Abstract

Queen conch (Strombus gigas) is a large gastropod found throughout the Caribbean, where it is a food source and economically important export product (Randall 1964). S. gigas has been overfished in many regions, and its international trade is now regulated under CITES. Until recently, Port Honduras Marine Reserve (PHMR) enjoyed a relatively stable population, regulated by the national shell length limit of 17.8 cm (7 inches) or market clean meat weight > 3 oz (85g), a 3-month closed season during reproductive season, and full protection in Replenishment Zones; measures intended to protect immature conch from harvest before reproducing. However, TIDE fisheries independent density data indicates a continu-ous decline in population with diminished reproduction during reproductive seasons since 2013 (Foley 2013). Fisheries-dependent catch surveys indicate PHMR fishers are complying with the shell length limit, yet the proportion of catch with lip thickness < 9 mm (minimum maturity threshold in other studies) increased from 30% in 2009 to 90% in 2012. Evidence suggests lip thickness is a more reliable proxy indicator of maturity (Avila-Poveda and Baqueiro-Cárdenas 2006, Stoner 2012), but also that maturity relationships vary by habitat on a local level and regionally (Appledoorn 1988, Stoner and Schwarte 1994), and that therefore relationships determined from studies in other areas cannot be applied to PHMR conch. PHMR is a dynamic inshore environment with significant freshwater input, giving rise to habitats and feeding behaviors distinct from the Belize barrier reef. Such relationships therefore need to be determined locally. This study aims to deter-mine the most reliable proxy indicator(s) of maturity in S. gigas specific to Port Honduras Marine Reserve (PHMR), southern Belize. Recommendations are made based on relationships between shell length, lip thickness, lip width, total meat weight, market clean weight and operculum dimensions, for revisions to the legal size limit definition to achieve long-term sustainability of S. gigas in Belize while meeting economic needs of fishers and associated livelihoods.

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