Poster Abstracts

FISHERIES MANAGEMENT/TECHNIQUES

[P001] Fill it and They Will Come, the Story of Fish Management on Ephemeral Lower Lake Mary, Coconino County, Arizona

Authors: C T Benedict, Arizona Game and Fish Department, 3500 South Lake Mary Road, Flagstaff, AZ 86004, 928-774-5045 (W), 928-779-1825 (F), cbenedict@gf.state.az.us, S J Reger Arizona Game and Fish Department, 3500 South Lake Mary Road, Flagstaff, AZ 86004, 928-774-5045 (W), 928-779-1825 (F), sreger@gf.state.az.us

Abstract: Lower Lake Mary is shallow weedy reservoir located in the southwest part of Coconino County, eight miles southeast of the City of Flagstaff, Arizona. The lake, when full, is one of the most productive waters in northern Arizona. Unfortunately the reservoir, which was constructed on the Kaibab formation, has developed several sinkholes through which a large volume of water is lost leading to the reservoir completely drying up during low precipitation years. The presence of these sinkholes has led to wildly fluctuating water levels since the dam’s completion in 1904. The National Forest Service maintains the picnic grounds and surrounding areas, while the Arizona Game and Fish Department stocks rainbow trout (Onchrynchus mykiss) when water levels are sufficient to allow the fish to survive. During years when the lake fills (approximately 1 year out every 10) the trout stocked in the lake have very high growth rates and provide a high quality year round fishery for the public. During years when the reservoir’s water level is sufficient (3 years out of 10), it supports a short-term spring trout fishery. The rest of the time the reservoir is dry. The benefits to the angler and the relative success of managing this ephemeral fishery will be discussed.

[P002] Fish Separation by Size Using Vertical Bar Racks

Authors: Cathy Karp, US Bureau of Reclamation, ckarp@do.usbr.gov, 303-445-2226; Leslie Hanna, US Bureau of Reclamation, lhanna@do.usbr.gov, 303-445-2146

Abstract: We have been developing and testing vertical wall fish separator systems with the objective to pass smaller more vulnerable fish to one holding system while diverting the larger more predaceous fish to another. Our goal is to reduce predation at the South Delta fish facilities, which ultimately should benefit the smaller species/life history stages (i.e., Delta smelt, young splittail, chinook salmon). To date we have tested parallel and angled vertical bar racks with bars oriented vertically and horizontally to the flow, and louver walls. The test flume is a 0.6 m wide, 0.6 m deep, 18 m long channel with unidirectional flow. Channel velocity was manipulated to achieve slow (0.2 m/s) and fast (0.4 m/s) separator approach velocities. All fish release experiments were conducted in the dark and a mesh crowder used to assist downstream fish movement. Wipers Morone saxatilis x M. chrysops, Sacramento blackfish Orthodon microlepidotus, splittail Pogonichthys macrolepidotus, and rainbow trout Oncorhynchus mykiss from 50 to 200 mm total length (TL) were released in each trial. Separation efficiency was the proportion of fish < 201 mm TL passing through the rack relative to the number passing through + the number diverted downstream (< 201 mm TL and <20 mm width). Preliminary analyses of 54 fish release-recovery experiments suggests that a vertical wall system with horizontal bars (6.3 cm diameter), spaced at 1.9 cm intervals, passes more that twice as many smaller fish than the other test racks (i.e., 49.6% to 10-26%). This is promising because this kind of bar rack appears to offer smaller fish a refugium and may be easier to keep clean in the debris-laden water of the South Sacramento-San Joaquin Delta.

[P003] Application of electromyogram telemetry in fisheries science

Authors: S.J. Cooke, Presenter, Centre for Applied Conservation Research, Department of Forest Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4, 604-228-1992 (Tel.), scooke@interchange.ubc.ca; E. Thorstad, Division for Aquatic Ecology, Norwegian Institute for Nature Research, Tungasletta 2, NO-7485 Trondheim, Norway; S.G. Hinch, Department of Forest Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4.

Abstract: Electromyogram (EMG) telemetry studies that involve remotely monitoring the locomotory activity and energetics of freshwater fish have become common place and are contributing important information to the conservation and management of fisheries resources. Here, we outline the development of this rapidly evolving field and synthesize the studies conducted to date that utilize this technology. To date, more than 50 studies have been conducted spanning more than 20 species that have utilized EMG transmitters. Several general trends were observed in the methodology of these studies that we have highlighted as standards that should be adopted. There have been numerous studies that have been methodological, although there are still some deficiencies in our basic understanding of issues such as the need for individual calibration and the method of reporting or transforming data. Increasingly, this technology is being applied to address issues in conservation, management, and aquaculture production, although this technology has been most frequently applied to the study of migration energetics. There have also been several recent studies that are focused on addressing more basic questions in ecological and evolutionary biology. Collectively, studies conducted using EMG telemetry have contributed important, yet previously difficult to obtain information on free-swimming freshwater fish.

[P004] F.E. Warren Air Force Base acts as a fish and macroinvertebrate hotspot in the middle of an urban gradient in Southeast Wyoming.

Authors: L. L. Curry-presenter, University of Wyoming, Zoology and Physiology Department, Laramie, WY 82071, (307)766-4156(W), (307)766-5625(F), lcurry@uwyo.edu, R.O. Hall, University of Wyoming, Zoology and Physiology Department, Laramie, WY 82071, (307)766-2877(W), (307)766-5625(F), bhall@uwyo.edu.

Abtract: Human alteration of the landscape by ranchland and urbanization can strongly impact stream ecosystems, yet we do not know the scale at which land-use may affect biota: can improved riparian land use mitigate watershed-scale impacts? Crow Creek in southeastern Wyoming spans sixty kilometers of high plains along a gradient of ranchland to urbanization separated by F.E. Warren Air Force Base (WAFB). Land use consists of ranchland at the upstream sites, light urbanization with intact riparian areas on WAFB, and heavy urbanization in Cheyenne, WY. We used fish and macroinvertebrate indices to examine land-use impacts along this gradient. Additionally we focused on biomass to facilitate comparison of fish and macroinvertebrates, and because biomass will relate more closely with functional processes. Many studies along a land-use gradient observe that fish and macroinvertebrate species diversity and species intolerant to human disturbance decrease while tolerant species increase. However, increases in fish species diversity, percent intolerant fish species, and percent Ephemeroptera-Plecoptera-Trichoptera taxa increased on WAFB. Similar to the density and species estimates, intolerant fish species biomass increased and tolerant species biomass decreased on WAFB compared to the upstream ranchland and the downstream urban sites. We suggest WAFB acts as a reserve for fish and macroinvertebrates, and that biotic diversity in urban streams may be maintained by restorations over short longitudinal distance.

[P005] Obtaining research permits for federally-listed endangered or threatened anadromous salmonids in California

Authors: R. B. Del Rosario, National Marine Fisheries Service, 650 Capitol Mall, Suite 8-300, Sacramento, California 95814-4706, 916-930-3614 (W), 916-930-3629 (F), rosalie.delrosario@noaa.gov; D. Logan, National Marine Fisheries Service, 777 Sonoma Avenue, Santa Rosa, California, 95404, 707-575-6053 (W), 707-578-3435 (F), dan.logan@noaa.gov.

Abstract: Researchers interested in studying federally-listed species are required to have a research permit under the Endangered Species Act (ESA). The National Marine Fisheries Service (NOAA Fisheries), Southwest Region, supports research on listed endangered and threatened anadromous salmonids and finds the knowledge gained helpful in managing for their recovery. "Take" of listed species for scientific purposes or to enhance the propagation or survival of the affected species is permitted under section 10(a)(1)(A) of the ESA. NOAA Fisheries has a simple three-step process for permitting research on listed anadromous salmonids. First, the researcher submits an application describing the proposed research, its significance, and how the research may affect listed salmonids. Second, public and peer review of the proposed research is invited and a biological opinion is prepared analyzing potential effects on listed salmonids. Third, a permit is issued, based on criteria developed through the biological opinion. Permit processing time has been expedited due to recent procedural changes and increased staffing.

[P006] Identification of Fish Passage Barriers at Road Crossings within the Northern Region

Author: Sheila Jacobson, Fisheries Biologist, USDA Forest Service, Northern Region, Regional Office, 200 East Broadway, Missoula, MT 59807, (406) 329-3549(W), sajacobson@fs.fed.us.

Abstract: Our transportation system in the Northern Region currently has thousands of stream crossings that impede accessibility to upstream habitat to both anadromous and resident juvenile and adult fish as well as other aquatic species. Fish passage at road-stream intersections is important in Region 1 not only because of the unparalleled sport fisheries that exist here, but because the Forest Service has a responsibility under the National Forest Management Act and Threatened and Endangered Species Act to take positive actions in order to maintain viable populations of fish. Bull Trout, Chinook, and Steelhead are listed as Threatened in the Northern Region and have been/are impacted by inadequate stream crossings. A comprehensive fish passage inventory and assessment process, which began in May 2002 on 8 of the 13 Region 1 Forests and Grasslands with plans to complete passage inventories across the entire region by the end of 2004, will aid in determining the extent and distribution of passage barriers throughout Region 1. The Northern Region embraced use of the newly developed National Inventory protocol. In addition to inventory work, the Northern Region has developed regional fish passage evaluation criteria and fish passage design flow requirements, and drafted a road-stream crossing remediation prioritization scheme for use in the region. We would like to share our documents and preliminary results.

[P007] Design of a gravity infiltration gallery as part of fish passage improvements for a small surface water diversion in York Creek, Napa County, CA.

Authors: E.M. Kegel, C.D. Wilkinson, and B. Peach, Presenters, California Department of Water Resources, Fish Passage Improvement Program, PO Box 942836, Sacramento, CA, 94236-0001, 916-651-9631(W), 916-651-9607(F), emkegel@water.ca.gov, cdw@water.ca.gov; bpeach@water.ca.gov.

