Scottish Government

Percentage of commercial continental shelf finfish stocks at full reproductive capacity: 1998-2006

Percentage at full reproductive capacity

Healthy fish stocks require a healthy marine environment and if stocks are in poor health the rest of the marine ecosystem may suffer. Therefore the health of commercial fish stocks may be taken as a proxy for the general health of the marine environment.

The health of fish stocks can be assessed by estimating the biomass of the spawning population of each stock ³. For each fish stock the biomass estimate is compared against a reference level and if above that level the stock is considered to be at full reproductive capacity and there is a good probability of stock replenishment. If a fish stock is below full reproductive capacity then it indicates that spawning levels may be insufficient to guarantee stock replenishment. The data shown here relate to 11 commercial continental shelf finfish stocks ⁴ located in waters surrounding Scotland.

The number of finfish stocks monitored that were at full reproductive capacity fell from 6 in 1998 to a low of 2 in 2000. This then rose to 5 finfish stocks between 2001 and 2004, then peaking at 7 in 2005, before returning to 1998 levels in 2006. Of the fish stocks assessed North Sea Sand Eels were said to be at full reproductive capacity in 1998 but not in 2006. The other fish stocks not at full reproductive capacity in 2006 were North Sea Cod and West of Scotland Cod. North Sea herring was stated as at risk of being below full reproductive capacity and the status of Northeastern Atlantic Mackerel was uncertain.

Source: Fisheries Research Services, ICES⁵