Pay to conserve: what we have achieved in 10 years of compensatory releases of threatened with extinction guitarfishes

Abstract

Guitarfishes are of particular concern for marine conservationists, as their populations are declining at alarming rates, and more than 70% of these species is listed under some threat category or as data deficient. Furthermore, for 60% of currently described species, risk assessments have not been reviewed for over a decade (Moore, 2017). Another aggravating factor for their conservation is that guitarfishes are not considered ‘charismatic’, posing an extra challenge to public commitment and fundraising. Many threatened species of guitarfish are endemic to regions where they are captured as bycatch in artisanal fisheries. Management plans for these species are, however, scarce or nonexistent (Moore, 2017). According to the International Plan of Action for Conservation and Management of Sharks (IPOA-SHARKS; which also includes batoids and chimeras), a promising way to reduce bycatch impacts is through compensatory release. The immediate releases of live animals regardless of their physical condition are also included in National Plans, such as the Brazilian PAN-Tubarões (MMA/ICMBio – Ordinance n˚. 125, December 2014). However, fishermen’s commitment is one of the main challenges for implementing compensatory release programs. Financial incentives have been used to increase fishermen’s willingness to participate (Leduc & Hussey, 2019). In fact, pay-to-release programs seem to bring excellent results in the short-term, and selecting endangered species with low commercial value can increase fishermen's commitment (Leduc & Hussey, 2019). Southern Brazil is considered a conservation hotspot for endemic elasmobranchs (Dulvy et al., 2014). Three guitarfishes are found in the region; two of them are listed as threatened with extinction (the Brazilian guitarfish, Psedobatos horkelli – Critically Endangered; and, the Shortnose guitarfish, Zapteryx brevirostris – Vulnerable), and one is listed as Near Threatened (the Southern guitarfish, Pseudobatos percellens). In the state of Paraná, all of these species are commonly caught as bycatch in bottom fisheries (Costa & Chaves, 2006). In 7 years of monitoring (2013–2019), thousands of guitarfishes were landed by the artisanal fleet, many of them still alive. Of particular concern is that the region could be a parturition area for guitarfishes, as pregnant females are often landed. Both Pseudobatos spp. are marketed and sold as ‘cação’ (Bernardo et al., 2020). Zapteryx brevirostirs, on the other hand, has a low commercial value, being sold only when the volume of fish catches is low (Wosnick et al., 2019). In the region, management plans are difficult to implement since all guitarfishes are found in the same areas where the species of commercial interest are legally caught. Therefore, the establishment of no-take zones and seasonal closures could cause conflicts between fishermen and conservationists. With this as the context, we decided to implement a pay-to-release initiative to reduce the impacts of bycatch on endemic and/or threatened with extinction guitarfishes. Given the high rates of post-capture survival (Wosnick & Freire, 2013), its conservation status, abundance as bycatch throughout the year (May–November), and low commercial value, the shortnose guitarfish (Fig. 1a) was chosen as a promising species for compensatory releases. The program started in May 2010 – the first phase (2010–2016) was very challenging as it was the first time that this type of activity was proposed to the local fishing community. For 6 years, the releases were made by just one person and without any funding support. At first, live animals were bought for $1 each. For logistical reasons, only 10–15 guitarfishes were released at a time, representing about 10% of individuals captured in 1 day. In phase one, about 350 shortnose guitarfishes were returned to the sea. It was only in 2017 that the compensatory releases intensified, as well as the ties with the fishing community improved, allowing more people to have access to the animals. It was at this time that the second phase of the program began, with more members of the fishing community committed to the releases and the establishment of a research team. Currently, five researchers and the secretary of the fishing colony perform the activities. Significant changes in the behavior of the fishing community have been observed. Upon realizing our commitment to release guitarfishes, without jeopardizing their activities and earnings, most fishermen began to donate live animals. Such cooperation allowed more guitarfishes to be acquired and released alive. Such was the change in behavior that many fishermen began to release shortnose guitarfishes as soon as they were removed from the fishing nets, with a significant reduction in landings observed in phase 2. Moreover, release rates now range from 60 to 80% of captured individuals, demonstrating the success of phase 2 as compared to phase 1. Some fishermen became so committed to the activity that they even bought live animals from colleagues using their own money before releasing the fish (Fig. 1b). The activity was also adopted by workers who process fish (Fig. 1c), fish stall employees, fishermen family members (Fig. 1d), tourists (Fig. 1e) and even local celebrities (Cadu Scheffer, from stand-up comedy show TesãoPia; Fig. 1f). To date, over a thousand shortnose guitarfishes have been released (Fig. 1g). An interesting point is that the other guitarfish species (Fig. 1f, h) are now being sold to our research group at lower prices, indicating that fishermen are increasingly willing to help with the species’ conservation, even if it means reducing their financial gain. Unfortunately, as a result of the COVID-19 pandemic, the release program has been interrupted on its 10th anniversary. A number of challenges will have to be overcome in the next months, and years. Many fishermen stopped fishing, and the fish market stayed closed for almost 2 months. As a result, many members of the fishing community are experiencing financial difficulties. This can negatively affect guitarfish releases when activities return to normal, with animals that were previously released being sold to recover part of the financial loss. Much remains to be done, and the long-term effects of the pandemic on the release program remain uncertain. Tagging guitarfishes to assess recapture rates and for monitoring post-capture survival is necessary to evaluate the real impacts of the program on guitarfish conservation. Also, manuals on best fishing practices need to be created so that the release protocol for our program can be disseminated to other fishing communities. We hope to return to the activities as soon as possible and start the third phase of our initiative. This phase will consist of seeking financial support to boost the releases of the other guitarfish species. By doing that, it will be possible to assess the potential of the ‘pay to conserve’ strategy, as well as its evolution for other species that also need urgent conservation measures. We thank immensely all the members of the Matinhos fishing community, the GEEP team and Dr Carolina Arruda de Oliveira Freire who embraced the idea and helped so much all these years. We also thank Isabella Simões for the photographic record (Fig. 1g). Lastly, NW thank CAPES for the postdoctoral fellowship granted.

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