OTN and Dalhousie researchers tag weasel sharks in Cabo Verde

by | Feb 17, 2017 | News

The waters of Cabo Verde off the coast of West Africa hold one of the last remaining hotspots for sharks in the North Atlantic Ocean containing more than 60 elasmobranch (shark, skate, and ray) species. In spite of this, the region is also one of the least researched sites.

In 2015, OTN deployed 18 acoustic receivers in a Cabo Verdean ocean area believed to have a large aggregation of Atlantic weasel sharks. Due to the high fishing pressure along the West African coastline, Cabo Verde is thought to be an important stronghold for this enigmatic species, which inhabits the inshore waters of western Africa. The high productivity of this ocean region in conjunction with the ability to study and protect habitats means it could offer some degree of sanctuary for threatened shark species.

During a follow-up mission in December 2016, OTN field personnel successfully fitted 14 Atlantic weasel sharks with internally implanted Vemco V13 acoustic tags, as well as external marker tags. Additionally, nine nurse sharks were fitted with external marker tags.

A weasel shark is internally implanted with a Vemco V13 acoustic tag and an external marker tag

A weasel shark is internally implanted with a Vemco V13 acoustic tag and an external marker tag

Sharks are among the most threatened wildlife on the planet, particularly in the Atlantic and even more so off the coast of West Africa. Although some researchers have highlighted methods for sustainable shark fishing, evidence suggests that the worldwide decline in sharks is triggered by a high demand for shark fins combined with unsustainable fishing practices, which lack adequate management and garner unwanted accidental catches – such as those in Cabo Verde.

The team, made up of OTN field technician, Joe Pratt, Dalhousie PhD student, Manuel Dureuil, and Dalhousie University Director of Animal Care, Dr. Chris Harvey-Clark spent three weeks in the field working with partner organizations including: Biosfera, the Instituto Nacional do Desenvolvimento das Pescas, the University of Cabo Verde, and Maio Biodiversity Foundation.

“We’re taking a collaborative approach with the goal of bringing together international and Cabo Verdean researchers, government representatives and resource managers, industry, non-governmental organizations, and local communities,” Dureuil explained.


“By translating scientific information into on-the-water conservation we can ensure effective fisheries management efforts are established.”

By using weasel sharks as an umbrella species, researchers hope to raise awareness for sharks in the West African region where detailed scientific information is scarce, preventing science-based management efforts. This study also provides the opportunity to train local researchers on non-lethal catch and minimally invasive research methods while improving scientific infrastructure in Cabo Verde.

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