Research Document - 2006/075

Characteristics for Recovery: Beluga Whale

By Lawson, J., M. Hammill, and G. Stenson

Abstract

For listed species, the Species at Risk Act (SARA) requires that the responsible jurisdiction set explicit recovery goals for abundance and distribution. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) does not provide specific criteria that would lead to down- or de-listing although the listing criteria will likely be important in the decision process to down- or de-list the species. Here, we develop a framework that links recovery criteria to a more general management structure employing the Precautionary Approach. We consider the following characteristics when trying to identify criteria for “recovery” for a listed species:

1. Characteristics should be generic to enable application across a number of species.
2. Characteristics for recovery should be based on general life history parameters.
3. Because data are often limited, we need to base the recovery characteristics on one or only a few measures (preferably absolute abundance or some index of abundance) that can be obtained relatively easily.
4. The characteristics must be robust to uncertainty in our measurement parameters, where the effects of variation in these parameters can be examined using simulation models.

The recovery framework was applied to four beluga populations (Eastern Hudson Bay, Cumberland Sound, St. Lawrence Estuary, and Ungava Bay) that have been designated as endangered or threatened by COSEWIC. Given the imprecision of our knowledge of pristine population size, we need to establish a reference point for the population size at and above which we would consider that we have achieved population recovery. Historical population estimates based on reconstructions from catch data provide a metric of pristine population size. At an April 2005 beluga meeting scientists decided that if the listed population grew to a level above 70% of the estimated historical population size then the recovery objective would be deemed to be met. Scientists also examined other metrics and how they related to the following categories: ecological role, historical population, percent of historical population, percent of historic range, status consistent with traditional ecological knowledge, number of mature animals, production, growth rate, population composition, and sex ratio.

In addition to the issue of the population size necessary to be considered “recovered” – and eligible for down- or de-listing – additional important considerations include the length of time it would it take for the required level of population recovery to be achieved (increased risk with longer exposure to adverse factors when at lower abundance levels), and what resources Department of Fisheries and Oceans (DFO) would need to detect this level of population change.

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