Wednesday April 15 Afternoon - Abstracts

Session: Status and Trends of Aquatic Resources in the Sea of Cortez

[3101] Biodiversity and fisheries: are they compatible?

Author: Donald A. Thomson, Presenter, The University of Arizona, Department of Ecology and Evolutionary Biology, Tucson, AZ 85721, 520-621-7287(W), 520-743-7827(H), dat@u.arizona.edu.

Abstract: The Sea of Cortez is a species-rich, highly productive and resilient sea. Recent tabulations of its biodiversity list about 6,000 species of macrofauna with over 1,000 species of vertebrates. However, during the past half of the 20th century a combination of factors, including overfishing, habitat alteration and natural environmental changes, have led to a significant decline in the populations of numerous species, especially the largest fishes. The outlook for sustainable fisheries is grim under present practices and needed wide-scale reforms may only be able to stop the bleeding. We cannot expect the Sea of Cortez to ever return to pre “Log” status under the inevitable intense pressure on its resources.

[3102] Field Guide to the Marine Fishes from the Gulf of California

Author: Michele L. Buckhorn. Department of Environmental Science and Policy, University of California, Davis, Davis, CA 95616. 530-752-2810. mlbuckhorn@ucdavis.edu.

Abstract: The Gulf of California is a subtropical sea located between the Baja California Peninsula and mainland Mexico. There are 17 families and 67 species of chondrichthians, 115 families and 753 species of fish, plus two species of myxinids present in the Gulf of California. This guide is a dichotomous identification key to the marine fish families in the Gulf of California with descriptions of over 300 species of fish that would be encountered fishing, snorkeling, diving, or nearshore collecting (exclusively deep water species are excluded). It includes 99 extant families from the Class Condrichthyes and the Division Teleostei (according to Nelson, 1994) that can be encountered from the shoreline to 100 meters depth within the Gulf of California (southernmost delimiter being an arbitrary boundary between Cabo San Lucas and Mazatlan, Mexico). It consists of three main sections: a key to 99 families of chondricthyes and teleosts, a key to 61 chondrichthian species, and an annotated list of over 300 species of teleosts with descriptions, meristics, and natural history. The inclusion of any species in this key is based upon museum collections, fishermen’s catches, personal observations made in the Gulf of California and from published accounts of fish species whose range includes or is wholly within the aforementioned parameters. Over 90 families and 150 species are illustrated by the author.

[3103] Is there any change in the productivity in the Gulf of California in last 5 years (1997-2002)?

Author: Sergio Hernández-Vázquez¹, S. Ortega-García², R. Rodríguez-Sánchez² and D.B. Lluch-Cota1; ¹: Centro de Investigaciones Biológicas del Noroeste, S.C. Mar Bermejo 195, Col. Playa Palo de Santa Rita, La Paz, B.C.S. 23090. E-mail: shernan@cibnor.mx; ²: Centro Interdisciplinario de Ciencias Marinas (CICIMAR)

Abstract: The Pacific warm episode (El Niño) during 1997-1998 increased the sea surface temperatures (SST) anomalies across the Gulf of California more than 24°C above normal. Consistent with that episode the oceanic thermocline remained deeper than normal across the central and eastern equatorial Pacific, and we have some evidence that it happened inside the Gulf of California. The next 4 year the equatorial Pacific and the eastern equatorial Pacific showed SST anomalies between -1 and 0°C, indicating La Niña-like oceanic conditions until the end of 2002, when the condition reversed to the El Niño situation. This contribution shows how these changes affected the productivity of the Gulf of California measured in Clorofila en mg/m^3 , using the SeaWiFS data set.

[3104] The Gulf of California shrimp fishery: environmental effects and management implications.

Authors: Juana López Martínez¹, S. Hernández Vázquez², Manuel O. Nevárez Martínez¹,³, S. Lluch Cota², E. Herrera Valdivia1, R. Morales Azpeitia1.¹Centro de Investigaciones Biológicas del Noroeste, S. C. Unidad Sonora. Km 2.5 Carretera a Las Tinajas, Col. Las Tinajas. Guaymas, Sonora. 85450, México.e-mail: jlopez@cibnor.mx; ²Centro de Investigaciones Biológicas del Noroeste, S. C. La Paz. Apdo. Postal 128. La Paz, B.C.S. 23000 ; ³Centro Regional de Investigación Pesquera Guaymas. Calle 20 Sur No. 605 Col. La Cantera, Guaymas, Sonora, 85400, México.

Abstract: The shrimp fishery in the Gulf of California is a valuable resource that contributes to incomes and employment for a very important sector of the fisherman community of Mexico. Fisheries based on penaeid crustaceans present a high interannual variability in the catch. Possible causes include: fishing effort, effect of some environmental parameters and a combination of both sources. In this study, we explored the effect of the environmental interannual variability on the growth, mortality, recruitment, reproductive period, and first maturity age of the Farfantepenaeus californiensis and Litopenaeus stylirostris shrimps for the 1978-2002 period. Results show the brown and blue shrimp can respond immediately to environment changes by means of changes in the first maturity age, shifts in reproductive period, changes in individual growth coefficient and recruitment magnitude. These changes modify the fishing season length and the catch pattern, impacting the regional economy. These changes should be considered in the management proposal.

[3105] From the river to the sea: Evaluating the influence of Colorado River flow on the corvina fishery in the northern Gulf of California

Authors: K. Rowell – Presenter, Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA, (W) 520-626-3323, (F) 520-621-2672, krowell@geo.arizona.edu; M. Román, IMADES, Apdo. postal 452, San Luis Rio Colorado, Sonora C.P. 83449 Mexico, delta2@telnor.net; J. Campoy, CONANP/SEMARNAT, Apdo. postal 452, San Luis Rio Colorado, Sonora C.P. 83449 Mexico, hdelta@telnor.net; K.W. Flessa, Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA, (W) 502-623-2907, (F) 520-621-2672, kflessa@geo.arizona.edu; D. L. Dettman, Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA, (W) 502-621-4618, (F) 520-621-2672, dettman@geo.arizona.edu .

Abstract: Populations of several economically important fish in the northern Gulf of California have declined significantly during the past 50 yrs. Overfishing and the lack of management are the most commonly cited causes for these fishery declines. However, little research has been directed towards the importance of another possible cause of fishery decline: the diversion of Colorado River flow away from the northern Gulf. We use oxygen isotopes in otoliths of the endemic and threatened Gulf corvina (Cynocion othonopterus) to address the importance of Colorado River inflow. Gulf corvina became commercially extinct during “no/low flow” years of the Colorado River (1960-1992). After the 1993 “excess” flows, Gulf corvina populations rebounded significantly. We document that Gulf corvina use the brackish-water habitat of the Colorado River estuary during spawning and in their juvenile years. Oxygen isotope values from annual rings of saggital otoliths track the salinity of the water corvina inhabit during different life stages. Winter values that are significantly more negative than expected from temperature alone indicate the influence of river water during juvenile development. These results are consistent with the hypothesis that the lack of Colorado River flow contributed to the commercial extinction of Gulf corvina.

[3106] Ecosystem-based management for the Gulf of California region

Author: Dr. Francisco Arreguin Sanchez; Centro Interdisciplinario de Ciencias Marinas del IPN; Apartado Postal 592, La Paz, 23090, Baja California Sur, México; Email: farregui@ipn.mx.