Abstract: The York Creek Diversion Structure has been identified as a significant temporal barrier to passage for federally listed steelhead trout (Oncorhynchus mykiss) in the threatened Central California Coast (CCC) Evolutionary Significant Unit. The channel of York Creek that is impacted by the current, inadequately screened diversion structure is known to provide spawning and rearing habitat for CCC steelhead. The project proposes to cut a trapezoidal notch in the diversion dam, construct a series of five boulder weirs to provide fish passage through the stream reach, and construct a gravity infiltration gallery to divert water up to an instantaneous rate of 11 cfs. An important next step will be to develop a monitoring program that will adequately assess the performance of the project to provide fish passage and continue to meet the City of St. Helena’s water needs. If successful, the infiltration gallery design could be applied to diversions on similar small streams.

[P008] Using a landscape perspective to understand the dynamics of habitat use by stream fishes.

Authors: Laura Thel, University of Wyoming, Department of Zoology and Physiology, Box 3166, Laramie, Wyoming, 82071, 307-766-2426 (Work), 307-766-5625 (Fax), lthel@uwyo.edu; Frank J. Rahel, University of Wyoming, Department of Zoology and Physiology, Box 3166, Laramie, Wyoming, 82071, 307-766-4212 (Work), 307-766-5625 (Fax), frahel@uwyo.edu;

Abstract: Knowledge of fish movements and habitat use is important in understanding the population dynamics, distribution and persistence of species as well as the structure and dynamics of fish assemblages. Most studies have focused on large-bodied species or seasonal movements and knowledge of the short, inter-patch movements of small, non-game species is limited. Several studies have demonstrated that factors such as distance, current velocity and cover availability affect the movements of small fish. However most studies investigating inter-patch movements have been conducted in experimental streams or with simplifying assumptions of homogenous intervening habitat characteristics. The objective of this research was to document the summer movement patterns of an assemblage of small fishes in a kilometer segment of a prairie stream. Fish were marked and recaptured every other week for ten weeks to assess movement rates between pairs of patches, a habitat survey was performed and the study segment was mapped using high precision GPS. We found inter-patch movements were common, with 45% of recaptured fish having changed patches. Fish moved considerable distances, up to 750 m within two weeks. Hypotheses regarding the effects of distance, velocity, cover availability and the spatial arrangement of patches on fish movements will be tested.

[P009] Rose Canyon Lake Rainbow Trout Fishery Renovation

Authors: D.C. Mitchell – Presenter, Arizona Game and Fish Department, 555 N. Greasewood Rd. Tucson, AZ. 85745, 520-628-5376 ext. 504 (W), 520-628-5080 (F), Dmitchell@gf.state.az.us; J. Taiz, United States Forest Service, Santa Catalina Ranger District, 5700 N. Sabino Canyon Rd, Tucson, Arizona, USA 85750, 520-749-7703 (W), jtaiz@fs.fed.us.

Abstract: Severe flooding in 1999 washed a large amount of sediment into this small mountain lake located in the Santa Catalina Mountains on the Coronado National Forest near Tucson Arizona. The United States Forest Service and the Arizona Game and Fish Department in cooperation with the Reserve Bulk Fuel Company A - 6th Engineer Battalion - Fleet Marine Force and Navy Seabee Reserves initiated a dredging project at this 7-acre lake to remove approximately 9,000 cubic yards of sediment from the inlet in an effort to increase the useable life span of this popular fishing spot. In addition to the removal of what ended up becoming nearly 13,000 cubic yards of sediment, the project also provided for the installation of a handicapped accessible parking lot, an improved handicapped accessible trail system around the lake as well as a handicapped accessible fishing pier. The completion of this project has added approximately 1,000 linear feet of shoreline access for anglers of all ages and abilities to enjoy for years to come. Additionally, the dredged material was used to improve an undersized helipad to a level, which allows the use of large helicopters, which were instrumental in fighting the Bullock Fire of July of 2002. The estimated cost of this project was determined to be approximately $300,000 but with the help of the Marines and Navy the project was completed for $36,000. This project was an outstanding example of what can be accomplished with teamwork between both state and federal agencies.

[P010] World Class River Restoration Research Opportunities

Authors: Rhonda J. Reed, Presenter, California Bay Delta Authority Ecosystem Restoration Program, 1416 Ninth Street, Suite 1155, Sacramento, CA 95616 (916)651-6478 (w) (916) 651-6486(f), rreed@water.ca.gov; Cesar Cadena Blanco, Anadromous Fish Restoration Program, US Fish and Wildlife Service, 4001 N. Wilson Way, Stockton, CA 95205, (209) 946-6400 (w) (209) 946-6355 (F) cesar_blanco@fws.gov; Jill A. Marshall, CALFED Science Program, c/o 1515 Clay St. Suite 1400, Oakland, CA 94612 (510) 622-2300 (w),(510) 622-2460 (f) JM@rb2.swrcb.ca.gov; Carrie A. Shaw, Information Center for the Environment, University of California, Davis, Dept. of Environmental Science and Policy, 1 Shields Avenue, Davis CA, 95616 (530) 754-6829 (w), (530) 754-6829 (F); Rebecca Fris, California Bay Delta Authority Ecosystem Restoration Program, 1416 Ninth Street, Suite 1155, Sacramento, CA 95616 (916)651-1334 (w) (916) 651-6486(f)

Abstract: There recently has been a blending of disciplines to enhance salmonid populations by restoring the natural functionality of rivers through re-constructing damaged sections of rivers. This, combined with unprecedented funding opportunities, has resulted in the development and implementation of several large-scale channel and riverine habitat improvement projects on the Merced and Tuolumne Rivers, and Clear Creek. These projects have restored and rebuilt the channel and floodplain in 4.5, 6 and 1.5 mile reaches of these rivers respectively. A recent review by nationally, and internationally, recognized experts in a range of fields, concluded that these projects offer unique, world class opportunities for river research. The CALFED Ecosystem Restoration Program is seeking to generate interest in these opportunities. Please visit our poster to review the opportunities or review reports on line at www.delta.dfg.ca.gov/afrp.

[P011] Trout versus Pike: The Story of Fish Management on Long Lake, Coconino County, Arizona.

Authors: S J Reger S J Arizona Game and Fish Department, 3500 South Lake Mary Road, Flagstaff, AZ 86004, 928-774-5045 (W), 928-779-1825 (F), sreger@gf.state.az.us, J. M. Jarosz , Arizona Game and Fish Department, 3500 South Lake Mary Road, Flagstaff, AZ 86004, 928-774-5045 (W), 928-779-1825 (F), and M. A. Bruner Arizona Game and Fish Department, 3500 South Lake Mary Road, Flagstaff, AZ 86004, 928-774-5045 (W), 928-779-1825 (F).

Abstract: Long Lake is an enhanced natural lake/wet meadow in North Central Arizona. The current lake was created in 1941 with sportsman dollars by digging a ditch from an existing reservoir to add water to an existing wet meadow. From 1941 until 1965 the lake was managed haphazardly as a bluegill – largemouth bass fishery. In 1965 a management decision was made to stock northern pike into the lake creating a largely unused fishery. Fingerling rainbow and brown trout were also stocked in the lake during the late 1960’s and 1970’s. In the late 1980’s, a concentrated effort was made to manage Long Lake as a productive trout fishery by stocking catchable rainbow trout. After several years the trout stockings were eliminated. In 1998, a public questionnaire was generated requesting input for a management strategy. At this time, Long Lake contained a viable, and largely underutilized, population of northern pike, walleye, channel catfish and carp. As a result of the data collected from the questionnaire, trout stocking resumed in the fall of 1999. Intense creel census and sampling were conducted to evaluate the success of the trout stockings. This presentation will present the pros and cons of managing a rainbow trout fishery in the presence of large numbers of northern pike.

[P012] Collaborative Research Initiatives: Linking Fishermen and Scientists

Authors: K. Russell, Institute for Fisheries Resources, PO Box 29196, San Francisco, CA 94129, 415-561-3474 (T), 415-561-5464 (F), krussell@ifrfish.org; N. Benjamin, Institute for Fisheries Resources PO Box 29196, San Francisco, CA 94129, 415-561-3474 (T), 415-561-5464 (F), nbenjamin@ifrfish.org.

Abstract: Collaborative Research is fast becoming a buzzword that has no universal definition in fisheries management. To some it draws to mind industry-dominated research that is de facto suspect, to others it symbolizes untapped opportunities untapped that can help to solve part of our fisheries management problems. As fisheries managers grapple to make well-informed decisions based on scarce data, scientists and fishermen are deciding to take a hard look at collaborating with each other. While both of these groups are inherently curious about the marine environment, they have diverse methods of working and communication styles. The Institute for Fisheries Resources has used its unique status as an organization led by fishermen, with a long history of working with scientists to begin to examine how successful partnerships have be created. This process includes questioning fishermen and scientists, as well as examining successful collaborative research endeavors currently underway on both the west and east coasts. We have found that collaborative research can be quite successful, leading to a more thorough understanding of fisheries. We have discovered patterns that can be used to help facilitate these collaborations and lead to mutual trust and better working relationships.

[P013] Using GIS to Analyze Interagency Consultations under the Endangered Species Act

Authors: Erik Schmidt and Lt. JG Kurt Dreflak; NOAA Fisheries; 777 Sonoma Avenue, Room 325; Santa Rosa CA 95404; Phone: 707.575.6083 (Erik Schmidt), 707.575.6099 (Kurt Dreflak); Fax: 707.578.3435; E-mail: erik.schmidt@noaa.gov or kurt.dreflak@noaa.gov.

Abstract: Section 7 of the Endangered Species Act requires federal agencies to ensure that their actions are not likely to jeopardize the continued existence of any endangered or threatened species. If a proposed project is federally funded, authorized or carried out, and a listed species of anadromous fish may be affected, NOAA Fisheries must be consulted to avoid and minimize effects to the species and its habitat. NOAA Fisheries’ salmonid conservation efforts in northern and central California depend in large part on the section 7 consultation process. Recently, as part of a pilot project to gain a better understanding of cumulative impacts to salmonids and their habitat, latitude and longitude coordinates were retroactively assigned to a database of all section 7 project reviews conducted in the San Francisco Bay and its tributary streams since 1997. Consultations were classified by project type and mapped using ArcView GIS software. The graphic output allows NOAA Fisheries biologists to improve their assessment of cumulative effects, including incidental take of listed species authorized under section 7 and impacts to salmonid habitat in SF Bay watersheds. Future efforts may expand the scope of this project and use it to increase opportunities for public access to NOAA Fisheries’ section 7 consultation information.

