Dolphins are playful creatures. Dolphin sighting remains a favorite tourism activity. It also helps that these marine mammals are found across the globe – in both tropical and warm water. Dolphins generally live in water that is warmer than 50 degrees F. They prefer water that is not too cold. For this reason, dolphins are not found near the North or South Poles.
Dolphins are spotted in coastal waters, bays, inlets, river basins, inland seas, gulfs, channels, etc. Being a Mammal they breathe through a hole on top of their head, called a blowhole. Hence they need to come to the water surface every few minutes to get fresh air.
To maintain their massive body, dolphins need to eat a lot. Hence, they tend to live in areas where food supply is plenty.
Dolphins are also known to migrate in search of warmer weather based on seasons. They also migrate in search of food.
Coastal & Offshore Habitats
Dolphin Habitats roughly fall under two categories – coastal and offshore.
Coastal dolphins live in water that is not too deep and comparatively warmer. Hence they are regularly sighted in harbors and bay areas. These are small in size and can move much faster.
Offshore dolphins love to live in deep water away from the coast. They have adapted to live in relatively cooler deep water. They are large in size and their huge bodies help trap heat and keep warm. The large size helps them handle deep-sea predators.
Let us check out a few common species of dolphins and where they live.
Bottlenose dolphins are the most commonly known variety of dolphins. They prefer to live in warmer weather. This species is spotted in every ocean of the world, except the Arctic and the Antarctic oceans. Their habitat range is quite wide – harbors, bays, gulfs, and estuaries, nearshore coastal waters, deeper waters, open ocean.
They are spotted from Australia to Japan, Hawaiian Islands triangles, the coasts of Chile,UK, southern United States amongst other locations.
Hector’s dolphins are one of the world’s smallest and rarest dolphins. They are natives of New Zealand and are only found in the inshore waters of the South Island of New Zealand. Akaroa Harbour and the Banks Peninsula have the highest concentration of them.
Commercial and recreational gillnets and trawls are the largest threat to their existence.
Māui dolphins are one of the subspecies of Hector’s dolphin. They are critically endangered with an estimated population of around 55-65. They are found on the northwest coast of the North Island, from Maunganui Bluff and Whanganui. They were also once found along most of the west coast of the North Island.
Amazon river dolphin
The Amazon river dolphins are also known as pink river dolphins or boto. They are freshwater dolphins and live in the rainforest rivers of South America. During the spring season, rain falls in South America. The Amazon River and its tributaries are flooded. The water spills to the rainforest and creates a vast seasonal sea. Botos are found thought the Amazon and Orinoco river basins in Brazil, Bolivia, Colombia, Ecuador, Peru, and Venezuela.
Irrawaddy dolphins are species of dolphins that are known to transition between seawater and freshwater. These are generally found in South and Southeast Asia coastal areas. They majorly inhabit three rivers – the Ayeyarwady in Myanmar, the Mahakam in Indonesian Borneo, and the Mekong. They are also spotted in Sundarbans mangrove forests of Bangladesh and India.
These popular dolphins get their name from their acrobatic ability, including leaping and spinning high in the air. They are found across the Atlantic, Indian and Pacific oceans. These mammals generally like to live in tropical and subtropical areas.
Spinner dolphins are relatively smaller in size than their ocean cousins. These species are usually pelagic and prefer deep water for hunting their prey. During the daytime, the coastal variety of Hawaiian spinner dolphins is found near the shore in shallow water. They return there to socialize, rest, take care of their young while also keeping a watch for their prey.
Ganges River dolphin
The Ganges river dolphin species was officially discovered in 1801. They live in the freshwater rivers of South Asia mostly in planes and slow-flowing rivers. And are also found in many tributaries, connecting lakes and streams.
Currently a threatened species, they once lived in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India, and Bangladesh.
Living in one of the world’s most densely populated areas, human activities like irrigation, electricity generation, etc pose a big threat to its habitat and existence.
Humpback dolphins are always found in shallow nearshore waters. Their range includes the West Coast of Africa to the coast of China and the east coast of Australia.
There are four different species spread across four different geographic regions. They are Atlantic humpback dolphins, Indian Ocean humpback dolphins, Indo-Pacific humpback dolphins, and Australian humpback dolphins.
Living on the shore their existence is susceptible to fisheries, boat traffic, pollution, other human activities.
Atlantic spotted dolphins live in warm temperate, subtropical, and tropical waters of the Atlantic ocean. They live in 65 to 820 feet deep water. In their northern range, they live in deeper water. Their range spreads from the U.S. East Coast, Brazil, Bahamas, the Azores and Canary Islands, and Gabon.
Spotted dolphins are fast swimmers and often seen to surf in the waves created by vessels.
Why Are Dolphin Habitats Important?
Dolphins’ habitat is critical for their existence, directly affecting this species and subspecies. These social creatures live in pods. This is where they give birth, nurse their young, socialize, spend time in recreational activities, hunt, feed.
Destruction of habitat is also one of the reasons for their migration.
Thus any threat to the habitat has a much larger effect on the overall existence of the ocean mammals.
Threats to Dolphin Habitat
Dolphins’ populations are currently threatened, with five species and six subspecies falling under the endangered category. Their habitat continues to get destroyed due to the following.
- Climate change
- Toxic contaminations of ocean, coasts, rivers
- Oil, gas, electricity generation and exploration near shores and water
- Increased shipping activity
- Marine based tourism
Only a tiny part of their habitat is currently protected. Strict rules and greater regulation are required to save this aquatic beauty.