3.4 Biological Resources
Nearby Sensitive Resources
Western snowy plover sites are located at the south end of Mission Beach and at Mission Bay where
California least tern nests also occur (Figure 3.4-1). All sites are located less than one mile away, and the
Mission Beach snowy plover nest sites are within one-half mile.
Nearshore habitat is sand. Artificial reefs and numerous sunken vessels are known to occur offshore. The
nearest hard bottom feature is the NOSC Tower at -60 feet MLLW located approximately 4,500 feet from
the receiver site (refer also to Section 3.6). No kelp canopy was mapped in 1999 in the vicinity of the site.
In 1997, small patches of kelp were found offshore of the northern half of the site and to the north of the
site. These patches were 1,150 feet offshore between -15 and -25 feet MLLW, which was about 800 feet
seaward of the site boundary (Table 3.4-2). Historically, kelp does not occur with any regularity or
persistence off Mission Beach.
Imperial Beach
Within Site Boundaries
Sand is the predominant intertidal habitat; however, an extensive band of 80 to 100 percent cobble
extended up to 110 feet from the back beach throughout most of the site. During the May 1999 survey,
the beach width was wider at the north end of the site and about 100 feet narrower towards the south end.
Rip-rap revetment occurred the length of the site at the back beach. Sand depths were highly variable in
the upper and mid intertidal zones (4 to greater than 48 inches), and generally deeper in the low intertidal
(28 to greater than 48 inches). Sand depths averaged 18 inches in the upper, 15 inches in the mid, and 34
inches in the low intertidal.
Sand crabs, bean clams, and polychaete worms were found in the sand habitat. No marine life was
observed on the cobble. Common splash zone organisms such as Enteromorpha, acorn barnacle, and
limpets were noted on the revetment in areas where it was closer to the water.
California grunioneggs were not observed in shovel samples collected during the May survey. Sand depths
were sufficient to support grunion egg laying and the site was sampled four days after a new moon. Dense
cobble cover over most ofthe upper intertidal and/or narrow beach width probably limited potential habitat
for grunion along most of the site.
Regional Beach Sand Project EIR/EA
Page 3.4-33
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