Brazilian marine mammalogist Pedro Fruet has studied Lahille’s bottlenose dolphins, a rare endemic sub-species of the bottlenose dolphin found in Argentina and the southern Brazil-Uruguay region, since 2000. He was awarded the prestigious Whitley Award in 2021 for this work and now hopes to reduce bycatch and raise awareness of the social species.

Oceanographic Magazine (OM): What was it like holidaying by the ocean as a child?

Pedro Fruet (PF): I am very lucky to have had the opportunity to spend long periods on the beach during my childhood, especially at Cassino beach in southern Brazil. The ocean is so special to me. Everyone should have the opportunity to see and feel the energy of the sea and connect with wildlife. I don’t remember having a specific moment that made me realise that the ocean needed protection. It was a process that grew as I began to understand our dependence on the oceans and the sensitivity of ecological processes.

OM: When was the first time you had an encounter with the Lahille’s bottlenose dolphins?

PF: I had my first encounter with Lahille’s bottlenose dolphins during a surf session when I was 12 years old. After my incessant requests, my parents took me surfing in the late afternoon. They waited in the car while I ran out to sea. I was alone in the ocean when a small group of dolphins came by. The group of dolphins stayed quite a long time with me and came very close. For a split second I was scared, but then I enjoyed every second of that encounter as I realised that those animals were curious and looked for a way to interact with me. A few seconds felt like hours. Time stopped. The event connected me with these animals. It made me reflect on the way in which humanity understands and interacts with wildlife, and it pointed out the need for us to change our attitudes.

OM: Which came first – a love of science, or a love of the ocean?

PF: A love of the ocean. Through science I found a way to focus my energy on understanding ecological processes and promoting conservation.

OM: What is so special about the Lahille’s bottlenose dolphins?

PF: The cooperative behaviour with artisanal castnet fishers is the most special and unique feature of Lahille’s bottlenose dolphins (they have started cooperating with artisanal fishers to catch mullet). The first time I witnessed this amazing cooperation was during a field survey in 2000. I was an intern at Universidade Federal do Rio Grande do Sul providing support to Dr. Lilian Sander Hoffman, who at the time was conducting her doctoral thesis studying the bioacoustics and social structure of cooperative dolphins in the Tramandaí River estuary, on the north coast of Rio Grande do Sul.

OM: What is it like to interact with these dolphins? Why was it only recently that the Lahille’s bottlenose dolphins were described as a subspecies?

PF: In brief, the taxonomy of bottlenose dolphins has been the subject of debate among scientists over decades and more than 20 nominal species have been described for the Tursiops.  In the decade of 1980, most of them have been subsequently suppressed and synonymised under the single cosmopolitan species T. truncatus. However, new data, including genetics, morphology, and distribution, has shown that the bottlenose dolphins inhabiting the coastal waters of the Atlantic Coast of South America are in fact isolated from their counterparts and are following a distinct evolutionary path. These new studies indicated that Lahille’s bottlenose dolphins are restricted to the coastal waters of southern Brazil, Uruguay, and Argentina, have different skull and vertebral column morphology and are genetically isolated from their counterparts. All of this evidence was key to internationally recognise the Lahille’s bottlenose dolphin as a subspecies in 2018.

OM: What sort of fishing gear and techniques are causing the dolphins to become entangled?

PF: Fisheries are very dynamic and each region uses different fishing methods. Around the Patos Lagoon Estuary, where the largest number of Lahille’s bottlenose dolphins can be found, the most acute threat comes from gillnets. Two types of gillnet fisheries kill these animals in the area: the boat-based artisanal gillnetting and trammel net fishing from the beach. Artisanal beach seine also kills Lahille’s bottlenose dolphins but at lower rates than gillnets. The beach trammel nets are traps for dolphins when they are moving along the southern Brazil coast. Bycatch, on the other hand, is higher in Brazil, low in Uruguay and very rare in Argentina.

OM: Are there any other kinds of threats to these dolphins?

PF: They also suffer from chemical and noise pollution, overfishing and boat strikes. In the north of their distribution range, they suffer from acute skin diseases too.

OM: Why is it so important that the Lahille’s bottlenose dolphins are protected?

PF: We have a moral obligation to prevent species from becoming extinct or living under bad conditions and these dolphins are threatened by human actions. We must learn to coexist with wildlife. Cetaceans are unique animals that have the power to connect people with nature and we can’t lose this connection. They are beautiful animals and people love them. If we can’t protect what we love, what will our motivation be to fight for a better world?

OM: How does the species impact the ecosystem?

PF: It is important to remember that Lahille’s bottlenose dolphins are top predators that exclusively inhabit coastal waters, which are key to the productivity of the oceans and the development of commercially exploited species. Like other cetacean species, they help regulate ecosystem functions on which we rely heavily. They prey on many species and help to maintain the structure of the trophic food chain. If we succeed in protecting Lahille’s bottlenose dolphins, it could benefit the conservation of many other species and habitats that help to sustain ecosystem functions.

OM: Why is it important to you that you build bridges between different disciplines such as science and local communities?

PF: In this specific case, we are not dealing with an isolated environmental problem where the solution solely lies in science. The origin of the conservation problem for Lahille’s bottlenose dolphins is social. For a long time, we have been thinking about conservation in an isolated and disconnected way from the socio-environmental reality. For this reason, in my point of view, we have failed. The artisanal fisherman is part of a group that is subject to high socio-environmental vulnerability and the reduction in the mortality of dolphins in fishing nets depends on changing the behaviour and attitudes of these actors. They, artisanal fishermen, have been excluded from decision-making and management processes. We cannot think of reducing the dolphin bycatch simply by announcing a no-take zone when there is no prospect of an alternative income for the community. Institutions need to think about establishing control and inspection rules in an integrated and fair manner. Our approach aims to develop transparent, inclusive and fair local fisheries management.

OM: How do you plan to curb bycatch in the area while also protecting fishers’ livelihoods?

PF: There is no definitive answer, but I hope that at the end of this project we will have viable proposals or at least have a direction. I believe that this scenario will only be possible if we change our way of thinking about conservation and seek to understand the detailed impacts and the socio-economic context of fishing. We intend to use local knowledge to collectively build alternatives. This is key. People need to feel part of the process. Artisanal fishermen and the institutions that establish public surveillance policies have a vast knowledge that must be integrated to collectively think of sustainable alternatives, observing the socio-environmental and economic aspects. With this project we want to start this shared management process in which decisions are agreed among actors, rather than imposed.