COSEWIC Assessment and Update Status Report on the Lake Sturgeon Acipenser fulvescens in Canada Western Hudson Bay populations – ENDANGERED Saskatchewan River populations – ENDANGERED Nelson River populations – ENDANGERED Red-Assiniboine Rivers-Lake Winnipeg populations – ENDANGERED Winnipeg River-English River populations – ENDANGERED Lake of the Woods-Rainy River populations – SPECIAL CONCERN Southern Hudson Bay-James Bay populations – SPECIAL CONCERN Great Lakes-Upper St. Lawrence populations – THREATENED 2006 COSEWIC COSEPAC COMMITTEE ON THE STATUS OF COMITÉ SUR LA SITUATION DES ENDANGERED WILDLIFE ESPÈCES EN PÉRIL IN CANADA AU CANADA COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows: COSEWIC 2006. COSEWIC assessment and update status report on the lake sturgeon Acipenser fulvescens in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xi + 107 pp. (www.sararegistry.gc.ca/status/status_e.cfm). Previous report: Houston, J.J.P. 1986. COSEWIC status report on the lake sturgeon Acipenser fulvescens in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 1-32 pp. Production note: COSEWIC would like to acknowledge T.A. Dick, R.R. Campbell, N.E. Mandrak, B. Cudmore, J.D. Reist, J. Rice, P. Bentzen and P. Dumont for writing the status report on the Lake Sturgeon Acipenser fulvescens in Canada. This report was first initiated by T.A. Dick, and received funding from the Natural Sciences and Engineering Research Council of Canada, Manitoba Hydro, Fisheries and Oceans Canada (Winnipeg), Environment Canada, Tembec Paper Co. (Pine Falls), Manitoba Model Forest, and Manitoba Conservation. The COSEWIC report review was initially overseen by Dr. Robert Campbell, and later by Dr. Claude Renaud, both Co-chairs of the Freshwater Fishes Species Specialist Subcommittee, with input from members of COSEWIC. The status report to support the May 2005 COSEWIC re-assessments of the Lake Sturgeon(Acipenser fulvescens) (Western populations, Lake of the Woods- Rainy River populations, Southern Hudson Bay-James Bay populations,Great Lakes-Upper St. Lawrence populations) was not made available following the 2005 assessment. In November 2006, COSEWIC reassessed again the Lake Sturgeon(Acipenser fulvescens) (Western Hudson Bay populations, Saskatchewan River populations, Nelson River populations, Red-Assiniboine Rivers-Lake Winnipeg populations, Winnipeg River-English River populations, Lake of the Woods-Rainy River populations,Southern Hudson Bay- James Bay populations, Great Lakes-Upper St. Lawrence populations). The status report was then finalized following the COSEWIC 2006 reassessment. For additional copies contact: COSEWIC Secretariat c/o Canadian Wildlife Service Environment Canada Ottawa, ON K1A 0H3 Tel.: 819-953-3215 Fax: 819-994-3684 E-mail: COSEWIC/[email protected] http://www.cosewic.gc.ca Ếgalement disponible en français sous le titre Évaluation et Rapport de situation du COSEPAC sur le esturgeon jaune (Acipenser fulvescens) au Canada – Mise à jour. Cover illustration: Lake sturgeon — Drawing by Anker Odum, from Scott and Crossman (1998) used with permission. ©Her Majesty the Queen in Right of Canada 2007 Catalogue No. CW69-14/484-2007E-PDF ISBN. 978-0-662-45964-4 Recycled paper COSEWIC Assessment Summary Assessment Summary – November 2006 Common name Lake sturgeon – Western Hudson Bay populations Scientific name Acipenser fulvescens (DU1) Status Endangered Reason for designation A precipitous > 98% decline from 1929-1939 has been followed by a slow, steady decline in the Churchill River to the point that records of mature individuals are almost non-existent in the past five years. Historically, overexploitation probably was the primary threat; more recently, dams are probably the most important threat. Occurrence Saskatchewan, Manitoba Status history The species was considered a single unit and designated Not at Risk in April 1986. When the species was split into separate units in May 2005, the "Western populations" unit was designated Endangered. In November 2006, when the Western populations unit was split into five separate populations, the "Western Hudson Bay populations" unit was designated Endangered. Last assessment based on an update status report. Assessment Summary – November 2006 Common name Lake sturgeon – Saskatchewan River populations Scientific name Acipenser fulvescens (DU2) Status Endangered Reason for designation Seventy-six of 111 historic sites in Saskatchewan and Alberta have been lost and there has been an 80% decline reported in the Cumberland House area from 1960-2001. A 50% decline from 1998 to 2003 has also been reported in the lower Saskatchewan River from Cumberland House to The Pas in Manitoba. Occurrence