[P014] Fishes present in the the Sierra Gorda Biosphere Reserve

Authors: Steve Lanigan; Module Leader; Aquatic and Riparian Effectiveness Monitoring Program; USDA Forest Service, Pacific NW Region, Strategic Planning; 333 SW First Ave., Portland, OR 97204; ph: 503.808.2261 cell: 503.703.5773 fax: 503.808.2255; slanigan@fs.fed.us; Salvadore Contreras- Balderas; Apartado Postal 504 ; San Nicolas, NL, MEXICO; 66450

Abstract: The results of two years of sampling fishes in the Sierra Gorda Biosphere Reserve (Quaretaro, Mexico) are presented.

[P015] Ecological evaluation of the hydropower pulsed flow releases on California stream system: An introduction to the project

Authors: P.S. Young – Presenter, Animal Science, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, 530-752-9546(W), 530-752-0175(F), psyoung@ucdavis.edu; D. E. Conklin, Animal Science, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, 530-752-4177(W), 530-752-0175(F), deconklin@ucdavis.edu; J. O’Hagan, California Energy Commission, 1516 Ninth Street, 1st Floor, Sacramento, CA 95814, 916-653-1651(W), 916-654-4303(F), johagan@energy.state.ca.us.

Abstract: Hydropower pulsed flows are created for recreational use, or as byproducts of a load following electrical production. The water flows are discharged to coincide with high power prices and/or periods of high recreational demand. The impacts of these pulsed releases on the aquatic habitat and associated biotic communities are poorly understood. The objective of this project is to assess short- and long-term ecological impacts of pulsed flow releases on California stream systems regulated for hydropower production. Understanding how pulsed flows impact sensitive species and aquatic communities will allow stream managers and regulatory agencies to effectively modify flows for maximal economic, recreational and environmental benefits. Proposals to conduct research to enhance the scientific understanding and assessment of pulsed discharges from hydropower facilities on aquatic communities will be solicited in the Fall of 2003. The California State Energy Resources Conservation and Development Commission is funding this project and will award approved proposals through the Center for Aquatic Biology and Aquaculture (CABA) of the University of California, Davis.

FISH ECOLOGY

[P016] Population Status of North American Green Sturgeon, Acipenser medirostris

Author: Peter B. Adams, National Marine Fisheries Service, Southwest Fisheries Science Center, 110 Shaffer Road, Santa Cruz, California 95060, 831-420-3923(W), 831-420-3977(F), pete.adams@noaa.gov.

Abstract: Little is know about green sturgeon, Acipenser medirostris, and this is a first attempt to draw together a population assessment. Green sturgeon have a complex anadromous life history, spending more time in the ocean than any other sturgeon. The majority of green sturgeon are thought to spawn in the Klamath River, but spawning also occurs in the Sacramento and Rogue rivers. First spawning occurs at 15 years for males and 17 years for females. Female green sturgeon are thought to spawn only every 5 years. Green sturgeon concentrate in coastal estuaries, particularly the Columbia River estuary and coastal Washington estuaries during the late summer and early fall. Most of the green sturgeon harvest occurs on these concentrations. Three green sturgeon data sets were analyzed for population trend, all of which have serious limitations, but all of which had increasing trends.

[P017] Spawning areas of Green sturgeon (Acipenser medirostris) in the upper Sacramento River, California

Author: Brown, K. U.S. Fish and Wildlife Service (USFWS) Red Bluff Fish and Wildlife Office 10950 Tyler Road, Red Bluff, CA 96080, 530-527-3043, (FAX) 530-529-0292. kurtis_brown@fws.gov.

Abstract: Despite wide geographic distribution in the northern Pacific Ocean, green sturgeon are considered a rare and vulnerable species in the United States, Canada and an endangered species in Russia. Green sturgeon are a species of special concern by California Department of Fish and Game and a species of concern by the U.S. Fish and Wildlife Service. The only known spawning populations in North America are in the Klamath, Rogue, and Sacramento rivers, which have flow regimes affected by water projects. The primary objective was to identify green sturgeon spawning locations in the upper Sacramento River using artificial substrates and larval nets. Twenty-two substrate nets were placed in the river and sampled twice weekly. Larval nets were fished for a total of 21 hours to capture larva. Two green sturgeon eggs were collected with substrate mats below Red Bluff Diversion Dam (RBDD). One green sturgeon larva was collected 16 river miles upstream of (RBDD). We concluded that green sturgeon spawn in the upper river, both above and below RBDD. Temperatures do not appear to be a limiting factor, however suitable habitat upstream of RBDD is inaccessible when dam gates are lowered in the spring.

[P018] Evidence for a contracted thermal niche of exotic Brook trout in the presence of native Bull Trout in the Lost River Systems of SE Idaho.

Authors: S. Chamberlain – Presenter, Department of Aquatic, Watershed and Earth Resources, Utah State University, Logan, UT, 84322-5210,435-797-****(W), cha@cc.usu.edu; J.L. Kershner, U.S. Forest Service – Fish and Aquatic Ecology Unit, Department of Aquatic, Watershed and Earth Resources, Utah State University, Logan, UT, 84322-5210,435-797-2500(W), 435-797-1871(F), kershner@cc.usu.edu.

Abstract: Widespread displacement of bull trout from their historic range has been attributed to both increases in water temperatures and competition with exotic brook trout. However, it is not well understood how these two threats interact at the population level. Bull trout are known to have lower thermal optima than brook trout. However brook trout are competitively dominant at temperatures near their optima which are well within the tolerances of bull trout. The observed pattern of isolation in headwater streams when brook trout are present leads to the question: Does the presence of bull trout limit the ability of brook trout to invade colder streams? Can low temperatures reduce the competitive and demographic advantages of invading brook trout enough to allow bull trout to persist? These questions were evaluated by comparing distributions of exotic brook trout in two adjacent watersheds with and without native bull trout. Allopatric brook trout have invaded streams with much lower temperatures than they have colonized in the presence of bull trout. This pattern suggests a contracted thermal niche in the presence of competitors and hints at the potential for a thermal gradient in the ability of brook trout to displace native bull trout.

[P019] Movement behaviors of the giant red sea cucumber, Parastichopus californicus in Southeastern Alaska.

Authors: Kristin Cieciel, Presenter, UAF, School of Fisheries and Ocean Sciences, 11120 Glacier Highway, Juneau, AK, 99801, 907-465-8572(W), ftkdc@uaf.edu; Dr. Ginny Eckert, University of Alaska Southeast, 11120 Glacier Highway, Juneau, AK, 99801, 907-465-6450(W), ginny.eckert@uas.alaska.edu

Abstract: Sea cucumbers, Parastichopus californicus, are an important fishery throughout Alaska, Washington, Oregon, and California, and yet limited biological information is available on the species. Information about life history, specifically movement, could improve management to ensure a sustainable fishery. In this study SCUBA divers tag sea cucumbers with Floy tags in situ at sites near Juneau, Sitka and Ketchikan, Alaska. Individual cucumber movements and orientation to current and shore are tracked at intervals of 24 hours over 4-5 days. These measurements are repeated in October, January, April and July to determine if cucumbers move more in different seasons. Densities are measured monthly at multiple depths to determine if cucumbers migrate from one depth to another. Preliminary results for daily movement in October 2002 show a rate of 1.15m for a 24 hour period and 1.68m for a 48 hour period. Future investigations include incorporating interval recording photography to determine speed and direction of movement of individual sea cucumbers.

[P020] Variation in Larval Fish Condition in the Consumnes River Floodplain

Authors: P.K. Crain, Wildlife, Fish and Conservation Biology, UC-Davis, One Shields Avenue, Davis, CA 95616 (pkcrain@ucdavis.edu), F. Ribeiro, Centro de Biologia Ambiental, Faculdade de Ciências Universidade de Lisboa, Edificio C2, 3º piso 1700 Lisboa Portugal (filvidas@fc.ul.pt), P. Moyle Wildlife, Fish and Conservation Biology, UC-Davis, One Shields Avenue, Davis, CA 95616 (pbmoyle@ucdavis.edu)

Abstract: Floodplains are believed to be very important habitats as nursery areas for native fish. This work assesses larval fish condition in different habitats from the Consumnes River floodplain. Five species of larval fish (splittail, blackfish, Sacramento sucker, golden shiner, and carp) were sampled between April and June of 2002, with beach seining, on a weekly basis. Larval fish were sampled in five sites, two floodplain areas, two riverine habitats, and one irrigation channel. Larval fish condition was studied using: 1) Fulton condition factor and 2) growth rates. All species had high variability in condition and growth between sites. Splittail and suckers from the riverine site below the floodplain had the highest condition, while splittail with the lowest condition were found in the irrigation channel. Growth for splittail was also highest downstream of the floodplain. The interaction between development stages and site conditions (e.g. temperature) may explain variability in larval fish condition and growth. These findings suggest that condition factors and growth rates of larval fish are useful indicators for determining importance of floodplain habitats as nursery areas.

[P021] Early Life history of Fishes in the San Francisco Estuary and Watershed: Symposium and Proceedings Volume

Authors: Frederick Feyrer, Aquatic Ecology Section, California Department of Water Resources, 3251 S Street, Sacramento, California 95816, ffeyrer@water.ca.gov, 916-27-2552; Larry Brown, U.S. Geological Survey, Placer Hall, 6000 J Street, Sacramento, CA 95819-6129; Jim Orsi, California Dept Fish and Game, 4001 N. Wilson Way, Stockton CA 95205; Randy Brown, CA Dept Water Resources and CALFED, 3251 S Street, Sacramento CA 95816

Abstract: This Interagency Ecological Program and CalFed supported symposium will take place at the 2003 American Fisheries Society Larval Fish Conference, August 20-23, at U.C. Santa Cruz. About 25 papers will be presented at the Symposium, 20 of which have been submitted for publication in a proceedings volume, which will be published by the American Fisheries Society. The authors of this poster will serve as volume editors. For more information and a list of current contributions visit http://iep.water.ca.gov/2003_elh/.

