Terms of Reference

Pre-COSEWIC Assessment for American Plaice

Zonal Peer Review – Newfoundland and Labrador, Maritimes, Gulf, Quebec, and Central and Arctic Regions

October 22-24, 2019
St. John’s, NL

Chairperson: Karen Dwyer

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 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).

Fisheries and Oceans Canada (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.

American Plaice (Hippoglossoides platessoides) was listed on COSEWIC’s 2018 Call for Bids to produce a new status report.

American Plaice (NL population) was originally assessed as Threatened in 2009 (COSEWIC 2009) due to an approximately 96% decline in abundance over a 47 year time series (about three generations). This population occurs from the southwestern corner of Newfoundland, eastward north of the Laurentian Channel to the southern limit of the Grand Bank and northward to Hudson Strait. While overfishing was considered the cause of the decline, natural mortality also increased in the 1990s when the largest part of the decline occurred.

American Plaice (Maritime population) was originally assessed as Threatened in 2009 (COSEWIC 2009) due to a decline in abundance of mature individuals of 86% in the Gulf of St. Lawrence, and 67% on the Scotian Shelf over a 36 year time series (about 2.25 generations). This population occurs on Georges Bank, in the Bay of Fundy, on the Scotian Shelf and in the Gulf of St. Lawrence. While overfishing was considered the cause of the decline, natural mortality also increased in the 1990s when the largest part of the decline occurred.

Objective

The overall objective of this meeting is to peer-review DFO existing information relevant to the COSEWIC status assessment for American Plaice 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. Publications 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
   • Growth parameters: age and/or length at maturity, maximum age and/or length
   • Total and natural mortality rates and recruitment rates (if data are available)
   • Fecundity
   • Generation time
   • Early life history patterns
   • Specialised niche or habitat requirements
2. Review of designatable units

   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, will be reviewed. Information on morphology, meristics, genetics and distribution will be considered and discussed.

3. Review the COSEWIC criteria for the species in Canada as a whole, and for each designatable units identified, if any.

   COSEWIC Criterion – 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.

COSEWIC Criterion – Small Distribution and Decline or Fluctuation: for the species in Canada as a whole, and for designatable units identified, using information in the most recent assessments:

1. Summarise the current extent of occurrence (in km²) in Canadian waters
2. Summarise the current area of occupancy (in km²) in Canadian waters
3. Summarise changes in extent of occurrence and area of occupancy over as long a time as possible, and in particular, over the past three generations.
4. Summarise any evidence that there have been changes in the degree of fragmentation of the overall population, or a reduction in the number of meta-population units.
5. Summarise the proportion of the population that resides in Canadian waters, migration patterns (if any), and known breeding areas.

COSEWIC Criterion – Small Total Population Size and Decline and Very Small and Restricted: for the species in Canada as a whole, and for designatable units identified, using information in the most recent assessments:

1. Tabulate the best scientific estimates of the number of mature individuals;
2. If there are likely to be fewer than 10,000 mature individuals, summarize trends in numbers of mature individuals over the past 10 years or three generations, and, to the extent possible, causes for the trends.

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

For transboundary stocks, summarize 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. 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.

3. 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 Recovery Potential Assessment 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

List and describe threats to the species considering:

• Threats need to pose serious or irreversible damage to the species. It is important to determine the magnitude (severity), extent (spatial), frequency (temporal) and causal certainty of each threat.
• Naturally limiting factors, such as aging, disease and/or predation that limit the distribution and/or abundance of a species are not normally considered threats unless they are altered by human activity or may pose a threat to a critically small or isolated population.
• Distinction should be made between general threats (e.g. agriculture) and specific threats (e.g. siltation from tile drains), which are caused by general activities.
• The causal certainty of each threat must be assessed and explicitly stated as threats identified may be based on hypothesis testing (lab or field), observation, expert opinion or speculation.


7. Manipulated Populations

An increasing number of wildlife species have seen their distribution or genetic make-up manipulated by humans, deliberately or accidentally. COSEWIC has developed guidelines to help determine the eligibility of populations for inclusion in wildlife species status assessments. Information available to DFO should be provided to facilitate such determination.

8. 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.

Expected Publications

• Proceedings
• Research Document

Expected Participation

• DFO: Science, Resource Management and SARA program
• COSEWIC sub-committee chairs
• Industry
• Province of NL

References

COSEWIC. 2009. COSEWIC assessment and status report on the American Plaice Hippoglossoides platessoides, Maritime population, Newfoundland and Labrador population and Arctic population, in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. x + 74 pp

DFO 2008. Proceedings of the Review of DFO Science Information for American plaice (Hippoglossoides platessoides) Relevant to Status Assessment by COSEWIC. DFO Can. Sci. Advis. Sec. Proceed. Ser. 2007/042.