Description

This indicator measures the percentage of stocks for which exploitation is at or below the level which would be expected to lead to maximum sustainable yield.  

Source

The data for this indicator are sourced from the relevant stock assessments and advice from the International Council for the Exploration of the Seas and Marine Scotland, and the relevant stocks are selected (on the basis of landed value) from Marine Scotland’s Sea Fisheries Statistics, which can be found at the Scottish Government website.

Definitions

Maximum sustainable yield (MSY): is the largest catch that can be captured from a fish stock under existing environmental conditions and can be sustained over time.  It represents the level of fishing at which a fish stock is able to continue replenishing itself at the maximum rate.  In some cases, MSY is provided as a range to reflect significant uncertainty in its estimation. 

Commercial fish stocks: fish stocks for which harvesting takes place in large quantities and that are marketed for human consumption or industrial uses.

Fishing mortality: the loss of fish from a stock due to death resulting from fishing activity or other natural causes.

Criteria for Change

The target for the indicator is to increase the share of commercial stocks where fishing mortality is below relevant MSY reference points.  A value of the indicator that is below 100% indicates that there are stocks where mortality is above sustainability thresholds.  A fall in the value of the indicator would suggests an increase in the number of commercial fish stocks with mortality levels above sustainability levels.  This indicates increased threat to the long term sustainability of commercial stocks.