Impacts of Whale-Watching on the Short-Term Behavior of Fin Whales (Balaenoptera physalus) in a Marine Protected Area in the Southeastern Pacific

Abstract

Whale-watching (WW) is an activity which has been increasing worldwide due to the great interest of tourists and the economic benefits it provides to local communities. However, it has been reported that this activity affects the behavioral patterns of some cetaceans, although for some species such as the fin whale (Balaenoptera physalus) this has not been extensively studied. To identify the effects of WW on the behavioral patterns of this species, we studied its traveling and resting behaviors in a locality of north-central Chile from 2015 to 2018. Using a theodolite, we calculated the response variables of swim speed, directness index, and reorientation for each behavior. We used the number of WW boats and the WW scenarios of “before”, “during”, and “after” the presence of boats as possible factors to explain the differences in the response variables of the whales, along with the factors of year, month, group size, and distance from the observation point. Reorientation increased significantly and the directness index decreased significantly for both traveling and resting behaviors from “before” to “during” WW scenarios, indicating more erratic and sinuous movements in the presence of boats. These changes in movement patterns are a commonly reported evasion response of cetaceans to the presence of WW boats. For traveling behavior, the swimming speed significantly increased, and trends showed increased reorientation and a decrease in the directness index in the “after” WW scenario, which suggests perturbation of the whales potentially associated with the speed and the direction in which the boats left. During resting behavior, the trajectories of the fin whales became straighter (decrease in reorientation) as the number of boats increased, thus evasion (more erratic and sinuous movements) is a behavior used less by fin whales as the number of boats increases. Notwithstanding the fact that tourism development in the study area is small in scale, we found that WW generates adverse effects that are reflected in changes in the whales’ movement patterns. This kind of information is valuable to the adjustment and/or design of management strategies for the species, which is fundamental for WW to continue to be a sustainable activity.

Abundance and distribution patterns of cetaceans and their overlap with vessel traffic in the Humboldt Current Ecosystem, Chile

“…The detrimental effects of interactions between cetaceans and vessel-based activities are diverse and involve collisions, behavioral disruption, noise exposure, entanglement in fishing gear and prey depletion by fisheries [103][104][105][106][107] . Some of these negative impacts are being evaluated in the HCE, but studies are few and localized [34][35][36] . In the particular case of bycatch, information for Chilean waters is extremely scarce, sparse over time and in some cases not necessarily confirmed 33,105,108,109 .…”

Fin Whale Balaenoptera physalus Historical Sightings and Strandings, Ship Strikes, Breeding Areas and Other Threats in the Mediterranean Sea: A Review (1624–2023)

“…Whales in the Gulf of Maine reduced their dives, duration and number of blows per surface sequence in the presence of vessels [58]. In Chile, fin whales also showed evasive responses to the presence of whale-watching vessels [59]. In the Mediterranean, an increase in speed and zigzagging movements together with a decrease in blowing frequency was reported as an avoidance response to the presence of vessels [19].…”

The role of operators in sustainable whale-watching tourism: Proposing a continuous training framework

“…Among ecotourism activities, whale watching has been increasing worldwide since the early ´90s, generating a wide range of opportunities and economic benefits for coastal communities [ 7 , 8 ]. Hoyt [ 9 p3] defined whale watching, as “tours by boat, air or from land, formal or informal, with at least some commercial aspect, to see, swim with, and/or listen to any of the 83 species of whales, dolphins and porpoises”.…”