Recordings of fish sound production were made in Charlotte Harbor, Florida using Long Term Acoustic Recording Systems (LARS) programmed to record 10 seconds of sound every 10 minutes. Results demonstrated a strong circadian pattern in fish sound production that occurred within a few hours of dusk each evening. Sound production lasted on average 8.7 hrs each evening during the peak spawning season. LARS were deployed when Hurricane Charley crossed Charlotte Harbor in August, 2004. The hurricane did not inhibit nightly chorusing events of spawning fish. Rather, sound levels produced by spawning fish on the night of and 3 days after the hurricane were higher and lasted longer than any of the 9 days recorded prior to the hurricane. Acoustic time series data recorded at multiple sites in Charlotte Harbor during 2005 revealed changes in the spatial distribution of fish sound production in response to increased freshwater inflow and consequent decreased bottom dissolved oxygen concentrations in early June. Fish sound production decreased rapidly over several days at study sites in the northern portion of the harbor most immediately affected by changes in environmental conditions. Meanwhile, fish sound production increased at the study site furthest seaward where normoxic levels were sustained. By August levels of fresh water inflow decreased substantially, bottom dissolved oxygen levels increased and sound production resumed at sites previously affected by these conditions. Fish sound production began intermittently in February and ended in November. Peak levels were reached by mid-late April / early May and continued throughout the summer time. Seasonal patterns of sound production match the reported spawning periods of estuarine sciaenid species recorded. Black drum sound production was measured in the canal systems of Cape Coral and Punta Gorda, Florida during the 2004-2006 spawning seasons. The circadian pattern of sound production was similar to other sciaenids documented in Charlotte Harbor. Seasonal patterns of black drum sound production occurred during October through April and peaked in February. This seasonal period of sound production also matched patterns of black drum reproductive readiness and spawning reported in the literature for the Gulf of Mexico. A hydrophone array was used in the Cape Coral canal system to localize calling black drum and measure source levels and propagation of calls. Source level estimates averaged 165 dBRMS re: 1muPa SPL (SD=1.0) (n = 1,025). Call energy was concentrated in the fundamental frequency (94 Hz) and first two harmonics (188 Hz and 282 Hz). A square root model best described propagation of the fundamental frequency and first harmonic and a log 10 model best described the second harmonic. Based on the mean RMS source level, signal propagation, background levels, and hearing sensitivity, the communication range of black drum at the study site was estimated at between 33 and 108 meters and was limited by background levels, not auditory sensitivity. The timing and levels of sound production and egg production were compared in black drum. Eggs were collected hourly from 1800 - 0400 by surface plankton tows on two consecutive evenings while black drum sound production was continuously recorded. This sampling effort was conducted five separate times from January through April, 2006. Evidence of the time of spawning was indicated by the collection of blastodiscs (fertilized single cell eggs) or back calculated early cleavage stage eggs. Neither the timing nor the quantity of sound production was positively correlated with egg production on a nightly basis and the greatest densities of eggs were collected on evenings which had the lowest levels of sound production. This may have been due to differences in the fecundity of individual females spawning on the evenings when sampling was conducted.

Cownose rays are benthic, suction feeders whose foraging activities have been implicated in severe damage to commercial shellfish industries and seagrass habitat. With jaws highly modified for durophagy, it has been assumed that they are crushing specialists, feeding primarily upon hard molluscan prey. In addition, R. bonasus are believed to be highly migratory, transient residents of coastal inshore waters. However, minimal quantitative data exist regarding R. bonasus feeding or movement patterns in the Gulf of Mexico. Stomach contents from 50 cownose rays caught within the Charlotte Harbor estuary between July 2003 and July 2004 were analyzed using the index of relative importance (IRI). Crustaceans, polychaetes, and bivalves were the dominant groups present, with bivalves representing the smallest proportion of the three dominant groups. High dietary overlap was observed between sexes, size groups and seasons. Shoalmates exhibited significantly more similar diets to each other than to members of other shoals. Although currently believed to be a hard prey specialist, these results suggest the cownose ray may behave as an opportunistic generalist, consuming any readily available prey. Between July 2003 and November 2004, 21 cownose rays were tagged and tracked within Charlotte Harbor using passive acoustic telemetry. Residence time ranged between 1-102 days. No significant relationship was detected between activity patterns and tidal stage or time of day. Minimum convex polygons (MCP) and kernel utilization distributions (KUD) were calculated to demonstrate the extent of an animals home range and core areas of use. Daily MCPs ranged between 0.01 and 25.8 km2, and total MCPs ranged between 0.81 and 71.78 km2. Total 95% KUDs ranged between 0.18 and 62.44 km2, while total 50% KUDs were significantly smaller, ranging from 0.09 to 9.68 km2.