Alberta, Saskatchewan, Manitoba Status history The species was considered a single unit and designated Not at Risk in April 1986. When the species was split into separate units in May 2005, the "Western populations" unit was designated Endangered. In November 2006, when the Western populations unit was split into five separate populations, the "Saskatchewan River populations" unit was designated Endangered. Last assessment based on an update status report. iii Assessment Summary – November 2006 Common name Lake sturgeon – Nelson River populations Scientific name Acipenser fulvescens (DU3) Status Endangered Reason for designation Portions of this designatable unit sustained large commercial fisheries from the early to mid-1900s, during which time there were dramatic declines in landings. More recently, a fishery at Sipiwesk Lake exhibited an 80-90% decline in landings from 1987-2000; and groups of 5-6 spawning fish were observed in the Landing River in 1990 compared to 100s observed several decades ago. Historically, overexploitation probably was the primary threat; more recently, dams probably are the most important threat. Occurrence Manitoba Status history The species was considered a single unit and designated Not at Risk in April 1986. When the species was split into separate units in May 2005, the "Western populations" unit was designated Endangered. In November 2006, when the Western populations unit was split into five separate populations, the "Nelson River populations" unit was designated Endangered. Last assessment based on an update status report. Assessment Summary – November 2006 Common name Lake sturgeon – Red-Assiniboine Rivers – Lake Winnipeg populations Scientific name Acipenser fulvescens (DU4) Status Endangered Reason for designation A very large commercial fishery existed between the late 1800s and early 1900s. Since then (i.e. in the last 3-5 generations), the species has virtually disappeared from the Red-Assiniboine River and Lake Winnipeg. This was primarily the result of overfishing, although dams probably also affect remnant populations. Occurrence Saskatchewan, Manitoba and Ontario Status history The species was considered a single unit and designated Not at Risk in April 1986. When the species was split into separate units in May 2005, the "Western populations" unit was designated Endangered. In November 2006, when the Western populations unit was split into five separate populations, the "Red-Assiniboine rivers – Lake Winnipeg populations" unit was designated Endangered. Last assessment based on an update status report. iv Assessment Summary – November 2006 Common name Lake sturgeon – Winnipeg River – English River populations Scientific name Acipenser fulvescens (DU5) Status Endangered Reason for designation Historically, populations in this designatable unit supported a large commercial fishery. However, there are limited historical and recent data. The limited recent data available show that populations are declining in the Winnipeg River above Seven Sisters Dam, and essentially have disappeared below the dam. Historically, overexploitation probably was the primary threat; now dams and poaching probably are the most important threats. Occurrence Ontario, Manitoba Status history The species was considered a single unit and designated Not at Risk in April 1986. When the species was split into separate units in May 2005, the "Western populations" unit was designated Endangered. In November 2006, when the Western populations unit was split into five separate populations, the "Winnipeg River – English River populations" unit was designated Endangered. Last assessment based on an update status report. Assessment Summary – November 2006 Common name Lake sturgeon – Lake of the Woods – Rainy River populations Scientific name Acipenser fulvescens (DU6) Status Special Concern Reason for designation Historically, populations in this designatable unit supported a substantial commercial fishery. Although this led to a severe decline, recovery has been sustained since 1970. Dams have not impeded access to important stretches of suitable habitat, but do restrict immigration from the adjacent Winnipeg River. Occurrence Ontario Status history The species was considered a single unit and designated Not at Risk in April 1986. When the species was split into separate units in May 2005, the "Lake of the Woods – Rainy river populations" unit was designated Special Concern. Status re-examined and confirmed in November 2006. Last assessment based on an update status report. v Assessment Summary – November 2006 Common name Lake sturgeon – Southern Hudson Bay – James Bay populations Scientific name Acipenser fulvescens (DU7) Status Special Concern Reason