Larger threats to porpoises include extensive bycatch in gill nets , competition for food from fisheries, and marine pollution, in particular heavy metals and organochlorides. History and Etymology for apropos Adjective, Preposition, and Adverb French à propos , literally, to the purpose. Additionally, civilian vessels produce sonar waves in order to measure the depth of the body of water in which they are. Preposition English borrowed "apropos" from the French phrase à propos, literally "to the purpose. The vaquita nearly became extinct in the twentieth century, due to bycatch in gill nets, with a predicted population of fewer than individuals. Japan Times. Help Community portal Recent changes Upload file. Left alone, the word probably wouldn't have gotten much attention, but in noted language expert H. After having been kept in captivity for 9 years, the first breeding happened in
The large bulge on top of the porpoises head is caused by the melon. Porpoises are recognised from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins e. Porpoises have a three-chambered stomach, including a fore-stomach and fundic and pyloric chambers. To protect the species, China's Ministry of Agriculture classified the species as being National First Grade Key Protected Wild Animal, the strictest classification by law, meaning it is illegal to bring harm to a porpoise. Dall's porpoise P. Hector's dolphin also lack a pronounced beak. As amended by the Conference of the Parties in , , , , , , , and ". As well as this, the eyes of a porpoise are placed on the sides of its head, so their vision consists of two fields, rather than a binocular view like humans have.
Ray Several species exhibit sexual dimorphism in that the females are larger than males. In order to try to prevent extinction, the Mexican government has created a nature reserve covering the upper part of the Gulf of California and the Colorado River delta. Johansson; E. Berlin Hong Fairin Industry Co. From Wikipedia, the free encyclopedia. Main article: Cetaceans in captivity. A dissection of three Burmeister's porpoises shows that they consume shrimp and euphausiids. Take the quiz Spell It Can you spell these 10 commonly misspelled words?
Parvorder Mysticeti Baleen whales. The calves are weaned at about 11 months of age. Retrieved 13 July All mammals sleep, but porpoises cannot afford to become unconscious for long because they may drown. Retrieved 30 August Protective measures in the Tian-e-Zhou Oxbow Nature Reserve has increased its population of porpoises from five to forty in 25 years. Cuvier's beaked whale Z. Biological Conservation. Can you spell these 10 commonly misspelled words?