ABSTRACTS OF PRESENTATIONS FOR THE SPRING 2005 MEETING

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Oral Presentations

Asian Carp Symposium

Origin and Perspectives of the National Triploid Grass Carp Inspection and Certification Program

Vincent A. Mudrak* U.S. Fish and Wildlife Service, Warm Springs, GA 31830

Asian grass carp (Ctenopharyngodon idella) were introduced into the United States in 1963 by the U.S. Fish and Wildlife Service (USFWS). The goal was to find a biological alternative to the use of chemicals as a control measure for invasive aquatic plants. Most scientists and managers of the 1960s focused on the positive aspects of the introduction. But the original premise, that grass carp life history requirements would preclude reproduction in open waters of the United States, proved false, and grass carp became established in some rivers. In order to control the proliferation of grass carp, studies led to the development of triploid grass carp, which contained three sets of chromosomes, and which were determined to be reproductively non-functional. Additionally, during the 1980s, the USFWS worked with the aquaculture industry and instituted a process to inspect grass carp for ploidy. The USFWS agreed to certify grass carp that were destined to go to states that would only accept grass carp that were certified as non-diploid by the U.S. Fish and Wildlife Service. Then in the early 1990s, because of budgetary shortfalls and changing priorities, the USFWS considered the withdrawal from active participation in the inspection and certification process. But state managers desiring the continued use of triploid grass carp sought help, and in 1995, the 104th Congress responded by passing a law that authorized the USFWS to collect fees to administer a certification program. The resultant USFWS program embraced quality assurance standards for inspectors and producers, and is presently known as The National Triploid Grass Carp Inspection and Certification Program.

Keywords: Asian, Carp, triploid, government,

Dietary overlap of Asian carp and native filter feeding fishes in the Upper Mississippi River System

Chick, J.H., Sampson, S.J., and Pegg, M.A. Illinois Natural History Survey

Bighead and silver carp became established in the Mississippi River during the 1980’s, and have been spreading through the drainage basin since that time. Data from the Long Term Resource Monitoring Program suggests that these species became established in the Upper Mississippi River System in the early 1990’s. Both species are filter feeders, consuming zooplankton and phytoplankton, and therefore have the potential to compete with native filter-feeding fishes including paddlefish, bigmouth buffalo, and gizzard shad. We collected dietary samples from the two Asian carp species and the three native filter-feeding fishes during the late spring of 2002 and 2003. We sampled fish and zooplankton in backwater lakes because all five species are known to congregate in these habitats during the spring, allowing for dietary comparisons from fish feeding in similar locations. Dietary overlap was greatest among bighead carp, silver carp, and gizzard shad. Rotifers dominated the diet of all three of these species, whereas bigmouth buffalo and paddlefish primarily consumed larger zooplankton (e.g., copepods and cladocerans). Our results suggest that of the native filter-feeding fishes in the Upper Mississippi River system, bighead and silver carp have the greatest potential for negative interactions with gizzard shad.

Keywords: Asian carp, dietary overlap, filter-feeding fishes, zooplankton

THE U.S. ASIAN CARP INDUSTRY: ECONOMIC VALUE AND IMPORTANCE

Engle*, C.R. and N.M. Stone. Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff

