Candidate Species

The Committee On the Status of Endangered Wildlife In Canada (COSEWIC) provides advice on the status of wildlife species in Canada, and assesses the level of risk of extinction for wildlife species based on information on the biological status of the species. These assessments are the basis for the Minister of the Environment's recommendations to the Governor-in-Council for the List of Wildlife Species at Risk. Candidate species are organisms that may be considered for listing as species at risk of extinction by COSEWIC, and are chosen based on expert recommendation, results from ongoing species monitoring efforts in Canada and various international assessment processes.

DFO holds current and historical information pertaining to marine species that can be used to determine whether species are at risk of extinction, and participates in a process with COSEWIC where DFO consolidates and reviews its information relevant to status designation, protection and recovery planning for marine species at risk. This information is compiled and presented at meetings that bring together experts from DFO, COSEWIC and academia. Following review, the information is presented in research documents that are available to the authors of subsequent COSEWIC species Status Reports, to ensure that its assessment is based on the best available information. These DFO reports use methods derived from COSEWIC species assessment criteria. These criteria include:

Determination of the Population "Unit":

A review of the population structure, range, and distribution in the context of "evolutionarily significant units".

Changes in Abundance:

An analysis of trends in population abundance. Several analyses are required:

  • A summary of 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 spawners).
  • Where declines have occurred over the past three generations, a summary of 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.
  • Where declines have occurred over the past three generations, a summary of the evidence that the declines have ceased, are reversible, and likely time scales for reversibility.

Changes in Distribution:

An analysis of trends or changes in the spatial distribution of the population unit. Under this criterion, it is necessary to summarize the:

  • current area of occupancy
  • changes in area of occupancy over as long a time as possible, and in particular, over the past three generations.
  • any evidence that there have been changes in the degree of fragmentation of the overall population, or a reduction in the number of metapopulation units.

Population Size:

An estimation of the total current population size. Estimates include a:

  • Tabulation of the best scientific estimates of the number of mature individuals, and
  • If there are likely to be fewer than 10,000 mature individuals, a summary of trends in numbers of mature individuals over the past 10 years or three generations, and, to the extend possible, causes for the trends.

For more information on candidate species reviews by the SABS SAR group, please see the following publications:

Johnston, T.L. and R.K. Smedbol. 2004. A numeric scoring matrix for use in the rapid assessment of extinction vulnerability of marine fish species in the NAFO regions 4VWX, 5Zc. Can. Tech. Rep. Fish. Aquat. Sci. 2525