Endangered River Dolphin
When she was going to be forced to marry a python she decided to throw herself into the Mekong River, where she was then transformed into a dolphin.
Irrawaddy dolphins (Orcaella brevirostris) are found in waters from Australia to India. Freshwater subpopulations also occur in countries in Southeast Asia including: Cambodia, Indonesia, Lao PDR, Malaysia, Myanmar, Thailand and Viet Nam. This species is able to occupy various bodies of water including oceans (near coasts), rivers and estuaries. The dolphin gets its name from the Irrawaddy River, extending from the Bay of Bengal to New Guinea and the Philippines.
Irrawaddy dolphins are most often observed as a group living species; comprising of up to ten individuals. They have complex modes of communication called echolocation or biosonar, using ‘clicks’ and ‘buzzes’ at frequencies of 60 kilohertz.
Although total range population surveys have not been carried out, the total estimated population of Irrawaddy dolphins is 7000 individuals, 90% (or 6300) of which occur in Bangladesh. Irrawaddy dolphin populations found in Lao PDR, Malaysia, Myanmar, Philippines and Thailand are classified as Critically Endangered species by the IUCN Red List, while populations in Bangladesh and India are classified as Vulnerable.
Unlike other dolphins that occupy deeper oceans, Irrawaddy dolphins are more susceptible to human induced threats as they live in a variety of aquatic habitats and closer to coastal areas.
The primary threats to the few remaining Irrawaddy dolphins are mainly due to:
- Habitat loss: as a result of dam building, pollution and gold mining
- Bycatch and other fishing practices including: bottom trawling, electro-fishing and drowning in gill nets and crab nets and
- Trade for the aquarium/tourism industry.
All cetaceans, including the remarkable Irrawaddy dolphin, belong in the wild. It is up to us to ensure their survival and welfare!
What does that mean?
Cetacian: Aquatic mammals including dolphins, porpoises and whales.
Bycatch: Describes fish and other aquatic life that has been caught unintentionally while fishing for other species and is often attributed to overfishing. The Organization for Economic Co-operation and Development (OECD) defines bycatch as ‘total fishing mortality, excluding that accounted directly by the retained catch of target species.’
Cephalopods: Include the mollusk species, all of which are marine invertebrates that have large heads and arms/tentacles. The name comes from Greek meaning “head-feet.” Examples of cephalopods include: squid and octopus species.
Echolocation or Biosonar: This is a form of communication used by many animals. This works by animals emitting calls into the environment and listening to the echoes of these calls that return from various objects around them. Echolocation is used to communicate with other individuals and for navigation and foraging. Donald Griffin first described the term echolocation in 1938, whwn he discovered and described this means of communication in bats.
Dolphinarium: An aquarium for dolphins
What you can do?