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Accurate identification of human-induced injuries that lead to death or interfere with reproduction is important for marine mammal management, as deaths exceeding established limits can lead to restrictions on fisheries or vessel operations. The fates of cetaceans last seen swimming with attached gear, particularly in pelagic fisheries, or with vessel strike lacerations, have been difficult to predict. Survival and reproduction data from long-term research on resident common bottlenose dolphins near Sarasota, Florida were examined relative to consequences of fishing gear ingestion, line entanglements, vessel strikes, and amputations of unknown origins. Fishing hooks embedded in the throat, goosebeak, or esophagus, or line wrapped around the goosebeak, generally lead to death. Multiple, constrictive line wraps around fin insertions can lead to amputation, blood loss, impaired mobility, or infection. Dolphins with ingested gear or severe entanglements may swim away with the gear, but likely die later. Propeller injuries involving only soft tissue were often survivable. Some dolphins survived amputations of the distal ends of fins, and continued to reproduce. As a precautionary approach, dolphins with ingested gear or severe constrictive entanglements should be considered mortalities, but extrapolations of findings from coastal bottlenose dolphins to other cetaceans and different gear must be done with caution.

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The temperature differential (ΔT) between a body surface and the environment influences an organism's heat balance. In Sarasota Bay, FL, where ambient water temperature (Tw) ranges annually from 11° to 33°C, ΔT was investigated in a resident community of bottlenose dolphins (Tursiops truncatus). Dorsal fin surface temperatures (Tdfin) were measured on wild, free‐swimming dolphins using infrared thermography. Field and laboratory calibration studies were also undertaken to assess the efficacy of this non‐invasive technology in the marine environment. The portability of infrared thermography permitted measurements of Tdfin across the entire range of environmental temperatures experienced by animals in this region. Results indicated a positive, linear relationship between Tdfin and Tw (r2= 0.978, P < 0.001). On average, Tdfin was 0.9°C warmer than Tw across seasons, despite the 22°C annual range in Tw. Changes in integumentary and vascular insulation likely account for the stability of ΔTdfin − w and the protection of core temperature (Tcore) across seasons. The high thermal conductivity of water may also influence this ΔT. The use of infrared thermography is an effective, non‐invasive method of assessing dorsal fin skin surface temperatures (±1°C) across large numbers of wild, free‐swimming dolphins throughout their thermally dynamic aquatic environment.

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