3.4 Biological Resources
During the beach surveys, the distribution of sand versus hard substrate habitat within the intertidal zone
was mapped. Survey teams measured the length and width of all hard substrate areas relative to distance
from the northern site boundary. Photographs of representative views of the beach habitats were taken.
The depth of sand, up to a depth of four feet, was measured within upper, mid, and low intertidal zones at
several locations along the beach using a one-quarter inch diameter calibrated rod. At selected locations
the rod was pushed into the sand up to four feet deep or to the point of refusal (until it hit something that
prevented further penetration like a rock or reef) whichever occurred first. There were at least nine sample
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locations at each receiver site. The focus of the sand depth measurements was to identify occurrence of
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habitat for various organisms and egg laying by California grunion. Since those habitat functions typically
occur within sand depths ranging up to two to three feet, depths greater than four feet were not measured.
The sand substrate was further characterized by examination of organisms living within upper, mid, and low
intertidal zones. Shovel samples (up to 24 inches deep or refusal) were collected from the three intertidal
zones at three locations corresponding to near the northern boundary, near the middle, and near the
southern boundary of each site. The sides and interior of the holes were examined for marine organisms
(e.g., grunion eggs, sand crabs, worms, clams, etc.). Sand removed from the holes was sieved through a
1 mm screen to assist the evaluation of the presence of marine organisms. The wave wash area was
examined for sign of sand crabs (i.e., v-shaped antennae extended), clams, and sand dollars.
The hard substrate areas were described according to type (e.g., cobble, boulders, rock bench) and relief
height. Relief was defined in a manner consistent with previous Navy documentation. Pursuant to the
previous Navy documentation, low relief was defined as being less than three feet in height and high relief
was defined as being greater than three feet in height (Department of the Navy 1997a, 1997b). Animals
and plants living on hard substrate areas were identified consistent with the previous Navy studies, and their
relative abundance was noted.
Intertidal and Subtidal Surveys
Inshore surfgrass beds located between Oceanside and Torrey Pines were surveyed during extreme minus
tides (-1.8 to -2.1 MLLW) on January 21 and 22, 2000. Differential Global Positioning System (DGPS)
coordinates were takenat the onshore-offshore and upcoast-downcoast edges of exposed surfgrass beds.
Beds were delineated by biologists and plotted using DGPS.
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