[P022] Test of Sedimentation Effects on Population Densities of Small Fishes in Restored and Historic Salt Marshes in Suisun Bay, California

Authors: Elisa C. Gill, Presenter, County of Alameda Public Works Agency, 951 Turner Court Room 300, Hayward, CA, 94545, 510-670-5435 (W), 510-670-5262 (F), elisag@acpwa.org; C.L. Kitting, California State University at Hayward, 25800 Carlos Bee Blvd., Hayward, CA, 94542, 510-885-3001 (W), ckitting@csuhayward.edu.

Abstract: Limitations on aquatic fauna and sedimentation are inadequately understood, particularly within restored salt marshes. These entire habitats are vulnerable to sediment imbalance. Without suitable sediment supply and a site configuration that allows sedimentation rates to approximate erosion rates, tidal marshes quickly can choke with sediment, erode away, or remain too deep for marsh vegetation. Two main sources of sediment are predominant in upper San Francisco Bay Estuary. Silts and clays are transported by freshwater flows from rivers and runoff, and bay sediment may be deposited through cyclic tidal action. Since January 1999, we have compared seasonal sedimentation rates and fish abundances [have been monitored] at four pairs of restored and historic marsh sites in North San Pablo and Suisun Bays, California. United States Geological Survey [(USGS)] provided turbidity data from nearby waters, where California Department of Fish and Game provided additional data on densities of small fishes. The hypothesis is that small native fish species, are robust enough to thrive in either the restored or historic San Pablo and Suisun Bay marsh environments, and would be correlated, positively or negatively, with turbidity or sediment flux.

[P023] Physiological measures of chronic stress in green sturgeon

Author: S. E. Lankford, Presenter, Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Ave., Davis, CA 95616, 530-752-8659, selankford@ucdavis.edu; T. E. Adams, Department of Animal Science, University of California, Davis, One Shields Ave., Davis, CA 95616; J.J. Cech Jr., Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Ave., Davis, CA 95616.

Abstract: Metabolic scope for activity (MSA) and critical swimming velocity (Ucrit) were utilized as measures of chronic stress in green sturgeon, Acipenser medirostris. We hypothesized that chronic stress would increase maintenance requirements with 1) increased matienance metabolic rates (MMR), 2) decreased MSA, and 3) decreased Ucrit. To simulate chronic stress, groups of three 0+ green sturgeon were place into flow-through, indoor tanks and stressed twice daily (1000 and 1600 h) for 28 consecutive days. Fish were exposed to two of three randomized acute stressors: a 5-min confinement stressor, a 5-min chasing stressor, or a 10-min water depth reduction stressor. These stressors resulted in a graded acute plasma cortisol response, and fish were responsive to a stressor over the entire 28-d regime. Metabolic measurements and Ucrit were conducted using a closed, variable speed, Brett-type respirometer. Exposure to the chronic stress regime resulted in a 25% reduction in MSA due to a significantly increased MMR (supporting hypotheses 1 & 2). There was no difference in Ucrit between the stressed and control fish (rejecting hypothesis 3). We conclude that our chronic stress regime resulted in a significant maintenance cost to green sturgeon, without decreasing their swimming performance.

[P024] The Feeding Habits of Three Juvenile Scorpaeniform Fishes in the Eelgrass Beds of Bodega Harbor, California.

Authors: Levi Steele Lewis; Bodega Marine Laboratory; University of California, Davis; 2099 Westside Road, P.O. Box 247; Bodega Bay, Ca 94923-0247

Abstract: Rockfish are an economically important fisheries resource on the west coast of California. In the last twenty years, populatons of Sebastes spp. have plummeted. Therefore, many factors affecting rockfish recruitment have been studied intensively, including predation. Juveniles of many rockfish species use near shore vegetation such as eelgrass beds as nursery habitat. Eelgrass has generally been accepted to serve as a refuge from predation; however, larger juvenile cabezon, lingcod, and bocaccio may prey upon small, newly settling rockfishes in eelgrass beds. Distibutions of size and abundance, feeding habits, and trophic relationships of these three species were observed and compared to develop a better understanding of the extent that pisivory by young-of-the-year fishes occurs in Bodega Harbor eelgrass beds. This study revealed juvenile bocaccio as important predators of other juvenile rockfishes. Large lingcod juveniles preyed upon a variety of fishes while juvenile cabezon primarily consumed invertebrates. Stable isotope analysis showed no clear distinction between trophic level or carbon source between fish species. The classical idea of eelgrass as a nursery habitat may not apply once juvenile piscivores have begun to feed on other competing juvenile fishes; a phenomina known as "intraguild predation."

[P025] Growth in juvenile green sturgeon (Acipenser medirostris) at elevated and fluctuating temperatures

Authors: Peter Allen- presenter, (w) 530-752-8659, (f) 530-752-4154, pjallen@ucdavis.edu; Joseph J. Cech, Jr., (w) 530-752-3103, (f) 530-752-4154, jjcech@ucdavis.edu; Mary Nicholl, and Stephanie Cole; Department of Wildlife, Fish, and Conservation Biology, University of California, Davis 95616

Abstract: Juvenile green sturgeon (Acipenser medirostris) are periodically subjected to high water temperatures in their natal rivers depending on the timing and duration of regulated water releases. Growth was measured at three temperature regimes (19°C, 24°C, 19-24°C -oscillating gradually every 12 hours) toward the warmer end of the expected range. Post yolk-sac fish (19°C) were randomized into 24 tanks (50-L circular, 8 tanks/treatment, 40 fish/tank), and temperature was increased 1°C /day to 24°C in elevated and fluctuating temperature tanks, after which 19-24°C tanks were started on a daily cycle (between 24°C at 1700 and 19°C at 0500). Fish were kept on a natural photoperiod, receiving flow-through well water (~3 L/min) and constant aeration. Ad libitum rations (Silver Cup Semi-Moist) were supplied by 24-hr feeders, and wastes and uneaten food were siphoned daily. Dissolved oxygen (always > 80 % of air saturation) and ammonia (always < 300 ppb) were measured daily and weekly respectively, from all tanks. Significant differences (ANOVA, a=0.05) were found between final weights (24°C > 19°C) and total lengths (24°C & 19-24°C > 19°C), indicating that temperatures within this range may not adversely affect juvenile fish. Research funded by CALFED and Anadromous Fish Restoration Program (USFWS, USBR).

[P026] Ontogeny of salinity tolerance in juvenile green sturgeon (Acipenser medirostris)

Authors: Peter Allen- presenter, (w) 530-752-8659, (f) 530-752-4154, pjallen@ucdavis.edu; Joseph J. Cech, Jr., (w) 530-752-3103, (f) 530-752-4154, jjcech@ucdavis.edu; Stephanie Cole, Mary Nicholl, and Brian Hodge; Department of Wildlife, Fish, and Conservation Biology, University of California, Davis 95616

Abstract: Green sturgeon (Acipenser medirostris) generally occur in rivers with small estuaries, indicating that their ability to osmoregulate in seawater may occur at an early age. We measured salinity tolerance through gradual and abrupt salinity exposures using seawater. Experiments using freshwater or brackish water-acclimated (>14 days at 15 ppt) fish were repeated every two weeks until 100% survival at 34 ppt was achieved. Treatment groups (0, 15, 20, 25, 30, 34 ppt; and direct exposure: 30, 34 ppt) were adjusted as fish developed and exhibited greater tolerance. Fish were held in individual containers (4-L, 9-L, 25-L, or 50-L depending on size/age), randomized by treatment groups (6 fish/treatment), and subjected to a step increase in salinity (5 ppt/12 h) that culminated in a 72-h exposure to a target salinity. Surviving fish were sampled for plasma ionic concentrations (Na+, K+, Cl-), osmolality, hematocrit, hormone concentrations (cortisol, T3 and T4), and gill tissue (chloride cells, Na+-K+-ATPase). A long-term (28-day) seawater (33 ppt) exposure conducted after the last 72-h experiment found 100% survival (38 fish). Juvenile green sturgeon increased in salinity tolerance with size and age, achieving seawater tolerance at 7 months or younger. Research funded by CALFED and Anadromous Fish Restoration Program (USFWS, USBR).

[P027] Shokihaze goby life history in the San Francisco Estuary

Authors: Steven B. Slater, California Department of Fish and Game, 4001 North Wilson Way, Stockton, CA 95205, 209-942-6087(W), 209-946-6355(F), sslater@delta.dfg.ca.gov; Thomas A. Greiner, California Department of Fish and Game, 4001 North Wilson Way, Stockton, California 95205, 209-942-6080(W), 209-946-6355(F), tgreiner@delta.dfg.ca.gov.

Abstract: The first recorded capture of a shokihaze goby, Tridentiger barbatus (Günther), in California occurred in the San Joaquin River near Big Break in November of 1997 by the California Department of Fish and Game’s San Francisco Bay Study (Bay Study). The shokihaze goby is native to Taiwan, Korea, China, and Japan and was probably introduced into the San Francisco Estuary via ballast water release. Bay Study shokihaze goby catch for the years 2000 through 2002 have far exceeded catch for the two other introduced Tridentiger species, the chameleon goby, T. trigonocephalus, and the shimofuri goby, T. bifasciatus. Shokihaze gobies are widely distributed from San Pablo Bay to the western delta; the Bay Study collected most in the Suisun Bay and the lower Sacramento River channel stations. Shokihaze gobies have been caught at depths from 2.2 – 25.9m, in salinities ranging from 0.23 – 28.81‰, and temperatures ranging from 7.6 – 21.6°C. Diet items of the shokihaze goby include amphipods, isopods, mysids, polychaetes, and Crangon spp. shrimp. Ripe females have been found with up to 16,000 eggs. An aggressive fish in captivity, the impacts of the shokihaze goby on native species have yet to be determined.

