Characterization of queen conch (Aliger gigas) artisanal fishing prior to and after the five-year ban at Chinchorro Bank Biosphere Reserve, Mexico

Abstract

The queen conch Aliger gigas (Linnaeus, 1758) is one of the most important fishery resources in the Caribbean. However, due to its biological characteristics and high commercial demand, its populations have been overexploited. In Mexico, the Chinchorro Bank is the only site where extraction of this resource is allowed through catch quotas; however, due to its drastic population decline and fishing pressure, in 2012, a five-year temporary ban was established and ended in 2017. This study describes and compares the artisanal fishing of the queen conch for the last catch season in 2011 prior to the ban and the second catch season after the ban ended in 2018. A total of 15 fishing sites were registered, and it was found that fishermen visited the central zone of the Chinchorro Bank more frequently than the northern or southern zones, probably due to the proximity and availability of the resource. An increase in the CPUE was observed from 5.09 to 8.0 kg of meat conch/fisherman per hour between fishing seasons, likely a result of the queen conch recovering during the five-year ban. Using shell length (SL) and lip thickness (LT) from a total of 4882 organisms, a decrease in the mean size and size structure of the queen conch was observed between fishing seasons, probably due to the overharvesting of adult conchs throughout the years, affecting the population structure at Chinchorro Bank. However, a significant increase in lip thickness was observed, which may be due to earlier maturation of the conchs. An increase in surveillance as well as integrated management between stakeholders (fishermen, consumers, authorities, among others) is recommended to guarantee the conservation of the queen conch population.