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Draft Terms of Reference

Zonal Peer Review Meeting

Pre-COSEWIC Assessment of Atlantic Halibut

15-16 September 2009
BIO, Dartmouth, Nova Scotia

Chair: T. Worcester

Context

The implementation of the federal Species at Risk Act (SARA), proclaimed in June 2003, 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 has been established under Section 14(1) of SARA to perform species assessments which provide the scientific foundation for listing species under SARA.  Therefore, an assessment 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 under the Act.  If the species is already on Schedule 1 of SARA, the Minister may decide to keep the species on the list, reclassify it as per the COSEWIC assessment, or to remove it from the list (Section 27 of SARA).

DFO, as a generator and archivist of information on marine species and some freshwater 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. 

Atlantic halibut was evaluated in COSEWIC’s February 2007 Prioritization Exercise, and later identified in their winter 2008 Call for Bids, with the following justification:

Species:
There is evidence for more than one designatable unit.
Proportion of global range in Canada:
Found in Canada, U.S., Greenland, and Europe. 80% of the North American distribution of Atlantic halibut occurs in Canadian waters.
IUCN Red List or Nature Serve Rank:  
Endangered A1d (1996). Not yet assessed by NatureServe.
Canadian population size and trends:
Species was heavily exploited in the early 1900s, recent abundance probably much lower than historically. Recent declines of 80% on Grand Banks northeast of Newfoundland (since 1960’s), 95% on southern Grand Banks/south coast Newfoundland (since 1980’s), 18% or 58% on Scotian Shelf (depending on survey), 99% on George’s Bank; increasing in Gulf of St. Lawrence.
Threats:
The species never fully recovered from severe overfishing up to the 1940s. A restricted directed fishery exists.
Limiting biological factors:
very large maximum size (2.5 m), late maturity (females 50% mature at 10-12 yrs, 70-115 cm length)

Meeting Objectives

The overall objective of this meeting is to peer-review DFO information relevant to the COSEWIC status assessment for Atlantic halibut 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 species status report, and the co-chairs of the applicable COSEWIC Species Specialist Subcommittee. Output from the peer-review meeting (see below) will be posted on the CSAS website.

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

1)  Life-History Characteristics

2)  Review of Designatable Units

Discussion on the species will consider 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) Review the COSEWIC Criteria for the species in Canada as a whole, and for each designatable units identified (if any), the most relevant for Atlantic Halibut being:

Declining Total Population

  1. Summarize 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).  Additionally, present data on a scale appropriate to the data to clarify the rate of decline.
  2. Identify threats to abundance — where declines have occurred over the past three generations, summarize the degree to which the causes of the declines are understood, and the evidence that the declines are a result of natural variability, habitat loss, fishing, or other human activity.
  3. Where declines have occurred over the past three generations, summarize the evidence that the declines have ceased, are reversible, and the likely time scales for reversibility.

Summarise the options for combining indicators to provide an assessment of status, and the caveats and uncertainties associated with each option.

For transboundary stocks, summarise the status of the population(s) outside of Canadian waters.  State whether rescue from outside populations is likely.

4)  Describe the characteristics or elements of the species habitat to the extent possible, and threats to that habitat

Habitat is defined as “in respect of aquatic species, spawning grounds and nursery, rearing, food supply, migration and any other areas on which aquatic species depend directly or indirectly in order to carry out their life processes, or areas where aquatic species formerly occurred and have the potential to be reintroduced”.

The phrasing of the following guidelines would be adapted to each specific species and some could be dropped on a case-by-case basis if considered biologically irrelevant.  However, these questions should be posed even in cases when relatively little information is expected to be available, to ensure that every effort is made to consolidate whatever knowledge and information does exist on an aquatic species’ habitat requirements, and made available to COSEWIC.

  1. Describe the functional properties that a species’ aquatic habitat must have to allow successful completion of all life history stages.

    In the best cases, the functional properties will include both features of the habitat occupied by the species and the mechanisms by which those habitat features play a role in the survivorship or fecundity of the species. However, in many cases the functional properties cannot be described beyond reporting patterns of distribution observed (or expected) in data sources, and general types of habitat feature known to be present in the area(s) of occurrence and suspected to have functional properties. Information will rarely be equally available for all life history stages of an aquatic species, and even distributional information may be missing for some stages. Science advice needs to be carefully worded in this regard to clearly communicate uncertainties and knowledge gaps.

  2. Provide information on the spatial extent of the areas that are likely to have functional properties.

    Where geo-referenced data on habitat features are readily available, these data could be used to map and roughly quantify the locations and extent of the species’ habitat. Generally however, it should be sufficient to provide narrative information on what is known of the extent of occurrence of the types of habitats identified. Many information sources, including Aboriginal Traditional Knowledge (ATK) and experiential knowledge, may contribute to these efforts.

  3. Identify the activities most likely to threaten the functional properties, and provide information on the extent and consequences of those activities.

    COSEWIC’s operational guidelines require consideration of both the imminence of each identified threat, and the strength of evidence that the threat actually does cause harm to the species or its habitat. The information and advice from the Pre-COSEWIC review should provide whatever information is available on both of those points. In addition, the information and advice should include at least a narrative discussion of the magnitude of impact caused by each identified threat when it does occur.

  4. Recommend research or analysis activities that are necessary

    Usually the work on the other Guidelines will identify many knowledge gaps.

Recommendations made and enacted at this stage in the overall process could result in much more information being available should a RPA be required for the species.

5)  Describe to the extent possible whether the species has a residence as defined by SARA

SARA s. 2(1) defines Residence as “a dwelling-place, such as a den, nest or other similar area or place, that is occupied or habitually occupied by one or more individuals during all or part of their life cycles, including breeding, rearing, staging, wintering, feeding or hibernating.”

6)  Threats

A threat is any activity or process (both natural and anthropogenic) that has caused, is causing, or may cause harm, death, or behavioural changes to a species at risk or the destruction, degradation, and/or impairment of its habitat to the extent that population-level effects occur. Guidance is provided in: Environment Canada, 2007. Draft Guidelines on Identifying and Mitigating Threats to Species at Risk. Species at Risk Act Implementation Guidance.

List and describe threats to the species considering:

7)  Other

Finally, as time allows, review status and trends in other indicators that would be relevant to evaluating the risk of extinction of the species. This includes the likelihood of imminent or continuing decline in the abundance or distribution of the species, or that would otherwise be of value in preparation of COSEWIC Status Reports.

Output of the meeting

The key conclusions/recommendations will address the basis for assessing status of the Canadian Atlantic halibut population(s) to be considered by COSEWIC. The final version of the minutes of the meeting will be part of the CSAS Proceedings series. A CSAS Research document is also expected from the working paper(s) submitted for review.

Participation

Participation is expected from:

Participation may also include:

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