Golfo Dulce, a tropical fjord located on Costa Rica’s Pacific coast, exemplifies the need for conservation action in areas that provide critical ecosystem services to migratory species. In the marine realm, few point endemic or severely range restricted species exist and it is rarely possible to secure protection for the entire range of a species within a single Marine Protected Area. This exacerbates the need to prioritize sites with the greatest conservation potential for the establishment of MPAs. Protection is needed most in breeding, feeding, spawning, resting, and nursery grounds, where aggregations occur and migratory species visit seasonally.
Golfo Dulce’s sheltered waters benefit many migratory species that visit the area to breed, feed, rest, and give birth (Morales-Ramírez, 2011). It contains mangroves, coastal shallows, beaches, and some coral reef habitat, which support a wide array of elasmobranchs, chelonians, and cetaceans (Gutierrez, 1996). These productive estuarine waters provide known nursery habitat for the Eastern Pacific Scalloped Hammerhead population (Sphyrna lewini), which is currently assessed as Endangered on the IUCN Red List. Pacheco-Polanco et. al. (2015) suggest that Golfo Dulce supports feeding aggregations of Whale Sharks (Rhincodon typus), also listed as Endangered by IUCN. Three species of threatened sea turtles utilize the gulf to breed, feed, and rest, including the Critically Endangered Hawksbill (Eretmochelys imbricate), Endangered Green Turtle (Chelonia mydas), and Vulnerable Olive Ridley (Lepidochelys olivacea) (Osa Conservation, 2012).
While the importance of the gulf for threatened species is clear, current regulations do not provide sufficient protection to halt, much less reverse population declines. Many species, including Scalloped Hammerheads, are still subject to fishing pressure and entanglement in illegal gillnets (Segura and Campos, 1990). The establishment of a MPA in Golfo Dulce could help bolster the populations of these species. It would not only help ensure that more individuals survive to breeding age, but would also provide a haven when adults venture into Golfo Dulce’s waters to feed and reproduce. Other species that would benefit from an increased level of protection include tiger sharks, bull sharks, several species of reef sharks, and a variety of rays. Apart from the seasonal aggregations of whale sharks, many of the sharks that inhabit the gulf are juveniles, which further implicates Golfo Dulce’s importance as a nursery (Lopez-Garro and Zanella, 2015). In addition to sharks and rays, the biodiversity of Golfo Dulce includes cetaceans such as humpback and Bryde’s whales, sea snakes, reef fish and invertebrates.
For threatened highly migratory species, establishing formal protection for areas that support breeding aggregations and provide nursery habitat is key for the survival of the species as a whole. Prioritizing these sites will ensure that conservation actions are concentrated in areas with the greatest potential to boost declining populations by safeguarding valuable resources for reproduction.
Bessesen, B.L. 2010. Project report and summary of multi-species marine sighting survey in Golfo Dulce, Costa Rica. Retrieved from osaconservation.org
Bessesen, B.L. 2011. Rainy season extension of the muti-species marine sighting survey in Golfo Dulce, Costa Rica. Retrieved from osaconservation.org
Lopez-Garro, A.M. 2012. Identification, evaluación y manejo de habitats críticos utilizados por el tiburón martillo (Sphyrna lewini) y otros elasmobranquios en Golfo Dulce, Costa Rica. Retrieved from golfodulce.org
Lopez-Garro, A.M. and Zanella, I. Tiburones y rayas capurados por pesquerias artesanales con linea de fondo en el Golfo Dulce, Costa Rica. 2015. Rev. Biol. Trop. 63(2): 183-198.
Osa Conservation. 2012. Osa Conservation Supports Research in Golfo Dulce: So Many Sea Turtles! Retrieved from osaconservation.org
Segura, A. and Campos M., J.A. 1990. Perdidas poscaptura en la pesqueria artesanal del Golfo Ducle y su proyeccion al Pacifico de Costa Rica. Rev. Biol. Trop. 38(2B): 425-429.