Abstract: Several contributions about the state of the fisheries in the world has shown the depletion of many stocks. There are several causes for this, fishing, ecosystem deterioration, and environmental stress, among the more relevant. Despite these causes the global conclusion is that fisheries management must be done within the scope of the ecosystem. The Gulf of California is a highly productive sea where several fisheries are developed such as sardine, shrimp, squid and an artisanal, targeting on multiple species. This region is also important because its biodiversity where we can find endemic, endangered, charismatic and rare species. Different regions of the Gulf have also different fisheries management problems. In this contribution some examples of ecosystem-based fisheries management exemplify the advantages of this approach. In La Paz Bay yields of the artisanal fleet suggest a declination without clear possibilities for increase or maintenance. Ecosystem-based management supports the possibility for an increasing efficiency if management is based on fleet and targets controls. In the central Gulf of California a sardine, shrimp, squid and artisanal fisheries operates. As in many regions of the world clupeoid stocks largely varied causing changes in ecosystem structure. Ecosystem-based analysis show that efficiency of the fisheries can be increased through an adaptative management controlling fleets. In the upper Gulf of California there is a conflictive management problem because the need of conservation versus the traditional shrimp trawl and gillnet fisheries. Ecosystem approach support a platform to analyze how compatible could be conservation and fishing activities. In general terms ecosystem approach appears to be an important management tool to support management decisions; moreover, this also provides a tool to evaluate the impact of fishing on the ecosystem structure and function, which yield with policies for sustainability.

[3107] The Gulf of California: ecosystem view and environmental trends

Author: S.E. Lluch-Cota, Centro de Investigaciones Biológicas del Noroeste, S.C. Apdo Postal 128. La Paz, BCS, México 23000. slluch@cibnor.mx.

Abstract: In this report we approach abiotic (hydrography and climate, ocean circulation, chemistry) and biotic (phyto and zooplankton, fish, invertebrates, marine mammals and birds) components of the marine ecosystem, the related human dimension (fisheries and mariculture, management and conservation), and the scientific view (monitoring efforts, ongoing research, future scientific tasks) of the Gulf of California, with special focus on recent human and natural driven environmental changes. Several knowledge gaps are recognized and enlisted. We conclude our report by providing a series of what we believe are outstanding scientific questions and research tasks, a strategic plan to keep track of future ecosystem changes in Gulf of California, and an invitation to all interested contributors.

Session: Aquatic Habitat Restoration and Management

[3201] Evaluation of common habitat restoration techniques in the Pacific Northwest: a synthesis of seven years of restoration research by the Watershed Program

Authors: Phil Roni*, Todd Bennett, Patsy Garcia, Sarah Morley, and George Pess; Watershed Program; Environmental Conservation Division; Northwest Fisheries Science Center; 2725 Montlake Blvd. E.; Seattle, WA 98112; (206) 860-3307; phil.roni@noaa.gov ; todd.bennett@noaa.gov; patsy.garcia@noaa.gov; sarah.morley@noaa.gov; george.pess@noaa.gov.

Abstract: We summarize the results of seven years of research evaluating fish response to habitat improvement techniques including: large woody debris (LWD) and boulder weir placement, reconnection off-channel habitats, and constructed side-channels. In 30 small streams, higher levels of coho salmon (Oncorhynchus kisutch), steelhead (O. mykiss), and cutthroat trout (O. clarki) were found in reaches treated with LWD though the level of response varied by season and species. Higher levels of coho salmon were also found in streams treated with boulder weirs in eight southwest Oregon streams. An increase in juvenile and adult salmon abundance and species richness was found in habitats associated with constructed logjams in two large western Washington rivers. We analyzed existing smolt-trapping data from over 30 off-channel habitat enhancement projects and found that constructed groundwater channels were particularly productive for juvenile coho salmon. We then examined groundwater channels intensively and found that constructed channels supported higher densities of coho salmon during the winter, but fish diversity was higher in naturally occurring channels. Our results suggest that these habitat improvement techniques increase the abundance of specific salmonids (e.g., coho) and also species richness, but results vary by species, season, and magnitude of habitat improvement.

[3202] Protecting and Restoring Riparian Area Structure and Function Along Forest Highways and Low Volume Roads

Authors: James E. Doyle, Fish and Watershed Restoration Program Manager, USDA-Forest Service, Mt Baker Snoqualmie National Forest, 21905 64 Ave West, Mountlake Terrace, WA, 98043; phone: 425 744-3422, e-mail: jdoyle@fs.fed.us; Anthony Edwards, Project Leader and Civil Engineer, USDA-Forest Service, San Dimas Technology & Development Center, San Dimas, CA; phone: 909 599-1267, ext 235, e-mail: aedwards@fs.fed.us.

Abstract: Transportation corridors have had profound effects on riparian area structure and function in the United States as well as abroad. Aquatic habitat fragmentation is one of the most significant ecological impacts resulting from highway and road construction. These transportation corridors can modify or alter the migration, reproduction, feeding and rearing of a number of aquatic species. With over 600,000 km of system roads to manage across the United States, protecting and restoring aquatic habitat in riparian areas along these roads has become a priority, long-term management need for the USDA-Forest Service. Beginning in 1999, the USDA-Forest Service in partnership with other federal agencies and non-government natural resource organizations, initiated a interdisciplinary, multi-year project to evaluate efforts for protecting and restoring riparian area values impacted by roads. After 2 1/2 years of field and literature reviews, the project identified and documented 12 of 24 treatments and techniques currently being used across the country to either protect or restore aquatic habitat associated with Forest Service highways and roads. This presentation highlights successful treatments or techniques that directly protect or restore aquatic habitat impacted by forest highways and low-volume roads; these include fish passage improvement, channel and floodplain structure placements, and re-connecting water bodies.

[3203] The Adaptive Management Forum for Large-Scale Riverine Habitat Enhancement Projects: A Collaborative Peer Review

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: The “Adaptive Management Forum for Large-Scale Riverine Habitat Enhancement Projects” created a process to peer review complex, interdisciplinary, large-scale channel and salmon habitat improvement projects on the Merced and Tuolumne Rivers, and Clear Creek. Given the scale and the large cost of implementation (>$30 million) we wanted assurance that the projects were based on sound science, and to assess the potential learning that could be gained by a structured, scientific adaptive management approach. The project has convened a panel of seven nationally, and internationally, recognized experts in a range of fields, including academics and practitioners. The Forum format allowed for both communication among the proponents and reviewers, but also allowed for independent assessment by the reviewers. The Panel evaluated how adaptive management was used, and recommended improvements by project, river and comparatively. Reports are available at www.delta.dfg.ca.gov/afrp. Key results: 1) Valuable learning and communication occurred among participants, different watersheds, and between the Panel and local project implementation teams. 2) Although scientists may be involved in the projects, the adaptive management was generally passive and lacked structured experimental design, which could significantly enhance scientific learning. 3) These restoration projects offer “world class” opportunities for scientific study and experimentation.

[3204] Recommended Flow Mitigation from Libby Dam for Pre-spawn Burbot Movement in the Kootenai River, Idaho, USA, and British Columbia, Canada

Authors: Vaughn L. Paragamian (presenter), Brian Gunderman, Ryan Hardy; Idaho Department of Fish and Game; 2750 Kathleen Ave., Coeur d ‘ Alene, ID 83815, USA; vparagam@idfg.state.id.us.

