of Baja California in Mexico up to the Aleutian Islands of Alaska, at depths from 370 m to 1600 m. In British Columbia this species occurs along the continental slope at depths between 500 and 1,600 m. The predominant population group can be found in DFO fisheries management region WCVI (West Coast Vancouver Island), with two smaller observed groupings in the Tidemarks and Rennell regions further north. Although the absolute population level remains unknown, approximately 6,500 t of longspine thornyhead were captured from Canadian waters during the period 1996-2005.

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Habitat

The species prefers soft sand or mud bottoms in deep-water environments characterized by low productivity (slow growth), high pressure, and reduced oxygen concentrations. At these depths, where few species can survive, there is limited food available. Deep-water longspine thornyheads have adapted to this environment with extremely slow metabolisms and sedentary natures that allow them to wait an average of 130 to 180 days between feedings.

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Biology

In spring, females release 20,000 to 450,000 fertilized eggs embedded in a gelatinous mass that floats to the surface. Here, the eggs hatch and the larvae and early stage juveniles remain in the upper 200 m of water for 6 months. As the juveniles mature they go progressively deeper, and generally remain at depths around 600 m for one year. Eventually, young fish settle directly into adult habitat at 600-1,200 m. Juveniles eat krill; adults target brittle stars and other species found on the ocean bottom. Larger longspine thornyheads regularly prey upon smaller ones. Longspine thornyheads stop growing at a length of about 30 cm and an estimated age of 25 to 45 years. It is not yet known how long longspine thornyheads can live, although estimates range from 45 to 70 years.

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Threats

The primary threat to the population stems from overfishing a deep-water species that occupies a low-productivity environment. Longspine thornyheads caught in Canada are typically exported to Japan where they are considered a delicacy. Since the beginning of the targeted commercial fishery in 1996 there has been a substantial decline in the commercial catch per unit effort of over 50% in 8 years.

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Protection

Federal Protection

More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Longspine thornyhead receives protection under the Fisheries Act and total allowable catches broken down by area and fleet are in place for longspine thornyhead. Fisheries management has closed the Flamingo region (west coast of Moresby Island) to all directed trawling on longspine thornyhead. There is also no trawling activity in the region known as Triangle due to the steepness and roughness of the bottom topography. As well, commercial trawlers do not usually fish at depths greater than 1,200 m, while longspine thornyheads were found to exist in waters as deep as 1,600 m (from 1996-2005).

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.

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Documents

PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

8 record(s) found.

COSEWIC Status Reports

COSEWIC Assessments

Response Statements

  • Response Statement - Longspine Thornyhead (2007)

    This slow growing rockfish has adapted to survive in deep waters where oxygen concentrations are minimal and productivity is low. Since the beginning of the fishery in the mid-1990s there has been an estimated decline in commercial catch per unit effort of over 50% in 8 years. Fishing is the primary and probably sole cause of this decline. While the fishery is managed by catch limits, and there is good monitoring of fishing activities, there is no management strategy in place that assures catches will be adjusted in response to abundance changes. The substantial decline in abundance indices over a short period taken together with the very conservative life history characteristics are cause for concern but commercial catch per unit effort may not reflect abundance changes accurately and there is potential for rescue from adjoining populations in the USA.

Action Plans

  • Multi-species Action Plan for Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site (2016)

    The Multi-species Action Plan for Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site meets the requirements for an action plan set out in the Species at Risk Act (SARA (s.47)) for species requiring an action plan that occur inside the boundary of the site. This action plan will be updated to more comprehensively include measures to conserve and recover the marine species at risk once the first integrated Land, Sea, People management plan for Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve & Haida Heritage Site (hereafter called Gwaii Haanas) is complete. Measures described in this plan will also provide benefits for other species of conservation concern that regularly occur in Gwaii Haanas.

Management Plans

  • Management Plan for the Rougheye/Blackspotted Rockfish Complex (Sebastes Aleutianus and S. Melanostictus) and Longspine Thornyhead (Sebastolobus Altivelis) in Canada (2012)

    The Rougheye/Blackspotted Rockfish complex comprises two species, Rougheye Rockfish (Sebastes aleutianus) and Blackspotted Rockfish (Sebastes melanostictus). Both species belong to the family Scorpaenidae, and are possibly among the longest lived fish species on earth. In Alaska, scientists aged one specimen to 205 years. These species appear red with dark or dusky blotches of pigment in the back dorsal region, and generally do not exceed 80 cm in size. The two species have similar appearances with slight variations in colour. The complex occurs in the Pacific Ocean, with a range that extends from the northwestern Pacific to British Columbia and southern California. The relative distribution and abundance of these two species in Canadian waters is unknown.

Orders

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2007 (2007)

    2007 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.