Marine vertebrates
by Cindy
in Blog
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What is the classification of marine vertebrates?

We can classify marine vertebrates in 4 different families: fishes, birds, reptiles, and mammals

Fishes have about 20’000 marine species. They are present in pelagic, coastal, and deep sea. They are essential for many marine ecosystems and habitats. They have cold blood and a single or pairs of fins. These allow them to stay in a position or move in the water. Their swim bladder allows them to control their buoyancy. Most common ones: sharks, clown fishes, sardines, tunas, barracudas.

Marine birds (also known as seabirds) have between 300 and 400 different species. They spend most of their lives in marine ecosystems. They possess the capacity to swim at high speed and can be found in different marine habitats. On top of their different abilities, they have a special gland that allow them to swallow salt water and reject the excess of salt. Most common ones are penguins, petrels, pelicans, albatross, cormorant.

Reptiles have about 100 different marine species. They mostly are in tropical and subtropical water, except for the turtle who can be found in cold water. They are “ectotherms” or “cold-blooded” which means that they do not regulate their body temperature and need external heat to warm their body. It also means they can tolerate extremely cold temperatures (in comparison of other marine vertebrates). They have scales of keratin and a slow metabolism that allow them to stay a long time in the water before they need to breathe at the surface. The most common ones are turtles, marine iguanas, sea snakes, crocodiles.

Marine mammals have about 129 different species. They can be found all around the world, in tropical and subtropical zones, in coastal and pelagic zone, and even in polar water. They have an outstanding capacity to dive for prolonged periods of time, due to their circulatory system. When they dive, they slow their heart rate, stop to breath and that is what we refer to when we do apnea, and we speak about the reflex mammal. The most common ones are whales, dolphins, orcas, seals, polar bears.

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