Fish Spawning Aggregations: Field Surveys

Fish Spawning Aggregations: A Reef Resilience Toolkit Module

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Park manager conducting underwater surveys. Photo © Juan Pablo Carnevale

Once the general location of a spawning aggregation is known or inferred, field surveys are typically necessary. These usually, but not always, require an ability to conduct underwater visual censuses.

Underwater visual censuses allow the marine manager to observe and describe the FSA in fine detail, including observing reproductive behavior, defining seasonality and spawning times, and characterizing the spawning area and composition of the FSA. These details are typically needed when determining whether changes to the FSA have occurred over time following implementation of a management measure, whether it be a closed catch season, gear ban or placement of a marine protected area. Without such monitoring, it is difficult for managers to understand the impact of the management imposed, or the need to make alterations or improvements. Similarly, fishers will almost always want to know that the management measure has improved their ability to catch fish elsewhere (e.g., as increased numbers of fish in areas surrounding MPAs). Therefore, field surveys should be considered an integral part of any FSA conservation plan.

Field surveys are important in order to verify spawning aggregations that are reported anecdotally by fishers, dive operators, and other stakeholders. Although these individuals are extremely valuable partners in the FSA identification process, their contributions are usually purely observational in nature. Any information gained should be verified through surveys, so that accurate data on the FSA can be obtained and proper management can ensue.

Resources

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)