Abstract: Burbot Lota lota spawning migration in the Kootenai River Idaho, USA and British Columbia, Canada is inhibited by flow from Libby Dam. Burbot may be at risk of demographic extinction in Idaho. Hypothesis tests to provide winter flow recommendations for spawning migration were largely unsuccessful. Thus, we examined existing telemetry records of 68 burbot collected from 1994 through 2000 to further define how flow factors effect burbot travel distance and travel rate. Burbot travel distance and rate were established by examining those records of a travel distance of 5 km or more in 10 d or less, referred to as “stepwise movement”. There were a total of 1,835 telemetry contacts, of which 1,494 contacts occurred during the October through February period (81%). We found significant differences in movement of burbot when flows from Libby Dam were at or below 300 m3/s. We recommend recovery measures that include winter Libby Dam operating flows that do not exceed 300 m3/s.

[3205] Improving Chinook Salmon Passage and Spawning Habitat on the Merced River.

Authors: Randall Mager-Presenter, California Department of Water Resources, 3251 S St. Sacramento CA 95816, 916.227.2490 (W), 916.227.7554 (F), rcmager@water.ca.gov; Tim Heyne, California Department of Fish and Game, Tuolumne River Salmon Restoration Center, P.O. Box 10, La Grange, CA 95329, 209.853.2533 (W), 209.853.9017 (F), theyne@dfg.ca.gov; Aric Lester, DWR, 3251 S St. Sacramento CA 95816, 916.227.2488 (W), 916.227.7554 (F), alester@water.ca.gov; Fred Jurick, California Department of Fish and Game, Central Valley Bay-Delta Branch, 830 S Street, Sacramento, CA 95814, 916.445.3967 (W), 916.445.1768 (F), fjurick@dfg.ca.gov; and Rhonda Reed, California Bay-Delta Authority, 1416 Ninth Street, Suite 1155, Sacramento, CA 95814-5511, 916.657.2666(W), rreed @water.ca.gov.

Abstract: Historic aggregate mining on the Merced River has left deep in-channel pits, expanses of shallow sheetflow, and channel devoid of gravel. This has severely impacted migration of spawning Chinook salmon and out-migrating smolts, contributing to the drastic decline of the Central Valley fall-run Chinook salmon population. The Merced River Salmon Habitat Enhancement Project is a cooperative, multi-agency project to restore salmonid habitat and river function to 4.5 miles on the Merced River severely degraded by past aggregate mining and floods. Phase one, in 1999, isolated a 43-acre warmwater pond from the river with an engineered berm and 0.5 mile of designed channel to improve juvenile salmon passage and increase the quantity and quality of spawning and rearing habitat. Phase two, in 2001, included the relocation of 1.5 million tons of material to rebuild 2 miles of abandoned channel, fill shallow gravel ponds, restore floodplain, and provide almost 22,000 yds2 of spawning habitat. With the last phase to be constructed in 2004, indications are that restoration benefits are being realized. Use by spawning Chinook salmon has already increased drastically in the sections of restored channel, and release and capture studies indicate increased survival of smolts migrating downstream.

[3206] Overview of USBR’s fish passage research and developments with internal screw-type lifts and pumps in California

Authors: C. R. Liston, US Bureau of Reclamation, Mid-Pacific Region, Resources Management Division, 2800 Cottage Way, Sacramento, CA 95825, 502/255-9168, Crlist@aol.com.

Abstract: Lifts and pumps that pass fish unharmed while creating hydraulic head for bypasses could enhance fish protection at water diversion facilities. Studies with a small pump (850 rpm, 0.1 m diameter, 0.016 m3/s) demonstrated fish eggs and larvae could be passed unmutiliated. Experiments using juvenile Chinook salmon with Archimedes lifts (26.5 rpm, 3.05 m diameter, 2.3 – 2.8 m3/s) and a Hidrostal pump (350 – 375 rpm, 0.91 m diameter, 2.3 – 2.8 m3/s) at Red Bluff yielded mean survival of 96.5 – 99.5 %. Concurrent 24 h runs with lifts and pump entrained 3,337 juvenile Chinook salmon and 2,773 fish of 27 other species with survival of 94 – 98 %. Tests at Tracy in the south Delta using juvenile Chinook salmon and splittail with a Hidrostal pump (461 – 601 rpm, 0.41 m diameter, 0.17 – 0.40 m3/s) showed no pump effects for mortality, descaling, or body injuries. Immediate survival for splittail and salmon averaged 99% and 96 h survival averaged 93% and 96 %, respectively. Wild fish entrained during Tracy trials demonstrated 99% immediate survivorship. Of special note was pumping of 15 adult and 543 juvenile Delta smelt with 99 % immediate survival. This pumping technology is now being implemented at other diversion sites in California and elsewhere.

[3207] Mitigation Measures for Levees and Other Stabilized Banks: Reducing Impacts to Juvenile Salmonid Rearing Habitat

Author: Roger J. Peters; U.S. Fish and Wildlife Service; 510 Desmond Dr. SE, Suite 102; Lacey, WA 98503-1263; Phone: 360-753-9549; FAX: 360-753-9407; roger_peters@fws.gov.

Abstract: Construction of flood control levees and stabilization of riverbanks are common river management practices throughout the United States. Several studies have demonstrated the impacts of these management activities to lotic ecosystems, in general, and to juvenile salmonid rearing habitats in particular. As a result, many natural resource agencies require mitigation for these management activities. Mitigation often takes the form of introducing large woody debris (LWD) to stabilized banks. However, evidence suggests that these measures are inadequate. I used data and observations obtained during more than 10 years of field investigations, along with published information, to develop favorable habitat features for levees and/or other bank stabilization activities. These features should reduce impacts to seasonal and diurnal salmonid rearing habitats. Favorable habitat features include: backwater sloughs; complex LWD and small woody debris; overhanging cover; cove, eddy, shelf, and depositional habitats; and side channels when possible in levied systems. The distribution of these habitat features along a levee and/or stabilized bank will obviously be site specific. Further data are needed to provide insight into spatial relationships of features providing day and night habitat.

Session: Ocean Ecology of Pacific Salmon (Part II)

[3301] Interannual and spatial variability in feeding habits of juvenile salmon in the Columbia River Plume in relation to zooplankton availability

Authors: R.D. Brodeur-Presenter, Northwest Fisheries Science Center, HMSC, 2030 S. Marine Science Drive, Newport, OR, 97365, 541-867-0336 (W), 541-867-0389 (F), Rick.Brodeur@noaa.gov; R. Schabetsberger, Cooperative Institute for Marine Resource Studies, Oregon State University, HMSC, Newport, OR 97365; C.A. Morgan, Cooperative Institute for Marine Resource Studies, Oregon State University, Corvallis, OR 97331

Abstract: The Columbia River plume is an extremely dynamic coastal feature heavily influenced by strong river flow, wind forcing and tidal forcing. Enhanced production and accumulation of prey within the plume may increase availability of food during the critical period of early ocean survival for salmon. Stomach contents of juvenile coho and chinook salmon collected from a cross-shelf transects both inside the plume and completely outside the plume (off central and northern Washington) were examined and compared with zooplankton and neuston samples from the same stations during the summer of 1998 through 2000. Substantial inshore-offshore variability in diet composition was observed. The dominant taxonomic groupings in the neuston and especially the zooplankton collections were less variable between stations than those in the stomach contents. Fishes, decapod larvae, and hyperiid amphipods occurred in greater proportion and copepods and euphausiids in lesser proportions in the stomachs compared to the plankton, which suggests that juvenile salmon select the larger and more visible prey taxa. Within a cruise, no consistent differences in feeding intensity were observed between the stations in the plume and outside the plume, although on an interannual basis, feeding intensity appeared to be much reduced during the El NiZo of 1998.

