Dolphins: The Wonderful Marine Mammals of Sal Island

Dolphins in the Atlantic Waters

Off the coast of West Africa, where Saharan winds sweep into the Atlantic, lies Cape Verde. The waters surrounding Sal Island are among the richest in the region, home to a diverse array of marine species. For many visitors, it is the dolphins that leave the most profound impression — sleek, playful, and visible throughout the year.

Reports from researchers and tour operators list an extraordinary cast: Atlantic spotted dolphins, bridled dolphins, long-beaked common dolphins and bottlenose dolphins, but also whales — blue, humpback, and Blainville’s beaked — alongside porpoises, turtles, sharks, barracuda and moray eels, for anyone heading out from Santa Maria, a glimpse of a fin breaking the surface can turn an ordinary boat trip into something unforgettable.

Currents’ Meeting Point

Cape Verde sits where ocean systems converge. Cold, nutrient-rich upwellings mix with warm currents, creating vast feeding grounds that attract a wide range of life. Scientists have recorded 24 different species of whales and dolphins here — a remarkable figure for such a small archipelago.

Atlantic spotted dolphins (Stenella frontalis) are among the most frequently seen. Calves are born plain grey. As they age, spots spread across their bodies, forming a natural record of their passage of time. Adults grow to just over two metres and weigh around 130–140 kilos. They are acrobatic swimmers, often approaching boats to ride the pressure wave at the bow.

Bottlenose dolphins, more robust and instantly recognisable, are also common. Sightings often include mixed groups, such as bottlenose dolphins with spotted dolphins, and occasionally with pilot or beaked whales. These encounters illustrate how species share resources in Cape Verde’s seas, forming fluid associations that enable them to feed or travel together.

The Rhythm of the Seasons

Dolphins appear year-round, but seasonal shifts bring new spectacles. From March to May, humpback whales migrate through these waters. Occasionally, dolphins and whales are seen side by side — two very different animals bound together by the same ocean currents.

Guides in Santa Maria favour morning departures. At first light, when the sea is glassy, the tell-tale signs are easier to spot: a splash, a curved fin, the mist of a blow. Excursions are timed to these calm conditions, and it is not unusual for passengers to return with reports of multiple pods in a single morning.

Social Lives and Behaviour of Dolphins

Atlantic spotted dolphins live in groups of five to fifteen, sometimes larger, and often with bottlenose dolphins mixed in. Their social structures are intricate. They communicate with clicks, whistles and bursts of buzzing sounds. They also release streams of bubbles, thought to signal intent or reinforce group cohesion.

Their feeding strategies are equally sophisticated. In shallow waters off Sal, dolphins use their beaks to dig into the sand, flushing out hidden fish. At night, they may hunt cooperatively, encircling schools of small fish or squid with coordinated movements that rival the strategies of wolves on land. These displays of intelligence continue to challenge our understanding of marine mammals.

Santa Maria and the Tourism Boom

Santa Maria, on Sal’s southern coast, has transformed from a quiet fishing village into the island’s main tourist hub. Dolphin-watching tours are now a central part of that economy. Catamaran trips, often half-day outings, combine dolphin watching with snorkelling in Murdeira Bay. Groups of fifty or more dolphins are sometimes encountered.

Trips usually begin with a short briefing. As boats clear the harbour, captains — many of them former fishermen with intimate knowledge of the currents and seabed — guide vessels to the areas where sightings are most likely. Channels where currents meet, the edges of canyons, or shallow sandbanks all provide feeding grounds.

Conservation at a Crossroads

Cape Verde’s waters are recognised as a global biodiversity hotspot. More than 20 species of whales, dolphins and porpoises live here, but this richness is under pressure. Overfishing, increased boat traffic, and climate change all pose threats.

Conservation efforts are growing. Protected areas have been established around Santa Luzia, Raso and Branco. Programmes such as the Conservation of Cape Verde Endangered Marine Species Project have sought to safeguard both turtles and cetaceans. Local NGOs, including Guardians of the Sea, collaborate with fishermen to monitor catches and promote sustainable fishing practices.

Yet challenges remain. Boat noise can, among other things, disrupt echolocation, reduce fish stocks, limit prey, and alter migration and feeding patterns in warming seas. The future of Cape Verde’s dolphins depends on striking a balance between economic development and ecological limits.

The Morning at Sea

Witnessing dolphins here is often a blend of science and wonder. A catamaran leaves Santa Maria’s pier at dawn. Fishing boats are returning, crews hauling nets as the tourist vessel heads out. After half an hour, someone spots movement — splashes ahead.

A pod of Atlantic spotted dolphins appears. They close on the boat, swimming along its bow, calves keeping close to their mothers. Some leap clear of the water, twisting before they fall back in. Others glide just beneath the surface, bellies pale against the blue. The engine slows. For a few minutes — or an hour — the humans and dolphins share the same pace, each observing the other.

Tour operators work within international guidelines, limiting approach distances and avoiding repeated pursuit. The intention is clear: encounters must remain on the dolphins’ terms.

Research and Science

Cape Verde has become a valuable site for cetacean research. Photo-identification studies — tracking dolphins by their dorsal fin markings — are building records of population size and social links. Researchers are also investigating whether humpback whales here belong to the Southern Hemisphere population.

