Bruno Serranito

The sperm whale is an emblematic species of the Azores archipelago. After a century of intensive whaling, the species has become a focal point for ecotourism since the late 1980s, enabling collaborative research during tourism activities. This study assessed the feasibility of using a citizen science based non-invasive sampling approach to evaluate the genetic diversity of local sperm whales. Seven local whale-watching companies contributed to collect 70 fecal samples and 34 sloughed skin fragments between 2019 and 2024. A 588-bp fragment of mitochondrial DNA Control Region (MCR) was successfully sequenced from 56 fecal samples and all skin fragments, yielding 90 MCR sequences assigned to 79 individual sperm whales. MCR sequences from both sources of the same individuals were in perfect agreement, validating the use of fecal samples for mitochondrial haplotype analysis - the first study to do so in sperm whales. Four MCR haplotypes, including a newly determined one, evidenced different maternal lineages within the Macaronesia population. Haplotypes showed a clear geographic pattern around São Miguel Island: one was restricted almost exclusively to the south coast, while the other three occurred predominantly on the north. This contrasted distribution is likely correlated to different matrilineal groups.

Similarly to other abalone species, the ormer ( Haliotis tuberculata ), considered a delicacy, faced multiple anthropogenic pressures, including overfishing from legal and illegal harvesting. While the ormer is extensively studied in aquaculture, limited information has been available on the status of the wild population H. tuberculata in France since the Vibryo harveyi pandemic occurring in the late 1990s. Such a lack of data may contribute in the gradual shift in the perception of stock changes, known as the Shifting Baseling Syndrome (SBS). To address this gap, we combined historical monitoring data collected in the 1980s in the Emerald Coast (North Brittany; France) with recent participatory science diving surveys conducted by a local NGO in the same area. Using quantile regression and mixed models, we investigated changes in density and size structure over three decades, and further explored the ecology of H. tuberculata . Results showed a size-depth relationship, suggesting an age-related vertical distribution. Models indicated no change in density between the two periods, highlighting population recovery from the pandemic that cause high mortality in the region. However, mean individual size declined by approximately 2 cm compared to the 1980s, mainly related to the decline of individuals larger than the legal catch size (9 cm). Such changes could potentially result from anthropogenic pressures including overfishing, ocean warming or acidification. These preliminary findings highlight the interest of combining participatory science initiative along with historical records to tackle shift baseline syndrome, and to inform conservation and management strategies for overlooked and exploited marine species.

The common bottlenose dolphin (Tursiops truncatus) exhibits significant intraspecific diversity globally, with distinct ecotypes identified in various regions. In the Guadeloupe archipelago, the citizen science NGO OMMAG has been monitoring these dolphins for over a decade, documenting two distinct morphotypes. This study investigates whether these morphotypes represent coastal and oceanic ecotypes, which have not been previously identified in the region. We characterized morphological differences between the two morphotypes, analyzed genetic variation in individuals stranded around Guadeloupe over the past ten years, and modeled their habitats. Results revealed that these morphotypes align with the ecotypes described in the Atlantic Ocean, forming two distinct genetic groups corresponding to Caribbean ecotypes. Habitat modeling showed differences in habitat preferences between the morphotypes. These findings provide strong evidence for the existence of two distinct ecotypes of T. truncatus in Guadeloupe. Considering the varied risks of exposure to maritime traffic, our study suggests that these ecotypes should be managed as separate units within the species to better inform conservation strategies in the region.