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Shark conservation on Sal Island
Elasmobranchs - sharks, rays, and skates - play a vital role in maintaining the health and balance of marine ecosystems. As top predators and bioindicators, their presence (or absence) offers insight into the overall condition of the ocean. Healthy elasmobranch populations help regulate species abundance and prevent imbalances that can disrupt food webs.
Cabo Verde hosts more than 60 species of sharks and rays and is recognised as a distinct eco-region within the nearshore North Atlantic and tropical zones, thanks to its high elasmobranch diversity and overall abundance.
Elasmobranchs: Key to healthy oceans
Elasmobranchs are more than just iconic ocean predators. They are essential to healthy marine ecosystems.
Here's why:
Balancing the web
As apex or meso-predators, sharks help maintain the balance of marine food webs by controlling prey populations and preventing species overpopulation.
Ocean indicator
Because they are sensitive to environmental changes, shark populations serve as indicators of broader ocean health and biodiversity.
Habitat guardians
By influencing the behaviour of other species (like turtles and herbivorous fish), sharks help prevent overgrazing and protect vital habitats such as reefs and seagrass meadows.
Predation by sharks removes weak or sick individuals from fish populations, supporting the health and resilience of fish stocks
Balancing the web
As apex or meso-predators, sharks help maintain the balance of marine food webs by controlling prey populations and preventing species overpopulation.
Elasmobranchs at a glance
1200+ Species globally
More than 1200 different species of sharks, rays and skates have been identified to date. In Cabo Verde more than 60 have been found so far.
© Vsevolod Rudyi
Dwarfs & Giants
The species size varies greatly, from the lanternshark (barely 20 cm long) to the whale shark, the largest fish in the world, which can reach over 12 meters in length.
Flexible skeleton
Elasmobranchs are fish, however they have cartilaginous skeletons, making them lighter and more flexible than bony fish.
Electroreceptor
They are highly adapted and have specialised organs that detect electric fields, this allows them to detect other organisms, especially their prey.
© Sander van der Wel
Slow growth
Like sea turtles they grow slowly, late maturity, and low reproductive rates makes them highly vulnerable to overfishing and habitat degradation.
Global Picture
Sharks and rays are among the most threatened vertebrates on the planet. Oceanic shark and ray populations have declined by more than 70% over the past 50 years.
According to the IUCN, more than 37% of shark and ray species are currently at risk of extinction, primarily due to overfishing, habitat loss, and bycatch. It is estimated that more than 100 million sharks are killed annually, many just for their fins.
Lemon sharks
Scientific Name: Negaprion brevirostris
Habitat: Mangroves, lagoons, reefs, sandy bays
Size: Up to 3 meters
Diet: Bony fish, crustaceans
IUCN Status: Vulnerable
Fun Fact: Give live birth and live in social groups.
Juvenile lemon sharks depend on specific shallow coastal areas—most notably Parda Reef—as nursery grounds, where they remain for at least 18 months. This rocky basaltic reef, located in the island’s northeast, offers shelter and protection critical for their development. Consistent, seasonal patterns highlight the importance of these habitats and the need for informed, science-based conservation and coastal management.
Lemon sharks are viviparous, giving birth to live young every 2 to 3 years, with litters ranging from 7 to 14 pups. The young are born fully independent and are estimated to stay in nursery areas for up to five years. Remarkably, females often return to the same nursery grounds where they were born—a behaviour known as natal philopatry. While juveniles remain close to shore, adults can migrate across regions, though they show strong site fidelity, making them particularly vulnerable to habitat degradation.
Despite their ecological importance, lemon sharks face growing threats from overfishing (including bycatch), coastal development, and unregulated tourism. Globally, they are listed as Vulnerable by the IUCN, yet they remain unprotected under Cabo Verdean law. The year-round presence of juveniles at Parda Reef presents a rare opportunity: to protect a threatened species while promoting responsible and sustainable ecotourism.
Our team is working to study the different species, to better understand their needs and adapt our approaches to protecting the sharks and rays, that call Sal their home.
Elasmobranchs of Sal Island
Aside from the lemon shark, we record many other elasmobranchs in the coastal waters of Sal. The following are small sample of the many sharks and rays call Sal their home.
