Section 3.5 Marine Biology

Section 3.5 Marine Biology

3.5 MARINE BIOLOGY 3.5.1 Introduction 3.5.1.1 Definition of Resource For purposes of this EIS/OEIS, marine biological resources are defined as marine flora and fauna and habitats that they occupy, occurring within the Point Mugu Sea Range, Mugu Lagoon, and the intertidal and nearshore environment of San Nicolas Island and Point Mugu. This section specifically addresses marine invertebrates and flora. Fish and sea turtles are addressed in Section 3.6, marine mammals are addressed in Section 3.7, and seabirds are addressed in Section 3.8. Threatened and endangered species, as defined by the U.S. Fish and Wildlife Service (USFWS), are also addressed. Species that are federally listed are afforded a degree of regulatory protection, which entails a permitting process including specific mitigation measures for any allowable (incidental) impacts on the species. Species that are proposed to be listed by the USFWS are treated similarly to listed species by that agency; recommendations of the USFWS, however, are advisory rather than mandatory in the case of proposed species. A federally listed endangered species is defined as any species, including subspecies, that is “in danger of extinction throughout all or a significant portion of its range.” A federally listed threatened species is defined as any species “likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” “Proposed” endangered or threatened species are those species for which a proposed regulation has been published in the Federal Register, but a final rule has not yet been issued. 3.5.1.2 Regional Setting The Sea Range straddles the ocean off Point Conception which is considered a major geographic feature that affects marine biological diversity. North of Point Conception, the marine resources are under the influence of the cold, southward flowing California Current. The shape of California’s coastline south of Point Conception creates a broad ocean embayment known as the Southern California Bight (SCB). The SCB encompasses the area from Point Conception south to Mexico and is influenced by two major oceanic currents: the southward flowing, cold-water California Current and the northward flowing, warm-water California Countercurrent (refer to Figure 3.4-1). These currents mix in the SCB and strongly influence patterns of ocean water circulation, sea temperatures, and distributional trends in marine flora and fauna assemblages along the southern California coast and the eight Channel Islands (Murray and Littler 1981; Engle 1994). These factors cause extreme differences in species composition and abundance both north and south of Point Conception, as well as within the SCB. Bottom topography in the SCB varies greatly from broad expanses of well developed continental shelf lands to deep basins (refer to Figure 3.4-2). Southwest of the Channel Islands is the Patton Escarpment, a steep ridge with contours bearing in a northwesterly direction; this ridge drops approximately 4,900 feet (1,500 m) to the deep ocean floor. Between the Patton Escarpment and the mainland lie the Santa Rosa- Cortez Ridge, three deep shelf basins (Santa Cruz, Santa Monica, and Santa Catalina to the south), Santa Barbara Basin to the north, two important channels (Santa Barbara and San Pedro), and a series of escarpments, canyons, banks, and sea mounts (e.g., Cortez Bank, Tanner Bank, 60-Mile Bank, Farnsworth Bank, and Lausen Sea Mount), some of which are located outside Sea Range boundaries (refer to Figure 3.4-2). Banks and sea mounts possess unique physical characteristics that affect local biological processes. They are the focus of upwelling which results in increased primary, and perhaps secondary productivity, and attracts pelagic fishes and their predators (i.e., seabirds and marine mammals) (Cross and Allen 1993). In the SCB, nutrient rich upwelling occurs mainly from February through August when surface waters, driven offshore by winds, are replaced by colder, richer waters 3.5-1 overturning from below. Thorough and frequent mixing of these waters create conditions which support a rich and varied marine flora and fauna year-round (Leatherwood et al. 1987). The Channel Islands National Marine Sanctuary (CINMS) encompasses the waters within 6 NM (11 km) of San Miguel, Santa Rosa, Santa Cruz, Anacapa, and Santa Barbara islands (Figure 3.5-1). The Channel Islands National Park (CINP) boundaries extend 1 NM (1.9 km) beyond the coast of each of these islands. The CINMS was established in 1980 for the purpose of protecting areas off the southern California coast which contain significant marine resources. The CINMS is located over the continental shelf (refer to Figure 3.4-2), with water depths generally less than 360 feet (110 m). Waters surrounding the Channel Islands are relatively undisturbed and provide a habitat for a diverse assemblage of marine organisms. A Presidential Proclamation signed on 11 January 2000 established the California Coastal National Monument, an area on the California coast extending from mean high tide to a distance of 12 NM (22 km) offshore. The monument