[3302] Growth of post-smolt coho salmon off the Oregon and Washington Coasts as indexed by plasma IGF-I levels: June of 2000, 2001, 2002.

Author: B. Beckman-Presenter, NMFS, Northwest Fisheries Science Center, 2725 Montlake Blvd. E. Seattle, WA, 98112, 206-860-3461(W), 206-860-3267(F), brian.beckman@noaa.gov.

Abstract: It has been suggested that growth rates of post-smolt coho salmon, soon after ocean entry, may be related to overall ocean survival. Testing this hypothesis is hampered by the lack of cheap and accurate growth indices. Recently the hormone IGF-I has been tested as a growth index and laboratory validations suggest that plasma IGF-I values are highly correlated with growth rate. Blood samples from juvenile coho salmon were collected as part of a larger study surveying salmon off the Oregon and Washington coasts in June of 2000, 2001, and 2002. Growth estimates from coded wire tagged fish ((capture length – mean release length) x (number of days post-release)-1) were positively correlated with plasma IGF-I levels. Significant differences between mean IGF-I value were found between stations on East – West transects off the coast and were also found between transects. Plasma IGF-I values from inshore stations off the north and central Washington coasts were relatively low compared to other areas sampled in both 2001 and 2002.

[3303] Overwinter lipid dynamics in juvenile coho and chinook salmon

Authors: M. Trudel-Presenter, Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada, V9T 6N7, 250-756-7049(W), 250-756-7053(F), trudelm@pac.dfo-mpo.gc.ca; S. Tucker, Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J1; D. Higgs, Fisheries and Oceans Canada, West Vancouver Laboratory, West Vancouver, British Columbia, Canada, V7V 1N6,; D.W. Welch, Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada, V9T 6N7

Abstract: Winter is generally considered to be a critical period in the early life of fish. It is commonly believed that food consumption rates of juvenile fish are greatly reduced over winter and insufficient to meet their energy demands due to lower water temperature and prey availability. As a consequence, fish are expected to rely on the energy reserves accumulated during the growing season to fuel their metabolic functions during the winter months. Because laboratory experiments have consistently showed that mass specific metabolic rates decreased with size, we may expect that energy depletion over the winter months would be higher in smaller fish. In this study, we tested the hypotheses that energy depletion was higher in smaller salmon over winter. We collected juvenile salmon at sea in the fall and following winter, and compared their energy and lipid contents between these two periods. Lipid classes and fatty acids have also been measured. Our analyses showed that larger salmon utilized a larger fraction of their energy reserves over winter than smaller salmon. These results suggest that larger fish have higher mass specific metabolic rates.

[3304] Aspects of the population biology of euphausiids along the southwest coast of Vancouver Island and their implications for the marine survival of coho (Oncorhynchus kisutch) and sockeye (O. nerka) salmon.

Author: R. Tanasichuk-Presenter, Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada V9T 6N7, 250-756-7197(W), 250-756-7053(F), tanasichukr@pac.dfo-mpo.gc.ca;

Abstract: We have been monitoring the population biology and production of euphausiids (Thysanoessa spinifera, Euphausia pacifica) along the southwest coast of Vancouver Island since 1991. There has been an order of magnitude variability in biomass among years and interannual variation in the timing of spawning events. Recent analyses have shown that euphausiid biomass accounts for 50 and 23% of the explained variation in the marine survival rates of Barkley Sound sockeye and Carnation Creek wild coho respectively. Sockeye move through Barkley Sound early (April-June) and feed on 3-5 mm T. spinifera whereas coho occur later (June-August) and feed on 9-12 mm T. spinifera. We will explore whether interannual variation in food availability is a consequence of variations of population productivity or spawn timing. We hope to summarise information on freshwater diet to compare prey characteristics between the two environments.

[3305] Differences in early ocean ecology of chinook and coho salmon in SE Alaska: Possible cause for differential survival?

Author: Laurie Weitkamp, National Marine Fisheries Service, Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112, (laurie.weitkamp@noaa.gov, Ph. 206 860-3246, FAX 206 860-3335)

Abstract: The marine survival rates for coho salmon originating from SE Alaskan rivers in the last decade have been truly astounding, reaching 35% for Auke Creek in 1994 and 27% in 2001. In contrast, marine survival rates for chinook salmon originating from the same area are unremarkable—on the order of 2-3%. Using juvenile chinook and coho salmon collected in marine waters of southeast Alaska as part the NMFS Auke Bay Lab’s Southeast Coastal Monitoring Program, I am exploring possible differences in the early ocean ecology of these two species that might account for the differences in survival. I will discuss the results of spatial, bioenergetic, and diet analyses that suggest that coho salmon are using different habitats than chinook salmon, have similar diets while tending to greater relative stomach fullness, yet have an overall lower condition factor than chinook salmon. This suggests that most coho salmon are surviving—those that skinny and those that are fat--while only fat chinook salmon survive. In addition, I will review observed interannual variation in marine environments of SE Alaska during the strong 1997 El Nino and 1999 La Nina and its potential impacts of juvenile chinook and coho salmon.

[3306] Juvenile Pink Salmon in the Marine Ecosystem of the Northern Gulf of Alaska

Authors: L. Haldorson-Presenter, School of Fisheries and Ocean Sciences, University of Alaska Juneau, AK 99801, 907-465-6441 (w), lew.haldorson@uaf.edu; J. Armstrong, School of Aquatic Sciences and Fisheries, University of Washington; J. Boldt, , School of Fisheries and Ocean Sciences, University of Alaska Fairbanks; N. Davis School of Aquatic Sciences and Fisheries, University of Washington; K. Myers, School of Aquatic Sciences and Fisheries, University of Washington; T. Walker, School of Aquatic Sciences and Fisheries, University of Washington

Abstract: Juvenile pink salmon occupy the continental shelf of the northern Gulf of Alaska (NGOA) in summer and fall after entering nearshore marine waters in late spring. We sampled near-surface pelagic fishes on the Seward Line in August 1999-2000, and monthly, including Prince William Sound (PWS) in July – October 2001. In July 2001 catches in PWS were very high, however, in subsequent months the distribution shifted onto the shelf. Highest abundance on the Seward Line occurred in August and September. In August 1999 – 2002, pink salmon were the most abundant juvenile salmonids on the Seward Line, and juvenile salmonids dominated the community of near-surface planktivorous fishes. PWS hatcheries release around 600 million pink salmon annually. In 2001, the percentage of hatchery fish decreased from 66% in July to less than 15% in October. While in shelf waters, pink salmon grow from less than 100 mm fork length in July to over 200 mm in October, while weight increases ten-fold. Fish were largest fish in 2000. In 2001, diet of fish over the shelf increased in diversity from July – September, and shifted from reliance on larvaceans and euphausiiids in July to large copepods in August, and a very diverse diet in September. The importance of large copepods in August 2001 was unusual, as in 1999 and 2000 the diet was dominated by the pteropod Limacina. Larvaceans and Limacina are important prey - they are mucous net-feeders that are able to capture very small prey; consequently they appear to be an important trophic link between planktivorous fishes and the very small primary producers and primary consumers that dominate summer plankton production in the NGOA shelf ecosystem.

