Fish Spawning Aggregations: A Reef Resilience Toolkit Module

Connectivity

Understanding how communities are connected, and which systems are self-recruiting, or dependent on an adjacent source for larvae recruits, is important for managers. Photo © S. Summerhays

Understanding and maintaining the ecological patterns of connectivity is an important component of coral reef management. Connectivity describes the extent to which populations in different parts of a species’ range are linked through the exchange of eggs, larval recruits, propagules, juveniles, or adults. Imagine what might happen if a particular reef is strictly protected, while its neighbor reef, historically an important source for larvae recruits, is zoned as a high impact tourism area. The likelihood of a continued relationship (supplying coral recruits) is certainly reduced. Understanding how communities are connected, and which reef communities are largely self-recruiting, is important for managers. Yet, in most cases, we do not have this information.

Connectivity has been identified as a key consideration in the design and management of coral reef resources. However, acquiring information about connectivity is quite challenging. Recent advances in science and technology are providing answers to the connectivity questions, indicating that a substantial amount of self-recruitment1 occurs within reef communities, and that there is great variation in dispersal distances2 than once thought. Models are also being used to predict the connectivity of adjacent or distant reefs3.

Because most locations don’t have the benefit of focused scientific research to answer these questions, some rules of thumb for connectivity have been developed and are being refined.

In the absence of connectivity information, rules of thumb can be considered for MPA and MPA network design. For more information see Resilient MPA Design and the special section on Connectivity in the Coral Reef module of this toolkit.