ARCHIVED REPORTS_DRAFT ENVIRONMENTAL IMPACT REPORT

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73°F(Hassler 1988). Adult and juvenile striped bass can tolerate short-term exposures to temperatures as high as 93°F; however, long-term exposures to temperatures exceeding 77°F result in stress and 86°F is often lethal (Moyle 2002). At temperatures less than approximately 80°F, adult fish can tolerate abrupt temperatures changes, such as those encountered when shifting from seawater to freshwater. Based on available information,the following temperature guidelines have been identified for striped bass: ► Optimal/suitable range: 59°F to 75°F ► Range of increasing adverse effects: 77°F to 91'F ► Lethal effects: > 86°F MACROINVERTEBRATE POPULATIONS Aquatic insects and other macroinvertebrates perform many ecological roles in aquatic habitats. The abundance and composition of macroinvertebrate populations are critical to the survival of both common and special-status fish species. Most fish species either directly consume invertebrates or prey on fish species that consume invertebrates. Fry in streams feed extensively on drift insects,but zooplankton are more heavily eaten in the lower San Joaquin River and Delta. Adult and juvenile chironomids(Diptera)insects and crustacean zooplankters, especially Cladocera and Copepoda, are principal food items of Chinook salmon and steelhead fry and juveniles in the larger river systems (e.g., lower Sacramento and San Joaquin rivers) (Kjelson et al. 1982). Smolts feed on gammarid amphipods and larval fish in brackish waters; larger and older smolts select larger crustaceans (Corophium and Neomysis)and fish as food(Cannon 1982). The shift from shallow epibenthic prey to larger, often pelagic species reflects the movement of juveniles from shallow littoral habitats into deeper river and tidal channels as they increase in size(Allen et al. 1986). Other typical macroinvertebrates inhabiting the Delta and lower reaches of the San Joaquin River include amphipods,mysid shrimp, and bay shrimp. The thermal tolerance of chironomids, cladocerans, copepods, amphipods,mycid shrimp, and bay shrimp ranges from 82°F to 87°F depending on the species(Bradley 1976; Hair 1971; Heubach 1969). REGULATORY SETTING Fisheries and aquatic resources in California are protected and/or regulated by a variety of laws and policies. Before project implementation,the proposed project must comply with these regulations. Key regulatory issues applicable to the proposed project are discussed below. FEDERAL Federal Endangered Species Act Pursuant to the federal ESA,the USFWS and the NMFS have authority over projects that may result in take of a species federally listed as Threatened or Endangered.Under the ESA,the definition of"take"is to"harass,harm, pursue,hunt, shoot,wound,kill,trap, capture,or collect, or to attempt to engage in any such conduct."USFWS and NMFS have also interpreted the definition of harm to include significant habitat modification that could result in take. If a project has a likelihood that it would result in take of a federally listed species, either an incidental take permit,under Section 10(a)of the ESA, or a federal interagency consultation,under Section 7 of the ESA, is required. Fish species occurring in the project vicinity are covered under the federal ESA. Sustainable Fisheries Act In response to growing concern about the status of U.S. fisheries,the Sustainable Fisheries Act of 1996 (Public Law [PL] 104-297)was passed by Congress to amend the Magnuson-Stevens Fishery Conservation and Manteca WQCF and Collection System Master Plans EIR EDAW City of Manteca 4.13-11 Fisheries and Aquatic Resources