environmental-dna-sampling-from-whale-watching-vessels-for-cetacean

Environmental DNA Sampling from Whale-Watching Vessels for Cetacean Monitoring

Environmental DNA (eDNA) offers a non-invasive approach for monitoring cetaceans, yet its widespread application from operational platforms requires ...

Tethys Research Institute

The Marine Strategy Framework Directive (MSFD) requires the assessment of the environmental status in relation to human pressures. In this study the biodiversity of the cetacean community is proposed as MSFD descriptor of the environmental status and its link with anthropogenic pressures is investigated. Functional groups are generally favoured over indicator species since they are thought to better reflect to anthropogenic stressors. Cetaceans are in many situations the most well known component of pelagic ecosystems. Their habitat requirements are known and can be used to evaluate the theoretical biodiversity that should be expected in a certain area. The deviations between the theoretical biodiversity and the actual biodiversity may be used to detect the impacts of human activities. Based on this analysis fishery resulted to be by far the most significant of the existing pressures. Among all the species, bottlenose dolphin was found the most correlated with the fishery sector dynamics.

An index based on the biodiversity of cetacean species to assess the environmental status of marine ecosystems.

Sperm whale trumpets are sounds only occasionally documented, with a well recognisable and stereotyped acoustic arrangement. This study investigated the acoustic features of the trumpets and the context in which these sounds were recorded, using acoustic data collected over 22 years, in the Pelagos Sanctuary area (North-Western Mediterranean Sea). Analysed trumpets (n = 230), recorded at the beginning of a dive after the whale fluke-up, comprised a series of acoustic units organized in short sequences. Acoustic parameters were derived for the entire trumpet and for each distinguishable unit in a trumpet. Overall, trumpet durations and their initial frequencies were higher in recordings collected when multiple whales were visually or acoustically detected in the observation area. The identity of 68 whales was assessed through photo-identification, with 29 individuals producing trumpets within and between years. The variability of the acoustic parameters appeared to be higher within the same individuals rather than between different individuals, suggesting an individual plasticity in composing and arranging units in a trumpet. Different click patterns were observed before and after the trumpets, with more complex sequences when (1) other whales were visually/acoustically detected, and (2) individuals were in suitable foraging sites (i.e., canyon areas). Trumpets were commonly followed or preceded by click patterns suited for communication, such as codas and/or slow clicks. Significant relations between the trumpet emission and the male-only long-range communication click pattern (i.e. slow clicks) emerged, supporting the hypothesis that a trumpet is a sound emitted by maturing/mature males in feeding grounds. This study provides the first evidence that trumpets were conserved in the sperm whale acoustic repertoire at the decadal timescale, persisting across years and individuals in the same area. This persistence may be functionally specific to foraging activities performed by males in a well-established feeding area.

Trumpet sounds emitted by male sperm whales in the Mediterranean Sea.

The common bottlenose dolphin is a cosmopolitan species that can be found worldwide in all oceans except polar and sub-polar waters. This wide distribution is associated with a certain level of morphological variation, which seems consistent with the presence of a globally distributed pelagic/offshore ecotype and several coastal/inshore ecotypes distributed along the continental shelf. In the Mediterranean Sea, the common bottlenose dolphin is a regularly occurring species and the second most sighted cetacean after the striped dolphin. According to some studies, the Mediterranean bottlenose dolphin is more closely related to the Atlantic coastal ecotype, while others suggest a closer link with the pelagic ecotype. This apparent contradiction could stem from the coexistence of two ecotypes also within the Mediterranean Sea, as suggested by genetic analyses. We analysed data collected from 2004 to 2019 by 43 different research groups, distributed in different areas of the basin, and shared on the web-based GIS platform Intercet. We analysed the distribution and movements of 4919 bottlenose dolphins, individually identified through their natural dorsal fin markings, in relation to bathymetry and in particular to the 200-meter isobath that marks the edge of the continental shelf. In addition, we reconstructed the associations between individuals within connectivity networks, to identify possible segregations between ecotypes. Our results show that most bottlenose dolphin geographical units find their habitat over the continental shelf, while the analysed data do not support the coexistence of different ecotypes (pelagic vs. coastal) living in parapatry, as described in the adjacent waters of the eastern Atlantic Ocean.

Investigating the presence of different bottlenose dolphin ecotypes in the Mediterranean Sea.

Marine biodiversity faces challenges due to climate change, pollution, and human activities. Conservation efforts are often constrained by limited resources and public disengagement. This study evaluates the potential benefits of incorporating environmental DNA (eDNA) sampling and citizen science into whale-watching tours to raise environmental awareness and promote marine conservation. A Likert-scale questionnaire evaluating attitudes, knowledge, and willingness to contribute to conservation through financial support, behavioral changes, and volunteering was administered to 224 participants across the Pelagos Sanctuary (Italy), the Azores (Portugal), and Skjálfandi Bay (Iceland). Environmental awareness, interest in environmental DNA (eDNA), and higher education levels were identified as significant predictors of willingness to pay (WTP). Conversely, higher ticket prices negatively impacted financial commitment. The majority of respondents reported an increased awareness of marine biodiversity and eDNA, along with a strong sense of personal responsibility toward marine protection. The study outlined various participant profiles, indicating how age, education, and ecotourism experience influence conservation attitudes. Specifically, younger individuals who are highly educated and have prior whale-watching experience were more inclined to provide financial support and engage in citizen science activities. These findings demonstrate that integrating citizen science-based activities and environmental DNA (eDNA) sampling, into whale-watching tours is an effective way to foster meaningful pro-environmental engagement. This model presents a scalable and cost-effective approach to enhancing public participation in marine conservation and biodiversity monitoring, with potential applications extending to broader marine governance and ecotourism settings.

Article	Year
An index based on the biodiversity of cetacean species to assess the environmental status of marine ecosystems. Marine environmental research\| PubMed ID: 25016937	2014
Trumpet sounds emitted by male sperm whales in the Mediterranean Sea. Scientific reports\| PubMed ID: 33712633	2021
Investigating the presence of different bottlenose dolphin ecotypes in the Mediterranean Sea. Scientific reports\| PubMed ID: 39952977	2025
Willingness to engage in marine conservation through eDNA-informed citizen science on whale-watching platforms. Scientific reports\| PubMed ID: 41290929	2025

Caterina Lanfredi

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