An evaluation of the behavioural response of southern right whales (Eubalaena australis) on boat and swimmer interactions in the bay of San Antonio, Patagonia, Argentina
Verheyen, D.A.M. (2011). An evaluation of the behavioural response of southern right whales (Eubalaena australis) on boat and swimmer interactions in the bay of San Antonio, Patagonia, Argentina. MSc Thesis. Ghent University: Gent. 29, V pp.
In 2006, the province of Río Negro in Argentina approved whale-watching and swim-with-whale activities on southern right whales (Eubalaena australis) by law. These tourist attractions are carried out in the bay of San Antonio ever since, without considering possible effects on the whales. This study evaluated the behavioural response of the whales in the bay, subjected to controlled human approaches. The results are essential to evaluate the impact of whale-based tourism on the animals and to implement adequate conservation measurements in order to protect the species in the area. Behavioural data of the whales were collected during July-September 2010 in the bay of San Antonio, Río Negro, Patagonia, Argentina. A total of 29 focal whales were approached during boat-based surveys (total effort of 78.3h). Positive observations were noted before (9.6h), during (21.7h) and after (8.6h) interaction with boat and/or swimmers. Additional land-based surveys were preformed (total effort of 27.4h) obtaining 9.4h of undisturbed behavioural observations of 10 focal animals. Results suggest the bay appears to become an important mating ground, since 41.4% of the boat-based observed group compositions were related with courtship behaviour (46.2% for land-based observations). Compared to the behaviour observed before an interaction, whales spent less time in an active behaviour (-25%) when being approached, whilst they tended to travel more (+24%) and longer at a stretch. After human interaction ended, the whales returned to their normal behavioural patterns, but more tendency to start resting and active behaviour was observed. Results suggest that the whales were more disturbed (+18.4% approach; +23.2% avoidance) if swimmers were present. Although the significant differences in mean lengths of time spent in a certain behavioural state prove that boat and/or swimmer interactions altered the behaviour of the animals, the real extent of this impact could not be identified. No major impacts on the whales were found until the boat entered the 500m zone around the animal. To improve the conservation of the southern right whales in the province of Río Negro, short- and thus possible long-term impacts on the animals have to be reduced to a minimum. For this, the whale-based tourism must be restrained and controlled urgently. In order to make recommendations for adequate regulations and conservation measurements for the species in the area, more research is necessary.
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