The top four finfish species cultured worldwide, in terms of volume of production, are Asian carps. This group of fish has been introduced into many different countries and constitutes an important source of food for many people across the globe. Grass carp (Ctenopharyngodon idellus ) were introduced into the U.S. in 1963, bighead (Hypophthalmichthys nobilis) and silver (Hypophthalmichthys molitrix) carp in the 1970s and black carp (Mylopharyngodon piceus) were introduced somewhat later, in the 1980s. The U.S. Fish and Wildlife Service, the Arkansas Game and Fish Commission, Auburn University, and the Illinois Natural History Survey were among the pioneers that conducted research on culturing Chinese carps and promoted their culture on private fish farms. As investigators sought solutions for two critical issues of that era, clean water and the food supply for a growing world population, early research focused on using the carps in polyculture to treat wastewater and to turn agricultural wastes into animal protein. In spite of their 30-year history in the U.S., a great deal of controversy has emerged over the presence of these fish species in U.S. waters. The controversy has extended to attempts to prevent the interstate shipment of various Asian carps as fish farmers transport fish from their farms to Asian grocery stores for live sales. Asian carp are commercially traded in the U.S. on a significant scale. Farmers have a substantial investment in broodstock and in the infrastructure to produce, haul, and sell carp. Restrictions on production and sale of Asian caps will affect large numbers of small businesses. The economic impact of destroying this industry will represent millions of dollars of economic losses. Bighead carp are commonly co-cultured in catfish ponds and with other fish species in the U.S. Budgets have shown that bighead carp generate an additional $192/acre. Sales of bighead carp have enabled catfish farms to survive times of low prices by providing an alternative crop to sell to diversify farm revenue. Bighead are hauled from fish farms to New York, Chicago and other major cities. Based on informal polls in Arkansas and Mississippi, farm-gate sales in 2003 were estimated at $5.36 - $6.5 million/yr with an additional revenue of $6.09 - $21.7 million/yr through the supply chain. Moreover, closures of catfish farms that did not have the risk reduction benefits of bigheads, would have incurred losses of $22 million, for a total economic impact of $135 million/yr. This would equate to losses of 1,026 jobs in the Delta regions of the two states. Grass carp are used in many states throughout the U.S. for aquatic weed control. It has been estimated that use of grass carp for weed control costs about $45-$125/acre while other means will cost from $100 - $26,200/acre to control aquatic weeds. Survey data show that 42% of catfish farms stocked grass carp in foodfish ponds. Black carp are used to control snails in fish ponds. A recent study estimated the economic effect of restricted access to black carp on hybrid striped bass farms. The effects stem from the higher mortality of fingerlings and reduced marketability of bass foodfish. Net farm revenues decreased by 58% to 100% with the greatest decreases on the smaller farms.

Keywords: Bighead carp industry, grass carp industry, black carp, economics

National Standards for Triploid Grass Carp Inspection and Certification Program

Heil*, N.P., and Hickson*, B.H. U.S. Fish and Wildlife Service (USFWS) Warm Springs, GA

The U.S. Fish and Wildlife Service (USFWS) offers a triploid grass carp inspection service for natural resource agencies in the United States and in other countries, to help States and others protect their aquatic habitats. The inspection program is to provide assurance to these agencies, and others concerned about protecting aquatic resources, that shipments of grass carp alleged to be all triploid, do not, within the confidence limits of the inspection program, contain diploids. A set of standards have been developed to provide quality assurance which the USFWS will use to provide consistency and fairness in dealing with different circumstances encountered in the implementation of a National Triploid Grass Carp Inspection and Certification Program. The critical elements of the Program are described in four categories: (1) Standards for USFWS Inspectors; (2) Standards for Grass Carp Producers; (3) Checklist for Inspectors and Producers; and (4) Standards for Collection and Fees. The standards are available at web address: http://warmsprings.fws.gov/FishHealth/index.html.

Keywords: Grass, Carp, Triploid, Standards, USFWS, Certificatio

Development of a National Asian Carp Management Plan

Conover*, Greg C.

The Aquatic Nuisance Species Task Force requested the U.S. Fish and Wildlife Service organize an Asian Carp Work Group and lead the development of a national management and control plan for bighead, black, grass, and silver carp. Representatives from federal, state, and Canadian natural resources management agencies, Native American tribes, industry professionals, universities, and non-governmental organizations are working together to draft the plan. Broad and diverse representation of stakeholders on the Work Group is intended to bring multiple interests together to collaborate on effective methods of prevention and control to protect native ecosystems from potential impacts of these species. The Work Group has developed goals and objectives for the plan and is beginning to draft the plan. This comprehensive plan will include a variety of control strategies and specific actions to be taken by federal, state, and local agencies, and by the private sector to limit the further spread, prevent additional introductions, and reduce the impacts of existing populations of Asian carps in the wild. Once drafted, the Working Group will lead efforts to solicit public comments and refine the draft management plan as necessary. The final management plan will then be submitted to the Task Force for implementation approval.

Keywords: Asian carp management

Telemetry and habitat characterization of bighead and silver carp in the lower Missouri River.

Chapman*, D.C.

