If, following management action, enforcement and monitoring, the condition of a spawning aggregation continues to deteriorate, additional conservation action or adaptation of existing management intervention is warranted.
Signs of deteriorating condition of an FSA may include declining numbers of spawners, or continued reductions in the age or size classes of fish within the FSA. To be able to detect these changes, continuous monitoring over a few years and during the spawning season will be required. A number of factors may exist to explain why an FSA is not responding to management, and some of these may be the result of natural, and not human-induced, causes. For example, several years of poor larval recruitment can cause a decrease in overall (and FSA) abundance, despite the implementation of management measures. However, a lack of improvement in the FSA for any reason should be cause for concern, and adaptive management should be introduced under continued monitoring.
If such circumstances occur, a number of questions can be asked, such as:
Is the existing enforcement adequate? If not, alter or increase patrols and enforcement measures. Fishers may be aware of enforcement maneuvers that are regularly timed, for example, when patrols move out of the area, poachers move in.
Are the fishes being caught along their migratory corridors to the FSA? If so, additional protection should be placed in these areas. Fishing along migratory corridors is common, so enforcement should include patrols along these areas, and catch should be checked for reproductively active individuals. Additional measures, such as seasonal or total catch bans, may be required if populations are in imminent danger of collapse.
Is the population over a large area in decline due to other causes, such as overfishing during non-reproductive periods? If so, develop management strategies to provide adequate protection for other life history stages and habitats. Overfishing of juveniles, or fishing of small adults can contribute to FSA decline, when this type of overfishing occurs.
Knowledge of these possible reasons for FSA decline is vital for MPA practitioners to be able to adapt conservation strategies and implement effective management actions. Be prepared to look for alternative explanations as to why an FSA may be in decline, and be prepared to take the necessary action to prevent this trend from continuing.