Meeting Abstract

41.5  Tuesday, Jan. 5  The energetic cost of surface active behaviors in dolphins NOREN, DP*; DUNKIN, RC; WILLIAMS, TM; NOAA NMFS Northwest Fisheries Science Center; Univ. of CA, Santa Cruz; Univ. of CA, Santa Cruz dawn.noren@noaa.gov

Surface active behaviors (SABs), such as tail slaps and breaches, are performed by cetaceans over a range of behavioral contexts. Some cetaceans perform SABs in response to disturbance, including close approaches by vessels. This study aimed to determine metabolic costs of SABs to assess the energetic impact of performing these behaviors in response to vessels. Oxygen consumption of two trained adult male bottlenose dolphins were measured via flow-through respirometry after swimming the length of the research pool, 30 second bouts of tail slaps, and bouts of five and ten bows (proxy for breaches). Oxygen consumption and respiration rates differed across trial types. For example, swimming was less energetically costly than both five and ten bow bouts. Metabolic rates following ten bow bouts were higher than those after five bow bouts, while metabolic rates following tail slaps were the lowest. Respiration rates following ten bow bouts were 1.2 and 1.4 times greater than those following five bow bouts and 30 second bouts of tail slaps, respectively. Finally, oxygen consumption did not return to resting values until 10-20 minutes post behavior, and recovery time varied by trial type. Recovery time was greatest following ten bows and least following swimming, which was similar to the recovery time for tail slaps. The results show that energetic costs of SABs can be high and that tail slaps are the most energetically economical SAB to perform in response to disturbance. Thus, it is not surprising that tail slaps are the predominant SAB observed during close approaches by vessels. By quantifying behaviors in terms of energetic costs to the individual, we can begin to understand how short-term behavioral responses may have long lasting impacts on wildlife.