In a bold gesture in November 2020, President Iván Duque announced a ban on shark fishing in Colombia’s waters. It was a move that polarised communities, artisanal fishers, researchers and citizens across the country, but the Colombian government had theoretically protected all chondrichthyans (sharks, rays, skates and chimaeras). However, the findings of Dr Camila Caceres suggest that, unless there is strong enforcement of the ban, fishers continue to fish in marine protected areas. ‘Without the inclusion and understanding of the community, conservation efforts are unlikely to succeed if they are not followed and supported by fishers and the community,’ she observes.
Camila is a Save Our Seas Foundation (SOSF) project leader who has written a new paper detailing the apparent declines in shark populations on coral reefs along Colombia’s Caribbean coast.
The paper, titled ‘Predatory fish exploitation and relative abundance in a data-poor region from the Caribbean coast of Colombia, inferred from artisanal fishery interview surveys and baited remote underwater video systems’, was published earlier this year in the journal Aquatic Conservation: Marine and Freshwater Ecosystems. ‘Now that Colombia has been declared a shark sanctuary, the government needs to make sure it has an ongoing and transparent dialogue with the community as to how shark resources will be handled and how the fishers will be compensated for losing part of their sustenance and livelihood,’ explains Camila. ‘Otherwise, they will continue their practices as always and laws that have been passed will not be followed.’
Camila used a combination of methods to investigate the exploitation, use and relative abundance of sharks and rays, as well as predatory fishes (teleosts, the bony fishes), along Colombia’s Caribbean coast. She interviewed fishers around Cartagena and the Corales del Rosario and San Bernardo Natural National Park. ‘The most rewarding part of this study was getting to know the fishers and learning from them,’ she notes. Camila also deployed baited remote underwater video systems (BRUVS) to film sharks, rays and predatory fishes such as jacks, groupers and snappers at four different reefs on the coast. This, she explains, was an important facet of her research that she could share with the fishers, making more transparent a research process that is often alien to local communities. ‘It was really rewarding showing the fishers how to deploy and collect data with BRUVS. We ended up spending a lot of time together on the boat and onshore, so we had lots of conversations ranging from sharks to seafood recipes and family histories.’
For Camila, who is obviously passionate about issues of inclusivity and the transparency of science and about contributing to conservation efforts in her home country, the work was still demanding in interesting and surprising ways. ‘The most challenging part of this study was finding bait for the BRUVS,’ she reveals. ‘On the small islands where I work, all fisheries are artisanal and the fishers generally do not catch massive amounts of fish. Finding more than 200 kilograms (440 pounds) of bait and keeping it fresh and refrigerated in an area with little electricity and small catches was very challenging.’
It’s perhaps not an issue that first comes to mind, but combining methods as Camila did for her work not only increases the information one can gather, but also presents double the logistics to decipher. ‘This study was done in conjunction with other studies in the Caribbean,’ she explains. ‘We wanted fast and relatively cost-effective methods to give us baseline data and insight into both shark populations and fishers’ perceptions, across various sites. We wanted a combination of methods that can be readily replicated and implemented, so that we could easily compare across the region. Having a fast and economical method also lends itself for other researchers to be able to replicate it anywhere in the world and compare results.’
The fishers whom Camila interviewed reported that they typically captured eight different species of shark and five species of ray in the areas they fished. Most (99%) of them said that they did not specifically target sharks, but when they did catch them, the majority (83%) said that they retained these sharks to sell or eat (or both). This result was an unexpected one for Camila. ‘I was surprised by how many fishers choose to retain shark catches even if it is not their intended or targeted catch. It just goes to show that there isn’t really any “bycatch” in artisanal fisheries; all catches are important for sustenance or trade.’ The reports were similar for rays: although they weren’t the intended target, 90% of fishers retained rays when they were caught. This is despite the fact that 84% of fishers agreed that they had noticed declining shark populations in their coastal waters. This is compared with the 41% of fishers who had noticed similar declines among rays.
The results from the BRUVS surveys supported what the fishers had reported. In fact, Camila detected no difference in the abundance and diversity of sharks, rays and predatory fishes in protected and unprotected waters. When one looks at the results holistically, it becomes apparent that these important populations have declined significantly on coral reefs along the Colombia’s Caribbean coast.
The ability to acquire this kind of insight into an issue, and the oversight to interpret the results, is a benefit of having explored the subject with different methods. ‘Each method has its own limitations,’ says Camila. ‘The BRUVS are great because they can give us a wide variety of information about coral reef species, not just sharks, from the images they gather. We also don’t need to capture the sharks, so there is no added stress or post-mortality risk for them in a place where populations are already low. However, the BRUVS are limited by daylight, visibility and the time and season when they are deployed, and how long the camera battery lasts. Fishers are able to complement that information because they fish every day, year-round, and their observations are not constrained like technology can be. I believe it’s important to complement fishery-independent methods with fishery-dependent methods.’
Although Camila’s findings seem very disheartening, there was an important exception to the trends in her study. In one marine protected area that had higher enforcement levels, there was a higher abundance of predatory fish inside the protected area than outside. It’s here that Camila sees a glimmer of hope. ‘From the predatory teleost results, we see that protected areas do work where there is enforcement. For sharks, protected areas might work if they are larger (than what is needed for certain teleost species) and if there is enforcement.’ But she introduces a note of caution. ‘Even though enforcement can be difficult across large areas and with limited resources, if the fishers and communities are involved in the creation and management of protected areas, then they will be motivated to implement the rules.’ For Camila, there is a caveat to any simplistic notion of increasing enforcement – one that we would do well to heed if sustainable conservation efforts are to succeed in the region. ‘If scientists and policy-makers make the effort to understand and include communities in the creation and application of protected areas, conservation measures are much more likely to be effective and long-lasting.’
**Reference: Camila Cáceres,Jeremy J. Kiszka,Andrea Luna-Acosta,Hans Herrera,Esteban Zarza,Michael R. Heithaus
Predatory fish exploitation and relative abundance in a data-poor region from the Caribbean coast of Colombia, inferred from artisanal fishery interview surveys and baited remote underwater video systems
Aquatic Conservation: Marine and Freshwater Ecosystems