Visual Censuses of Fish Populations at the Florida Middle Ground

Logistical constraints and bottom-time restrictions form major Impediments to visual censusing of fish populations at depths such as are found at the Florida Middle Ground. A sampling strategy which incorporated multiple short duration point-diversity counts enabled estimation of population densities of a number of species present at the Florida Middle Ground. The method described is most accurate for substratum-oriented, site tenacious species such as damselfishes, gobies, and some wrasses, as well as slow-moving or sedentary larger species such as angel fishes and groupers. Numerical classification of count data revealed that fish distribution patterns at the Florida Middle Ground were loosely defined, although differences between biotopes and stations could be discerned. Subjective indices of substratum sand, rubble, hard coral, soft coral, and sponge coverages indicated that these factors had a discrete influence on observed fish distribution patterns