Abstract
This study presents data on the distribution and relative abundance of macrofauna from four major benthic habitats in Rookery Bay Sanctuary near Naples, Florida. The Sanctuary occupies an area of 2,040 ha that include uplands, marshes, mangrove forests, tidal creeks and open-water areas. The latter three habitats are intertidal or shallowly submerged and account for over 95% of the surface area in the Sanctuary. Quantitative monthly samples were taken during darkness using a 3m otter trawl over a period of 27 lunar months (June 1970-July 1972). A total of 328,265 animals were collected and identified representing 174 species and 11 major taxa of animals. Catches were dominated by crustaceans, mollusks and fish which accounted for 96% of the total catch and 85% of the species. A species list is provided for the major taxa with monthly catch rates and observed ranges of temperature, salinity and dissolved oxygen for each species. Detailed statistical and biological analysis are provided for 14 species representing the dominant members of the major taxa. For the selected species a two-way analysis of variance was used to test the difference among habitats and the seasonal effect represented by months. A stepwise multivariate regression analysis was conducted for each of the selected species to evaluate the contribution made by dissolved oxygen concentration, salinity, temperature and vegetation weight in explaining the observed variation in catch rates. Results showed the vast majority of animals were found in habitats that contained seagrasses and benthic algae. Conversely there were only small differences in the species counts between habitats. For the 14 species tested, vegetation weight accounted for a statistically significant part of the variation in 11 species, salinity was significant in 6 and temperature in 3. In May and June 1971 a red tide outbreak occurred within the Sanctuary. The resulting animal mortality reduced animal catches 81% and species counts 34% between April and July 1971. Red tide induced mortality was heaviest in the shallow vegetated habitats and affected fish most severely. The duration of the effects on numeric abundance and species numbers were limited to two months for mollusks and three to four months for fish. Crustacean recovery was more prolonged requiring 9 months before catch rates recovered. Crustacean species counts recovered even more slowly.