ADDITIONAL STUDIES OF THE FISHES, MACROINVERTEBRATES, AND HYDROLOGICAL CONDITIONS OF UPLAND CANALS IN TAMPA BAY, FLORIDA

Hydrological and biological data from a concluding study of upland canals in Tampa Bay, Fla., are presented and compared with those collected the previous year. Critically low levels of dissolved oxygen occurred more frequently andovera longer period oftime in the second year. Most affected were the inland portions of the canal system where the number of species declined markedly over the previous year. Impoverishment of fauna on or near the bottom is expected to recur during summer months because of oxygen depletion resulting from a combination of continuing accumulation of decomposing organic sediment, warm water, and little circulation in the dead-end canals. In order to create waterfront property while not violating legislation that curtails dredging and filling of wetlands below the mean high-water line, land developers in Florida and elsewhere are digging access canals that lead from open water to upland acreage (Barada and Partington 1972). Florida's shoreline has already been extensively altered by such practice (McNultyet al. 1972), and further alteration can be expected because of ever-increasing demand for waterfront properly. Ifthe coastal zone is to be managed wisely, infor­ mation on the suitability of these man-made waterways as habitat for aquatic organisms is urgently needed.