[P028] The acute effects of gas saturation on cultured juvenile white seabass (Atractoscion nobilis) in the laboratory.

Authors: J. E. Smiley-Presenter, University of San Diego, 5998 Alcalá Park, San Diego, CA, 92110, 858-467-2719 (W), Triakiss@hotmail.com; R. S. Kaufmann, University of San Diego, 5998 Alcalá Park, San Diego, CA, 92110, 619-260-5904 (W), kaufmann@sandiego.edu; M. A. Drawbridge, Hubbs-SeaWorld Research Institute, 2595 Ingraham Street, San Diego, CA, 92109, 760-434-9501 (W), 760-434-9502 (F), mdrawbr@hswri.org; M. S. Okihiro, California Department of Fish and Game, 4065 Oceanside Blvd - Suite G, Oceanside, CA, 92056, 760-726-8170 (W), ms.okihiro@att.net.

Abstract: White seabass have been reared at the Leon R. Hubbard Jr. Marine Fish Hatchery in Carlsbad, California for the past seven years. During this period, levels of gas saturation were recorded from below saturation up to 117% of total gas pressure (TGP). Exophthalmia, symptomatic of gas bubble trauma (GBT), was observed routinely in juveniles. The purpose of this study was to evaluate the effects of gas supersaturation on white seabass under controlled laboratory conditions. Two age/size classes of seabass (110 ± 10 days/22.4 ± 6.1g and 59 ± 9 days/3.2 ± 1.3g) were exposed to 5 treatments ranging from 98% to 122% TGP for 96 hours at 18 and 23°C. White seabass from all treatment groups showed an increase in corneal lesions (gas blisters) compared to controls. Larger/Older seabass were more susceptible to GBT than smaller/younger fish. Susceptibility to GBT also increased with temperature, for treatments above 102% TGP. Histological examination of eyes revealed large retrobulbar/subretinal gas pockets, subretinal edema and hemorrhage, as well as iridal edema, hemorrhage, and inflammation. This suggests acute effects of gas supersaturation appear to be influenced by water temperature and age/size of white seabass. Additionally, careful post-mortem assessment revealed the pathogenesis of exophthalmia, iridal hemorrhage, and corneal blisters.

[P029] Effects of Surgically Implanted Ultrasonic Transmitters on Growth, Feeding Behavior, and Tissue Reaction in Adult White Seabass (Atractoscion nobilis).

Authors: G. M. Stutzer-Presenter, Pfleger institute of Environmental Research, 901B Pier View Way, Oceanside, CA, 92054, 760-721-2531(W), greg@pier.org.

Abstract: The use of information obtained from biotelemetry studies assumes fish behavior is unaffected by the attachment method and presence of the transmitter. I examined the effects of surgically implanted transmitters (representing 0.2-0.9 % of body weight) on growth, feeding behavior, and tissue reaction of 70 adult white seabass Atractoscion nobilis (725-1204 mm total length) over a 451 day period. On day 97 (expected transmitter life), analysis of growth in standard length revealed no significant difference among fish exposed only to handling and anesthesia (control), fish with surgery but no implanted transmitter (sham-surgery), fish with dummy transmitters surgically implanted (dummy-tagged), and fish with functional transmitters surgically implanted (active-tagged). However, growth in weight showed that active-tagged fish grew significantly less than sham-surgery fish. No significant difference in growth rate occurred among control, sham-surgery, and dummy-tagged fish over the remaining 354 days of the study. Differences in feeding frequency of fish among the four treatments were not significant. Two mortalities occurred during the study when sham-surgery fish died on day 17 and 41. Transmitters became encapsulated by connective tissue within 97 days, the composition of which is described. Results show that with proper surgical procedure, intraperitoneal implantation provides a suitable technique for biotelemetry studies on adult white seabass.

[P030] Distribution Of Squid Paralarvae Loligo opalescens (Cephalopoda: Myopsida) In The Southern California Bight In The Four Years Following The 1997-1998 El Niño

Authors: Louis Zeidberg

Abstract: Large numbers of paralarvae of the California market squid, Loligo opalescens (10,979 paralarvae from 456 plankton samples) were collected in the Southern California bight in 1999, 2000, 2001, and 2002 during the spawning season. Paralarvae abundance increased dramatically (p<0.0041) from 1.5 squid/1000m3 in 1999 to 77.9 squid/1000m3 in 2000 and 73.6 squid/1000m3 in 2001 following the El Niño of 1998. Paralarvae abundance dropped off in 2002 to 15.4 squid/1000m3. The effects on the squid fishery of the 1997-1998 El Nino thus were extended for two years, with larval abundance reduced until the 1999-2000 spawning season. Paralarvae were abundant close to shore for up to a month after hatching in 2000 (p<0.003), with tidal surface currents adjacent to shore in the Channel Islands dramatically affecting paralarvae abundance. Tidally reversing currents within 1-3 kilometers of shore create a boundary layer of "sticky water" within which paralarvae remain entrained inshore immediately after hatching. Neritic currents further from shore disperse older paralarvae within the Southern California bight. The greatest change in paralarval abundance, for all transects, was observed within one kilometer of the transition between these two flow regimes. Age of paralarvae (from statolith increments) entrained within the Catalina Island boundary layer averaged 13 days and 16 days, but some individuals remained nearshore for up to a month. Paralarvae within the boundary layer occur above 80 meters both day and night and they exhibit a statistically significant pattern of vertical diel migration (p<0.01). Paralarvae at sea were disproportionately abundant adjacent to fronts associated with upwelling events.

ONCORHYNCHUS

[P031] The relationship between temperature and dissolved oxygen on salmonid distribution in Lake Sammamish, Washington.

Authors: Hans B. Berge, Hans.Berge@metrokc.gov; King County Department of Natural Resources and Parks; University of Washington School of Fisheries and Aquatic Sciences; David A. Beauchamp, Daveb@u.washington.edu; University of Washington School of Fisheries and Aquatic Sciences; Washington Cooperative Fish and Wildlife Research Unit; USGS Biological Resources Division; Jonathan D. Frodge, Jonathan.Frodge@metrokc.gov; King County Department of Natural Resources and Parks

Abstract: Hydroacoustics were combined with gillnetting and limnological data to examine factors influencing the distribution of salmonids in Lake Sammamish during thermally-stratified conditions. Rapid warming of the surface waters causes the lake to stratify in July. Stratification intensifies through summer and fall with increasing temperature and deepening of the epilimnion. As the summer progresses, low hypolimnetic dissolved oxygen (DO) levels encroach into the metalimnion, thus reducing the amount of useable habitat available for salmonids. The resulting temperature/DO squeeze affects the distribution of salmonids and has important implications for their trophic dynamics in Lake Sammamish.

[P032] California Estuaries: Migratory Travel Corridors or Essential Habitat for Steelhead Rearing and Refugia?

Authors: Richard A. Bush, University of California-Davis, 286 Kerr Hall, Davis, CA, 95616, 530-758-4329 (W), 530-752-9109 (F), rabush@ucdavis.edu.

Abstract: The importance of estuaries in the north coast region of California for parr/smolt rearing presents a key information gap in the life history of coastal steelhead. It is a wide held belief that the size attained by juvenile Pacific salmonids prior to entering the sea is critical, so accelerated growth during a period of estuarine residence may confer advantages. The objective of this investigation is to determine and quantify the estuarine contribution to the life history of Navarro River steelhead using otolith microstructure in combination with elemental analysis. With the present advancements in the interpretation of otolith isotopic composition, the ability to infer daily growth rates of steelhead from different habitats within a watershed has never been more promising. We are currently attempting to construct a gradient of isotopic values for Sulfur isotopes within the Navarro River watershed to achieve a better understanding of estuarine arrival and length of residence. This study examines the use of daily growth increments in sagittal otoliths of wild juvenile steelhead to compare estuarine growth rates with tributary fish undergoing purely freshwater growth. Digitizing increment widths along a standard radius using image analysis software derived the data. This key area was selected because of the uniform spacing between daily growth rings allowed for accurate growth rate comparisons along the same transect between samples. Examination of otoliths from fish caught above the estuary (n=100) has provided a means of characterizing known freshwater growth increments and established a representative growth rate for riverine rearing fish. Estuarine growth rates will also be calculated using daily otolith increments, and these results will be compared with the riverine cohort. Continued monitoring of seasonal water quality and the fish community will be carried out to further our understanding of these potentially important salmonid-rearing environments.

[P033] Salmon spawning escapement data: critiquing the use of mark-recapture techniques for salmon carcasses

Authors: B. Cavallo, J. Kindopp, R. Kurth, and A. Seesholtz. California Department of Water Resources, Division of Environmental Services, 3251 S Street, Sacramento CA 95816-7017, 916-227-0437 (W), 916-227-7554 (F), bcavallo@water.ca.govskohin@ucsd.edu.

Abstract: Accurate salmon spawning population data is essential for managing and conserving salmon stocks. Biased data can lead to flawed management plans and faulty assessment of resource needs. In many rivers, salmon spawning escapement is assessed by carcass surveys. These surveys apply mark-recapture techniques to salmon carcasses to generate population estimates. To assess hatchery contribution and straying rates, the occurrence of coded wire tagged (CWT) fish is also assessed by collecting fin clipped carcasses as they are encountered. While these techniques are widely utilized, they have received very little critical evaluation. In 2000, 2001 and 2002, we conducted carcass surveys on a large California river designed specifically to evaluate sources of error and potential for bias in spawning escapement data. Simulation experiments with resulting data suggest that mark-recapture surveys are prone to biased estimates because tagged and untagged carcasses often do not “mix” and therefore, as assumptions require. CWT collections were also found to be bias prone, primarily due to under-collection by surveyors. Sampling bias in carcass surveys and CWT sampling will tend to be worse in large rivers or rivers with large spawning populations. Increased effort, spatial stratification of the river, and randomized sampling provide the best design tools for improving the quality of escapement data.

