Alteration of Southern Right Whale (Eubalaena australis) Behaviour by Human-Induced Disturbance in Bahía San Antonio, Patagonia, Argentina

A study was conducted to assess the behavioural response of southern right whales (Eubalaena australis) to human-induced disturbance in Bahia San Antonio, Province of Rio Negro, Argentina. Behavioural observations were made from June to October in 2008, 2009, and 2010. Aerial observations carried out in 2010 show that up to one third of the whale groups were mating groups, indicating that the study area is an important reproduction area for the species. The study compares 65.8 h (on a total effort of 120.3 h and 24 groups of whales) of land-based “undisturbed” whale behaviour observations to 43.6 h of boat-based whale behaviour in a “disturbed” state (total effort of 326.1 h and 34 groups of whales). Analysis of the behavioural data show that whales significantly altered their behaviour by cutting social interactions short (on average 13%) when confronted with human shortrange presence. At the same time, travelling whales experienced a significant increasing tendency to continue travelling (+21%) instead of starting to rest (-21%). However, social behavioural patterns returned swiftly to normal levels after the approach had ended, with a relative increase in “resting” (+18%) as opposed to “travelling” (-30%) rates. These data show that whale behaviour is altered by human approaches, pointing out the need for effective conservation measures and mitigation of behavioural impacts in relation to whale-based tourism.