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Coastal fish communities are under increasing levels of stress associated with climate variation and anthropogenic activities. However, the high degree of behavioral plasticity of many species within these communities allow them to cope with altered environmental conditions to some extent. Here, we combine meteorological information, data from hydroacoustic surveys, and recordings of goliath grouper sound production to examine the response of coastal fish communities to heavy rainfall events in South Florida, USA, that resulted in the release of excess storm water into surrounding estuaries and coastal waters. We observed a nearly 12,000% increase in water column acoustic backscatter following a heavy rainfall event of September 16th, 2015. Interestingly, estimates of school backscatter, a proxy for biomass, increased by 172% with the onset of the perturbation. Schooling fish density also increased by 182%, as did acoustically derived estimates of mean schooling fish length (21%). Following the perturbed period, school backscatter decreased by 406%, along with schooling density (272%), and mean schooling fish length (35%). Hydrophone and hydroacoustic data also revealed that goliath grouper ( Epinephelus itajara ) spawning aggregations were persistent in the region throughout the duration of the study and continued to exhibit courtship behavior during the perturbed period. Our observations demonstrate the high level of resistance common in coastal species but raises new questions regarding the threshold at which fish communities and reproductive activities are disrupted. As coastal land use continues to increase, and the effects of global climate change become more pronounced, more Before-After Control Impact (BACI) studies will provide improved insight into the overall response of nearshore communities to future perturbations and the cumulative effect of repeated perturbations over extended periods., Competing Interests: The authors declare there are no competing interests., (©2023 Binder et al.)

The timing and levels of black drum Pogonias cromis sound production and egg production were compared in an estuarine canal basin of Cape Coral in south-west Florida. Surface plankton samples were collected hourly from 1800 to 0400 on two consecutive nights while continuous acoustic recordings were made simultaneously at five locations in the canal basin. Five pairs of nights were sampled during a part of the spawning season from late January to early April 2006. Pogonias cromis sound production and egg production occurred on all evenings that samples were collected; however, both the timing and levels of sound production were negatively associated with those of egg production. Egg production estimates ranged from a low of 4·8 eggs m(-3) in February to a high of 2889·2 eggs m(-3) in April. Conversely, maximum nightly sound pressure levels (SPL) ranged from a low of 89·5 dB in April to a high of 131·9 dB (re: 1 µPa) in February. The temporal centre of sound production was relatively stable among all nights sampled but spawning occurred earlier in the day as the season progressed and exhibited a strong, positive association with increased water temperature. The negative relationship between the levels of sound production and egg production was unexpected given the usefulness of sound production as a proxy for reproduction on a seasonal basis and may possibly be explained by differences in the spawning potential of the female population in the study area on nights sampled. Egg mortality rates increased throughout the season and were positively associated with densities of hydrozoans and ctenophores., (© 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.)

A four hydrophone linear array was used to localize calling black drum and estimate source levels and signal propagation. A total of 1025 source level estimates averaged 165 dB(RMS) relative (re:) 1 μPa (standard deviation (SD)=1.0). The authors suggest that the diverticulated morphology of the black drum swimbladder increase the bladder's surface area, thus contributing to sound amplitude. Call energy was greatest in the fundamental frequency (94 Hz) followed by the second (188 Hz) and third harmonics (282 Hz). A square root model best described propagation of the entire call, and separately the fundamental frequency and second harmonic. A logarithmic model best described propagation of the third harmonic which was the only component to satisfy the cut-off frequency equation. Peak auditory sensitivity was 300 Hz at a 94 dB re: 1 μPa threshold based on auditory evoked potential measurements of a single black drum. Based on mean RMS source level, signal propagation, background levels, and hearing sensitivity, the communication range of black drum was estimated at 33-108 m and was limited by background levels not auditory sensitivity. This estimate assumed the source and receiver were at approximately 0.5 m above the bottom. Consecutive calls of an individual fish localized over 59 min demonstrated a mean calling period of 3.6 s (SD=0.48), mean swimming speed of 0.5 body lengths/s, and a total distance swam of 1035 m., (© 2011 Acoustical Society of America)

Hurricane Charley, a category 4 hurricane, passed through Charlotte Harbor, Florida, directly over an autonomous underwater acoustic datalogger used to record sound production by fishes associated with courtship and spawning. Acoustic recordings made on 9 days prior to the storm, during and 3 days after the storm provided unprecedented documentation of the hurricane's passage and its effect on fishes' calling behaviour. The hurricane did not inhibit nightly chorusing events of spawning fish. 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.