POPULATION PARAMETERS, LIFE-CYCLE, AND FEEDING OF MYSIDIUM-COLUMBIAE (ZIMMER) IN THE WATERS SURROUNDING A BELIZIAN MANGROVE CAY

The ecology of tropical Mysidacea is poorly known. Mysidium columbiae (ZIMMER), because of its ubiquitous distribution in the tropical weste rn Atlantic and the information available on its aggregative behavior, is an ideal subject of study to reconcile aspects of this problem. In formation and data were obtained on abundance, population size, shoal/ school structure, fecundity, development, and feeding of a M. columbia e population inhabiting waters surrounding Twin Cays, a mangrove archi pelago in Belize. Although reproduction was continuous and proportions of life stages within shoals remained relatively constant throughout the year, population size decreased by an order of magnitude from summ er to winter. Embryonic development averaged 4.7 days, with postlarvae being released near the surface before dawn. Aquarium experiments sug gested that olfaction may be more sensitive than vision, although both senses were used to locate food. This species is a detritivore, but g ut contents suggested that it may also be a predator.