Pre-COSEWIC Assessment of Barndoor Skate

Zonal Peer Review Meeting

BIO, Halifax, NS
November 19-20, 2008

Chair: Tana Worcester

DRAFT TERMS OF REFERENCE

Context 

The implementation of the Species at Risk Act (SARA) begins with an assessment of a species’ risk of extinction by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). COSEWIC is a non-government scientific advisory body that was established to perform species assessments as the scientific foundation for listing under SARA. An assessment by COSEWIC initiates the regulatory process whereby the competent Minister must decide whether or not to accept COSEWIC’s assessment and add a species to Schedule 1 of SARA, which would result in legal protection for the species. DFO, as the primary generator and archivist of information on marine aquatic species and some freshwater aquatic species, is to provide COSEWIC with the best information available to ensure that an accurate assessment of the status of a species can be undertaken.

Barndoor Skate (Dipturus laevis) was listed on COSEWIC’s Winter 2008 Call for Bids to produce a status report, with the following justification for inclusion on the priority list:

1. Taxonomic level: Species. No evidence for DUs
2. Portion of Global Range in Canada:
3. Existing Global Conservation Status: IUCN Red List: EN (2003). Listing under US ESA declined (2002) but remains on candidate list.
4. Canadian Population Size and Trends: Declined more than 90% in Canadian trawl survey catches 1950s to 1990s. Comparable declines in US surveys although some increase recently observed.
5. Threats: Principal threat is fishery bycatch. One of the largest skates in Canadian waters.
6. Small Extent of Occurrence or Area of Occupancy: Not applicable.
7. Limiting Biological Factors: Large maximum width (150 cm), late maturity and low fecundity.

Objectives

The overall objective of this meeting is to peer-review DFO information relevant to the COSEWIC status assessment for barndoor skate in Canadian waters, considering data related to the status and trends of, and threats to this species inside and outside of Canadian waters, and the strengths and limitations of the information. This information will be available to COSEWIC, the authors of the status report, and the chairs of the COSEWIC Species Specialist Subcommittee.

Specifically, DFO information relevant to the following will be reviewed to the extent possible:

1. Life-History Characteristics
   • Growth parameters: age and/or length at maturity, maximum age, and/or length.
   • Total and natural mortality rates and recruitment rates.
   • Fecundity
   • Generation time
   • Specialised habitat requirements
     
      
2. Population Structure
   • Available information on population differentiation, which could support a COSEWIC decision of which populations below the species’ level would be suitable for assessment and designation.
     
      
3. Status and Trends
   • Overall trends in population size (both number of mature individuals and total numbers in the population) over as long a period as possible and in particular for the past three generations (taken as mean age of parents).
   • Threats to abundance, including the degree to which the causes of declines (if any) are understood and evidence that declines (if any) are a result of natural variability, habitat loss, fishing, or other human activity.
   • Where declines have occurred over the past three generations, evidence that the declines have ceased, are reversible, and the likely time scales for reversibility.
     
      
4. Habitat Characterization

   Preliminary scoping of a species’ habitat requirements is needed for the COSEWIC assessment, with full identification and quantification occurring at the recovery potential assessment (RPA) stage. This includes describing, to the extent possible:

   • The functional properties that a species’ aquatic habitat must have to allow successful completion of all life-history stages.
   • The spatial extent of the areas that are likely to have functional properties.
   • The activities most likely to threaten the functional properties, including the extent and consequences of those activities.
   • Research or analysis necessary to provide sufficient information to an RPA (if needed).
   • Residence requirements (where applicable)

Products

CSAS Proceedings (record of discussion)
CSAS Research Document (technical detail)

Participants

DFO Science: Maritimes, Newfoundland, Gulf regions, and NHQ, Ottawa
DFO Fisheries and Aquaculture Management
DFO Species at Risk Program
COSEWIC
Provincial Representatives
Aboriginal communities
Academics
Other invited external experts as deemed necessary