Searching for Sawfish on the Amazonian Coast
SHOWNOTES
Patricia has been fascinated by sharks and rays since childhood [6.09]. Some of her fondest memories are of meeting local fishers and seeing what they had brought back from the sea, especially as by-catch. Most of these boats were small trawling vessels targeting shrimps, and so they would discard anything else, throwing it back to the water. Patricia loved looking in the baskets to see what marine life she could find – jellyfishes, marine snails and baby sharks and rays. “Sometimes they would be alive, and I was like cheering for the animals to go back into the water.” She says. “That was a big memory, and one of the main reasons I was interested in sharks and rays since a young age, you know seven or eight years old.”
These early interactions with the fisheries formed a solid foundation for Patricia’s future career [9.08]. Not only did it nurture her interest in marine life and conservation, but it also formed important relationships with the fishers, who later provided Patricia with specimens for her early studies on bony fishes: “I had to do some studies with live fish, and [the fishers] would be taking buckets of water and bringing me live catches so I could study them and do my reports.” She recalls. Building such trust with the fishers has helped to further Patricia’s work with sharks and rays, and she firmly believes that such relationships are important to achieving conservation goals. “These are the people that have direct access to the resources that we’re trying to access and conserve, and I think that once they believe in you, and they trust your work…it’s only going to get easier and easier.”
Patricia has worked with a number of different species across Brazil, including the incredible freshwater stingrays of the Amazon river. But a species that she has always considered her favourite, and one that she continues to come back to, is the sawfish. And her determination to work with and protect this species has brought her to northern Brazil and the Amazonian coast, a region she suspects is one of the last strongholds for the species in the Atlantic. But what is the Amazonian coast like – what kind of habitats and environmental conditions might we expect to find there [11.45]? Firstly, the waters are very warm, with temperatures hovering around twenty-two to twenty-six degrees Celsius. “It’s really like a hot bathtub!” Laughs Patricia. It’s also a very dynamic environment. This is where the Amazon river – the largest and most powerful river in the world – meets the Atlantic ocean. At certain times of the year, like the rainy season, the Amazon river can push back the Atlantic ocean for up to 200km off the coast! This means that there is a lot of mixing of waters with different salinities – the freshwater from the river, the saltwater from the ocean, and brackish water in between. Amazingly, some species can travel across these different salinities, sometimes switching from fresh to saltwater, like the bull sharks that have been known to travel up the Amazon. Others, like the freshwater stingrays, are restricted to a particular salinity, but the discharge of the Amazon allows them to travel further offshore. The warmth and dynamism of this region generates high productivity, resulting in a diversity of species – many of which are endemic to the Amazonian coast. Biodiversity is also supported by a rich diversity of habitats. For example, the region has one of the largest continuous stretches of mangroves in the world, a vital habitat for juvenile fishes including sharks and rays. There is also the open Atlantic ocean, sheltered bays and lagoons, and a variety of sediments, from sandy to muddy. The Amazonian coast is therefore considered by oceanographers one of the most dynamic environments in the world, in terms of temperature, current, temperature, productivity and species richness.
Living amongst this incredibly diverse and ever-changing place is a species that is rapidly disappearing elsewhere – the largetooth sawfish. Since her teenage years, Patricia has wanted to work with this species, but researching them proved to be a significant challenge [20.49]. As a master’s student, Patricia was warned against travelling to northern Brazil to study them, largely due to concerns for her own safety on account of illegal activities in the region. She was asked to change topic and ended up working with freshwater stingrays for many years. But this didn’t stop Patricia pursuing sawfish. She quietly built a substantial database – collecting saws and other sawfish products at local markets, searching through the literature, and speaking with fishers. Across fifteen years, Patricia collected over 120 sawfish rostra! These were donated to other research projects, mainly genetic studies, which Patricia is glad to have been part of: “It was extremely frustrating…but I’m very happy to see other projects using the teeth. If it’s a good cause for research, to learn more about these animals, then I’m happy to share samples.”
Although it was a long wait to officially work with sawfish, Patricia’s studies gave her an excellent understanding of what was happening to the population [26.44]. When she first moved to Belém – the capital city of the northern state of Pará and where Patricia carried out her masters studies – Patricia spent a lot of time in the local fish market, “where obviously anyone who studies sharks and rays eventually takes a look.” There, she found small, traditional medicinal stands, which had sawfish rostra hanging from them. She started interviewing the people selling these rostra, and they would tell Patricia that they would sell them as traditional medicine, mainly for the treatment of respiratory illnesses. They would not target sawfish for these purposes, but if sawfish were brought in as by-catch, the saws were retained for this purpose. “I was extremely shocked to see that.” Patricia recalls. “It is folklore. [The saws] are only cartilage, and skin, and tiny dermal denticles covering the saw. There is really nothing there that can be used as a medicine – but there is always the traditional, cultural uses…most of them were neonates, juveniles…small saws. And I was like, ‘this is not looking good’”.