[3307] Abnormal migration and premature mortality in Fraser River salmon

Authors: S.G. Hinch-Presenter, Department of Forest Sciences, University of British Columbia, Vancouver, BC, V6T 1Z4, 604-822-9377(W), 604-822-9102(F), shinch@interchange.ubc.ca; A.P.Farrell, Department of Biological Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6, 604-291-3647(w), 604-291-3496(F), farrell@sfu.ca; M.C. Healey, Institute for Resources and Environment, University of British Columbia, Vancouver, BC, V6T 1Z3, 604-822-4705(W), 604-822-9250(F), healey@interchange.ubc.ca; S. Jones, Pacific Biological Station, Fisheries and Oceans Canada, Naniamo, BC, V9R 5K6, 250-729-8351(W), joness@dfo-mpo.gc.ca; G. Van der Kraak, Department of Zoology, University of Guelph, Guelph, ON, N1G 2W1, 519-824-4120-3598(W), 519-767-1656(F), gvanderk@uoguelph.ca; S. Macdonald, Fisheries and Oceans Canada, Resource and Environmental Management, Simon Fraser University, Burnaby, BC, V5A 1S6, 604-666-7910(w), 604-666-1995(F), macdonaldst@dfo-mpo.gc.ca; M. Lapointe, Pacific Salmon Commission, Vancouver, BC, V6E 1B5, 604-684-8081(W), 604-666-8707(F), lapointe@psc.org; S. Cooke, Department of Forest Sciences, University of British Columbia, Vancouver, BC, V6T 1Z4, 604-822-1969(W), 604-822-9102(F), scooke@interchange.ubc.ca..

Abstract: The ‘late-run’ sockeye stock complex is one of the major groups of Fraser River salmon. Historically, late-run stocks milled in the estuary for several weeks before initiating their September and October up-river spawning migrations. However, in 1996, they arrived to the estuary at normal times but commenced river migration immediately. Late-run sockeye have entered freshwater progressively earlier each year and by 2000-2001, entered freshwater 5-6 weeks earlier than normal. Associated with this abnormal behaviour has been extraordinarily high mortality. In 2001, mortality during the migration ranged from 90-96%. Mortality of migrants that successfully reached spawning grounds but died without spawning was 10-30%. Prior to 1995, total freshwater mortality for late-run stocks rarely exceeded 20%. We recently began a 5-year study to examine physiological and environmental factors responsible for abnormal initiation of migration into freshwater, and to examine consequences of abnormal migrations on spawning success and fitness. In 2002, late-run fish were collected from various coastal and in-river locales, and at different times during the run. Preliminary findings suggest that ‘early migrating’ late-run fish had unusual ionic, osmotic and energetic states compared to ‘later migrating’ late-run fish indicating abnormal behaving sockeye may not be physiologically prepared for freshwater entry or migration.

Session: An Unique Ecosystem: The Salton Sea, A Saline Lake in a Desert Environment (Part II)

[3401] Salinity tolerance of juvenile red bellied tilapia during direct and gradual transfer to elevated salinity.

Authors: P. Davis, Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego California, 92182, slvrocean@yahoo.com; B. Sardella; Department of Zoology, University of British Columbia, Vancouver BC, Canada V6T 1Z2, quobee@yahoo.com; J. Cooper; Department of Biology, University of San Diego, 5998 Alcala Park, San Diego CA, 92110, jillc@sandiego.edu; R. Gonzalez; Department of Biology, University of San Diego, 5998 Alcala Park, San Diego CA, 92110, gonzalez@hannah.sandiego.edu; C. J. Brauner; Department of Zoology, University of British Columbia, Vancouver BC, Canada V6T 1Z2 brauner@zoology.ubc.ca.

Abstract: The Salton Sea is currently 43g/L and increasing annually. Red bellied tilapia (Tilapia zillii) are known to inhabit the freshwater (5 g/L) drainage ditches surrounding the Salton Sea, however, it is not known whether this species has the ability to enter the sea and potentially contribute to the food chain. Approximately 300 Tilapia zillii (4-10 g) were captured from drainage ditches in traps baited with cat food and transported back to San Diego State University. Fish were then gradually transferred (every 7 days) to progressively increasing salinities of 10, 20, 30, 40 and 50g/L to assess salinity tolerance as indicated by mortality and sublethal indicators such as plasma osmolality, Na+ and Cl- concentrations and muscle water content. No mortality was observed over the duration of this study indicating that T. zillii may have the physiological ability to enter the Salton Sea. A second series of experiments was conducted to determine the threshold of these fish for direct transfer to saline waters.

[3402] Studies in the epizootiology of type C botulism at the Salton Sea

Authors: P. Nol, United States Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, (tel)608-270-2489,(fax)270-2418 pauline_nol@usgs.gov; J.L. Williamson United States Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, 608-270-2453,(fax)270-2418,judy_Williamson@usgs.gov; T.E. Rocke United States Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, 608-270-2451,(fax)270-2418, tonie_rocke@usgs.gov.

Abstract: During the summer of 1996, type C avian botulism killed nearly 15,000 birds at the Salton Sea, over half of which were western white pelicans (Pelecanus erythrorhynchos) and close to 1,200 being endangered California brown pelicans (Pelecanus occidentalis californicus). In 1999, The National Wildlife Health Center launched a three-year study investigating the ecology of botulism at the Sea. In 1999, we conducted a yearlong survey to assess prevalence of Clostridium botulinum type C in the sediments around the Sea at different times of the year. In 1999, 2000 and 2001, we collected tilapia (Oreochromis mossambicus) at various sites during botulism outbreaks in order to determine the presence of toxin-producing bacteria in their intestines, as well as to look for the presence of type C botulinum toxin in their blood and intestines. We found that toxin-producing cells were present in the sediments during winter and spring. Within the tilapia population we noted differences among the years in regard to prevalence of the active bacteria. Tilapia captured in 2000 had significantly higher prevalences of toxin-producing bacteria than in the other years. This information, in conjunction with spatial data obtained from affected pelicans, can provide insight into the dynamics of this disease system.

[3403] Dynamics of selenium and other contaminants in the Salton Sea ecosystem

Authors: M. F. Coe, Presenter, Center for Inland Waters, San Diego State University, San Diego, CA 92182-4614, 619-594-2887, mcoe@sunstroke.sdsu.edu; S. H. Hurlbert, Center for Inland Waters, San Diego State University, San Diego, CA 92182-4614, 619-594-5409, shurlbert@sunstroke.sdsu.edu.

Abstract: The Salton Sea has been for decades the ultimate repository of pollutants released from the intensifying urbanization, industrial development and agricultural activities ongoing in the Coachella, Imperial, and Mexicali valleys and other parts of the watershed. In addition to anthropogenic contaminants, naturally occurring inorganic chemicals such as selenium and arsenic are brought into the Sea via its tributaries. Because the Salton Sea is a closed hydrologic basin, any contaminant brought in either via the Sea’s tributaries and to a lesser extent via atmospheric deposition will bioconcentrate and bioaccumulate, be sequestered in the sediments, undergo degradation processes at varying rates in the different abiotic compartments of the ecosystem, or be converted into a form that is released to the atmosphere. Bioconcentration and bioaccumulation in the fish present at the Sea could potentially be harmful to human consumers as well as to fish-eating birds. All existing data on organic and inorganic contaminants in the various abiotic (sediments and water) and biotic compartments of the Salton Sea and its tributaries have been compiled and synthesized in order to determine the potential risks incurred by human consumers as well as the fish and birds present at the lake.

[3404] Fish and fish-eating birds at the Salton Sea: Past trends and future prospects.

Authors: A. H. Hurlbert, Dept. Biology, Univ. New Mexico, Albuquerqe NM, hurlbert@unm.edu; K. Sturm, Canaan Valley Natl Wildl. Refuge, US Fish Wildl. Serv., Davis WV, Ken_Sturm@fws.gov, S. H. Hurlbert, Dept. Biology and Center for Inland Waters, San Diego State Univ., San Diego CA, shurlbert@sunstroke.sdsu.edu.

