Abstract

The queen conch Strombus gigas represents one of the most important fishery resources of the Caribbean but heavy fishing pressure has led to the depletion of stocks throughout the region. The inlet of Xel-Ha has been used since 1995 as a park for ecotourism and fishing is strictly prohibited. The Park is considered a sanctuary for the conservation of the queen conch, hosting an important number of juveniles and adults. Sustainable management requires biological knowledge and protection of reproductive stages is crucial. Population size of S. gigas aggregations is mainly determined by recruitment processes, but recruitment may be temporally and spatially variable. Growth is paramount for estimating maturation and natural mortality. In the present study we evaluated growth, recruitment and mortality using mark-recapture methods, over a period of 3 years and compared the results of direct assessment to length frequency analysis. Growth of S. gigas was high within the inlet. Conch with an initial size of 110 – 129 mm grew 0.32 mm/day. An L? of 278.73 mm was estimated and the growth constant k was 0.71/year. Recruitment peaked twice per year (March-May and July-September) but was highly variable between years. Natural Mortality (z), estimated by mark-recapture methods, reflected natural conditions with values between 1.06 and 3.87, but a length converted catch curve showed that it was exceptionally high in conch bigger than 200 mm with z = 4.71. Since fishing is banned, this was attributed to mobility and emigration of adults. The results may be of importance to fishery management and rehabilitation.

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