Concern about overfishing of culturally important species such as conch and lobster arose in the early 1980’s. In 1988 the DOE began monitoring the status of shallow water populations of queen conch both inside and outside of the Marine Park Replenishment Zones. This is done annually in selected sounds around Grand Cayman and Little Cayman.
Results to date indicate that the mean density of conch is decreasing throughout the Cayman Islands, most likely due to increasing human populations and tourism; in addition poaching continues. Marine park and replenishment zones do appear to function as refugia for reproductively mature adults, and during 1997-1998 the DOE conducted plankton tows to investigate levels of larval abundance at 3 locations in North Sound. Laboratory analyses of the plankton samples to date have shown that certain areas in North Sound are important sources of conch larvae. Thus the continued protection of breeding stocks in these areas, as well as of the immature conchs which will be potential future breeders, should remain in effect as an integral component of the management strategy for this important marine resource.
Based on recommendations from the DoE, the legal catch limit for conchs has recently been reduced and a closed season established (Insert link to Marine cons laws). It is hoped that this increased protection will lead to a stabilization and eventual increase in conch populations around the Cayman Islands. The Department will continue to monitor shallow water conch populations so that any changes can be factored into future management plans.
Abundance of Veligers of the Queen Conch in North
Sound: An Executive Summary
By Gene Parsons, Bradley Johnson, and John Bothwell. Research and Assessment Section, Department of Environment, Cayman Islands Government. April 2001.
To determine the abundance of queen conch (Strombus gigas) veligers at 3 locations in the North Sound, an 18-month sampling program that collected 76 plankton samples on an average frequency of about once every 2 to 3 weeks was conducted from July 1997 through December 1998. Near-surface, horizontal plankton tows of 20-minutes duration were undertaken at each location using a bongo-net frame equipped with 2 conical nets of 0.5-meter diameter and 202-micron mesh. Of the 2,077 queen conch veligers collected through tow 36, 10 had broken shells that could not be measured; therefore, 2,067 were analysed for maximum shell length (SL). Of these 1,992 (96.4%) corresponded to Stage 1 (< 500 microns SL), 75 (3.64%) to presumptive Stage 2 (500-900 microns SL), and none to Stage 3 (settlement stage). In the 6 samples containing veligers, density varied from 0.06 to 34.86 per 10m³. The preliminary results indicate that the back-reef areas of the replenishment zones of Barkers and North Sound might be larval source areas owing to these zones partially functioning as refugia for queen-conch breeders.