Publications scientifiques

Quelques publications scientifiques pour en apprendre plus sur l’activité d’observation des cétacés à La Réunion : 

Hoarau, L., Dalleau, M., Delaspre, S., Barra, T. & Landes, A.E. Assessing and Mitigating Humpback Whale (Megaptera Novaeangliae) Disturbance of Whale-watching Activities in Reunion Island. Tourism in Marine Environments, Volume 15, Numbers 3-4, 2020, pp. 173-189(17).


Whale watching, including swim-with-whales activities, is developing at an enormous rate in Reunion Island. This is raising concerns about its impacts on breeding humpback whales and challenging the sustainability of the activity. In 2017, a dedicated-at-sea patrol team, « Quiétude, » was created to observe, monitor, and raise awareness to the whale watchers in order to improve compliance with local guidelines. In this context, the team assessed whale watching in Reunion Island during two humpback whale breeding seasons in 2017 and 2018, between June and October. Sighted groups were mostly composed of mother/calf pairs spending most of their time resting near or at the surface. Whale-watching vessels were present in 85.1% of sightings, of which 68.4% were recreative. Swimwith-cetaceans activities were very frequently observed in 42% of sightings. Overall, compliance with the charter was as high as 68% of whale sightings with vessels/swimmers were in line with the recommendations. However, low compliance (32.8%) was observed with the specific recommendations of swim-with-cetaceans activities. Swimmers were reported in surface active groups displaying agonistic behaviors, which poses evident human safety concerns. Humpback whale resting behaviors were disrupted significantly by whale-watching activities. Humpback whales tended to avoid vessels and swimmers, especially when their behavior was intrusive or not compliant with the charter. Positive humpback whale responses were more likely to occur if the charter’s recommendations were not breached. Our results highlight how a nonbinding regulation, with recommendations scrupulously pursued, allows for a reduction in whale-watching disturbances and supports a better tourism experience. Our results advocate for reinforcing tourism education, whale-watching adaptive management and regulations, specifically for vulnerable groups with a calf, and for the swim-with-whales activities. This could be efficiently achieved by engaging all stakeholders and the permanent team on the field « Quietude » to enhance dissemination of best practices and sensitivity around sustainable values of implemented regulations.

Barra, T., Bejder, L., Dalleau, M., Delaspre, S., Landes, A.E., Harvey, M. & Hoarau, L. Social Media Reveal High Rates of Agonistic Behaviors of Humpback Whales in Response to Swim-with Activities Off Reunion Island. Tourism in Marine Environments, Volume 15, Numbers 3-4, 2020, pp. 191-209(19).

The effect of nature-based tourism on wildlife has been the focus of much attention. Studies have demonstrated how boat-based cetacean-watching tourism can cause both short-term and long-term effects on targeted populations. However, limited attention has been given to the effect of swim-with activities on humpback whales (Megaptera novaeangliae). This study qualified whale responses to swim-with activities off Reunion Island during the 2018 humpback whales breeding season. We used both under- and above-water videos collected from social media outlets, commercial whale-watching operators, and audiovisual professionals. We documented a high rate of agonistic whale behaviors (during 42.1% of all observations; n = 164) towards swimmers within videos containing swim-with events. We documented seven agonistic behaviors including threat, attack, or defense behaviors that were predominantly exhibited by mother/calf groups (73.8%; n = 121) and by singletons (16.5%; n= 27). Pectoral shears (27.4%) and fluke thrashes (23.2%) were the most exhibited agonistic whale behaviors aimed towards swimmers, both of which pose a danger and serious injury to swimmers. During swim-with attempts whales changed their behavioral state (82.3%, n = 159) and used avoidance tactics to avoid swimmers (56.1%, n = 92). Whales exhibited a higher rate of agonistic behaviors when swim groups were active and dispersed, in contrast to when they were quiet and compact. To mitigate whale disturbance and improve swimmer safety, we recommend avoiding swimming with whale groups containing calfs. Our findings support the implementation of strong regulations and educational tools to ensure a sustainable practice of whale watching off the Reunion Island.

Chazot, J., Hoarau, L., Carzon, P., Wagner, J., Sorby, S., Ratel, M. & Barcelo, A. Recommendations for Sustainable Cetacean-Based Tourism in French Territories: A Review on the Industry and Current Management Actions. Tourism in Marine Environments, Volume 15, Numbers 3-4, 2020, pp. 211-235(25).

Whale-watching activities provide important socioeconomic benefits for local communities and constitute powerful platform incentives for marine mammals’ protection or more broadly marine environments. However, these activities can cause adverse effects on targeted populations, with considerable downside associated risks of injuries and fatality for whale watchers during inwater interactions. France with its overseas territories has the second largest exclusive economic zone (EEZ), in which more than half of existing cetacean species are encountered. In these territories, recreational and commercial whale watching, including swim-with cetacean activities, have recently developed. Yet few studies focused on these activities and their associated impacts across French territories, leading to an unclear assessment of the situation. To address this issue, we reviewed cetaceans’ occurrence within the French EEZ, whale-watching industry, targeted species, local management of marine mammal-based tourism activities, and regulations in France mainland and some overseas territories (Reunion Island, Mayotte, and French Polynesia). Fortyeight species are encountered in the French EEZ, and 15 are targeted by whale-watching activities. A total of 185 operators, including 34% offering swim-with-cetaceans tours, offered trips in France and overseas in 2019. While several more or less restrictive regulations exist locally, our results indicate that French’s national legal framework for marine mammals’ protection remains inadequate and insufficient to cope with the recent development of this activity. As conservation biologists, managers, and stakeholders from these French territories, we cooperated to provide general guidelines for a sustainable development of whale watching at a national scale. We urge (1) to legally acknowledge and regulate whale-watching commercial activities; (2) to create a national legal framework regarding whale watching and swim-with marine mammals practices, while accounting for local distinctiveness and disparities across regions; (3) to conduct more research to evaluate local short- and long-term impacts on targeted marine mammal populations as well as the socioeconomic benefits; and (4) to reinforce synergetic relations between the different stakeholders.