Abstract
In Mexico and elsewhere in the Caribbean, the queen conch Strombus gigas is an endangered species. Understanding the genetic connectivity of their populations will support management strategies for long-term conservation of the species. Genetic diversity and population differentiation was assessed from samples collected at Banco Chinchorro and Isla Cozumel in the Mexican Caribbean and at Arrecife Alacranes in the Gulf of Mexico. Samples were obtained from the commercial capture at Banco Chinchorro (n = 50) and Isla Cozumel (n = 40) on March 2004. On November 2004, a non-invasive method for the Arrecife Alacranes sampling was applied, taking the hemolymph of live animals (n = 65) and releasing them to the wild. The mitochondrial DNA variation at two genes (COI and Cyt-b) was analyzed. Genetic diversity at the three locations ranged between 0.55-0.65 in COI and 0.87-0.94 in Cyt-b, showing no bottleneck evidences. A non-significant fixation index (F(ST) = 0.019, p = 0.161) and a Maximum Parsimony Network tree that did not show particular clades associated with any of the geographical locations, suggested a lack of statistically significant genetic differentiation among populations. Nevertheless, the cline patterns observed in both genetic diversity and haplotypic frequencies from Banco Chinchorro through Arrecife Alacranes, and the larger genetic distance between these locations from those between Isla Cozumel, Banco Chinchorro and Arrecife Alacranes, suggest the possibility of a pattern of isolation-by distance. The role of the main current systems over the potential genetic differences in S. gigas populations along the Mexican Caribbean, and the conservation management of S. gigas at these locations as discrete units is discussed.
Highlights
The queen conch Strombus gigas has been an important fishery resource for several countries along the Caribbean Sea, but it is subjected to different threats
Some studies on queen conch population genetics based on allozymes have been carried out since the 80s and 90s, when Mitton et al (1989) and Campton et al (1992) found that, even though a high gene flow was evident in locations within the Caribbean, populations were not panmictic, since genetic differences occurred between beds located near each other
Genetic diversity: In spite of the endangered status of the queen conch, the overall genetic diversity in the cytochrome oxidase subunit I (COI) and cytochrome b (Cyt-b) genes varied from medium to high values, suggesting that S. gigas has not reached genetically threatened levels, as would be expected if a serious bottleneck would had happened
Summary
The queen conch Strombus gigas has been an important fishery resource for several countries along the Caribbean Sea, but it is subjected to different threats (overfishing, poaching, habitat destruction, pollution, etc.). The species is recognized as endangered (CITES 1973) due to low population levels in several parts of the Caribbean (Theile 2001), with specific surveys in Venezuela (Schweizer & Posada 2006), the British Virgin Islands (Gore & Llewellyn 2005) and in other countries as well (Theile 2005, Mateo & Tejeda 2008, Oxenford et al 2008). In other areas such as Puerto Rico, poaching has been pointed as a concern issue (Hernández 2008). In an analysis of reef fish based on mtDNA, Shulman & Bermingham (1995) showed that the extension of the larval phase was not essential in defining genetic differentiation patterns
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
