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

COMPTUEX/JTFEX EA/OEA Final Chapter 3toothed dolphins in the SOCAL OPAREA; therefore seasonal occurrence can not be determined (Ferreroet al., 1994).Acoustics—The vocal repertoire of the rough-toothed dolphin includes broad-band clicks, barks, andwhistles (Yu et al. 2003). Echolocation clicks of rough-toothed dolphins are in the frequency range of 0.1to 200 kHz, with a peak of about 25 kHz (Miyazaki and Perrin, 1994; Yu et al., 2003). Whistles show awide frequency range: 0.3 to >24 kHz (Yu et al., 2003). There is no published information on hearingability of this species.Short-beaked Common Dolphin (Delphinus delphis)Status—This is the most abundant cetacean off California (Dohl et al., 1981; Forney et al., 1995; Carrettaet al., 2005). The single current management unit for the short-beaked common dolphin in this area is aCalifornia/Oregon/Washington Stock, with a minimum population estimate of 449,846 (CV = 0.25)individuals (Carretta et al. 2004). The abundance of common dolphins varies seasonally but may beincreasing in California with a northward shift in the population (Heyning and Perrin, 1994; Barlow et al.,1997; Forney, 1997). The short-beaked common dolphin is not listed as endangered under the ESA or asdepleted or strategic under the MMPA.Distribution—Along the U.S. west coast, the short-beaked common dolphins’ distribution overlaps withthat of the long-beaked common dolphin. The short-beaked common dolphin is distributed between thecoast and at least 556 km from shore (Carretta et al., 2005). Short-beaked common dolphin abundanceoff California has increased dramatically since the late 1970s, along with a concomitant decrease inabundance in the ETP, suggesting a large-scale shift in the distribution of this species in the eastern NorthPacific (Forney et al., 1995; Forney and Barlow, 1998). The northward extent of short-beaked commondolphin distribution appears to vary inter-annually and with changing oceanographic conditions (Forneyand Barlow 1998). Short-beaked common dolphins are found in the SOCAL OPAREA throughout theyear (Forney and Barlow, 1998).Stomach contents of Delphinus from California waters revealed 19 species of fish and 2 species ofcephalopods; Delphinus feeds primarily on organisms in the vertically migrating DSL (Evans, 1994).Diel fluctuations in vocal activity of this species (more vocal activity during late evening and earlymorning) appear to be linked to feeding on the DSL as it rises during the same time (Goold, 2000). Atagged individual tracked off San Diego conducted dives deeper than 200 m, but with most in the range of9 to 50 m (Evans, 1971, 1994).Acoustics—Recorded Delphinus vocalizations include whistles, chirps, barks, and clicks (Ketten, 1998).Clicks and whistles have dominant frequency ranges of 23 to 67 kHz and 0.5 to 18 kHz, respectively(Ketten, 1998). Maximum source levels were approximately 180 dB 1 Pa-m (Fish and Turl, 1976).Oswald et al. (2003) found that short-beaked common dolphins in the ETP have whistles with a meanfrequency range of 6.3 kHz, mean maximum frequency of 13.6 kHz, and mean duration of 0.8 sec. Popovand Klishin (1998) recorded auditory brainstem responses from a common dolphin. The audiogram wasU-shaped with a steeper high-frequency branch. The audiogram bandwidth was up to 128 kHz at a levelof 100 dB above the minimum threshold. The minimum thresholds were observed at frequencies of 60 to70 kHz.Short-finned Pilot Whale (Globicephala macrorhynchus)Status—The short-finned pilot whale is not listed under the ESA. However, theCalifornia/Oregon/Washington Stock is considered strategic under the MMPA because the averagehuman-caused mortality may not be sustainable (Barlow et al., 1997). A recent calculation of the3-53 February 2007