Telemetry and depth temperature archival tags were used to determine habitat selection and behavior of bighead (Hypophthalmichthys nobilis) and silver carp (H. molitrix) in the Missouri River from fall 2002 – summer 2004. A variety of habitat characterization techniques were used to characterize the habitats selected by the fish, including water quality measurements, bathymetry, substrate classification, acoustic imaging, and acoustic Doppler current mapping. Both species were active during cold-water periods. Both species mostly occupied the midwater zone in coldwater periods, but bighead carp sometimes came to the surface, especially at night. Fish generally used deep water with low velocity. More than 90% of fish locations, all months, were over 3 m deep. Many fish moved upstream during high water events during the warm months. Movements of over 150 miles within a season, both upstream and downstream, were recorded. Silver carp tended to move longer distances than bighead carp. Bighead carp used tributaries more than silver carp. Among Missouri River sites, chlorophyll concentrations at silver carp locations were higher than at bighead carp locations or the main channel of the river. Turbidity at bighead carp locations was lower than that of the main channel.

Keywords: Asian bighead silver carp habitat telemetry turbidity chlorophyll behavior

Morphometrics for the determination of sex and hybridization in Hypophthalmichthys species.

Chapman, D.C. USGS Columbia Environmental Research Center, Columbia, MO.

Bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) apparently hybridize readily in the wild in the United States. Five percent of Hypophthalmichthys captured in the Missouri River in the summer of 2005 were nominal hybrids. Hybrids can be difficult to identify because they can closely resemble either of the parent species, and because the hybrids are fertile and backcrosses may exist. Incorrect identification hybrids can compromise research findings. Various authors have had success in identification of the sex of Hypophthalmichthys using the ridges on the pectoral fins, but other researchers have found that those secondary sexual characteristics are not always adequate, especially during periods when the fish are not sexually active. We measured several morphometric parameters on a large number of fish to determine which parameters would be most useful in determining hybridization and the sex of Hypophthalmichthys. Genetic analysis was used to verify the hybridizaton in a subset of samples.

Keywords: Asian bighead silver carp hybrid gender sex morphometrics

QUALITY ASSURANCES WITHIN TRIPLOID GRASS CARP INDUSTRY

Freeze, M. Keo Fish Farm, Keo, AR

Quality control within the triploid grass carp industry is assured not only by the USFWS but also by the triploid grass carp industry itself. Failing a USFWS inspection is not only a major embarrassment; it creates economic problems for the farm that fails if customers are waiting or in route to pick up scheduled fish. Besides the progressive USFWS fine, each fish in a failed certification must be individually retested before another certification can be rescheduled. Normally fish shipments are tightly scheduled and such an event can wreck havoc with such schedules.

The triploid grass carp industry also polices the illegal transportation of grass carp. An unscrupulous individual that is shipping diploids into a triploid state is taking dollars away from legitimate farms and such incidents are quickly reported by the industry to appropriate officials. The shipment of any grass carp into states that currently prohibit all

grass carp is also reported as such activity serves as an impediment to the eventual legalization of sterile triploid grass carp in that state. Many private individuals that want to illegally import grass carp into such states are discouraged after legitimate farms explain state laws and the Lacy Act to these misguided people.

Keywords: grass carp quality assurance

Asian Carp Impacts

Jerry L. Rasmussen, MICRA, P.O. Box 774, Bettendorf, IA 52722

The invasion and spread of Asian carp (silver and bighead) into many mainstream rivers and tributaries of the Mississippi River Basin has occurred at an alarming magnitude and rate. The biological impacts of these large (100+ lb.), prolific invaders on native fish species and their habitats has not been well documented scientifically, but observation and experience with other carp invasions raises significant concerns for the long term. More than 100 years after the introduction of the European or common carp this species remains the number one most troublesome fish species to fish and wildlife managers in the Basin. The bighead and silver carp have quickly achieved second and third place on this most troublesome list, followed by yet another Asian carp species, the black carp. The black carp was introduced to control snails in fish culture ponds, and has recently found its way into the wild where biologists are gravely concerned for the welfare of the Basin's endangered snail and mussel species that could fall prey to the invasive black carp. This paper explores the biological, physical, emotional and economic impacts of the Asian carp invasion on fish and aquatic organisms, fishing, recreation, and fish and wildlife management in the United States.

