Abstract

Queen conch (Strombus gigas) is an intensively exploited specie all over Caribbean and particularly in Guadeloupian archipelago. Considering the economical importance of this fishery and threats on the regional stock, Regional Fisheries Committee is initiating on European and French national subsidy, a monitoring of Guadeloupian Queen conch stocks variation. A simple methodology allowing evaluation of the queen conch’s densities using an underwater towed camera was developed in order to be freed from logistical and financial diving’s constraints. This study allowed in 2009, a first estimation of stocks densities in 6 station (4 to 10 transects per station) of the Guadeloupian fisheries. This protocol offers the advantage of sampling large surfaces in few times and for a moderate cost. The experimental average density was estimated about 26.89 conch.ha-1, with a minimum of 4.1 conch.ha-1 and a maximum of 59.48 conch.ha-1, for a total sampled surface of 7.07 ha. The study reveals that a minimum surface of 1 500m² is requested to observe a stabilization of the estimated conch densities, whose distribution is very dynamic and heterogeneous. In Marie Galante, the highest densities observed between 5 to 10 meters of depth in 2008, were confirmed in 2009. This reliable and easily implemented method is now used to monitor the exploitable stock of queen conch and white sea urchin in Guadeloupe. This process is by now applied to monitor of a bay of Marie Galante, which will be the site of a fishing reserve project.

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