Project Information

Title: Survey and Evaluation of Instream Habitat and Stock Restoration Techniques for Wild Pink and Chum Salmon R105

Project Year and Number: 1992: R105

Other Fiscal Years and Numbers for this Project: 1995: 95139-B, 1994: 94139-B2, 1994: 94139-B1, 1993: 93063

Principal Investigator (PI): Mark Willette (Alaska Department of Fish & Game)

Managing Agency: ADFG

Assisting Personnel: Greg Carpenter, Mark Dickson, Nick Dudiak, Steve Honnold

Research Location: All Spill Affected Areas

Restoration Category: Damage Assessment

Injured Resources Addressed: Pink Salmon

Abstract: The Exxon Valdez oil spill injured wild pink and chum salmon in Prince William Sound. Various amounts of oil were deposited in intertidal habitats where up to 75% of the spawning occurs. Salmon eggs deposited in 1989 and all subsequent years have been contaminated and direct egg mortality has been documented. A higher incidence of somatic, cellular, and genetic abnormalities were also found among alevins and fry in oiled creeks. Wild salmon fry were further injured when they entered the near shore marine environment and consumed oil contaminated prey. This caused reduced growth and fry-to-adult survival, because predators targeted the smaller, slower growing fish. Migration patterns indicated that nearly all the salmon fry exiting Prince William Sound passed through heavily oiled habitats in the southwestern Prince William Sound. Diminished growth and survival during the early marine period may have reduced the wild and hatchery reared salmon return to Prince William Sound in 1990 by 15 to 25 million fish. Recently detected genetic injuries may further reduce the productivity and fitness of wild salmon populations in Prince William Sound for many years to come. This project has focused on identifying the most appropriate restoration techniques for injured anadromous fish spawning habitats and specific stocks of anadromous fish. The project was initiated in 1991, by the Alaska Department of Fish and Game (ADF&G). The study area includes Prince William Sound, lower Cook Inlet, and Kodiak Island. In 1992, the project will be conducted cooperatively by the ADF&G and the U.S. Forest Service (USFS). The USFS will provide expertise in habitat restoration in Prince William Sound, and the ADF&G will focus on stock and habitat restoration in the Exxon Valdez oil spill impact area. The USFS will conduct hydrological surveys at sites in the National Forest, further evaluate fish pass sites identified in 1991, and determine appropriate restoration techniques for anadromous fish (salmon and trout) stocks and habitats in the most heavily oiled streams in Prince William Sound. The ADF&G will estimate the area of salmon spawning habitat injured by the oil spill in Prince William Sound, determine the most appropriate techniques for replacing this habitat within the oil spill impact area, and coordinate with the USFS on evaluation of fish stock restoration techniques. Results from ongoing genetic studies will be used to determine the most appropriate restoration techniques for stocks in oiled areas. If genetically discrete stocks are identified within the oiled area, restoration efforts will concentrate on restoring or replacing injured habitat or stocks. If genetically discrete stocks are not identified within the oiled area, injured habitat and stocks will be restored throughout the Exxon Valdez oil spill impact area using the most cost-effective methods. Specific study sites were identified in 1991 from previous reports, aerial photographs, aerial surveys, and ground surveys. Identification of study sites will continue in 1992. More intensive investigations of sites identified in 1991 will also be conducted. Appropriate restoration or enhancement techniques may include spawning channels and improvement of fish passage through fish ladders, or step pool structures to overcome physical or hydrological barriers. These measures will provide oil free spawning habitat to replace oil impacted spawning areas. Additional wild salmon stock rehabilitation measures may include stream side incubation boxes, remote egg takes and incubation at existing hatcheries for fry stocking in oil impacted streams, and fry rearing.


Proposal: Not Available

Reports:
Final Report: View (82,024 KB)

Publications from this Project: None Available