And it wasn’t long until Patricia discovered another use for sawfish products [28.20]. Small bags of loose teeth were also being sold, and Patricia started to investigate why. “I found out they were using the teeth to be exported to neighbouring countries, and to some parts of Brazil, to be used as spurs in cockfighting.” Cockfighting is a practice where two or more specially bred, domesticated birds are forced to fight. It is illegal in Brazil, but still practiced in neighbouring countries. Man-made ‘spurs’ may be attached onto the bird’s leg to aid in the fight. These can be metal, but Patricia found that in some cases, sawfish teeth are used instead. “It’s one of the best spurs, because it keeps the fight going. It doesn’t kill the opposing rooster immediately, but it hurts enough to encourage the fighting.” Again, it was the teeth of smaller or juvenile sawfish that were being used. This finding, coupled with the saws collected for traditional medicine and threats from fisheries (where sawfish were caught as by-catch), seemed to be forming the “perfect storm”.
Despite these threats, the Amazonian coast is still considered one of the last stronghold for largetooth sawfish in the Atlantic [32.16]. The exact reason why is unknown, but there are some hypotheses. One is that the coastline has many sand and mudbanks that are too shallow for fisheries to operate. These are thought to act as refuges for sawfish, which are known to hang out in shallower areas. There are also the extensive mangrove forests that provide nursery grounds for newborn and juvenile sawfish, alongside numerous inlets, islands and bays that also restrict fisheries. “This could change as fishing equipment and technology improves,” says Patricia, “but for now these areas are acting as refuges for the species.” It is also reported that larger individuals can be found in deeper waters, around 50m. The majority of fishing vessels operating on the Amazonian coast trawl at shallower depths, another factor that Patricia believes is currently protecting the sawfish. “Deeper waters will be sheltering the adults…but also the natural characteristics of the region provide refuges for the juveniles.”
This isn’t to say that sawfish are completely protected [35.20]. Patricia’s interviews with fishers have suggested that the region has seen declines, particularly from shallower areas. In one interview, a fisher described being able to see sawfish in water so shallow that the two, distinctive dorsal fins so characteristic of the sawfishes – which are located on the tail – would be sticking out of the water’s surface. Now, he told Patricia, he could canoe all around that same area and not see one. So, there has been damage to the population, and that is exactly why Patricia and her colleague Vincente are working so closely with fishers for their SOSF funded project, Conserving Largetooth Sawfish on the Amazonian Coast [39.50].
The project involves speaking with fishers across the region to improve education and awareness around the sawfish. Many fishers know little about the species and how threatened it is, so Patricia and Vincente discuss with them what sawfish are, their importance and why they need to be protected. “We teach them about the sawfish, and tell their story…that it is something that part of their biodiversity. That these individuals are some of the last ones on earth of this kind of species. If you kill one, you are not leaving your children this benefit.” Patricia explains that, most of the time, the initial reactions of the fishers is one of shock. But once they have learned more about the animal, they experience a sense of ownership and pride, and want to protect the species. “They’re very receptive – the small-scale, artisanal fisheries that is.” Says Patricia. “When you go to the industrial fisheries, the unions, it’s a different story.”
For the latter, conservation requires a different tactic [44.55]. This requires understanding and tackling illegal trade in sawfish products – knowing who is catching what, where it is going, and assisting law enforcement agents to identify and prosecute perpetrators. “It’s very challenging. [The perpetrators] just disappear. We had people moving and hiding in islands for six months to avoid getting caught.” Sometimes, individuals can be identified through posts on social media and Whatsapp, but actually catching and arresting them is extremely difficult. “That’s why we believe that education is key.” Says Patricia. “Trying to get the fishers to respond to the fact that the species is in trouble, threatened…so please release it so your kid will get to see it when he or she grows up.” Also key is mapping where the sawfish are – something that Patricia and Vincente are attempting to do using ‘eDNA’ – and working with government and law enforcement agencies to build capacity and knowledge [47.09]. “We’re also training enforcement agents to recognise sawfish parts…because if they are in doubt, they don’t seize the material. So, if we teach them how to identify [sawfish parts], then they can be more reassured about taking any kind of enforcement measure.”
In short, Patricia is working across all levels – small-scale fishers on the ground, industrial scale fisheries, enforcement agencies and government – to ensure meaningful, sustainable protections for this species. It’s no easy task, and one which requires a lot of hard work, self-motivation, and dedication. “I often feel like I need to be more than one person.” Laughs Patricia. But, for someone who has loved sawfish for as long as she can remember, the effort is worth it in order to see this species brought back from the brink of extinction.
You can read more about Patricia’s project here:
ABOUT OUR GUEST
DR PATRICIA CHARVET
Patricia is a biologist, with a master’s degree in Zoology and a PhD in Biological Sciences with emphasis on Zoology. She has been working on marine and freshwater elasmobranchs (sharks and rays) on topics related to biology, life-history, management and conservation. She is especially keen on sawfishes due to the conservation challenge associated to this group. Patricia is one of the leading scientists of a research project funded by the SOSF in the Amazonian Coast, which involves past and present species’ records, increase of public awareness about sawfish species importance and improvement of protection measures for these critically endangered rays. Currently she is a visiting researcher at the Federal University of Ceará (UFC) and a very honored recipient of a SOSF Conservation Fellowship.
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