Gephyreus Project
Introduction
We are an international conservation initiative launched in 2018, dedicated to reversing the critical conservation status of Lahille's bottlenose dolphin (Tursiops gephyreus) and its habitat.
The initiative aims to promote and provide coordinated support for research and conservation actions in strategic locations across southern Brazil, Uruguay, and Argentina, covering the entire distribution range of the species.
Our actions include systematic population monitoring following rigorous scientific and academic standards, environmental education with coastal communities, training, and social communication, fostering engagement with local stakeholders, governments, and decision-makers.
The network is supported by a multidisciplinary team with extensive experience in the study and conservation of marine mammals, working in alignment with international conservation organizations and initiatives such as the International Union for Conservation of Nature (IUCN), International Whaling Commission (IWC), the Latin American Society of Specialists in Aquatic Mammals (SOLAMAC), and the Society for Marine Mammalogy (SMM).
History
The Gephyreus Project was born as a response to the urgent need for research and conservation of Lahille's bottlenose dolphin, which for decades was overlooked in conservation efforts due to being classified as a globally abundant species (the common bottlenose dolphin, Tursiops truncatus).
However, the recognition that coastal dolphin populations across southern Brazil, Uruguay, and Argentina constitute a distinct taxonomic unit brought attention to the newly named Lahille's bottlenose dolphin, which faces incidental capture and other threats such as pollution and historical declines in parts of its range.
In 2010 and 2017, workshops brought together researchers from Brazil, Uruguay, and Argentina, fostering collaborations that resulted in several projects focused on the species, highlighting the possibility of a very small population size for the entire species. As research progressed, the need for a more coordinated and comprehensive approach became evident.
In 2018, the Gephyreus Project was established as a multi-institutional research network to enhance the study and conservation of Lahille's bottlenose dolphin in southern Brazil and Uruguay, conducting simultaneous and coordinated sampling in six locations.
By 2021, the initiative expanded to include Argentina, aiming to coordinate conservation efforts across the species' entire distribution range.
Mission
The mission of the Gephyreus Project is to reverse the critical conservation status of Lahille's bottlenose dolphin, an endemic and threatened species of the coastal waters along the Atlantic coast of South America.
The project brings together scientists and organizations from around the world to promote community engagement in the conservation process and to support, in a coordinated manner, research, conservation, and management actions addressing impacting factors across the species' entire distribution range.
Research Lines
Nature Data Collection
The fieldwork of the Gephyreus Project involves boat-based and/or fixed-point monitoring (for photo-identification and biopsy data collection) and beach monitoring (for mortality data collection). Monitoring activities take place along the coasts of Brazil, Uruguay, and Argentina, with different partner institutions responsible for specific regions.
Photo-identification is an effective tool for studying the population ecology of aquatic mammals. It is used to identify individuals through photographs of body parts that exhibit unique characteristics. For Lahille's bottlenose dolphin, the focus is on its dorsal fin, where permanent marks such as cuts, deformities, pigmentation patterns, scratches, and spots are typically visible, aiding in individual identification.
Through photo-identification, we track key life events of individuals, enabling the monitoring of population trends through successive estimates of ecological parameters such as abundance, survival, and reproductive rates. Catalogs of photo-identified animals from each region and the sharing of this data among partner institutions allow for understanding the movement of individuals between areas.
During boat-based monitoring, we also collect biopsies from photo-identified individuals, providing skin and blubber samples from the animals. The technique involves the use of crossbows equipped with modified darts and tips that minimize potential impacts on the animals. Although invasive, the amount of information generated is highly relevant for conservation, especially when there is previous data on the life history of the sampled individual. Skin samples are used for genetic and trophic ecology studies, while blubber samples contribute to research on contaminants and hormones.
Beach monitoring is conducted using four-wheel-drive vehicles over large areas. For carcasses found during the surveys, which may cover distances ranging from tens to hundreds of kilometers, a range of data is collected, including morphometric measurements, assessment of interactions with fishing activities, and the collection of organ, skull, and skeletal samples. This information forms a rich database for science and contributes to research on taxonomy, health, and temporal and spatial mortality patterns, allowing the detection of abnormalities in the animals' life cycle patterns, such as their relationship with extreme climatic events or epidemics.
