Long Term Monitoring
A long-term monitoring program is needed to track and measure natural and human-induced changes in the spawning aggregation, as well as the response of the FSA to management choices over time. Monitoring over a long-term period (years to decades) is important, because of the high variability that is inherent in marine populations. Fish populations may experience variable levels of larval recruitment success at each reproductive period. Therefore, some level of variation in the population size and structure will be expected to occur independently of any anthropogenic forces.
Protocols for data collection should remain consistent throughout a monitoring program, so that data are comparable. Data collected with different methods are not comparable, and so changes in monitoring protocols and monitoring personnel should be avoided. To ensure consistency, re-training in monitoring techniques is highly recommended.
Long-term monitoring provides evidence that should compel managers and policymakers to take appropriate actions. These actions can include limiting fisheries to prevent significant declines in spawning biomass, or extending management measures beyond protection of spawning aggregations.
Three important questions should be addressed with long-term monitoring. These questions and the principal information needs for each are discussed below.
1. What is the condition of the FSA?
- Determine whether the population of spawning fishes is stable, growing or shrinking.
- Verify whether the spawning site is used consistently, and whether there are changes in the temporal patterns of use.
- Determine the characteristics of the spawning population, such as the abundance of individuals and the spatial habitat use.
2. Has the FSA been adequately protected?
- Determine whether the entire site is enclosed by a protected area, or if there is a fishing closure enacted during spawning season.
- Confirm whether there is effective enforcement.
- Determine whether illegal fishing activities are occurring.
- Find out if alternative livelihoods have been developed or are possible in the region for fishers who may be or have been dependent on the FSA.
3. Has the population of spawning fish that supply the FSA been adequately protected?
- Determine the source of spawning stock biomass.
- Determine whether migratory corridors exist and are adequately protected.
Introduction to monitoring of spawning aggregations of three grouper species in the Indo-Pacific: A manual for field practitioners (Pet et al. 2006) (download pdf, 3,812k)