Crime scene investigation of recreational marine fisheries: The impact of shore-based recreational fishing of Queen Conch (Strombus gigas) in Culebra Island, PR
Hernández-Delgado, Edwin A.
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Queen conch (Strombus gigas) is one of the most significant edible benthic invertebrate species through the Caribbean, but its populations have largely declined through time. Its recreational fishery impact still remains poorly documented. Crime Scene Investigation (CSI) approaches were used to examine shell dumps (“concheros”) along the shoreline in Culebra Island, PR, to test four hypotheses: (1) Conch is illegally captured within the Luis Peña Channel No-take Natural Reserve LPCNR); (2) Illegal-sized shells constitute most of the fishery; (3) There is shell harvesting within the seasonal closure; and (4) There is no difference in shell parameters within and outside the no-take reserve. Six replicate 50 x 4 m (200 m2) belt transects along or close to the shoreline were used to count and measure all recent empty shells along the shoreline at eight shores in Culebra Island (4 within LPCNR, 4 control sites outside) between 2007 and 2009. There was significant poaching of shells within the no-take reserve. Mean shell size was 12.1 cm within LPCNR, and 16 .4 cm outside the reserve, and mean lip width was below 1.06 mm. More than 99% of the shells inspected failed to meet minimum size limits [Minimum shell length: 9” (22.9 cm); Minimum lip width: 3/8” (9 mm)]. Evidence of recent illegal captures within the seasonal closure was also found, even within the no-take reserve. There was no difference in shell abundance among sites, even within the no-take reserve. Shells were largely aggregated in specific remote locations, usually under tree shades. Crime scene locations are regular spots of difficult access, frequently used by poachers. Our study confirms that Conch is being continuously poached by recreational and/or artisanal fishers, even within the no-take reserve, suggesting the need of more aggressive education, patrolling and enforcement.