Analysis of gene flow of the Bermuda spiny lobster. Final Technical Report.
Abstract
The source of recruits to Bermuda's spiny lobster (Panulirus argus) stock was examined through genetic typing techniques. A total of 8 polymorphic loci were found in adults, sub-adults and juveniles, 4 in post-larvae and 2 in mid- to late-stage phyllosoma. Polymorphic loci were lost in these early life history stages due to weak activity and ontogenetic changes at settlement.No enzyme activity was found in encapsulated larvae or early-stage phyllosoma.
No convincing evidence for population substructure was found within the Bermuda stock when genetically tested by spacial distribution, sex and size class. Tests for macrogeographic heterogeneity using Menzies' (1981) database for Caribbean stocks were complicated by uncertainty regarding electromorph compatibility and temporal stability of allele frequencies. Genetic comparisons with contemporary samples obtained from south Florida demonstrated no significant heterogeneity. Monthly post-larval samples were in genetic equilibrium and indistinguishable from Bermuda and Florida adult stocks.
Three eddies approached to within 60 nautical miles of Bermuda and two attempts were made to strategically sample eddy 'B' waters for phyllosoma. The role of warm-water outbreaks and cold-core eddies in larval transport and recruitment to Bermuda, however, remains uncertain, as does the relative contributions of non-Bermuda and Bermuda-derived larvae to the resident stock.
These results are consistent with a single Florida/western Atlantic stock. Increased co-operation with Florida State and United States Federal authorities is therefore recommended for effective resource management. However, as significant self-replenishment has not been excluded by this study, and in view of stable annual post-larval recruitment and the recent exploitation rates being sustainable, current fisheries regulations in Bermuda appear appropriate.
Preliminary results are also presented on species identification of Panulirus phyllosoma and comparisons in collecting efficiencies between three post-larval collector designs.
Citation
Analysis of gene flow of the Bermuda spiny lobster. Final Technical Report. 40pp
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