[P034] Russian River Chinook: Relict or Thriving

Authors: S. D. Chase and S. K. White. Sonoma County Water Agency, P.O. Box 11628, Santa Rosa CA 95405(707) 547-1986, shawnc@scwa.ca.gov.

Abstract: Historical literature suggested that Chinook salmon were never abundant in the Russian River. A few sources did suggest that Chinook salmon inhabit the Russian. However, it was widely believed that these fish were the remnants of earlier attempts to establish a run through hatchery propagation or strays from the Eel or Sacramento rivers. In 1999, the Sonoma County Water Agency began assessing the impacts of a seasonal dam on the migration of salmonids in the Russian River. Outmigrant traps were fished during the spring and underwater time-lapse video cameras were operated to count adults at the fish ladder outlets during the fall. Chinook salmon were the most abundant salmonid captured and observed during the monitoring program, with 296, 1,455, 1383, and 5,474 adult Chinook salmon observed migrating through the fish ladders between 1999 and 2002, respectively. The entire adult migration period was surveyed only in 2000. We estimated over 200,000 Chinook smolts migrated past the dam in 2001. Recent genetic analysis concluded that the Russian River Chinook population is not closely related to Eel River or Central Valley populations. Further, Chinook in the Russian River do appear to belong to a diverse set of coastal Chinook populations.

[P035] Estimating the abundance of Sacramento River juvenile winter chinook salmon with comparisons to adult escapement.

Authors: C.D. Martin, USFWS, Lake Champlain Field Office, 11 Lincoln St., Essex Junction, VT, 05453, (802) 872-0629, craig_martin@fws.gov; P.G. Gaines, Presenter, USFWS, Red Bluff Fish and Wildlife Office, 10950 Tyler Road, Red Bluff, CA, 96080, (530) 527-3043, phillip_gaines@fws.gov; R.R. Johnson, USFWS, Region 1 Office, 911 NE 11th Avenue, Portland, OR, 97232, (503) 872-2763, rich_r_johnson@fws.gov;

Abstract: We developed in-river quantitative methodologies for indexing juvenile winter Chinook production (JPI) in the upper Sacramento River using data collected by rotary-screw traps at Red Bluff Diversion Dam (RBDD). These indices were used in conjunction with and in support of adult escapement and for evaluating year-class strengths in winter Chinook abundance. Estimates of juvenile winter Chinook production derived from escapement estimates based on RBDD ladder counts, winter chinook carcass surveys and the National Marine Fisheries Service's (NMFS) juvenile production estimate (JPE) were compared to the JPI to identify possible sources of bias and determine whether these surveys were correlated in magnitude and trend. We concluded that escapement estimates from winter Chinook carcass surveys and RBDD ladder counts were relative predictors for evaluating year-class strengths (r2 $ 0.566); however, no correlation was found between ladder escapement estimates and rotary-screw trap JPI's (P=0.555; r2=0.128; N=5). Paired comparisons with JPI and JPE, a production estimate that uses female escapement as the primary variate, did not significantly differ (carcass survey JPE, paired t-test, P=0.903, df=3; ladder count JPE, paired t-test, P=0.097, df=4), yet evidence suggested that ladder count JPE underestimated in-river abundance of juvenile winter Chinook. We concluded that NMFS's JPE model, based on estimates of escapement using ladder count data, underestimated juvenile winter Chinook production, while carcass survey escapement estimates were found to be a satisfactory replacement for RBDD ladder counts.

[P036] Discrimination of Coho (Oncorhynchus kisutch) and Steelhead (Oncorhynchus mykiss) Redds and Comparison of Methods for Estimating Spawning Populations in Several Unregulated Streams in Mendocino County, California

Authors: Sean P. Gallagher, Presenter, California State Department of Fish and Game, Steelhead Research and Monitoring Program, 1031 South Main Street, Suite A, Fort Bragg, California 95437, (707) 964-1492 (W), (707) 964-1487 (F), sgallagh@dfg.ca.gov; Colin M. Gallagher, Department of Mathematics and Statistics, California State University, Chico, Chico, CA 95929, (530) 898-6367 (W), cmgallagher@csuchico.edu.

Abstract: This study was conducted in coastal Mendocino County, California to develop a method for estimating coho (Oncorhynchus kisutch) and Steelhead (Oncorhynchus mykiss) spawning populations. Logistic regression was used to reduce redd identification uncertainty due to spatial and temporal overlap in coho and steelhead spawning, classify known redds, and predict species for unknown redds. Steelhead populations were estimated using capture-recapture, area-under-the-curve (AUC), redd counts, and redd area in one river over two years and by AUC, redd counts, and redd area in two rivers and three creeks during one year. Total redd count population estimates were different than other methods. Coho populations were estimated using AUC, carcass capture-recapture, redd counts, and redd area in three creeks and two rivers over two years. Population estimates were not different between methods. To reduce field effort, stratified random block sampling was tested using data collected over two years in one river and in one river and three creeks during one year. Only steelhead population estimates based on redd counts were significantly different between total and stratified sampling estimates. Discrimination of coho and steelhead redds and redd area population estimation in a stratified sampling design is conceptually straightforward, noninvasive, technically simple, significantly decreases effort and cost, and produces reasonable population estimates.

[P037] Life history monitoring of salmonids in the West Fork Smith River, Umpqua Basin, Oregon.

Authors: Bruce Hansen, USDA, Forest Service, PNW Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, 541-750-7311 (W), 541-750-7329 (F), bhansen@fs.fed.us; S. R. Hendricks, - Presenter, USDA, Forest Service, PNW Research Station, 3200 SW Jefferson, Corvallis, OR 97331, 541-750-7394 (W), 541-750-7329 (F), stevehendicks@fs.fed.us; J.L. Ebersole, U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, 200 SW 35th St., Corvallis, OR 97331, Ebersole.Joe@epa.gov; B. Miller, Oregon Department of Fish and Wildlife, 4475 Boat Basin Dr., Charleston, OR., millerb@fsl.orst.edu; and S.N. Lampson, 541-750-7320, slampson@fs.fed.us.

Abstract: As a life-cycle monitoring basin for the Oregon Salmon Plan. The Oregon Department of Fish and Wildlife has estimated adult returns, distribution and smolt outmigration of coho, chinook and winter steelhead in the West Fork Smith River since 1998. In 2001/2002, the Environmental Protection Agency and USFS Pacific Northwest Research Station initiated research to assess factors influencing juvenile salmonid movement, distribution and growth within the basin. Objectives of this research are to 1) quantify seasonal movement between tributary and mainstem habitats (including passage through culverts?), 2) relate seasonal movement to dynamic habitat conditions, and 3) relate movement and habitat quality to growth and survival of juvenile salmonids. All three agencies are collaborating to track the movements and growth of juvenile salmonids implanted with PIT tags throughout the basin. PIT-tagged fish are monitored with stationary PIT tag readers located in three tributaries and with portable PIT-tag readers throughout the watershed. These data will be used to determine seasonal movement, habitat utilization, survival and growth in tributaries and mainstem reaches of the West Fork Smith River. Empirical field data will inform spatially explicit models of coho salmon life history-habitat interactions, and will help guide habitat protection and restoration of critical freshwater habitats for salmonids.

[P038] Mortality of juvenile steelhead in artificial pools - lessons learned from a restoration effort.

Author: Peter Johnsen-NOAA Fisheries, Protected Resources Division, 2550 North State Street, Ukiah, California 954482, (707) 463-2643(W), (707) 468-4027(F), peter.johnsen@noaa.gov.

Abstract: Many Californian streams lack deep pools to support summer rearing of salmonids. Therefore, many restoration projects aim at increasing pool frequency. However, artificial pools might adversely affect juvenile survival by going dry, or because of crowding, high temperatures, low dissolved oxygen content, and increased predation as pool volume decreases. In a California stream, a successful effort was made to create several plunge pools with boulders in a low-gradient depositional segment. However, a site visit conducted in July 29, 2002, showed many dry pools. Algae grew thick in the shallow remaining pools. Despite this, hundreds of juvenile steelhead were observed in pools. However, based on the fact that many pools dried up, that remaining pools were shallow, and that the observation was made in the middle of the dry season, the mortality in these pools is expected to have been high. This example shows the need to use hydrology and geomorphology to calculate depth needed to maintain pool habitats during dry years, and to use information on stream velocity, energy, sediment loads, etc. in designing pool-forming structures. However, it might not be desirable to create pools where hydrological conditions cannot sustain summer rearing during low and normal flow periods.

[P039] Demography, distribution, and habitat use of juvenile steelhead in a large, regulated river.

Authors: R. Kurth, B. Cavallo, J. Kindopp, and A. Seesholtz. California Department of Water Resources, Division of Environmental Services, 3251 S Street, Sacramento CA 95816-7017, 530-534-2505 (W), 530-534-2394 (F), rkurth@water.ca.gov.

Abstract: Our study sought to identify factors potentially limiting steelhead success in Northern California’s Feather River. Factors considered were habitat, water temperature, flow conditions, predation, and food supply. To address these topics we applied multi-scale snorkeling surveys, seining, rotary screw traps, and short-term field experiments. Results show that most steelhead spawning and early rearing occurs at the upstream end of the river. Over time age-0 steelhead disperse to suitable habitats throughout the LFC, especially cover-rich side channels. Steelhead rearing downstream appeared to grow faster, and were generally larger than upstream fish. Many age-0 steelhead appear to emigrate from the river shortly after emerging. Age-0 abundance declined throughout the summer in each survey year. This decline suggests that relatively few age-0 steelhead remain in the Feather River through their first year. Age-1+ sized steelhead trout (or resident rainbow trout) were relatively rare. Since LFC water temperatures and flow conditions appear suitable for steelhead, the apparently low production of juveniles suggests other limiting factors. For example, side channels and tributaries seem to provide the best rearing habitat in large, low elevation rivers, and yet these habitats are rare in the lower Feather River. Food availability for drift feeding fishes may contribute to the observed pattern.

