Recruitment of bonefish, Albula vulpes, around Lee Stocking Island, Bahamas

The onshore movement of settlement-stage bonefish, Albula vulpes, leptocephali was monitored over four consecutive winters (1990-91 to 1993-94) and summer 1992 near Lee Stocking Island, Exuma Cays, Bahamas. Total catch over the four winters ranged from 316 to 1,421 fish per 70-day sampling period, whereas 1,112 were taken during the single 72-day summer sampling period. An analysis of otoliths from 87 fish collected during the last winter indicated continuous spawning activity during the fall and early winter and an estimated larval duration of 41 to 71 days. The collection of larvae in summer 1992 suggested that spawning continues until late spring. Virtually all recruiting leptocephali were collected at night and in the upper 1 m of the water column. Time-series analysis of the four winters linked together by lunar date revealed a strong cyclical pattern of recruitment, with a period of 30 days, and a strong association with the number of hours of flood tide occurring under dark, moonless conditions. The one major peak in the summer samples occurred during the first 12 days of sampling when the hours of dark flood tide was at its maximum level for the month; subsequent dark periods had low levels of recruitment. There were no strong associations between recruitment levels and wind and current patterns. These data suggest that the cyclical pattern in hours of dark flood tide creates "windows of opportunity" for the leptocephali to move onshore at times that minimize their vulnerability to visual predators in reefs and seagrass beds.