Abstract: Christmas Bird Count surveys and censuses of colonial nesting birds at the Salton Sea, CA show that fish-eating birds increased in numbers by two to four orders of magnitude during the 1970s, suffered a decline of less than an order of magnitude in the 1980s, and subsequently recovered to varying degrees during the 1990s and headed downwards again in the early 2000s. In contrast to piscivorous species, most non-piscivorous birds did not show an upward trend following the 1960s. North American Breeding Bird Survey data indicate that fish-eating birds have increased throughout western North America from 1968-1996, but not to the same degree as they have at the Salton Sea. Likely causes of these trends are decline in use of organochlorine insecticides, increased abundance of fish at the Salton Sea following introduction of tilapia, and fish-dieoffs caused by high salinity and cold weather in the late 80s, and erratic fish reproduction. Future prospects of fish-eating birds at the Salton Sea are grim given continuing increase in salinity, now at about 44

[3405] How Not to Structure an Ag to Urban Water Transfer

Authors: K. M. Doyle, environmental consultant, PS Enterprises, 3350 Ocean Park Blvd., Suite 205, Santa Monica, CA 90066, 310-392-6195, kdoyle@psenterprises.com.

Abstract: When California was pressured by the Federal government and the other Colorado River basin states to cut back its historical overuse of Colorado River water, the idea for the largest agriculture-to-urban water transfer in the U.S. was born – a 200,000 acre foot transfer from the Imperial Irrigation District to the San Diego County Water Authority over 75 years. But did anyone stop and examine the potential consequences to the wildlife values of the Salton Sea? Or the air quality ramifications to Imperial County residents? Or the socio-economic impacts to Imperial Valley farmers? Or the subsequent growth-inducing harm on San Diego’s rich and already imperiled environment? Is part of the problem a lack of guidance from existing federal or state laws? Is there a recipe for water transfers that don’t reap such devastation? The presenter will examine these and other questions.

Session: Determining the number of salmon historically present and implications of those estimates on management and recovery of populations and ecosystems (Part II)

[3501] Why is it important to determine how many salmon used to be there?

Author: John H. Michael Jr.-Presenter, Washington Department of Fish and Wildlife, 600 Capitol Way N, Olympia, WA 98501-1091, 360-902-2659 (W), 360-902-2943 (F), michahhm@dfw.wa.gov.

Abstract: As we move toward “restoration” of salmon runs, it becomes important to define a goal; an end point where the stock in question has been recovered. Various methods have been developed and are in use. They are as much as an order of magnitude different and this difference can create difficulties. The population size at which “recovery” is achieved can dictate the timeline for restrictions on fisheries, the size of hatchery programs, and affects water quality planning. In order for society to rationally plan, it will be necessary to fully understand the implications inherent in selecting a definition of recovery for a salmon population.

[3502] The importance of considering density dependency and carcass nutrient interactions in determining escapement goals and harvest strategies for pacific salmon.

Authors: Dana C. Schmidt -Presenter, Golder Associates Ltd., 201 Columbia Avenue, Castlegar, BC V1N 1A2, 250-365-0344 (W), 250-365-0988 (F), Dschmidt@golder.com.

Abstract: Attempts at establishing “ecosystem” based escapement goals have often addressed poorly defined “ecosystem requirements” rather than what escapements are needed to maintain long term harvests. Unless management objectives address sustainable harvests rather than “ecosystem needs”, I contend that freshwater ecosystems will always “benefit” from decreasing harvest rates to produce maximum possible escapements and this will by default, necessarily result in zero harvest rates as the optimum. Limnological principles integrated with population dynamic theory can be used to determine the tradeoff between increased habitat productivity from salmon carcasses and the decreased survival related to density dependency responses of increased adult spawning and juvenile rearing densities. These relationships will usually indicate escapement goals should be higher than that obtained by estimating maximum sustained yield using only density dependent responses estimated from short term spawner-recruit data. Establishing ecosystem based escapement goals without a clearly defined harvest related objective function and the inclusion of density dependent responses during the freshwater stage of the rearing progeny of the spawning fish or competition for spawning areas by the spawning adults will not likely further the goal of providing for long term sustainable fisheries.

Session" Emerging Theory, Experiences, and Issues Related to Fire, Fire Management, and Aquatic Resources (Part II)

[3601] A simple recipe for better integration of aquatic and fisheries issues in wildland fire planning in western landscapes.

Author: Danny C. Lee, USDA Forest Service, Pacific Southwest Research Station, 1700 Bayview Drive, Arcata, CA 95521, 707-825-2965 (W), 707-825-2965 (F), dclee@fs.fed.us.

Abstract: The western United States is embroiled in an intense social debate about what should or should not be done regarding wildland fire. Much of the debate focuses on where and when active fuels management can be effective in mitigating wildland fire impacts or in helping restore fire to a more natural role. Also important are the potential effects of fire suppression and control and post-fire treatment. Specialists in aquatic and fisheries science are increasingly being drawn into both policy debate and actual planning or management exercises. The opportunity to influence wildland fire management in ways that enhance and protect aquatic resources is easily squandered. I suggest a four-part recipe for improving the manner in which aquatic and fisheries issues are integrated in management. The logical first priority is to gain better understanding of the ecological interactions of fire and aquatic resources. A close second is enhanced appreciation of the larger management context, i.e., what values and resources are at stake, who makes decisions, and why. The third ingredient is joint engagement of the research and management communities at a level commensurate with the challenge. The fourth component is active public and stakeholder involvement. Melding these components into a coherent whole may require creative institutional arrangements and would be facilitated by an aggressive research and development program that includes increased attention to decision sciences.

[3602] Effects of fire on aquatic biodiversity in high-elevation lakes of the Oregon Cascade Range

Authors: R. E. Gresswell, USGS-FRESC, 3200 SW Jefferson Way, Corvallis, OR 97331, 541-750-7410 (W), 541-758-8806 (F), robert_gresswell@usgs.gov, G. L. Larson, USGS-FRESC, 3200 SW Jefferson Way, Corvallis, OR 97331, USA, gary_larson@usgs.gov, W. Liss, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA, willliam.liss@orst.edu.

Abstract: In 1996, a late-season wildfire burned approximately 4,000 hectares in the central Oregon Cascades. The burned area and neighboring unburned areas contained numerous lakes in a relatively uniform physiographic setting. This situation provided a unique opportunity to evaluate the effects of fire on lakes, and beginning in July 1997, we sampled 32 lakes (16 lakes in areas that had been intensely burned and 16 in unburned areas). Sampling was focused on small lakes (<1.5 hectare surface area) without fish populations. Physical, chemical, and biological (phytoplankton, zooplankton, and amphibians) data were collected during each of two sample periods (one month apart). Although there was little sign of recovery of terrestrial vegetation during 1997, riparian areas surrounding all of the lakes in the area were flourishing. Nitrogen levels were above average for high mountain lakes in Oregon, but within-lake zooplankton diversity appeared to be similar to other small mountain lakes in the Pacific Northwest that do not support fish populations. Amphibians were thriving in all of the lakes regardless of the effects of fire on the upland portions of the watershed. These observations underscore the importance of small lakes as refugia for aquatic organisms from fire and other natural disturbances.

[3603] Does Wildfire Favor Invasion of Nonnative Fishes?