Oral Presentations

Defining a Catch and Release Research and Education Model Symposium

Hooking Mortality of Deep and Shallow Hooked Striped Bass Under Different Environmental Conditions In Chesapeake Bay

Lukacovic*, Rudolph. Maryland Fisheries Service, Annapolis, MD

Catch-and-release fishing for striped bass along the Atlantic coast has grown substantially as have concerns about release mortality. Physical injury and stress are the two major causes of death of released fish. Anatomical location of the hook wound is the single most important factor, but temperature, salinity, and fish size are also risk factors. Trials comparing hook styles were run during 1999’s fishing season. Standard J-hooks were used the first day of each trial and non-offset circle hooks were used the second. Striped bass were caught by chumming and were kept in holding pens for three days. Striped bass caught on J-hooks were deep-hooked 17.2% of the time throughout the season but were deep-hooked only 3.4% with circle hooks. Mortality rate of striped bass deep-hooked with J-hooks was 53.1% and 23.5% with circle hooks. Mortality of shallow-hooked fish was 3.5%. Shallow-hooking mortality when air temperatures were low was 0.8%, but was 17.2% when air temperatures ranged above 35C. Combining deep-hooking rates with deep-hooking mortality for each style of hook indicates a reduction in mortality from 9.1% to 0.8% using circle hooks.

Keywords: striped bass circle hooks catch-and-release mortality deep-hooking

The National Symposium on Catch and Release in Marine Recreational Fisheries: Progress and Issues Since 2001

Lucy*, J. A. VA Institute of Marine Science, College of William and Mary, Gloucester Pt., VA

The National Symposium on Catch and Release (CR) in Marine Recreational Fisheries was held December 1999. Participants developed “Action Agendas” for research and education priorities. However, since 2001 effort in North America shows little coordinated effort. For example, there have been diverse studies on snook, red drum, spotted sea trout, striped bass, white and blue marlin, reef fish venting, white seabass (CA), salmon, trout, sunfish, walleye, live weigh-in tournaments and physiological-behavioral impacts of CR. Overviews of research effort include meta-analysis of circle hook research and a review of angling mortality studies pertaining to no-take reserves. Neither are educational efforts coordinated, the Catch and Release Association for FL Fishing Guides, “Tips for Saltwater CR (from Federation of Fly Fishers), fishing ethics and circle hook materials (Sea Grant Programs and Boat U.S.), “Released Salmon—Do They Survive? (video, Canada), and circle hook outreach (largely targeting billfish tournaments). Starting in 2001, Australia developed a national research and education program, “The National Strategy for the Survival of Released Line Caught Fish.” This program offers a model for consideration by the US. Highlights of CR research and education projects on both continents will be discussed, along with suggestions for better coordinating research and education productivity.

Keywords: catch and release, research, education, North America, Australia

Evaluating the physiological and physical consequences of capture on post-release survivorship in large pelagic fishes

Skomal, G.B.* Massachusetts Marine Fisheries, Oak Bluffs, MA

Sharks, tunas, and billfishes are exploited by extensive recreational and commercial fisheries throughout the world. Quotas, minimum sizes, and bag limits imposed by state, federal, and international management bodies result in the mandated release of a high, yet poorly quantified, number of large pelagic fishes annually. Evaluating post-release survivorship in these fishes is difficult because standard methods are simply not applicable to large oceanic animals. Post-release mortality in fish is directly related to the acute and chronic effects of physiological stress and physical trauma. Exhaustive exercise and time out of water cause physiological stress, which can be quantified in large pelagic fishes through the sampling of blood and muscle biochemistry. Fishing gear and handling cause physical trauma, which is manifested as external and internal tissue and organ damage. Gross examination and histopathological sampling of tunas, sharks, and billfishes can be used to assess physical trauma and to infer post-release survivorship. Moreover, these methods have shown that hook retention can cause chronic systemic disease that may lead to delayed mortality. Conventional, ultrasonic, and satellite tagging can be used to assess recovery and post-release survivorship in large pelagic fishes exposed to the physiological stress and physical trauma associated with capture.

Keywords: sharks, tunas, billfishes, physiological stress, physical trauma, post-release survivorship

Post-release mortality of blue marlin and white marlin caught in the western North Atlantic recreational and commercial fisheries

Graves*, J.E., Kerstetter, D.W, and Horodysky, A.Z. Virginia Institute of Marine Science, College of William and Mary

Atlantic blue marlin and white marlin are caught in directed recreational fisheries and are taken incidentally in pelagic longline fisheries that target tunas and swordfish. Both species of marlin are seriously overfished. Currently, most blue marlin and white marlin caught by recreational anglers are released alive, and U.S. commercial fishermen are required to release all billfish whether they are dead or alive. Recently, member nations of the International Commission for the Conservation of Atlantic Tunas (ICCAT) adopted a binding management measure requiring the release of all live blue marlin and white marlin taken in longline and purse seine operations. In order for these measures to reduce overall fishing mortality, fish must have a reasonable chance of survival following release. We employed short duration (5 - 10 day) pop-up satellite archival tag technology to evaluate survival of white and blue marlin released from recreational and pelagic longline fisheries. Our results indicate that release of live animals will substantially reduce fishing mortality of both species in both fisheries. Furthermore, the use of circle hooks appears to significantly reduce white marlin mortality in the recreational fishery.