Population Structure
The degree of connectivity and the geographic boundaries between populations of a species define its population structure, a key element for developing research and conservation plans tailored to the reality of each population unit.
Lahille's bottlenose dolphin exhibits a population structure that is becoming increasingly understood, divided into two subpopulations with a high degree of genetic differentiation. One subpopulation occurs in southern Brazil and Uruguay, spanning the states of Paraná, Santa Catarina, and Rio Grande do Sul, up to areas near the Rio de la Plata, with at least five Management Units. The other subpopulation is found in Argentina, consisting of a single Management Unit represented by the local population in Bahía San Antonio.
The Gephyreus Project works to increase the sample size of photo-identified individuals and biopsies (skin and blubber) across Lahille's bottlenose dolphin distribution. The goal is to refine the delineation of each Management Unit and assess the degree of reproductive connectivity between them through genomic studies.
Demography
The study of demography helps us understand the extinction risks of a species or its populations. Demography involves mathematical analyses of various parameters, allowing us to understand how population characteristics change over time.
The Gephyreus Project collects data to generate estimates of the following parameters: population size, age structure, fecundity (birth rates), stage-specific survival, and sex ratio. Photo-identification data collected from different local populations are analyzed in an integrated manner to provide estimates that represent the two known subpopulations (southern Brazil-Uruguay and Argentina).
Using this information, we develop Population Viability Models (PVMs) to assess extinction risk, project future population trends, and define conservation and management strategies.
Mortality and Bycatch
The greatest threat to the conservation of Lahille's bottlenose dolphin is bycatch in gillnet fisheries, as even low levels of bycatch can significantly affect population viability.
Understanding the impact of bycatch on populations helps propose fisheries management measures aimed at reducing captures to more sustainable levels.
To achieve this, we focus on the following main approaches:
- Estimation of mortality and its impact on age and sex structure;
- Socioeconomic and ethnoecological work with fishing communities;
- Scientific outreach and environmental education;
- Testing new technologies;
- Proposing public policies and evaluating their effectiveness in reducing bycatch levels.
Health
Veterinary techniques for health assessments in small cetaceans have been standardized and improved over the years, resulting in precise, safe, quick, and responsible examinations. A hypothesis-driven health assessment can significantly enhance the understanding of how environmental and external factors (such as fishing activities, pollution, and prey depletion) impact the health, movement, reproduction, and survival of Lahille's bottlenose dolphins.
The National Marine Mammal Foundation (NMMF), a partner of the Gephyreus Project, leads studies on individual and population health of bottlenose dolphins (Tursiops truncatus) in U.S. waters. With NMMF's expertise, the Gephyreus Project aims to develop a Health Monitoring Program for Lahille's bottlenose dolphin. To this end, we are assessing the health of the animals through photo-identification data, drone imagery, and contaminant analysis of biopsy samples.
There is potential to implement a long-term health assessment program through the capture and release of individuals. This could involve a series of veterinary examinations as well as the deployment of satellite transmitters to understand fine-scale movements and diving patterns of the species.
Action Plan 2022–2027
Lahille's bottlenose dolphin, endemic to the Atlantic coast of South America, is a critically endangered species with immense social value as one of the few cetaceans in the world to have developed cooperative behavior with artisanal fishers for mullet capture.
Recognizing the critical status and urgent need for the conservation of Lahille's bottlenose dolphin, and its inclusion as a priority species in the IUCN's Integrated Conservation Planning for Cetaceans (ICPC), in January 2023, the Yaqu Pacha Foundation and the Nuremberg Zoo commissioned a strategic action plan to strengthen conservation efforts.
The development of the plan involved a comprehensive review of previous recommendations and consultations with various experts, focusing on five strategic lines:
- Scientific Research and Conservation
- Legislation and Policy
- Communication, Outreach, and Awareness
- Institutional Strengthening and Education
- Citizen Science
Actions were prioritized due to limited financial resources, with eight of the 26 projects identified as high priority.
By addressing the challenges faced by Lahille's bottlenose dolphin and enhancing international cooperation, the plan aims to protect and reverse the critical conservation status of this endangered species.
Gephyreus Project Team