Authors: C.M. Sestrich-Presenter, Montana State University, Ecology Department, Bozeman, MT 59717, csestrich@montana.edu, T.E. McMahon, Montana State University, Ecology Department, tmcmahon@montana.edu, M.K. Young, USDA Forest Service, Rocky Mountain Research Station, 800 East Beckwith Avenue, Missoula, MT 59801, mkyoung@fs.fed.us.

Abstract: We are testing the hypothesis that post-fire changes in stream temperature, sedimentation, and habitat complexity favor the increased abundance or distribution of nonnative trout in mixed native and nonnative salmonid communities. We are conducting the study in the upper Bitterroot River drainage, Montana, the site of a 1,440- km2 wildfire in 2000. Westslope cutthroat trout, bull trout, and brook trout have a patchy distribution across the drainage. Pre-fire fish population data from 1985 to 1999 permit comparisons of changes in fish species composition, relative abundance, and habitat among sites varying in fire severity, presence of fire-induced debris flows, and distance to source populations. Preliminary results indicate that post-fire summer water temperature in high-severity burn study reaches increased by an average of 3.7°C, compared to 0.9°C in unburned reaches and 1.5°C in reaches with low to moderate severity. In high-severity burn sites without debris flows, fish abundance declined 54% from pre-fire estimates to 2001, but showed marked recovery in 2002. In contrast, fish abundance in sites affected by debris flows has increased little since 2001, averaging only 8% of pre-fire abundance. We have not observed trends in increased relative abundance or number of sites occupied by brook trout following wildfire, though continued monitoring is planned.

[3604] Wildfires and fishes in the southwestern United States: regional short and long-term effects and their management implications

Authors: John Rinne; Rocky Mountain Research Station, 2500 S. Pineknoll Drive, Flagstaff, Arizona 86001; Codey D. Carter. Northern Arizona University and Rocky Mountain Research Station, 2500 S. Pineknoll Drive, Flagstaff, Arizona 86001

Abstract: There is little to no information on the effects of wildfire on aquatic ecosystems in the southwestern United States. Most information is from more mesic landscapes and less fragmented aquatic ecosystems in the northern Rockies and Pacific Northwest. Wildfires appear to be increasing on southwestern landscapes. By contrast, native fishes, mostly threatened and endangered and their habitats are decreasing. The interaction of these three components (i.e. wildfires, fragmented aquatic habitats, and T&E fishes) may write the final chapter of the epitaph of southwestern native fishes. Extensive wildfires occurred in summer 2002 in Arizona and New Mexico. The short-term effects on fishes and their habitats were studied. Three fires, a half dozen streams, and about a dozen fish species were studied. The results of these short term data are combined with information on longer-term effects of fires in the Southwest to begin to make recommendations for management and sustainability of native fishes in forests in the southwestern region.

[3605] An initial evaluation of the short-term effects of the Hayman fire on aquatic ecosystems

Authors: J.L. Kershner, USFS, Fish and Aquatic Ecology Unit, Aquatic, Watershed, and Earth Resources, Utah State University, Logan, UT.84322-5210, 435-797-2500(W), 435-797-1871(F), kershner@cc.usu.edu; L.M. Decker-Presenter, USFS, Fish and Aquatic Ecology Unit, Geospatial Services and Technology Center, 2222W 2300S, Salt Lake City, UT.84119 , 801-975-3803(W), 801-975-3483 (F), ldecker@fs.fed.us; D. Winters, USFS, Rocky Mountain Region, 740 Simms St -P.O. Box 25127 Lakewood, CO 80225-0127, 303-275-5023(W), dwinters@fs.fed.us.

Abstract: The Hayman fire was the largest in Colorado since statehood was granted in 1876. The watersheds within the Hayman fire area represent a mosaic of ephemeral, intermittent and perennial streams of various sizes, including the South Platte River, a highly valued blue ribbon fishery. The aquatic ecosystems of the South Platte River within the Hayman fire area represent a highly altered landscape that has been influenced by a variety of human activities. Given the intensity of the fire, the effects on these streams varied from mild to severe. The speed and trajectory of aquatic ecosystem recovery within the Hayman fire area will be affected by many different factors. The recovery of the hillslope and riparian vegetation will influence how quickly the aquatic environments recover. Clearly, areas that were less severely burned will recover to pre-fire conditions most rapidly. Recovery of aquatic ecosystems within severely burned watersheds will be most dependent on riparian recovery, the juxtaposition to high quality habitats that can provide sources for re-colonization, and the mitigation of additional chronic disturbances. The disturbance resulting from the fire will be followed by an initial response period that can be highly variable, but generally moving toward recovery in the absence of more chronic disturbances.

[3606] The Endangered Species Act, Fire Management, and Interagency Cooperation: Success Stories from California and Nevada

Author: Chad Mellison, Fish and Wildlife Biologist, Nevada Fish and Wildlife Office, 1340 Financial Blvd., Ste 234, Reno, Nevada 89502, 775-861-6300 (Ph), 775-861-6301 (Fax); chad_mellison@fws.gov.

Abstract: Two success stories involving the Endangered Species Act (ESA) and wildfire management will be presented. The first focuses on fire management planning and ESA compliance. The Elko District of the Bureau of Land Management in Nevada has been working closely with the U.S. Fish and Wildlife Service (FWS) to create standard operating procedures for species protection during wildfire suppression activities. These procedures will enable the Fire Management Officer to make informed decisions about species protection during wildfire situations. The second highlights FWS participation on a Forest Service Burned Area Emergency Rehabilitation (BAER) team for the Cannon Fire. This 23,000 acre fire burned on the Humboldt-Toiyabe National Forest along the eastern slope of the Sierra Nevada Range near the California-Nevada border. Nearly four miles of occupied Lahontan cutthroat trout (LCT) habitat was burned. FWS involvement on the BAER team facilitated ESA compliance, allowed the identification, and where possible, avoidance of suppression activities that could affect LCT, resulted in treatment recommendations that reduced adverse effects to LCT, and provided an opportunity to apply recent research results from the AFire and Fish@ workshop held in Boise, Idaho.

Session: Biology and Management of Native and Exotic Freshwater Fish, Amphibians, Aquatic Reptiles in Coastal Southern California and northern western Mexico (Part III)

[3701] Current Research and Status of the Mountain Yellow-Legged Frog (Rana muscosa) in Southern California

Authors: A. R. Backlin, Presenter, USGS, Western Ecological Research Center-BRD, 5745 Kearny Villa Road, Suite M, San Diego, CA 92123, USA, 949-215-3390, abacklin@usgs.gov. C. J. Hitchcock, USGS, Western Ecological Research Center-BRD, 5745 Kearny Villa Road, Suite M, San Diego, CA 92123, USA, 619-206-5689, chitchcock@usgs.gov.; R. N. Fisher, USGS, Western Ecological Research Center-BRD, 5745 Kearny Villa Road, Suite M, San Diego, CA 92123, USA, 858-637-6882, rfisher@usgs.gov.