Nurse shark
Scientific Name: Ginglymostoma cirratum
Habitat: Shallow reefs, sandy flats, caves
Size: Up to 3 meters
Diet: Bottom-dwelling fish, crustaceans
IUCN Status: Vulnerable
Fun Fact: Can remain motionless and often rests in groups during the day.
© Philippe Guillaume
Roughtail stingray
Scientific Name: Dasyatis centroura
Habitat: Muddy and sandy substrate
Size: up to 4.3m length and 2.1m width
Diet: Bony fish, crustaceans, invertebrates
IUCN Status: Vulnerable
Fun Fact: Poisonous tail can grow twice as long as the body.
Spinner Shark
Scientific Name: Carcharhinus brevipinna
Habitat: Coastal tropical waters, open ocean
Size: Up to 3 meters
Diet: Schooling fish, squid
IUCN Status: Vulnerable
Fun Fact: Known for leaping and spinning out of the water when feeding.
Atlantic Blacktip Shark
Scientific Name: Carcharhinus limbatus
Habitat: Shallow coastal waters, estuaries
Size: Up to 2.5 meters
Diet: Small fish, rays, squid
IUCN Status: Vulnerable
Fun Fact: Easily identified by the black tips on its fins and fast swimming.
Scalloped Hammerhead Shark
Scientific Name: Sphyrna lewini
Habitat: Coastal and offshore waters, near reefs
Size: Up to 4 meters
Diet: Rays, fish, squid
IUCN Status: Critically Endangered
Fun Fact: Uses its wide, flat head to detect prey through electroreception.
Tiger Shark
Scientific Name: Galeocerdo cuvier
Habitat: Tropical and subtropical oceans, near shorelines
Size: Up to 5 meters
Diet: Opportunistic - fish, turtles, seabirds, even garbage
IUCN Status: Near Threatened
Fun Fact: Nicknamed the "garbage can of the sea" for its varied diet.
Blue shark
Scientific Name: Prionace glauca
Habitat: Tropical and temperate open ocean
Size: Up to 3.5 meters
Diet: Squid, mackarel and achovies
IUCN Status: Near Threatened
Reproduction: Viviparous with litter sizes between 33-34
Fun Fact: Most widespread and abundant shark species. (Most frequently caught as bycatch).
Threats to elsmobranchs
Elasmobranchs—sharks, rays, and skates—face increasing anthropogenic threats. Since 1970, global populations of oceanic sharks and rays have dropped by over 70%. Their slow growth and low reproductive rates make it difficult for populations to recover.
Tools For Conservation
Cabo Verde is recognized as an important ecoregion due to its high diversity and abundance of over 60 shark and ray species. While this highlights its ecological significance, there remains a critical gap in ecological data on elasmobranchs in the country. At the same time, increasing pressures from overfishing, pollution, climate change, and rapidly growing tourism are placing these species and their habitats at risk.
This mix of rich biodiversity and limited research creates an important chance, and urgent need, for ongoing studies, regular monitoring, and focused conservation action.
We are working on collecting specific data that will provide critical information on the ecology and distribution of sharks and rays around Sal, and by extension, the surrounding ecosystem.
To do so, here are some of the methodologies that we use to monitor them:
Scientific Research:
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BRUVS (Baited Remote Underwater Video Surveys): Used to monitor shark and ray populations non-invasively by capturing video footage in their natural habitats.
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Tagging: Involves placing identification or tracking tags on sharks to study their movements, habitat use, and behaviour over time.
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Collection of biometric data and tissue samples: To support studies on growth, health, and genetics, providing key insights for conservation and species management.
Community engagement and research:
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Interviews: Conducted with local fishers and community members to gather traditional knowledge, fishing practices, and perceptions of elasmobranchs.
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Community involvement: Engaging the local communities in data collection and conservation efforts, such as Guardians of the sea
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Trials of bycatch reduction devices: Collaborating with artisanal fishers to test tools and techniques that reduce accidental capture of sharks.
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Promotion of environmental education in schools and children centres;
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Training on sustainable practices of shark observations with guides and tour operators
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