Queen conch, Strombus gigas, in fished and unfished locations of the Bahamas: effects of a marine fishery reserve on adults, juveniles, and larval production

Designate a Marine Protected Area and prohibit all types of fishing

A site comparison study in 1988–1994 in two sandy areas with seagrass in Exuma Cays, North Atlantic Ocean, central Bahamas (Stoner & Ray 1997) found that inside a protected marine reserve closed to all fishing for 33–36 years, abundance of adult and larval queen conch Strombus gigas were higher, but abundance of juveniles was similar, compared to a nearby unprotected fished area. Adult conch abundance was higher in the closed area (34–270 conch/ha), compared to the fished area (2–88 conch/ha). In six of 13 comparisons, larval abundance was significantly higher in the closed area (1–50 larvae/10 m³) compared to the fished area (0.06–6), and statistically similar in seven comparisons (closed: 0.2–55; fished: 0.25–1.6 larvae/10 m³). Juvenile conch abundance was statistically similar in closed (2–6 conch/ha) and fished areas (0–2). The marine reserve (456 km²) was designated in 1958, closed to all fishing and the collection of any animals prohibited. Inside the fished area, taking juvenile queen conch and using SCUBA gear for fishing is prohibited. A snorkeller counted adult queen conch along 12 transects (6 m wide; total area of 28 ha) in March–September 1991 (fished area) and 1994 (closed area). Divers also measured adult conch abundance, shell length and lip thickness (see paper for details). Juvenile conch abundance was estimated in each area (annually in 1988–1991 in the fished area; in 1991 in the closed area; see paper for details). Queen conch larvae were surveyed in June–August 1993–1994 using plankton nets.

(Summarised by: Anaëlle Lemasson & Laura Pettit)