Evaluation of the spatial extent, density and growth rates of barnacles in Crystal, Homosassa and Withlacoochee Rivers, Florida.

Abstract

Site visits to the Crystal, Homosassa, and Withlacoochee Rivers in Florida, were conducted on March 18, 2009, reconnaissance, May 14 and 15, placement of artificial substrates, and June 29 - July 2, to retrieve the artificial substrates, make in-situ measurements and collect field scrape samples. Artificial substrates had an incubation period of 47 to 49 days. The objectives of the field sampling effort were to identify barnacle species; determine relative proportion of live to dead; determine size range, based on basal diameter; determine the farthest upriver extent of live / dead barnacles; and apply these items to a river kilometer system for Homosassa and Withlacoochee Rivers and salinity strata for Kings Bay in Crystal River. This reconnaissance survey of a section of each river was to be included in the survey for the purpose of locating barnacle habitats and determination of the upriver most extent of barnacles. Information on salinity distribution within the tidal sections of these rivers was provided which served as the basis to determine the reconnaissance survey areas. Along the chosen sections of each river fixed hard substrates were examined for evidence of barnacle growth. Suitable barnacle substrate consisted primarily of channel markers, dock pilings, metal sign posts and PVC pipes. Deadwood snags and submerged rocks were also examined in areas where these were present. Results and data are provided.