3.4 Biological Resources
Commercial fishermen provided information that reef and scattered rock occurs offshore and south of the
Del Mar site. Surveys by the Navy in 1994 documented sand at the -10, -20, and -30 feet depth contours
offshore the site. No kelp canopy was mapped in the vicinity of the site in 1999. In 1997, the nearest kelp
bed was over 3,000 feet to the north. Historical mapping indicates that kelp has occurred offshore from
the south end of the site and up to about 6,000 feet further south. While conflicting reports of the
occurrence of hard substrate offshore Del Mar exist, the locations of intertidal surfgrass and historic kelp
beds indicate that the more sensitive hard substrate habitats occur south of the receiver site.
Commercial fishermen also reported occurrence of scattered rock and reef habitat north of the site and San
Dieguito Lagoon. The side-scan sonar survey in January 2000 included the closest scattered rock area
to the north. Scattered rock and reef were noted at depths between -10 and -20 feet MLLW. Dives in
February and March 2000 to assess resources on hard substrate in this area found that all the substrate was
vegetated with opportunistic coralline turf.
Torrey Pines
Within Site Boundaries
The proposed site consists of sand habitat with cobble. During the May 1999 survey, sand occurred
mainly in the mid and low intertidal zones. Cobble occurred in a dense band (100 percent cover) three to
100 feet wide from the back beach, and a band with about 30 percent cobble cover occurred seaward of
that for most of the site. In July, cobble cover was restricted to a narrow band (20 feet wide) in the upper
intertidal from the mid to south end of the site.
Sand depths were very shallow in the upper intertidal (average of 5 inches), moderate in the mid (average
of 18 inches), and deeper in the low intertidal (average of 42 inches) during the May 1999 survey. By July
1999, there had been substantial build up of sand with average sand depths of 34 inches in the upper
intertidal, 36 inches in the mid, and 46 inches in the low intertidal zones. Sand habitat was occupied by
sand crabs, polychaete worms, and bean clams. One dead sand dollar was noted in the low intertidal
during the May beach survey and four dead sand dollars were noted in July 1999. This indicates the
presence of offshore sand dollar beds in the vicinity of the site.
California grunion eggs were not observed in shovel samples collected during the May and July surveys.
Sand depths were insufficient and cobble cover was dense in the upper intertidal in May. In July sand
Regional Beach Sand Project EIR/EA
Page 3.4-31
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