Endangered species : Dolphin

Common name : Dolphin

Scientific name : Delphinus delphis

Species : Total up to 60 species

Size : up to 2.5 m / 8 ft long

Habitat
- Tropical and temperate oceans
- some freshwater forms in rivers in Asia, Africa, and South America


Special abilities
Dolphins are famous for their intelligence and learning abilities. Dolphins communicate using an underwater sonar that consists of high pitched whistles and squeaks. Dolphins have a highly developed sense of hearing. Dolphins often travel in groups like a herd.


Why Dolphins are endangered ?

There are many species of dolphins that are endangered such as the Ganges river dolphin , Indus river dolphin , Yangtze river dolphin , Amazon river dolphin and also La Plata river dolphin. The first three are found in Asia and the remaining are found in South American.There are only about 1800 Ganges river Dolphins left while Indus river dolphins numbers only counted to 500 . In January 2000, there were believed to be only five Yangtze river dolphins remaining in the wild.

These dolphins main threat are fishing nets and commercial killing. Several fishing practices have taken a toll on dolphin populations. Most lethal are drift nets and nets called purse seines, used to fish for yellowfin tuna. Because tuna often swim beneath dolphin schools, dolphins are actively searched for. Fishermen then circle the tuna with mile-long (1.6-km) seine nets that trap fish and mammals alike.More than q quarter of million dolphins were killed when this practice started around 50 years ago .Now boat captains are trained to employ manoeuvres that help release the dolphins but still the number of killed dolphins are high at around 20,000 a year.

Other method of fishing is the drift net which is the most indiscriminate killing device yet used at sea.It measured up to 40 miles (64 km) long, drift nets hang draped from floats, trapping virtually everything in their path. Fishermen haul the nets aboard, store the fish or squid, and discard everything else, including dolphins that have drowned while trapped.


sources :
i. http://www.idw.org/
ii. http://www.panda.org/what_we_do/endangered_species/cetaceans/
iii. http://encyclopedia2.thefreedictionary.com/Dolphin+habitat