Utilization by Fishes of Space and Food Resources on an Offshore Puerto Rican Coral Reef and its Surroundings

Parrish, J.; Zimmerman, R.

A cross-section of the fish community was studied on and near a coral reef 9.5 km west of Puerto Rico. Utilization of reef and off-reef habitat and diel activity cycle were observed for several diverse groups. The nature and degree of reef association were documented. Diet, based primarily on gut contents, was compared with quantitative benthic samples from the adjacent sand flat. The reef-restricted scarids and Clepticus parrai (Labridae) were diurnally active, feeding respectively on benthic algae and zooplankton. Serranids appeared reef-restricted, but without clear diurnal/nocturnal pattern. Holocentrids and pomadasyids used reef protection by day and fed abroad at night, apparently mostly on the sand flat benthos. Opisthonema oglinum (Clupeidae), Caranx ruber and the mullids ranged widely day and night over reef and flats. The former fed mostly in mid-water, and the latter two apparently ate primarily sand flat benthos. Sphyraena and Synodus species were wide-ranging piscivores day and night, the former stalking in mid-water, the latter lying in wait on the bottom. Calamus (Sparidae) was a dominant exclusively sand flat species, feeding on the sand flat benthos day and night. Herbivores, planktivores, piscivores and macro-invertebrate carnivores are all substantial components of the fish community. Feeding by macro-invertebrate carnivores on the sand flats provides an important energy input to the reef community. The sand flat benthos receives substantial energy from the water column. Most of the energy this group passes on to fish may come from detritus, much of which may be reef-derived.

Utilization by Fishes of Space and Food Resources on an Offshore Puerto Rican Coral Reef and its Surroundings

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