Abstract

This study was designed to examine the fate of queen conch (Strombus gigas) larvae produced in the region encompassing the Florida Keys, the north shore of Cuba, and the Yucatan Peninsula. We released a total of 9,000 drift vials during June 2004 at ten locations in the Florida Keys, three sites in the Gulf Stream (near Cuba), three sites at Banco Chinchorro (Mexico), three sites on the northeast Mexican Yucatan, and one at Alacranes Reef (Mexico). The release sites were chosen based on the existence of conch aggregations, hydrographical patterns, and questions relative to connectivity in the region. A piece of waterproof paper with a unique code along with directions to report the code, date, and location of the recovery was placed inside each drifter. In order to increase reporting, respondents were entered into a drawing for prizes funded by the Exxon-Mobil Foundation. Overall, 11% of the vials were recovered. The recovery rate was 15% in the Keys, 10% from Gulf Stream sites, and only 4% from Mexican sites. Most of the recovered vials (76%) were recovered within one month of release which coincides with the amount of time that conch larvae are planktonic. Most of the drifters released in the Keys were recovered in the Keys. Drifters that were released in the Gulf Stream bypassed the Keys and were recovered from Miami to North Carolina. All of the recoveries from Banco Chinchorro were located in Mexico. About 80% of the drifters from the northeast Mexican Yucatan were recovered in Mexico; however, the other 20% were recovered in Texas. All of the recovered drifters from Alacranes Reef were found in Texas. The results lend credence to the new paradigm that populations are more dependent on local retention of larvae than on recruitment from upstream sources. Based on the recoveries, it seems that larvae produced upstream (e.g., Mexico, Cuba) do not recruit to Florida in great numbers and that conch populations in Mexico and Florida rely on local retention and recruitment.

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