Composite Training Unit Exercises and Joint Task ... - Govsupport.us

COMPTUEX/JTFEX EA/OEA Final Chapter 3Distribution—Dwarf and pygmy sperm whales are sighted primarily along the continental shelf edge andover deeper waters off the shelf (Hansen et al., 1994; Davis et al., 1998). However, along the U.S. westcoast, sightings of the whales have been rare, although that is likely a reflection of their pelagicdistribution and small size rather than their true abundance (Carretta et al., 2002). Several studies havesuggested that pygmy sperm whales live mostly beyond the continental shelf edge, whereas dwarf spermwhales tend to occur closer to shore, often over the continental shelf (Rice, 1998; Wang et al., 2002;MacLeod et al., 2004). Barros et al. (1998), on the other hand, suggested that dwarf sperm whales mightbe more pelagic and dive deeper than pygmy sperm whales.Another suggestion is that the pygmy sperm whale is more temperate, and the dwarf sperm whale moretropical, based at least partially on live sightings at sea from a large database from the eastern tropicalPacific Ocean (Wade and Gerrodette, 1993). There, the pygmy sperm whale was not seen in truly tropicalwaters south of the southern tip of Baja California, but the dwarf sperm whale was common in thosewaters. This idea is also supported by the distribution of strandings in South American waters (Muñioz-Hincapié et al., 1998). Also, in the western tropical Indian Ocean, the dwarf sperm whale was much morecommon than the pygmy sperm whale, which is consistent with this hypothesis (Balance and Pitman,1998). There have been few sightings of Dwarf sperm whales in the SOCAL OPAREA; therefore,seasonal occurrence can not be determined (Wade and Gerrodette, 1993).Acoustics—There is no information available on dwarf sperm whale vocalizations or hearing capabilities.The pygmy sperm whale clicks range from 60 to 200 kHz, with a dominant frequency of 120 kHz(Thomson and Richardson, 1995). An auditory brainstem response study indicates that pygmy spermwhales have their best hearing between 90 and 150 kHz (Ridgway and Carder, 2001).False Killer Whale (Pseudorca crassidens)Status—The false killer whale is not listed under the ESA, and the individuals found off California arenot part of a strategic stock. There are no abundance estimates available for this species in the NOAAStock Assessment Report for this area of the Pacific.Distribution—False killer whales occur predominantly in tropical to subtropical pelagic waters(Leatherwood et al., 1987; Bonnell and Dailey, 1993). In the eastern North Pacific Ocean, the species hasbeen reported rarely north of Baja California (Leatherwood et al., 1982, 1987; Mangels and Gerrodette,1994). There are four stranding records from San Nicolas Island (Stager and Reeder, 1951), and a reportof a probable capture of this species off the west end of Santa Catalina Island (Norris and Prescott, 1961).The only sightings in the 5 Ferguson and Barlow (2001) survey blocks that contain parts of the SOCALRange Complex were 2 sightings in Block 72, which includes the southeast corner of the SOCAL RangeComplex. There have been few sightings of false killer whales in the SOCAL OPAREA; therefore,seasonal occurrence can not be determined (Ferguson and Barlow, 2001).Acoustics—The dominant frequencies of false killer whale whistles are 4 to 9.5 kHz; those of their clicksare 25 to 30 kHz and 95 to 130 kHz (Thomas et al., 1990; Richardson et al., 1995). The source level is220 to 228 dB re 1 μPa-m (Ketten, 1998). Best hearing sensitivity measured for a false killer whale wasaround 16 to 64 kHz (Thomas et al., 1988, 1990).Harbor Porpoise (Phocoena phocoena)Status—The harbor porpoise from the Morro Bay Stock (from just south of Monterey Bay to PointConception) is not listed as endangered under the ESA and is not considered depleted or strategic.Previous SARs listed the harbor porpoise as part of a larger California/Oregon/Washington Stock butgenetic studies have divided that stock into six separate stocks. The Morro Bay Stock of harbor porpoises3-45 February 2007