Positive Impacts: food body parts are source of valuable material ecotourism research and educationĬetaceans have vital ecosystem roles as consumers of plankton, fish, crustaceans, cephalopods, and other aquatic animals. Whales are also important cultural and mythological icons for peoples around the world. Currently cetaceans are important for entertainment and tourist industries: captive odontocetes are trained to perform tricks for large crowds of spectators, and whale-watching boats are popular attractions for tourists wishing to catch a glimpse of cetaceans in the wild. Harvesting for subsistence and scientific purposes continues, however, and several countries, including Iceland and Japan, continue to hunt whales under the name of "scientific" whaling. However, in 1986 a moratorium on commercial whaling was enacted by the International Whaling Commission, and today only Norway continues a commercial harvest. The late 19th and 20th centuries saw a boom in commercial whaling to provide oil for lighting and heating and facilitated by newer and deadlier technologies for hunting whales. Finally, all cetaceans face the threats of pollution and global climate change.įor centuries, cetaceans have been hunted for their meat, blubber, and oil. The use of military sonar in the oceans, as well as the increase of ocean noise, is becoming more widely recognized as a serious and growing threat to cetaceans. Captive breeding programs may be the only hope for such critically endangered odontocetes as Yangtze river dolphins ( Lipotes vexillifer). They also risk being struck by vessels, and some wild populutions have been depleted by people capturing live animals for oceanariums. Sometimes they are killed on purpose by fishermen who see them as competitors. They become entangled in nets and drown or they are killed by explosives. Many species of small odontocetes are threatened by commercial fishing operations. Continued whaling by some nations as "scientific whaling" may still threaten some species. Since whales were given legal protections in the latter half of the 20th century and commercial whaling was banned in 1986, some populations seem to be recovering, albeit slowly. Commercial whaling in the 18th, 19th, and 20th centuries took a huge toll on many populations of mysticetes, which have low reproductive rates and cannot recover quickly from overexploitation. All cetaceans are listed in CITES Appendix II, except for Lipotes vexillifer, Platanista spp., Berardius spp., Hyperoodon spp., Physeter catodon, Orcaella brevirostris, Sotalia fluviatilis, Sousa spp., Neophocaena phocaenoides, Phocoena sinus, Eschrichtius robustus, Balaenoptera acutorostrata, Balaenoptera bonaerensis, Balaenoptera borealis, Balaenoptera edeni, Balaenoptera musculus, Balaenoptera physalus, Megaptera novaeangliae, Balaena mysticetus, Eubalaena spp., and Caperea marginata, which are listed in Appendix I. The IUCN lists 28 cetacean species as lower risk, 5 as vulnerable, 7 as endangered, 2 as critically endangered, and 39 as data deficient. Perception Channels: visual tactile acoustic ultrasound echolocation chemical Social odontocetes use touch extensively with pod-mates, which may be an important form of communication.Ĭommunication Channels: tactile acoustic River dolphins ( Inia, Lipotes, Platanista, Pontoporia) are the exception there is little use for vision in the turbid waters where they reside, so their eyes are greatly reduced and some are nearly blind. Though they rely mainly on sound to communicate, most cetaceans are able to see fairly well in both water and air. Odonocetes have a hearing range that greatly exceeds that of humans they can perceive ultrasounds up to 120 kHz. They have a fatty organ called a melon on the forehead that focuses acoustic signals as they are emitted, and they receive sounds in the middle ear via the mandible. Odonotocetes also use clicks for echolocation, to navigate and to find food. Odontocetes communicate with whistles these sounds are most likely produced by opening and closing nasal plugs. Low-pitched moans produced by some baleen whales may be the loudest sounds produced by any animal they carry underwater for hundreds of kilometers. Male humpback whales ( Megaptera novaeangliae) "sing" for up to 40 minutes at a time, presumably to attract females. Baleen whales moan, grunt, chirp, whistle, and click to communicate these sounds are made by the larynx.