15 - Bermuda

Research and adaptive management lead to better protection of spawning aggregations in Bermuda 

The discovery of a black grouper Mycteroperca bonaci)spawning aggregation site in 2004 located between two seasonally protected (May to August) areas for red hind (Epinephelus guttatus) at the eastern end of Bermuda led to the incorporation of this site into a newly configured seasonally protected area encompassing all three sites. Initial observations of abundance and behaviour of black grouper were made in 2005 to confirm the nature of the aggregation (Luckhurst, 2010). The closure of the red hind sites was based on their known spawning period during the summer months. However, the duration of the spawning period for black grouper was poorly documented and this presented a management challenge as black grouper would be vulnerable to fishing pressure if they continued to aggregate outside the four month closure period. To better understand the dynamics and duration of this black grouper aggregation, an acoustic tagging programme was initiated in 2008. ‘Vemco’ acoustic transmitter tags were surgically implanted into the body cavities of 37 black grouper during the first two summers of field work and an array of acoustic receivers was set up around the aggregation site.

 

Data downloaded from the receivers subsequently demonstrated that tagged black grouper were present at the aggregation site from May to November with the highest activity levels from June through October. Abundance was greatest in the period after the full moon in each aggregation month. These data suggest that black grouper have a more protracted spawning period than red hind and validate the decision to extend the closure period. As a result, the existing legislation is being amended to maintain the extended closure period on a permanent basis.

Brian E. Luckhurst
Tammy Trott
Joanna Pitt 
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Reference

Luckhurst, B.E. (2010) Observations of a black grouper (Mycteroperca bonaci) spawning aggregation in Bermuda. Gulf Caribb Sci 22:1–8.

Due to uncertainty over the duration of the aggregation period of black grouper and the possibility of capturing tagged fish at the site, a management decision was taken to extend the closure period of the area around the black grouper aggregation until November. This was done using a provision for emergency site closures under the Fisheries Act. Under this provision, the Minister responsible for fisheries may declare a defined geographical area closed to fishing for a period of up to 90 days if the Minister believes that there is a significant threat of overfishing at the site. This declaration only requires publication of the notice in the Official Gazette. This has proved to be a powerful management tool in Bermuda as it provides the opportunity for scientists to study an aggregation considered vulnerable without being in conflict with fishermen at the site. The information gained can then be used to refine legislation to adequately protect an aggregation both spatially and temporally.