[P040] Adult Salmon Escapement: A Non-traditional Variable to Predict the Timing of Juvenile Salmon Emigration.

Author: J. Kindopp. California Department of Water Resources, Division of Environmental Services, 3251 S Street, Sacramento CA 95816-7017, (530) 534-2381 (W), 530-534-2394 (F), jkindopp@water.ca.gov.

Abstract: Rotary screw fish traps are often used to calculate production values and determine emigration timing for juvenile salmonids. Many juvenile sampling programs also attempt to determine the relationship between emigration pulses and environmental variables. Flow, turbidity and temperature are often correlated to juvenile emigration pulses. Efforts to determine the environmental variables that best explain patterns of juvenile fall-run emigration in the Feather River were unsuccessful. We therefore examined the relationship between adult escapement and juvenile emigration to determine if the two were correlated temporally. We found a significant correlation between the period of adult spawning and the period of juvenile emigration. Initial analysis indicates that this relationship may better explain emigration than traditional variables such as turbidity, flow and temperature. In highly regulated rivers the cues for juvenile salmon emigration are often muted or absent, precluding the use of traditional variables to explain juvenile salmon movement. Less traditional variables must be examined to better explain this crucial phase of salmon life history.

[P041] Coho Salmon (Oncorhynchus kisutch) Spawner Escapement and Distribution in Olema Creek, Marin County, California, 1997-2003

Authors: Brannon J. Ketcham and Gregory G. Brown; Point Reyes National Seashore; Bear Valley Road; Point Reyes Station, CA 94956; phone: (415) 464-5192; fax: (415) 663-8132; e-mail address: brannon_ketcham@nps.gov.

Abstract: Olema Creek is the largest undammed tributary within the Lagunitas Creek watershed in coastal Marin County, California. This area is considered one of the most southerly stable populations of coho salmon in the Central California Coast Evolutionarily Significant Unit. The Coho and Steelhead Restoration Project (CSRP) began monitoring coho salmon spawning activity in Olema Creek in 1997, building on previous work by local area volunteers and National Park Service biologists. From late November through February, CSRP biologists and volunteers conduct regular surveys for spawning adult coho, redds, and carcasses. Survey objectives are to: (1) develop an index and/or total escapement estimate of adult coho salmon for the analysis of long-term population trends; (2) determine the distribution of spawning activity by collecting georeferenced redd location data; (3) determine population characteristics of coho adults including fish size, age, and sex and redd size; and (4) collect tissue and scale samples for genetic and age analysis. All data collected are entered into a GIS compatible database, enabling precise spatial analysis. The poster presents spawn timing and relationship to discharge, spawning distribution and trends since 1997-98.

[P042] Coho Salmon (Oncorhynchus kisutch) Return to Pine Gulch Creek, Marin County, California

Authors: Brannon J. Ketcham and Gregory G. Brown; Point Reyes National Seashore; Bear Valley Road; Point Reyes Station, CA 94956; phone: (415) 464-5192; fax: (415) 663-8132; e-mail address: brannon_ketcham@nps.gov.

Abstract: Pine Gulch Creek drains 19.8 square kilometers and is the primary freshwater input to Bolinas Lagoon in coastal Marin County, California. The watershed supports a population of steelhead trout (Oncorhynchus mykiss). Prior to 2001, the last documented siting of coho salmon (O. kisutch) was made by the Department of Fish and Game in 1968. National Park Service monitoring has documented the return of three coho salmon year classes to the watershed. Results of winter spawner surveys, spring outmigrant trapping, and summer modified Hankin-Reeves population estimates are reported for this returning population. Results of modified Hankin Reeves surveys conducted in September 2001 and 2002 yielded estimates of 538 ± 349 juvenile coho in 2001, and 1205 ± 337 juvenile coho in 2002. The 2002 survey indicate coho were more abundant and widely distributed in the watershed than in the 2001 survey. A smolt trap operated in the spring of 2002 captured 250 coho smolts. In addition, a third year class has been detected during winter 2002-03 spawner surveys. Collected tissue samples have been submitted to the NMFS Santa Cruz lab. Results may assist with determination of fish origin and relatedness within the stream system.

[P043] Migratory Behavior of Radio-Tagged Steelhead Smolts in Free-Flowing and Impounded Reaches of the Russian River: Attempts to Enhance Passage by Manipulating Dam Spill

Authors: David Manning¹, John Mann², Sean White¹, Ron Benkert¹, and Ben White^1
1Sonoma County Water Agency, P.O. Box 11628, Santa Rosa, CA 95406
707-547-1988 (W), 707-524-3782 (F), dmanning@scwa.ca.gov.
²National Marine Fisheries Service, 777 Sonoma Ave. Rm 325, Santa Rosa, CA 95404

Abstract: The Sonoma County Water Agency is evaluating the effects of an inflatable rubber dam on steelhead smolt emigration in the mainstem Russian River. Radio tracking in spring 2000 showed the percentage of fish that passed the dam site differed substantially before and after the river was impounded. We expanded the study in 2001 and 2002 to include a free-flowing control reach and released 297 smolts 11 km above the dam. Multiple telemetry stations were used to compare travel rates and residence times in free-flowing (river) and impounded reaches during both years. In 2002 we compared flow characteristics and smolt responses to three dam configurations: (1) full inflation, (2) partial deflation, and (3) partial deflation to create a notched effect.

Median travel rates through the river and impounded reaches were similar in both years. River residence time was also similar in 2001 and 2002. However, residence time in the reservoir and dam forebay decreased by more than 50% in 2002. When the dam was notched and spill depth and velocity were maximized, median forebay residence time was 3 min. Migratory delays in the impoundment appear directly related to flow conditions in the forebay. We will continue to investigate spill characteristics and smolt behavior in hopes of enhancing steelhead outmigration.

[P044] Estimating juvenile production of winter-run Chinook salmon as a management tool for water operations in the Sacramento-San Joaquin Delta

Author: B.F. Oppenheim, National Marine Fisheries Service (NOAA Fisheries), Sacramento Area Office, 650 Capitol Mall, Suite 8-300, Sacramento, CA, 95814-4706, 916-930-3600(W), 916-930-3629(F), bruce.oppenheim@noaa.gov.

Abstract: Each year millions of acre-feet of water are pumped from the Sacramento-San Joaquin Delta in California for agricultural, municipal, industrial, fish and wildlife uses. In the process, thousands of endangered Sacramento River winter-run Chinook salmon are injured or killed as fish and water are pumped through the State Water Project's Harvey O. Banks Pumping Plant and the Central Valley Project's Tracy Pumping Plant. These losses occur despite fish protective devices at both plants. NOAA Fisheries has developed a juvenile production estimate (JPE) as an important management tool, to determine the allowable incidental take level at those facilities that will avoid or minimize impacts to the winter-run Chinook salmon population. The JPE model uses adult escapement, sex ratio, fecundity, and early life stage survival indices to estimate the annual juvenile production entering the Delta. The JPE guides management decisions of water operations at the pumps to prevent jeopardy to the recovering winter-run Chinook salmon population. Since 1993, the JPE has been an integral part of balancing the demand for water with fish protection in the Central Valley.

[P045] Restoration of Coho Salmon in the Russian River Basin.

Authors: Sara F. Randall, Institute for Fisheries Resources, P.O. Box 29196, San Francisco, California 94129-0196, 415-561-3474 (W), 415-561-5464 (F), srandall@ifrfish.org; Daniel J. Logan, National Marine Fisheries Service, Protected Resources Division, 777 Sonoma Avenue, Santa Rosa, California 95404-6515, 707-575-6053 (W), 707-578-3435 (F), dan.logan@noaa.gov; Linda Curry, Russian River Watershed Council, P.O. Box 3908, Santa Rosa, California 95402, 707-526-7868 (W), steward@rrwc.net; Paul G. Olin, University of California Sea Grant Extension, 2604 Ventura Avenue Santa Rosa, California, 95403, 707-565-2621 (W), 707-565-2623 (F), pgolin@ucdavis.edu; Leah Mahan, National Marine Fisheries Service, Habitat Conservation Division, 777 Sonoma Avenue, Santa Rosa, California 95404-6515, 707-575-6077 (W), 707-578-3435 (F), leah.mahan@noaa.gov; Shirley Witalis, National Marine Fisheries Service, Protected Resources Division, Suite 8-300, 650 Capitol Mall, Sacramento CA 95814-4706, 916-930-3606 (W), 916-930-3629 (F), shirley.witalis@noaa.gov; Nancy Rogers, San Francisco District, U.S. Army Corps of Engineers, 2100 Bridgeway, Sausalito, CA 94965, 415-332-3871 (W), 415-332-0761 (F), nrogers@spd.usace.army.mil.

Abstract: Coho salmon (Oncorhynchus kisutch) in the Russian River basin are listed as threatened under the Endangered Species Act (ESA). In 2000, several non-governmental organizations and government agencies formed the Russian River Coho Salmon Recovery Work Group (Work Group) to address the concerns of critically low populations of coho salmon in the Russian River basin. The Work Group developed a pilot hatchery program that focuses on restoration of wild populations using a captive broodstock program. The populations in the Russian River basin are at dramatically low levels with most brood year lineages nonexistent. Low overall abundance and weak brood year strength increases the risk of extinction from adverse effects of stochastic events or manipulations to the basin. The captive broodstock is derived from naturally-produced juveniles which are raised entirely in freshwater, then propagated using a spawning matrix to increase genetic diversity. Releases from the program will occur into underseeded tributaries of the Russian River in which habitat has been restored. The objective is that the released fish will return to the tributary in which they were released, spawn naturally, and eventually eliminate the dependence on the hatchery, leaving a thriving population of coho salmon.

