Related Posts
In-Depth Look at Lemon Sharks in the Shark Bay
The lemon shark (Negaprion brevirostris) is a large, coastal species of requiem shark found in tropical and subtropical waters throughout the Atlantic Ocean. Recognisable by its stout body, blunt snout, and yellowish-brown colouring, it is named for the pale hue that provides camouflage in sandy shallows. In places like Shark Bay on Sal Island, lemon sharks appear not as predators, but as vulnerable juveniles — pups navigating the earliest stages of their life cycle in the safety of a natural nursery.
Morphology and Identification of Lemon Sharks
Adult lemon sharks can grow up to 3.4 metres in length and weigh more than 180 kilograms. They are stocky, with two dorsal fins of nearly equal size and a rounded head. Their teeth are slightly serrated, suited for grasping rather than cutting — a trait that supports their feeding strategy, which includes small fish, rays, crustaceans, and molluscs. Juveniles, like those seen in Shark Bay, are much smaller — often under 1.2 metres — and pose no threat to humans.
Lemon Sharks’ Life Cycle and Reproduction
Lemon sharks are viviparous, meaning they give birth to live young after a gestation period of about 10 to 12 months. Litter sizes range from 4 to 17 pups, depending on the mother’s size and condition. After birth, females abandon the pups in shallow, protected environments — such as mangroves, bays, and lagoons — where natural structures and low predator density increase the pups’ survival chances. These nursery zones are critical to the species’ development. Young lemon sharks spend several years in such areas before dispersing to deeper or more open waters as adults.
Shark Bay on Sal Island appears to serve this purpose. While lacking mangrove cover or dense vegetation like those in the Caribbean or western Africa, its combination of warm, shallow, calm waters and low competition creates ideal conditions for rearing.
Habitat Use and Site Fidelity
Studies in the Caribbean, Florida, and West Africa have shown that lemon sharks exhibit strong site fidelity, returning to the same nursery grounds where they were born. This behaviour makes nursery habitats particularly important to the long-term stability of regional populations. Shark Bay may be one such site, though long-term tracking studies on Cape Verdean lemon sharks are still limited.
The sandy-bottom habitat, paired with occasional rocky crevices, allows juveniles to forage safely. Their diet consists mainly of bony fish and small invertebrates, which they eat more actively at night. During daylight hours, they tend to remain still or swim slowly, which is why they’re so observable by humans wading in the bay.
Lemon Sharks’ Role in the Ecosystem
Lemon sharks are mesopredators — intermediate-level predators that play a balancing role in marine ecosystems. They help regulate fish populations and support the overall health of coral reefs and coastal ecosystems by preying on weaker or diseased individuals. Their decline, often due to habitat loss or overfishing, can trigger imbalances, leading to prey overpopulation and degraded marine biodiversity.
Because they occupy a high place in the food chain and are relatively long-lived (20–30 years), lemon sharks are particularly vulnerable to environmental change. Their slow maturation and low reproductive output mean population recovery is slow. Protecting nursery habitats like Shark Bay is therefore not just about safeguarding a location—it’s about maintaining an entire ecological rhythm.
Conservation Status
The IUCN (International Union for Conservation of Nature) currently classifies the lemon shark as Vulnerable. Its global population is thought to be decreasing due to coastal development, pollution, and bycatch in commercial fisheries. In some regions, lemon sharks are targeted for their meat, skin, and fins.
Cape Verdean waters, although less industrialised, are not free from these pressures. The increasing popularity of coastal areas for tourism, coupled with inadequate enforcement of marine protection laws, could threaten habitats like Shark Bay if unmanaged. The country has taken steps in recent years toward marine protection, including MPAs (Marine Protected Areas. But enforcement and ecological monitoring remain inconsistent.
Shark Bay as a Living Laboratory
What makes Shark Bay noteworthy isn’t just the visibility of the sharks — it’s the opportunity to observe marine life in a functioning nursery. Here, visitors witness a critical phase in the life cycle of a threatened species. Unlike in aquariums or curated dives, the encounter at Shark Bay is passive, open-ended, and unscripted. Juvenile sharks move according to tidal rhythms, their patterns shaped not by human control but by water, food, and instinct.
This makes Shark Bay a valuable space for education. Researchers, tour operators, and conservationists alike view it as an opportunity to foster awareness: not by lecturing about threats from afar, but by inviting people into a shared habitat, with clear boundaries, of course.
Bibliography
-
Rui Rosa et al. (2023). “Evidence for the first multi-species shark nursery area in Atlantic Africa (Boa Vista Island, Cabo Verde)”, Frontiers in Marine Science (link);
-
“First nursery of multiple shark species in the Eastern Atlantic described in Cape Verde”, Rui Rosa et al, Evidence for the first multi-species shark nursery area in Atlantic Africa (Boa Vista Island, Cabo Verde), Frontiers in Marine Science (2023), University of Lisbon, (link);
- “Lemon shark”, Wikipedia;
- Kristine L. Stump, “Shark nursery habitat loss – doctoral thesis”, University of Miami (link);
-
“Sharks in Cabo Verde, Canarias, Madeira and Azores islands”, Frontiers in Marine Science (link).
