Whales and dolphins (Dolphins and Whales) are warm-blooded animals, breastfeeding, breathing with lungs, and having a constant body temperature most of the time. Whales and dolphins live in the open sea. There is a cross-border migration within the country or between countries. Migration may concurrence to the food source, season, propagation reason. Thai waters are an area with high temperatures at all the time. The different of temperatures between each season is very small. Therefore, Thai water is an appropriate area for breeding and feeding.
According to the Wildlife Preservation and Protection Act, B.E. 1995, whales/dolphins are classified as a legal protected wildlife that haunting for, trading, possessing and breeding are all prohibited that the enforcement extends to include eggs and carcasses as well as the parts of them. Whales/dolphins are also listed on the list of the Convention on International Trade in Endangered Species of Flora and Fauna (CITES), especially for the Irrawaddy dolphin that it is in a critical to extinction. So, it is listed in Appendix I. For dolphins, other whales and whale sharks are listed on CITES Appendix II.
There are 27 species of dolphins and whales found in Thailand, categorized into localize near shore species and remotely migratory offshore species. There is a study on the status and distribution of six nearshore populations of dolphins and whales including (Indo-Pacific Bottlenose dolphin, Tursiops aduncus) (Finless porpoise, Neophocaena phocaenoides) (Indo-Pacific Humpback dolphin, Sousa chinensis) (Irrawaddy dolphin, Orcaella brevirostris) (Bryde’s whale, Balaenoptera edeni) (Omura’s whale, Balaenoptera omurai).
Dolphin and Bryde’s whale
Status of whales and dolphins in Thai waters
1. In the Gulf of Thailand: 19 species of whales and dolphins out of 27 species are found. In the lower Gulf of Thailand, coastal areas of Nakhon Si Thammarat Province to Narathiwat Province, mostly found humpback dolphins and Irrawaddy dolphins. In central Gulf of Thailand, coastal area from Prachuap Khiri Khan Province to Surat Thani Province, mostly found schools of humpback dolphins and bald-headed dolphins, smooth back. In the upper Gulf of Thailand, coastal areas of Phetchaburi Province to Samut Prakan Province, found a school of Irrawaddy dolphins and porpoises, and Bryde’s whale, and in the eastern Gulf of Thailand, from the coast of Chonburi Province to Trat Province, found schools of Irrawaddy dolphins.
2. In the Andaman Sea: found up to 23 species of whales and dolphins that the predominant are bottlenose dolphins, humpback dolphins and jumping dolphins, toothed dolphins and speckled dolphins.
Causes of stranding of whale/dolphin are firstly due to the natural illness for approximately 63 percent which the most common is respiratory tract infections. Secondly, due to the impact of fishing tools, fishing activity and marine debris which dramatically increase from year to year. The average of 3% dolphins swallow marine debris and accumulated in their gastrointestinal tract.