Assessment of the Queen conch Strombus gigas (Gastropoda: Strombidae) Population in Cayos Cochinos, Honduras* Alexander Tewfik1, Héctor M. Guzmán2* & Gabriel Jácome2 1 75 Hazelglen Drive, Apart. Nº 304, Kitchener, Ontario, Canada N2M 2E2 2 Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Panamá *All reprint requests to second author. Abstract: A visual preliminary assessment of the Strombus gigas population in the area of the Cayos Cochinos Biological Reserve was conducted by SCUBA divers swimming transects. Additional data on size/age structure, morphometries (shell length, shell width, shell lip thickness, and total weight), habitat, and reproductive activity were also collected. Size frequency distributions are given for shell length and shell lip thickness in an effort to reveal growth and age of the various cohorts. Linear regression analyses were conducted between various morphometric measurements. A total of 40 transects were completed covering a total area of 45504 m2. The mean area of a transect was 1137.6 m2 at a mean depth of 15.3 m. The overall density was calculated as being 14.6 conch/ha (S.D. = 36.15) over the study area of 15330 ha giving an approximate total abundance of 223818 conch. The majority (58.8%) of conch found in transects were found in depths of less than 10 m. A total of 177 conch were collected in and out of the transects with 48% juveniles and 52% adults. The population was further sub-divided into six categories for quick assessment during transects: four juvenile; small (0%), medium (10.7%), large (19.8%), sub-adult (17.5%): and two adult normal (27.1%), and stoned (24.9%). Reproductive activity included copulation, spawning, and solitary egg masses concentrated on seagrass slopes from five to 18 m in depth. New details on copulation were observed. It is felt that the low density and abundance is a direct result of 30 years of heavy exploitation by the Garifuna fishermen and commercial divers prior to the creation of the reserve. Future management measures should include the increase of the minimum shell length restriction to 240 mm, the use of a mature lip regulation, banning of SCUBA in fishing, and seasonal closures of important breeding areas. Key words: Strombus gigas, queen conch, population assessment, growth, reproduction, Honduras. The queen conch, Strombus gigas Linnaeus, 1758, is a large marine gastropod mollusk of the order Mesogastropoda and is one of seven species of the family Strombidae occurring in the Western Atlantic. It has long been valued for meat and shell and has been fished since prehistoric times (Brownell et al. 1977, Berg & Olsen 1989). A sizable commercial fishery has developed over the last 25 years. This is due to the increasing demand for conch internationally as well as the demands by growing populations of natives and tourists in the region. Once common in shallow waters, conch are now caught in ever increasing depths by fishermen equipped with SCUBA and Hookah gear in place of traditional conch hooks and free-diving techniques. The most up-to-date figs. for regional conch harvest is just under 6000 MT annually (Tewfik 1995). Fears of the disappearance of commercial conch fisheries by some biologists have caused S. gigas to be included on appendix II of the Convention on the International Trade of Endangered Species (CITES). International trade of queen conch is therefore only allowed by permit from nations documenting that the exploited population is not threatened by commercial fishing. With the recent designation of the Cayos Cochinos area as a biological reserve (1993) it seemed appropriate that an assessment of the queen conch population be undertaken. This assessment was limited in spatial (number of sites, 1/3 of reserve area) and temporal (single summer sampling) ranges and serves as a basis for further comprehensive investigations. The conch population has been under intense fishing pressure from the local Garifuna people, some based on cays within the reserve, for approximately 30 years. The assessment was to provide estimates of total abundance and density as well as a description of the size/age structure, morphometric analysis, relative distribution within habitats and depth, and identification of critical spawning areas and nursery grounds that may require special protection within the reserve. This information could also allow decisions to be made regarding potential rehabilitation of this critical tropical littoral species with regards to the basic ecology of the area and sustainable fisheries potential for the human population living within the reserve. MATERIALS AND METHODS The study was conducted in the area around Cayos Cochinos Biological Reserve located at 15? 59' N and 15?51' latitude and 86?25' W and 86?35' longitude, between July 18/96 and Aug. 6/96. These boundaries enclosed an area of approximately 153.3