One of their prime activities was the monitoring of the Illex spawning stock biomass (SSB).

Different commercial management measures and recreational management measures were employed to control overall fishing mortality rates and rebuild stock biomass.

The crucial measurement the science panel took is the weight of all the fish old enough to reproduce, a measure called spawning stock biomass.

Increasing the spawning stock biomass to a target level is the approach taken by managers to restore an overfished population to sustainable levels.

Similarly, current knowledge of the stock biomass of spiny dogfish and skates is based only on surveys, since catch-at-age based studies have not been undertaken.

Changes in growth and maturity parameters directly influence assessment calculations related to spawning stock biomass, yield per recruit and percent of maximum spawning potential.

Originally the model had a more specific usage; it was devised to describe the dependence of recruitment on spawning stock biomass.

To support this hypothesis, Reuben Lasker cited the disconnect between spawning stock biomass and the recruitment of numerous fish species.

If the harvest rate is increased, then the stock biomass will further decrease.

Now the scientists agree that there are an estimated 400 000 tonnes of haddock spawning stock biomass in the North Sea.