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Data Sources and Methods for the Sustainable Fish Harvest Indicator

4. Methods

The indicator is a simple tabulation of stocks based on whether harvest levels are within Removal reference levels, within other harvest limits, or over harvest limits.

The Removal reference is an approach for determining the maximum acceptable removal rate. In the past, annual harvest levels were set on the basis of scientific and economic information and in consultation with stakeholders. For an increasing number of stocks, a formal precautionary approachFootnote 1 is now being applied. This is a more rigorous, risk-based approach, common across stocks, and includes the use of a Removal reference for assessing whether harvests are sustainable. In this approach, the harvest strategy for a fishery must contain a set of standard components (reference points, harvest decision rules, etc.)

The removal rate is the ratio of all human-induced removals and the total exploitable stock size. The Removal reference is determined when there is sufficient historical data on stock productivity to allow those levels to be estimated analytically. It is adjusted based on the stock's abundance and its location in the three stock status zones defined in federal policy (i.e., Healthy, Cautious and Critical zones; see the Status of Major Fish Stocks indicator for more information on stock status). With this approach, managers report whether the harvest rate is above or below the reference level.

In 2015, 60 stocks (38%) have fully defined Removal references, and a further 18 stocks (11%) have Removal references defined for one or two of the three stock status zones (i.e., Critical, Cautious and Healthy). Marine mammal stocks use Potential Biological Removal indicators as a Removal reference for the purposes of the indicator but, as these are not based strictly on the Precautionary Approach Policy, they are not included in the total number of Removal references reported here. While most of the major stocks have had some components of the precautionary approach implemented (72%), only 21% have had all components fully implemented.

All components of the precautionary approach have not been implemented fully for all stocks and there are many different fisheries management measures in place. These measures depend on the species, area, fishing gear used, seasons, stock assessments, and other factors.

Whether a Removal reference is used or not, allowable harvest rates are determined by Fisheries and Oceans Canada based on scientific assessments, the condition of the stock, and economic and social considerations.

Stock groups used for reporting on this indicator are marine mammals, salmonids, groundfish, large pelagics, small pelagics, crustaceans (crab, lobster and shrimp), molluscs, and others. Each group comprises species with similar life history characteristics. For example, groundfish spend their adult life at or near the bottom of the ocean. The same groupings are used in the Status of Major Fish Stocks indicator.

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