Presence of endangered shark species in Straits of Florida renews calls for collaboration

(WASHINGTON – July 14, 2021) A new long-term study expands our understanding of a critically endangered species of shark residing off the northwestern Cuban coast near the U.S. waters of Florida, renewing calls for strengthened international collaboration between countries in the Gulf of Mexico and Caribbean region.

The eight-year study, published in Marine and Coastal Fisheries, gathered data on a Cuban multispecies fishery and found an outsized presence of endangered juvenile oceanic whitetip sharks in the area off the Havana coast. The presence of this species — once abundant, though populations have now decreased globally by more than 98% — suggests there should be greater cooperation and collaboration in the Straits of Florida, the narrow ocean passage between the tip of Florida and Cuba’s northern coast. The paper, “Seasonal Abundance and Size Structure of Sharks Taken in the Pelagic Longline Fishery off Northwestern Cuba,” underscores the need for international scientific and conservation collaboration due to the sharks’ presence across boundaries. Such international collaboration is essential to ensure that endangered species like the oceanic whitetip shark can recover.

“In these shared waters of the Gulf of Mexico and Caribbean, ocean ecosystems conservation and sustainable fisheries require international collaboration — such as through data-sharing and joint management — to ensure successful, long-term outcomes,” said Valerie Miller, Cuba director for EDF Oceans program.

The study is the result of a monitoring program from 2011-2019 on the longline fleet based in Cojímar, Cuba, a small coastal town near Havana. The longline fleet consists of 134 small-scale fishing vessels harvesting swordfish, billfish, tuna and some shark species. Data gathered during the study showed a constant presence of juvenile oceanic whitetip sharks — designated as critically endangered by the International Union for Conservation of Nature.

“Their presence highlights the value of the Straits of Florida as an important migratory route for apex predators like sharks and tunas as they move across international boundaries in the Gulf of Mexico, the Atlantic Ocean and the Caribbean Sea,” said corresponding author Dr. Robert Hueter of Mote Marine Laboratory & Aquarium.

The continued presence of the endangered sharks is a small but positive sign for a species that has suffered significant declines globally. Because continued catches — even incidentally — could undermine recovery of the species, Cuba has adopted an important national plan to conserve and sustainably manage shark species, like the oceanic whitetip, for their essential role in maintaining healthy, diverse ocean ecosystems. The Cojímar area also may be used as nursery or pupping grounds for this critically endangered shark species.

“The varying sizes of oceanic whitetip sharks in the Cojímar fishery zone suggests that sharks at multiple stages of life may be using the area, possibly as habitat safe for juveniles or as a nursery ground,” said the lead author, Alexei Ruiz of Cuba’s Center for Marine Research at the University of Havana. “This finding highlights the importance of sustainability in small-scale fisheries carried out in Cuba’s nearshore waters, where these juvenile sharks are being found.”

Species like the endangered oceanic whitetip shark regularly cross international boundaries, creating complexities and challenges to gathering data and learning more, something especially challenging if international collaboration isn’t considered. The study itself also showcases the importance and value of scientific collaboration. Environmental Defense Fund helped co-author the report with experts from Cuba, Mexico and the U.S., and EDF has worked alongside respected partners in Cuba for over two decades working to conserve marine ecosystems and build sustainable fisheries.

“To ensure success, conservation efforts must take place at different levels and in different places,” said Miller. “Collaboration across boundaries and geographies is essential and boosts our chances of creating more sustainable, climate-ready ecosystems and fisheries of the future.”

This study and the shark monitoring were led by a research team at the Center for Marine Research at the University of Havana, in collaboration with the fishers of Cojímar and advised by scientists from the Universidad Autónoma de Sinaloa, Mote Marine Laboratory & Aquarium, Eckerd College and EDF.