Population and growth of queen conch (Lobatus gigas Linnaeus, 1758) in the Sapodilla Cayes Marine Reserve of Belize

Abstract

Abstract Background The conservation effectiveness of marine protected areas is of substantial dispute. In the Belize Barrier Reef, there are several zones with increasing human activity and harvesting of overexploited species. Marine protected areas are designed to protect endangered species and increase the population size of exploited species. The present study investigated the population and morphological characteristics of Lobatus gigas (Linnaeus, 1758) in the Sapodilla Cayes Marine Reserve (SCMR) at the southernmost tip of the Belize Barrier Reef to estimate the effectiveness of the marine protected area. Results A total of 693 L. gigas conches were counted over the 7,200 m2 from 36 transect lines. The densities of juveniles and adult conches in the conservation zone were substantially higher (20.13 and 2.88 individuals/100 m2, respectively) than in the general use zone (5.29 juveniles and 0.58 adults individuals/100 m2). The shell length of adult individuals ranged from 14.4 to 18.5 cm in the conservation zone and from 14.6 to 18.1 cm in the general use zone. A comparison of shell length of juveniles and adults showed no significant differences between the conservation zone (11.39 ± 1.46 cm) and general use zone (11.62 ± 1.24 cm). There was a significant positive correlation for shell length with lip thickness in the conservation zone (Pearson's correlation, r = 0.729, p < 0.001) and general use zone (Pearson's correlation, r = 0.613, p = 0.02). Conclusions The function and effectiveness of marine protected areas are discussed using the results of the present study that identifies the primary objective which is to ensure a continuous recruitment of valuable targeted species by the protection of spawning stock biomass that is important for the management of marine protected areas in an environmentally sensitive ecosystem.