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Data Sources and Methods for the Sustainable Fish Harvest Indicator

Methods

The Sustainable Fish Harvest 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.

Stocks are subpopulations of a particular species of fish or other marine animal, for which factors such as growth, recruitment, and natural and fishing mortality are the only significant factors in determining population dynamics. Other factors such as immigration and emigration are considered to be insignificant.

The removal reference is the maximum acceptable removal rate. The removal rate is the ratio of all human-induced removals and total exploitable stock size. The removal reference is adjusted depending on the stock’s abundance and its location in the three stock status zones (i.e. healthy, cautious and critical zones; see the Status of Fish Stocks indicator for more information on stock status). In the cautious zone, the adjustment of the removal reference does not have to follow a linear relationship with stock abundance, but a progressive reduction in removals is required. Managers report whether the harvest rate is above or below the reference level, or if the information is unknown.

The precautionary approach has not been completely implemented for all stocks  and there are many different fisheries management measures in place. These measures depend on the species, area, gear used, seasons, stock assessments, etc. that facilitate the tracking of harvest levels.

In cases where a removal reference has not been determined, allowable harvest rates are determined by Fisheries and Oceans Canada based on science assessments, the condition of the stock, and economic and social considerations. The overall goal is always conservation, responsible and sustainable harvesting practices, and equitable distribution of the resource among user groups.

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. These same groupings are used in the Status of Fish Stocks indicator.