Short-term effects of whale watching boats on movement of southern right whale in PenÃnsula ValdÃ©s, Patagonia, Argentina
Ailen Chalcobsky, Enrique A. Crespo and Mariano A. Coscarella
The whale watching in Argentina began in 1973, in PenÃnsula ValdÃ©s, with the southern right whale (Eubalaena australis) as target, and it was regulated in 1984. Until now, only short-term effects of whale watching were evaluated, but the long-term effects were not. The population of whales is increasing locally and expanding to adjacent areas. Therefore, the commercial activity must adapt to this changing system, likely modifying their regulations. In the context of an integrative evaluation, the socio-biological system could be assessed using the concept of Limit of Acceptable Change. We evaluate the effect of the boats on the biological system, using a proxy of the energy expenditure of those individuals exposed to whale watching boats. The breathing rate, linearity, reorientation rate, movement speed, and total distance travelled were assessed between whales with and without whale watching boats around. Differences were not significant for every index analysed except for the breathing rate; the average number of blows decreases for all types of individuals when the boats were present. Whale watching at PenÃnsula ValdÃ©s at this level of activity is carried out without significant effects on the movement indices analysed. At the light of present work and previous local research, the whales that breeding at PenÃnsula ValdÃ©s may be habituated to whale watching boats.