comprises all lands above water in this area, including islands, rocks, exposed reefs, and pinnacles above the high water mark that are owned by the U.S. Government. Establishment of the California Coastal National Monument does not enlarge or diminish existing federal authority or use of adjacent waters. In addition, islands, rocks, exposed reefs, and pinnacles that are already reserved for other purposes are not affected by this designation. San Nicolas Island, as well as the other Channel Islands within the Sea Range, are located outside this designation. EO 13089, Coral Reef Protection, was issued to preserve and protect the biodiversity, health, heritage, and social and economic value of U.S. coral reef ecosystems and the marine environment. EO 13089 states that each federal agency whose actions may affect U.S. coral reef ecosystems: a) identify their actions that may affect U.S. coral reef systems; b) utilize their programs and authorities to protect and enhance the conditions of such ecosystems; and c) to the extent permitted by law, ensure that any actions they authorize, fund, or carry out will not degrade the conditions of such ecosystems. No coral reefs are located within the temperate waters of the Point Mugu Sea Range. A significant marine water resource at Point Mugu is Mugu Lagoon (refer to Section 3.4.3.1). Mugu Lagoon is one of the largest salt marshes in southern California. It is relatively undisturbed and provides a habitat for a diverse assemblage of marine organisms. 3.5.1.3 Region of Influence This section describes the marine biological resources that occur at the Point Mugu Sea Range, Point Mugu, and San Nicolas Island. Descriptions are based on literature surveys, previously conducted field surveys, and existing Geographic Information System (GIS) databases. For the purposes of this EIS/OEIS, the region of influence (ROI) consists of three major marine habitats: the Point Mugu Sea Range, Point Mugu (Mugu Lagoon and sandy beaches/nearshore environment), and the intertidal and nearshore subtidal areas surrounding San Nicolas Island. Fish and sea turtles are discussed in Section 3.6, and marine mammals are discussed separately in Section 3.7. 3.5.2 Point Mugu Sea Range The Point Mugu Sea Range encompasses a 36,000 square mile (93,200 km2) area that includes regions of complex bathymetry which provide diverse habitats for a variety of marine life. Soft substrates, such as sandy beaches, shelves, and slopes, are abundant along the mainland and the offshore islands. Hard substrates, such as the rocky intertidal, shallow subtidal reefs, deep rock reefs, and kelp beds, are also common along the coasts of the mainland and islands. Beyond the depths of kelp beds (greater than 3.5-2 sslnd2ywnership2nd2ghnnel2sslnds xtionl2rk2nd2wrine2ntury2foundries 5 ndenerg2epf nt2frr2gounty nt2frr 5 entur gounty vos2engeles gounty entur 5 ort2rueneme 5 xe2oint2wugu 5 nt2os n2wiguel enp nt2gruz 5 ve nt2frr nt2gtlin tte2iologil2eserves n2xiols n2wiguel enp nt2gruz nt2os nt2frr n2glemente n2xiols ywnership rivte xture2gonservny x rojetionX22 niversl2rnsverse2wertor xtionl2rk2ervie xorth2emerin2htum2IWPU xvy i one2II le2shown2is2IXIDQUSDHHH xtionl2rkGntury2foundries ghnnel2sslnd2xtionl2rk2 ghnnel2sslnd2xtionl2wrine2ntury2 pigure tte2iologil2eserves SH H SH xutil2wiles QFSEI 100 feet [30 m]), approximately 3 percent of the sea floor consists of rubble and rocky outcrops inhabited by marine invertebrate assemblages (Dailey et al. 1993). On the continental shelf regions, sand and gravel substrate is typically interspersed between these rocky areas. Offshore, the Channel Island shelves, Santa Rosa-Cortez Ridge, and Tanner and Cortez banks (refer to Figure 3.4-2) consist primarily of base rock and rocky outcrops that may be covered with a thin layer of sediment. Hard substrates occur to depths of over 1,640 feet (500 m) in the ROI and include sea mounts and man-made structures. Because they exceed diving depths (typically about 100 feet [30 m]) and cannot easily be sampled with coring devices or trawls, deep, hard substrate assemblages are the least-studied benthic habitats in the Sea Range. The following subsections broadly describe the marine flora and benthic marine invertebrates of the Sea Range. 3.5.2.1 Marine Flora Most of the marine flora in the Sea Range comprises phytoplankton. Phytoplankton are microscopic plants that live in patchy abundance throughout the water column. The distribution of plankton is dependent upon many factors including light intensity, salinity, temperature, currents, nutrients, and their reproductive cycles and predators (Smith 1977). Phytoplankton comprise mainly diatoms and dinoflagellates, which carry out photosynthesis and form the basis of the aquatic food chain. They are a food source for the larger zooplankton (microscopic animals) which in turn are a food source for invertebrates, fish, and other large marine species such as baleen whales. About 70 percent of the known algae species from California are known to occur in the SCB, and thus within the Point Mugu Sea Range (Dailey et al.

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