Restricted grouper reproductive migrations support community-based management.

Area of Science:

• Marine ecology
• Fisheries science
• Conservation biology

Background:

• Conservation efforts often involve balancing social and ecological objectives.
• Small-scale tropical fisheries typically employ small no-take locally managed marine areas (LMMAs), often under 1 km².
• Large coral reef fish, like groupers, migrate to spawning aggregations, posing challenges for small-scale management due to their extensive catchment areas.

Purpose of the Study:

• To investigate the reproductive migration and catchment areas of the grouper Epinephelus fuscoguttatus.
• To assess the feasibility of managing grouper spawning aggregations using no-take LMMAs in Papua New Guinea.
• To determine if moderate reproductive migrations allow for management at scales compatible with existing conservation tools.

Main Methods:

• Acoustic telemetry was used to track fish movements.
• Tag-returns provided data on migration patterns.
• Catchment areas of spawning aggregations were analyzed.

Main Results:

• The study examined the grouper Epinephelus fuscoguttatus at a spawning aggregation in Papua New Guinea.
• The total catchment area for these aggregations was approximately 16 km², deemed too large for current socially acceptable no-take LMMAs.
• Spawning migrations were found to be predominantly shorter-distance, suggesting that expanding LMMAs to 1-2 km² could protect 30-50% of the spawning population.

Conclusions:

• Effective management of grouper spawning aggregations is possible at spatial scales congruent with restricted management tools.
• Expanding no-take LMMAs to 1-2 km² can significantly contribute to conserving grouper populations with moderate migratory behaviors.
• This research challenges previous assumptions about the spatial scales required for managing aggregating reef fish.