[P046] Come hell or high water: rearing of juvenile Chinook salmon on a large river floodplain

Authors: T. R. Sommer, Presenter, California Department of Water Resources, 3251 S Street, Sacramento, CA 95816, 916-227-7537 (W), (916) 227-7554 (F); W. C. Harrell, California Department of Water Resources, 3251 S Street, Sacramento, CA 95816, 916-227-7619 (W), (916) 227-7554 (F), bharrell@water.ca.gov; M. Nobriga California Department of Water Resources, 3251 S Street, Sacramento, CA 95816, 916-227-2726 (W), (916) 227-7554 (F), mnobriga@water.ca.gov.

Abstract: Although river channels and estuaries have been well documented as beneficial rearing habitat for young Chinook salmon Oncorhynchus tschawytcha, it is unclear whether seasonal floodplain is a net “source” or “sink” for salmon production. To address this issue, we studied salmon distribution and migration in the Yolo Bypass, a 24,000 ha floodplain of the Sacramento River. Juvenile salmon were present in the Yolo Bypass during winter-spring; fish were collected in diverse habitat types including riparian, agricultural and wetland areas. However, salmon abundance was significantly higher in low velocity areas including the downstream portions of levees, islands and trees. Experimental releases of tagged hatchery salmon suggest that fish rear on the floodplain for extended periods. This conclusion is supported by the significantly larger size of wild salmon at the floodplain outlet than the floodplain inlet during each of the study years. Differences in emigration trends among seasons and years indicate that residence time in the basin is affected by flow. Several lines of evidence suggest that the majority of young salmon successfully emigrated the relatively well-drained floodplain. Adult ocean recoveries of tagged hatchery fish indicate that seasonal floodplain supports better survival than adjacent perennial river channels.

[P047] Reduced anti-predator response and enhanced growth due to genetic variability between different strains of wild and domestic coho salmon (Oncorhynchus kisutch)

Authors: W. E. Vandersteen Tymchuk, Presenter, Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, 604-666-4802(W), 604-666-4805(F), tymchuk@zoology.ubc.ca; C. Biagi, Department of Fisheries and Oceans, West Vancouver Laboratory, 4160 Marine Drive, West Vancouver, BC, V7V 1N6, 604-666-8997(W), 604-666-4805, biagic@pac.dfo-mpo.gc.ca; R.E. Withler, Department of Fisheries and Oceans, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC, V9T 6N7, 250-756-7148(W), 250-756-7053(F), withlerr@pac.dfo-mpo.gc.ca; R. H. Devlin, Department of Fisheries and Oceans, West Vancouver Laboratory, 4160 Marine Drive, West Vancouver, BC, V7V 1N6, 604-666-7926(W), 604-666-3497(F), devlinr@pac.dfo-mpo.gc.ca.

Abstract: Several coho salmon crosses were reared to enhance current understanding of how genetic variability relates to behavioural and physiological differences between slow-growing and fast-growing strains of fish. Crosses ranging from pure domestic to pure wild were reared as homogenous groups (a single family per group) and as four mixed groups (two families from each cross). Two mixed groups were reared under laboratory conditions and were fed to satiation, and two were reared under semi-natural conditions with an enriched environment and limited food resources. After six months of growth, the mean size of the crosses increased with an increase in the proportion of domestic genes in the genotype. The domestic genotype produced even larger fish in the mixed group under laboratory conditions, however the relative differences between domestic and wild fish were reduced in the mixed groups grown under semi-natural conditions. Preliminary studies indicate that anti-predator behaviour is reduced with an increase in domestic contribution to the genotype. Behavioural and physiological data relating to observed differences in growth will be discussed.

[P048] Relationship Of Hatchery And Wild Chum Salmon, Running To Spawn In The Paratunka River, East Kamchatka Over The Time Of Fisheries: Spatial-Temporal Trends

Authors: Zaporozhets O. M., Zaporozhets G. V. Kamchatka Research Institute of Fisheries and Oceanography, Russia (POSTER + Extended publication)

Abstract: Both wild and hatchery chum salmon enter Paratunka River where release of 20 million juvenile chum salmon has been used since 1993. Ratio between individuals of each population by different reaches of the river basin in the course of run was examined. Identification was carried out with discriminate analysis for a number of structural scale components. Wild population has found to be replaced consequently for hatchery population in recent years. Replace is of undulating character being related to poaching in spawning grounds selecting wild fish and to non-selective fishery in Avacha Bay. Hatchery fish percent was up to 90 in mediate and upper reaches of the river in particular years. Five recent years the percent in natural spawning grounds in lower reaches was 20-44. The percent in the tributary, where the hatchery situated, varied from 80 to 98. Analysis of origin of chum salmon caught in Avacha Bay in vicinity of Paratunka River outlet indicated of hatchery fish contribution over a half of catch sometimes. Hence it has been concluded that interrelations between populations and mutual genetic exchange occur in all biotopes mentioned above. The interrelations connecting with man are recommended to take them into account in fishery regulation.

GENETICS

[P049] Population genetics of introduced northern pike populations

Authors: and Robert K. Wayne; Department of Organismic Biology, Ecology and Evolution; University of California Los Angeles; 621 Charles E. Young Drive South; Los Angeles, CA 90095; 310-825-5014; aguilara@ucla.edu.

Abstract: We have investigated genetic variability of native and introduced northern pike populations using microsatellite markers. One of our main goals was to establish the origin of an introduced population in Northern California (Lake Davis). Lake Davis has subsequently undergone an eradication program, however pike still persisted in the lake and we wanted to also establish the origin of these post-eradication individuals. Introduced populations exhibit a wide array of variability, and in most instances genetic variability is lower than for native populations. Introduced populations also exhibit genetic signatures of population bottlenecks, reflecting the founding of these populations. Post eradication individuals appear o be survivors of the initial eradication efforts. The genetic data also reflects a slight population bottleneck for the current Lake Davis population. The ultimate origin of the initial Lake Davis population is currently unknown, however more source populations are currently being analyzed.

[P050] Identification of Genetic Structure among barriers in Steelhead (Oncorhynchus mykiss): A microsatellite analysis of the Russian River Watershed

Authors: K.L. Deiner, Presenter, SSU Biology Dept., 1801 E. Cotati Ave., Rohnert Park, CA, 94928, 707-664-4469(W) 707-664-3012 (F), humbert@students.sonoma.edu; B. Coey, Watershed Restoration Program CCR, PO Box 47, Yountville, CA 94599, 707-944-5582 (W), 707-944-5563 (F), BCoey@dfg.ca.gov; B. Freele, California Department of Fish and Game, PO Box 47, Yountville, CA 94599, 707-277-7052 (W), bfreele@dfg.ca.gov& D. J. Girman*

Abstract: We are conducting a collaborative study with the California Department of Fish and Game's (CDFG) Russian River Basin Planning Division on genetic analysis of steelhead (Oncorhynchus mykiss) populations. This project has two primary components: 1) comparison of genetic structure and diversity above and below ten impassable barriers in the Russian River watershed; and 2) Phylogeographic analysis of the Russian River watershed. We examined approximately 1000 samples with an analysis of 12 nuclear microsatellite loci. The microsatellite loci were chosen from previously published studies. We used these genetic markers to assess the differences in genetic diversity and structure between these longstanding natural and man made barriers to gene flow.

[P051] Genetic structure in the staghorn sculpin from Alaska to Southern California.

Authors: K.D. Louie – Presenter, Department of Organismic Biology, Ecology and Evolution. University of California, Los Angeles, CA, 90095-1606; (310) 206-7885 (W); (310) 206-3987 (F); kdlouie@ucla.edu. K.P. Koepfli, Department of Organismic Biology, Ecology and Evolution.University of California, Los Angeles, CA, 90095-1606; (310) 825-5014(W); (310) 206-3987 (F), klausk@lifesci.ucla.edu, and D.K. Jacobs Department of Organismic Biology, Ecology and Evolution. University of California, Los Angeles, CA, 90095-1606; (310) 206-7885 (W); (310) 206-3987 (F); djacobs@ucla.edu .

Abstract: We are investigating the population genetic structure of the Leptocottus armatus. This species has a protracted larval stage and juveniles recruit into the estuaries for use only as a nursery ground, and then adults migrate offshore. Due to this life history, we hypothesized that this fish would exhibit panmictic populations. Our mitochondrial control region sequence data show a shallow amount of geographic structure from samples from Alaska to Southern California, which may be due to isolation by distance. Additionally, haplotype distribution in this species may fit a glacial refugia and expansion hypothesis, as it exhibits higher haplotype diversity southern locations and those areas proposed to be glacial refugia, such as the Queen Charlotte Islands.

[P052] Assessment of the Molecular Evolution and Phylogeography of the Cabezon (Scorpaenichthys marmoratus) Based on mtDNA Control Region Sequence Data

Authors: R.T. Olive, Poster Presenter, Cal Poly State University, Biological Sciences Department, 1 Grand Ave., San Luis Obispo, CA, 93407, 805-756-7397(W), 805-756-1419(F) rtcolive@hotmail.com ; F.X. Villablanca, Cal Poly State University, Biological Sciences Department, 1 Grand Ave., San Luis Obispo, CA, 93407, 805-756-2200(W), 805-756-1419(F), fvillabl@calpoly.edu ; R. Nakamura, Cal Poly State University, Biological Sciences Department, 1 Grand Ave., San Luis Obispo, CA, 93407, 805-756-2740(W), 805-756-1419(F), nakamura@calpoly.edu ; R.D. Vetter, NMFS, Southwest Fisheries Science Center, 8640 La Jolla Shores Dr., La Jolla, CA, 92037, 858-546-7000(W), 858-546-7003(F), Russ.Vetter@noaa.gov.

Abstract: The cabezon (Scorpaenichthys marmoratus) is the largest species in the sculpin family Cottidae. From 1991 to 1998 commercial landings of cabezon rose from 7 to 170 metric tons in California. A rapidly growing source of fishing pressure for nearshore species, the live-finfish fishery, has become lucrative and recently live cabezon landings have been the highest in tonnage and dollar value in California’s live-finfish fishery. For this reason, and because of the lack of scientific information available for this species, the goal of this study is to assess the population genetic structure of the cabezon over a large portion of its geographic range by sequencing the mtDNA control region. More than 500 tissue samples have been collected from northern Washington to San Diego, California.