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COMPTUEX/JTFEX EA/OEA Final Appendix AMARINE MAMMAL DENSITY ESTIMATESIn order to estimate marine mammal densities specific to the operational areas addressed in theJTFEX/COMPTUEX EA/OEA and SOCAL EIS/OEIS, we used previously derived density estimates,namelyDensities calculated for the Point Mugu Sea Range EIS/OEIS (density estimates and a completedescription of the methods used to calculate them are included in the Point Mugu Sea Range EIS/OEISMarine Mammal Technical Report [U.S. Navy 1998]).Densities calculated for the SCIRC, which are based on NMFS aerial surveys conducted in 1998 and1999 over water depths from the shore of San Clemente Island to ~1,000 m depth (Carretta et al. 2000).There are separate estimates for cold- and warm-water periods.Density and effort data derived from NMFS 1986–1996 ship-based surveys, conducted in summer andfall (Ferguson and Barlow 2001). Ferguson and Barlow provided density estimates by species for blocks5° x 5° in area. The SOCAL OPAREA intersects 5 of those blocks (Figures 1 and 2).Point Mugu COMPTUEX/JTFEXIn order to assess potential impacts from COMPTUEX/JTFEX activities in the Point Mugu Sea Range,we will use the densities calculated for the Point Mugu Sea Range EIS/OEIS (see Appendix A, Table A-1in the Marine Mammal Technical Report [U.S. Navy, 1998]).SOCAL Range ComplexTo estimate marine mammal densities in the SOCAL Range Complex, we identified three strata for whichwe calculated separate density estimates based on available data: 1,000-m depth northof 30°N, and >1,000-m depth south of 30°N.Warm- and Cold-water Densities in Water 1,000 m DepthFor water depths >1,000 m, we calculated warm-water cetacean densities for two offshore areas, onenorth of 30N and one south of there. We used data provided in Ferguson and Barlow (2001) for Blocks58 and 59 to estimate cetacean densities in the area north of 30N, and the data for blocks 72, 73, and 88to estimate densities south of 30N. Pinnipeds were not recorded by Ferguson and Barlow (2001), but theonly pinnipeds known to occur in deep, offshore waters are adult male California sea lions and northernelephant seals during their migrations between haul-out sites and feeding areas.Blocks 58 and 59, from 30°N to 35°N and 115°W to 125°W, include water depths from shore to >4,000m. Cetacean density estimates calculated from the data of Ferguson and Barlow (2001) for those areasare relatively high (totals of 1.64/km² and 0.58/km² for Block 58 and 59, respectively). It is recognizedthat these estimates overestimate true densities of many species in deeper water and underestimate truedensities in shallower water because (1) the densities were calculated for the entire 5° x 5° blocks, and (2)many species are more abundant in relatively shallow water (i.e., 1,000–2,000 m) than in deep, oceanicwater. Densities from the two blocks were weighted by survey effort and size of the SOCAL RangeComplex in the block.Blocks 72 and 73 are due south of Blocks 58 and 59, and Block 88 is due south of Block 73. Blocks 73and 88 are entirely in deep (generally >4,000 m) water, and most of Block 72 is in deep water. Cetaceandensity estimates calculated from the data of Ferguson and Barlow (2001) for those areas are relativelyA-13 February 2007