Home range size and use of space by Bermuda chub Kyphosus sectatrix (L.) in two marine reserves in the Soufrière Marine Management Area, St Lucia, West Indies

Abstract

Marine reserves (MRs) are expected to conserve fish biodiversity and enhance fisheries production of surrounding areas through export of adult fish biomass. However, the extent to which these benefits occur is dependent on movement patterns of fish, for which there is a paucity of data, particularly for coral reef species. Eleven adult Kyphosus sectatrix were tracked [five in the Grand Caille marine reserve (MR) and six in the Petit Piton MR within the Soufrière Marine Management Area, St Lucia] from February to April 1999, using acoustic telemetry. Average number of days over which fish were tracked was 21.5 (range 5–51). Home range size of individuals, temporal use of space within the home range, and permeability of MR and habitat boundaries to fish movement were examined. Average minimum home range area of K. sectatrix was not significantly different between Grand Caille (30 514 m2) and Petit Piton (39 114 m2). However, the shape of home ranges was conspicuously different between the sites and reflected available reef shape. Individual home ranges overlapped strongly with those of other individuals at the same site, and use of space within the home range was generally restricted to a small number of preferred sites. Preferred sites were often shared among individuals and tended to be occupied at a specific time of day, with some sites were preferred in the morning and or afternoon, whilst others preferred during the middle of the day. Fidelity to a single sleeping‐shelter site was high at night. MR boundaries over contiguous reef at Grand Caille were frequently crossed with individuals spending, on average, 63% of their time (range 37–94) outside the MR. This demonstrates the need for the MR boundary at this site to be implemented farther offshore to encompass the reef, if the MR is to better protect K. sectatrix. At Petit Piton, where MR boundaries effectively encompass available reef, K. sectatrix spent, on average, only 11% of their time (range 0–40) outside the protected area. At Grand Caille boundaries were crossed more readily (individuals spent an average of 18% of their time off reef) than at Petit Piton where individuals spent an average of 0.7% of their time off reef.