|Scientific Name:||Pseudorca crassidens (Owen, 1846)|
|Red List Category & Criteria:||Not Applicable (Regional assessment) ver 3.1|
|Assessor(s):||Species account by IUCN SSC Cetacean Specialist Group; regional assessment by European Mammal Assessment team|
This species is assessed as Not Applicable as it is of marginal occurrence in the European Mammal Assessment region.
|Range Description:||False killer whales are found in tropical to warm temperate zones, generally in relatively deep, offshore waters of all three major oceans. In addition to deep, oceanic areas, they do sometimes occur over the continental shelf and appear to move into very shallow waters on occasion. They do not generally range poleward of about 50° in either hemisphere. However, some animals occasionally move into higher latitude waters. They are found in many semi-enclosed seas and bays (including the Sea of Japan, Bohai/Yellow Sea, Red Sea, and Persian Gulf), but they only occasionally occur in the Mediterranean Sea (Leatherwood et al. 1989). There are a few records for the Baltic Sea, which are considered extralimital.|
Native:Croatia; Denmark; France; Germany; Gibraltar; Greece; Ireland; Italy; Malta; Netherlands; Norway; Portugal; Spain; United Kingdom
|FAO Marine Fishing Areas:|
Atlantic – western central; Atlantic – northeast; Atlantic – eastern central; Atlantic – southwest; Atlantic – southeast; Atlantic – northwest; Indian Ocean – western; Indian Ocean – eastern; Mediterranean and Black Sea; Pacific – southeast; Pacific – northeast; Pacific – northwest; Pacific – eastern central; Pacific – western central; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are few estimates of abundance, and none for the global population size. Abundance estimates, even for large oceanic regions such as the eastern tropical Pacific, are only in the low tens of thousands (39,800, CV=64%: Wade and Gerrodette 1993). There is no information on population trends.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||As is the case for most of the tropical oceanic delphinids, this species is rather poorly-known (see Baird 2002). This species is considered to be extremely social. Groups of 10-60 are typical, though much larger groups are known. Some groups are very tight-knit, while others may be spread over a kilometer or more of ocean. |
This is one of the most common species involved in cetacean mass strandings, and in one case, over 800 stranded together. The false killer whale is a lively, fast-swimming cetacean, and occasionally rides bow waves of vessels. False killer whales are known to behave aggressively toward other small cetaceans, and have even been seen chasing and attacking dolphins (in particular, dolphins just released from tuna purse seines) and some large whales.
False killer whales occur in tropical and temperate waters worldwide (Stacey et al. 1994, Odell and McClune 1999), generally in relatively deep, offshore waters. However, some animals may move into shallow and higher latitude waters, on occasion (including some semi-enclosed seas such as the Red Sea and the Mediterranean). It seems to prefer warmer water temperatures. Although false killer whales eat primarily fish and cephalopods, they also have been known to attack small cetaceans, humpback whales, and sperm whales. They eat some large species of fish, such as mahi-mahi (also called dorado or dolphinfish), tunas (see Alonso et al. 1999) and sailfish.
|Major Threat(s):||Potential threats include decline in prey base, incidental mortality in fishing gear, and noise pollution.|
|Conservation Actions:||This is a relatively poorly-known species which, although mostly observed over deep water, is known to strand from many coasts. Abundance estimates as well as by-catch data do not exist for most areas, nor are there detailed accounts on migratory behaviour. Clearly, more research is needed.|
|Citation:||Species account by IUCN SSC Cetacean Specialist Group; regional assessment by European Mammal Assessment team. 2007. Pseudorca crassidens. The IUCN Red List of Threatened Species 2007: e.T18596A8494867.Downloaded on 23 June 2018.|
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