LUNAR AND SEASONAL-CHANGES IN A MANGROVE FISH ASSEMBLAGE OFF SOUTHWESTERN PUERTO-RICO DIEL

Forty-one species were visually identified among the mangrove prop-roots. Although diurnal variability was evident, the most pronounced feature was nighttime declines in species abundance. All species present during the day showed marked reduction in numbers of or complete absence at night. There was no evidence for a diurnal-nocturnal changeover of species assemblages in the mangrove. Low nighttime abundance was partly due to twilight migrational activities. Movements away from the mangrove prop-root habitat at dusk were observed for a variety of fishes, particularly haemulids. Predictable, well ordered migrations were observed for juvenile French grunts Haemulon flavolineatum and sub-adult bluestriped grunts H. sciurus. Timing, duration, and pre-and post-migratory behaviors differed among species. Some 76% of species examined showed significant seasonal differences between Oct/Nov 86 (rainy season) and Apr/May 87 (dry season). Lunar periodicity had no obvious effect on species abundance. -from Authors

DIEL, LUNAR AND SEASONAL-CHANGES IN A MANGROVE FISH ASSEMBLAGE OFF SOUTHWESTERN PUERTO-RICO Academic Article