En Búsqueda del Pez Sierra

En Busca del Pez Sierra – Costa Rica (Searching for the Sawfish) started in 2015 as a project from the University of Costa Rica and is now part of Costa Rica Wildlife Foundation’s marine conservation program. Our interdisciplinary team seeks to promote the protection and conservation of the sawfish in the country through research, environmental education, and community outreach, with the goal of expanding throughout Central America.

Sawfishes are relatives of sharks and rays and are one of the most threatened animal groups on the planet. Costa Rican waters are home to the Largetooth sawfish (Pristis pristis) and the Smalltooth sawfish (Pristis pectinata); two of the five sawfish species that exist globally. Both species are critically endangered according to the International Union for the Conservation of Nature’s (IUCN) Red List. They can grow up to 6.5m in body length and inhabit a great variety of aquatic environments including coastal lagoons, rivers, mangroves, and other wetlands. However, the Smalltooth sawfish can only be found on the country’s Caribbean Coast, whereas the Largetooth sawfish is present in the Pacific as well as the Caribbean.

Due to its great size, the sawfish fulfills a key ecological role as a top predator in aquatic environments, regulating the abundance and distribution of its prey. Both species in Costa Rica can be found throughout the American tropics, yet their populations have decreased dramatically due to overfishing and habitat destruction. Decades ago, sawfishes were common in Costa Rican waters, particularly near mangroves and wetlands; nowadays, however, sightings are increasingly rare. Therefore, our project aspires to generate information about the current state of sawfish populations, their distribution, critical habitats, and main threats that affect these species locally. This information will help focus our efforts on the recuperation of the country’s sawfish populations.

Initially, we interviewed members of fishing communities around the country to identify sites where sawfishes are still found and to identify their main threats.  With this initial phase we determined the historic and current distribution of the sawfish in Costa Rica. We even identified sites where these species had never been reported. Yet, results demonstrated a general reduction in their abundance and distribution throughout the country. With this evidence, we managed to establish legal protection for the sawfish in cooperation with members of the Legislative Assembly in 2017.  These new legal tools will help diminish the risk of local extinction for the sawfish and are therefore one of the greatest accomplishments of the project. Community outreach and environmental education have also been an essential aspect of our efforts. We have communicated knowledge of these species, their importance, and their dire situation in many communities around Costa Rica. Thanks to these efforts, people have contacted us to report sawfish sightings on multiple occasions, contributing to our growing knowledge of these species.

The critical sites identified in our interviews paved the way for the second phase of the project: fishing expeditions. We visited areas like the Térraba-Sierpe National Wetland, the Northern Caribbean and the North Pacific looking for the sawfish. After much effort and little luck, we decided to try a new strategy: searching for sawfish DNA left over in water. We found water samples containing DNA from sawfishes in several sites including the San Juan river where Costa Rica borders Nicaragua. By continuing our environmental DNA sampling, our current investigations aim to unravel more detailed sawfish distribution patterns in these critical sites, particularly in the country’s Northern Caribbean.

In our project – Searching for the Sawfish, we aim to continue generating essential information for the effective protection of these species and the areas they inhabit. Through research, environmental education, and the creation of strategic alliances we seek to guarantee the protection of these species, their habitats, and its coexistence with the communities they interact with.