There are two broad strategies for defining overfishing in practice today:

(1) Fishing mortality rate (F) strategies, and

(2) Spawning stock biomass (SSB) strategies.

Fishing mortality-based reference points are designed to prevent F from getting too high which could result in a subsequent decline in the population because individuals are being removed at too fast of a rate. Spawning stock biomass (SSB) based reference points are designed to prevent SSB from getting too low and compromising the ability of the stock to replenish itself. To accurately categorize the status of a stock one should look at both fishing mortality and biomass, simultaneously.

Generalized representation of overfishing definition utilizing both spawning stock biomass (B' and B") and fishing mortality (F' and F") targets and thresholds.

A target and threshold approach will be used to define stock status of Atlantic menhaden incorporating both fishing mortality and spawning stock biomass reference points. The Management Board will evaluate both sets of reference points before proposing any additional management measures. In general, if the current F exceeds the threshold level, the Board should take steps to reduce F to the target level; if current F exceeds the target, but is below the threshold, the Board should consider steps to reduce F to the target level. If current F is below the target F, then no action would be necessary to reduce F.

Likewise, if the SSB falls below its threshold level, action would have to be taken to allow the stock to rebuild. If SSB is above the threshold but below the target, the Board should consider taking steps to encourage stock rebuilding. If SSB is above the target, no action would be required. There may be times when one of the reference points is exceeded but not the other. In those cases the Board will consider the relative risk of the situation to stock status before proposing or taking any new action.

Preliminary projections of Atlantic menhaden spawning stock biomass based on F = 1.0 and historical recruitment levels observed from 1955-99, result in an estimated mean SSB of 75,000 mt over the next 25 years. These analyses have also demonstrated that varying fishing mortality has virtually no effect on future recruitment of Atlantic menhaden.

Future SSB targets and thresholds could change based on a new choice for the fishing mortality target and threshold, i.e. SSB could be higher or lower given a choice of a lower fishing mortality.

The Atlantic menhaden resource is not overfished under either definition.

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