Cusk (Brosme brosme) COSEWIC assessment and status report 2012: chapter 5

Preface

COSEWIC last assessed Cusk as Threatened in 2003. In 2006, following an Allowable Harm Assessment conducted by DFO in 2004 and subsequent consultations with the provinces, Aboriginal peoples, stakeholders and the public, the Governor in Council referred the assessment back to COSEWIC for reconsideration of the Threatened designation. The explanation provided was that significant emphasis was placed on DFO bottom trawl survey data, which may have exaggerated the decline of Cusk. In December 2006, COSEWIC reaffirmed the original assessment without reassessing the species, citing an absence of new information that would lead to a change in the status of this species. Thus, the species was once again considered for listing on Schedule 1 of SARA. In 2007, DFO undertook a Recovery Potential Assessment (RPA) in support of the SARA listing process. The Governor in Council elected not to list the species under SARA (Canada Gazette July 7 2012).

Since the 2003 COSEWIC assessment, there have been a number of advances in our understanding of Cusk biology, population dynamics and threats. Regarding Cusk biology, a 2009 genetics study further supports the existence of one designatable unit in Canada. Data collected on Canadian and US surveys have allowed more informed discussion on maturity and aging processes. Notwithstanding this, the results of a new Canadian aging study are still pending, which has limited the scope of the population analysis. Regarding population dynamics, the commercial and survey time series of abundance discussed in the 2003 COSEWIC assessment are updated to 2010. As well, a number of DFO-industry surveys that commenced in the mid- to late 1990s are also considered. Size composition data from these commercial and survey activities are a further addition in this assessment. In the 2007 RPA, a preliminary population model of Cusk population dynamics was developed and this model was updated in this status report. Regarding threats, two bycatch studies have been conducted since the 2003 assessment that significantly increase our understanding of Cusk sources of mortality.

Overall, this report provides a significant update to the 2003 COSEWIC assessment.

COSEWIC History
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership
COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2012)

Wildlife Species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)
A wildlife species that no longer exists.

Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)
A wildlife species facing imminent extirpation or extinction.

Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)*
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)**
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)***
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.

** Formerly described as “Not In Any Category”, or “No Designation Required.”

*** Formerly described as "Indeterminate" from 1994 to 1999 or "ISIBD" (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.

The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.

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