Abstract: Populations of mountain yellow-legged frogs (Rana muscosa-MYLF) continue to decline in well-protected areas in southern California. Monitoring of known populations and presence/absence surveys were conducted in the Angeles National Forest (ANF) and the San Bernardino National Forest (SBNF) from 1999-2002. Currently, there are two known remaining populations in the SBNF and five known populations in the ANF. Similar declines are being reported for the Sierra Nevada populations of this species. Because the Sierra Nevada populations are mainly found in lakes whereas the Southern California populations are found in creeks, there is some skepticism as to whether the decline causes are the same in these two regions. For example, introduced trout appear to be the frogs’ primary threat in the Sierra Nevada, however no studies had been conducted to test this hypothesis in Southern California. We began trout removal experiments in the fall of 2002 in collaboration with the California Department of Fish and Game, the US Fish and Wildlife Service and the US Forest Service. This experiment will examine the interaction between the introduced trout and the MYLF in stream habitat of southern California. Continued monitoring of known populations, in addition to further research of the frogs natural history, is imperative for protecting this endangered species.

[3702] Exotic amphibians, current status and possible impacts

Authors: T. A. Touré, Presenter, U. S. Geological Survey, WERC-San Diego Field Station, ttoure@usgs.gov; R. N. Fisher, U. S. Geological Survey, WERC-San Diego Field Station, rfisher@usgs.gov.

Abstract: There are at least three exotic amphibian species populations in southern California, African clawed frog (Xenopus laevis), Bullfrog (Rana catesbeiana), and Tiger salamander (Ambystoma tigrinum). Of these species the African clawed frog (X. laevis) is highly aquatic, seldom leaving water. This frog was introduced in the United States during the 1940’s and 1950’s as a laboratory animal for human pregnancy testing. Most authorities on the African clawed frog believe the spread of this exotic species was, in part, due to animals being released or escaping from laboratory stocks, and from the pet trade. The first documentation of this exotic as a feral animal in California was 1968 in Orange County in the Westminster flood control channel. Since 1968, the clawed frog has been documented in southern California drainages, including sites in Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, and Ventura Counties. Currently, studies are being conducted in order to eradicate and control the spread and distribution of the clawed frog in coastal southern California.

Session: Exotic Species

[3801] Ongoing invasion potential of an alien species (Micropterus coosae) into California waterways

Authors: Beth A. Chasnoff-presenter, Patrick K. Crain, Peter B. Moyle; Department of Wildlife, Fish & Conservation Biology, University of California, Davis, 95616; (530) 752-0205; bachasnoff@ucdavis.edu; pkcrain@ucdavis.edu; pbmoyle@ucdavis.edu.

Abstract: Species invasions pose a serious threat to biodiversity and native ecosystems, however, predicting and quantifying the impacts of invasive species has proven problematic. This research uses an integrated approach to quantify the invasion potential of a non-native predator, redeye bass (Micropterus coosae), into California waterways. Known life-history information, distribution, and physiological and environmental tolerance levels of redeye bass are combined with statewide GIS databases of river topography, temperature, flow, and gradient data to document the susceptibility of individual waterways to redeye bass invasion. Furthermore, trophic structures of rivers most susceptible to invasion are examined to predict likelihood of bass establishment. This research helps to clarify to what extent the ongoing redeye bass invasion may affect California rivers and to identify management actions that can aid in halting the spread of this alien species.

[3802] Alien fishes in natural streams: fish distribution and conservation in the Cosumnes River, California.

Authors: Peter B. Moyle, presenter, Patrick K. Crain, and Keith Whitener
Center for Integrated Watershed Sciences and Management, University of California, 1 Shields Avenue, Davis CA 95616, U.S.A. 530-752-6355 (W), 530-752-4154 (F) pbmoyle@ucdavis.edu.

Abstract: The fishes of the Cosumnes River were studied to answer:1. Why were alien fishes so abundant in a river with a ‘natural’ flow regime? 2. Did fish distribution reflect the underlying geology? 3. Were there features of the watershed that consistently favored native fishes? 17 of 25 species were aliens. Three native species have been extirpated and a fourth appears headed for extirpation. Only rainbow trout still occupied much of its native range. Native species have persisted mainly above barriers to alien invasions. The most widely distributed and abundant alien species was redeye bass. Species distributions were highly individualistic, reflecting dynamic patterns of introductions, invasions and local extinctions, as well as physiological tolerances and life history patterns. The distinct geological regions no longer support distinct fish faunas. Most native fishes are likely to persist only if summer flows are increased and if populations above natural barriers are protected from invasions, especially by redeye bass. Some conclusions: 1.Invasion by multiple species creates chaos in fish assemblages. 2. Redeye bass represent a major threat to foothill fishes of Central California. 3. Restoring flow regimes to favor native fishes requires restoring both high and low flows.

[3803] Use of otolith microchemistry to identify source and timing of exotic species introduction: lake trout in Yellowstone Lake

Authors: A.R. Munro-Presenter, Ecology Department, Montana State University, Bozeman, MT 59717, 406-994-1823(W), 406-994-7479(F), amunro@montana.edu; T.E. McMahon, Ecology Department, Montana State University, Bozeman, MT 59717; J.R. Ruzycki, National Park Service, Yellowstone National Park, WY (present address: Oregon Department of Fish and Wildlife, 211 Inlow Hall, Eastern Oregon University, One University Boulevard, La Grande, OR 97850).

Abstract: Exotic species pose serious threats to the integrity of freshwater ecosystems worldwide. The unauthorized introduction of lake trout Salvelinus namaycush into Yellowstone Lake, Yellowstone National Park is one such example. Lake trout were first discovered in the lake in 1994; however, the date of introduction and origin of the source population are unknown. We used secondary ion mass spectrometry to compare the elemental composition of otoliths from suspected transplants to lake trout from two possible source lakes (Lewis and Heart lakes) and to suspected offspring of the original founder population. The Sr:Ca ratios at the edge of the otoliths of suspected transplants and their offspring matched the chemical signature of Yellowstone Lake. In contrast, Sr:Ca near the otolith nucleus, reflective of the environment during the first year of life, was much lower among suspected transplants and matched the otolith Sr:Ca ratio of lake trout from Lewis Lake, identifying it as the likely source. Our results illustrate the utility of otolith microchemistry as a forensic tool for addressing the often problematic question of identifying where an invasive species originated and when the transplant or invasion occurred.

[3804] Amphibians and introduced fishes in wilderness areas of northern California: compatible or pathway to extinction?

Authors: Karen L. Pope - presenter, Entomology Department, University of California, Davis CA 95616 and USDA Forest Service, Redwood Sciences Laboratory, 1700 Bayview Dr., Arcata, CA 95521, email: kpope@ucdavis.edu, (530) 794-9448; Hartwell H. Welsh, Jr., USDA Forest Service, Redwood Sciences Laboratory, 1700 Bayview Dr., Arcata, CA 95521; email: hwelsh@fs.fed.us, (707) 825-2956.

Abstract: For the past four summers (1999-2002) we have sampled lentic habitats in wilderness areas of Northern California to examine the relationships between native amphibian distributions and introduced salmonids. Most or all water bodies in eight wilderness areas (six in the Klamath Bioregion and two in the southern Cascades Bioregion adjacent to Lassen National Park) were surveyed. Data was collected on faunal composition, substrate, hydrology, vegetation, and environmental conditions. As of August 2002 we have surveyed 1200+ lentic sites across these eight wilderness areas and on nearby national forest lands. We have detected eight amphibian species and three introduced salmonids. Preliminary analysis indicates that populations of palatable amphibians were either depressed or absent in a significant number of water bodies supporting either rainbow trout (Oncorhynchus mykiss), eastern brook trout (Salvelinus fontinalis) or both, whereas non-palatable amphibian populations, such as those in the genus Taricha and Bufo, appeared unaffected by fish. The Cascades frog (Rana cascade) and the long-toed salamander (Ambystoma macrodactylum) appear to be particularly vulnerable to population reduction or elimination due to fish.