For Cape Verdean scientists, this research provides training and resources that are building local expertise. Over time, these data will help shape conservation measures. Dolphins, as apex predators, are good indicators of ocean health. Shifts in their numbers or behaviour may reveal changes in fish stocks, water quality or climate patterns long before they are obvious elsewhere.

Cultural and Human Connections

Fishermen in Sal speak of dolphins with mixed feelings. They admire their skill but sometimes resent their competition for fish. Yet many recognise the broader truth: healthy dolphin populations signal a healthy sea.

Folklore casts a dolphin as a protector, a guide that leads sailors home or warns of storms. These stories survive in coastal communities, serving as reminders that the relationship between humans and these marine mammals in this area is not a new one. It stretches back generations.

Cultural and Human Connections

Fishermen in Sal speak of dolphins with mixed feelings. They admire their skill but sometimes resent their competition for fish. Yet many recognise the broader truth: healthy dolphin populations signal a healthy sea.

Folklore casts a dolphin as a protector, a guide that leads sailors home or warns of storms. These stories survive in coastal communities, serving as reminders that the relationship between human and dolphin in this area is not a new one. It stretches back generations.

Dolphins Beneath the Surface

Snorkelling in Sal’s waters offers another view. Visibility often exceeds thirty metres, revealing the dolphins’ environment in full: rocky ledges, sandy plains, schools of jack and barracuda. Dolphins slip through these spaces with characteristic fluid ease, navigating and hunting skillfully in the underwater three dimensions.

Navigating Through Climate Change

The climate is changing, and so is the Atlantic. Rising sea temperatures shift the distribution of prey. Storms are becoming more severe. For dolphins, survival depends on their ability to adapt quickly. They have done so before, but the pace of human-driven change is unprecedented.

Tourism brings awareness and income, but it also brings risks. More boats on the water mean more disturbance. Responsible practices — such as employing trained guides, limiting the number of boats, and strictly adhering to approach rules — are critical.

Future of Dolphins

There is reason for optimism. Marine protected areas are expanding. Conservation organisations are gaining ground. Young Cape Verdeans are studying marine biology, intent on protecting the seas they grew up beside. International collaborations are filling gaps in research.

Each sighting, each study, each new regulation is a step in writing the next chapter of this story.

Dolphins’ Dance

At sunset, as the Atlantic glows orange and purple, dolphins continue their movements just as they have for millennia. They hunt, play, raise calves and maintain bonds within their pods. For visitors, the sight lingers. It is both a privilege and a reminder that the ocean’s wealth is not limitless, and that conservation is not optional.

The dolphins of Sal Island are more than an attraction. They are an emblem of the ocean’s resilience and a measure of its fragility. Protecting them means protecting the seas on which both humans and marine life depend.

Bibliography & Further Reading

• Atlantic Spotted Dolphin, NOAA Fisheries;
• Stenella frontalis Atlantic spotted dolphin, Animal Diversity Web;
• Reserva Natural Baía da Murdeira, Protected Planet;
• Guardians of the Sea, Project Biodiversity;
• Acoustic Characteristics of Bubblestream-Associated Whistles Produced by Atlantic Bottlenose Dolphins (Tursiops truncatus) During the First Thirty Days of Life, Holli C. Eskelinen and Brittany L. Jones, Aquatic Mammals 2021, 47(4); 
• Whales and dolphins (Mammalia, Cetacea) of the Cape Verde Islands, with special reference to the Humpback Whale Megaptera novaeangliae (Borowski, 1781), Cornelis Hazevoet, Frederick Wenzel, Research Gate;
• Recent data on whales and dolphins (Mammalia: Cetacea) from the Cape Verde Islands, including records of four taxa new to the archipelago (PDF), Cornelis J. Hazevoet, Vanda Monteiro, Pedro López, Nuria Varo, Gergely Torda, Simon Berrow and Barbara Gravanita, Zoologia Caboverdiana 1 (2): 75-99 © 2010 Sociedade Caboverdiana de Zoologia;
• Humpback Whales (Megaptera novaeangliae) in the Cape Verde Islands: Migratory Patterns, Resightings, and Abundance, Frederick W Wenzel, Fredrik Broms, Pedro Lopez-Suarez and Katia Freire Lopes, Aquatic Mammals 46(1):21-31, ResearchGate;
• Presence of calves and breeding behaviour indicates Cape Verdean breeding habitat for humpback whales, Ryan, C. et al. (JCRM);
• First documented movement of a humpback from Cape Verde breeding ground to a western North Atlantic feeding ground, Chosson, V. et al. (2024), PubMed Central;
• Vocalisations and associated underwater behaviour of free-ranging Atlantic spotted dolphins, Stenella frontalis and bottlenose dolphins, Tursiops truncatus, Denise L. Herzing, Florida Atlantic University, Biological Sciences, Boca Raton, FL 33431, USA;
• Evidence of teaching in Atlantic spotted dolphins (Stenella frontalis) by mother dolphins foraging in the presence of their calves, Courtney E. Bender, Denise L. Herzing, David F. Bjorklund, © Springer-Verlag 2008.