In a recent study, researchers have documented the most extensive migration ever observed for a silky shark (Carcharhinus falciformis), providing crucial insights into the behavior of this heavily overfished species. This underscores the urgent need for international cooperation to manage and conserve populations effectively.
The study was a collaboration involving researchers from the Charles Darwin Foundation (CDF), the Guy Harvey Research Institute (GHRI) at Nova Southeastern University, and the Save Our Seas Foundation Shark Research Center (SOSF-SRC), along with the Galapagos National Park Directorate (GNPD).
Dubbed "Genie" in honor of the late shark ecologist Dr. Eugenie Clark, an adult female silky shark was equipped with a satellite transmitter near Wolf Island north of the Galapagos Marine Reserve in July 2021. Over the following 546 days, Genie embarked on an extraordinary journey covering more than 27,666 kilometers.
This remarkable voyage, equivalent to crossing the United States from coast to coast about four times, included two significant westward migrations extending as far as 4,755 kilometers from the tagging site into international waters. These regions are known for high fishing pressure and minimal regulation.
The study shattered previous movement records nearly sixfold, illustrating the silky shark's extensive use of open ocean areas beyond national jurisdictions. This highlights the pressing need to establish regulations for conserving ocean biodiversity in these remote waters.
Dr. Pelayo Salinas de León, lead author of the study and co-Principal Investigator of the shark ecology project at the Charles Darwin Foundation, emphasized, "Understanding the migratory pathways of silky and other threatened pelagic sharks is crucial for developing effective management strategies to reverse ongoing global population declines."
"Sharks have navigated the world's oceans for millions of years, unaffected by the human-drawn lines on maps," Dr. Salinas de León added. "Their long migrations through heavily fished international waters expose them to significant risks, underscoring the need for a coordinated global effort to ensure the survival of these highly threatened species."
Silky sharks face particular vulnerability to overfishing due to their slow growth, late maturity, and high demand in the global shark fin trade. Listed as Vulnerable on the IUCN Red List, they are among the most frequently caught sharks in artisanal and industrial fisheries, prioritizing their conservation for CDF and other organizations.
Notably, Genie spent over 99% of her tracked time in international waters west and south of the Galapagos Islands, well beyond Ecuador's Exclusive Economic Zone. This underscores the critical importance of international cooperation in protecting these long-distance oceanic travelers.
Dr. Mahmood Shivji, co-author from SOSF-SRC and GHRI, remarked, "Tracking sharks with such precision over more than a year is extremely challenging. In this case, we revealed consistent, extensive travel patterns far offshore, beyond current marine protected areas and national management."
"This study serves as a compelling call to action for all stakeholders involved in marine conservation and fisheries management," Dr. Shivji emphasized, "to collaborate in safeguarding these iconic species and the ecosystems they inhabit."
Ultimately, this research article serves as a vital reminder of how interconnected global marine environments are and the collective responsibility required to preserve ocean biodiversity.