Keywords: blue marlin white marlin post-release mortality

Measuring short-term catch and release mortality of tarpon in Boca Grande Pass, FL through the use of ultrasonic tagging techniques

Guindon*, K.Y., C.R. Powell, and L.R.R. Barbieri. Florida Fish and Wildlife Conservation Commission, Florida Fish and Wildlife Research Institute, St. Petersburg, FL 33701

The number of tarpon tags (permits) sold and used each year in Florida has been used to estimate annual tarpon fishing mortality due to harvest; however, determining annual fishing mortality using tags sold is unrealistic for a predominantly catch-and-release fishery. The objective of this study is to obtain current estimates of catch-and-release mortality rates for tarpon in Boca Grande Pass using ultrasonic telemetry. Tarpon landed on fishing charters were tagged with ultrasonic transmitters and tracked for up to 6 hours immediately following release. Of the 41 tagged tarpon, four were unconfirmed mortalities inferred from movement patterns and three were visually confirmed mortalities, all caused by shark attacks. The catch-and-release mortality rate evaluated for this study is 17.1% (7 out of 41). Statistical comparison showed no significant difference between jig- and live-bait fishing methods on catch-and-release mortality rates in Boca Grande Pass. No association between tackle used, hook placement, or fight time and tarpon catch-and-release mortality could be detected; however, the condition of the fish at time of release may affect survival. Tagging studies can be a valuable tool for estimating post-release mortality of game fish, especially for large species that might be difficult to maintain in floating pens or tanks.

Keywords: Tarpon tagging catch-and-release

Effect of Hook Removal on Recapture Rates on 27 Species of Angler-caught Australian Fishes

Wilde*, G. R., and W. Sawynok. Texas Tech University, Lubbock, TX, and Infofish Services, 142 Venables St., North Rockhampton, QLD, Australia.

We used data from a cooperative angler tagging program to assess the potential benefit of leaving hooks in fish captured and released by anglers. We assembled 248,010 records for 27 species of Australian fishes. Hooks were left in only 1.1% of released fish and the overall recapture rate was 8.8%. We used relative risk, the probability of an event (recapture) in a treatment group (those with hooks not removed) divided by the probability of an event in a control group (those with the hook removed), to assess the potential effects of leaving hooks in released fish. Relative risk ranged from 0.30 to 7.6, but did not differ significantly from 1.0 in any species. Thus, there was no evidence that hook removal affected recapture probability. Pooling results across all species yielded an overall relative risk of 1.18 (95% confidence interval, 1.02 to 1.36), which suggests that the recapture rate of fish in which hooks were not removed prior to release was marginally greater than that for fish released without hooks. Our results indicate there is no substantial benefit, nor adverse affect, of hook removal on recapture rates, which can be considered as a surrogate measure of survival of released fish.

Keywords: catch-and-release, hook removal, survival

Conceptual Models for Studying the Survival of Fishes Caught and Released by Anglers

Wilde*, G. R. Texas Tech University, Lubbock, TX.

A large, and growing, number of studies have examined factors that influence the survival of captured and released fishes. An important limitation of this body of literature is the lack of conceptual, or other models, that allow results of individual studies to be placed into a broader perspective. In this paper I (1) demonstrate the utility of simple conceptual models that describe survival of angler-caught and released fishes using largemouth bass as an example, and (2) provide a general framework for synthesizing results of diverse studies. Finally, I argue for development, validation, and application of quantitative models for predicting survival and show how these models might be quickly constructed.

Keywords: catch-and-release, conceptual models, survival

Conceptual Model for Reduction in Growth Performance of Fishes Caught and Released by Anglers.

Pope *, K. L., and Wilde, G. R. Texas Tech University, Lubbock, TX.

Many studies have examined factors that influence the survival of fishes caught and released by anglers. These studies document varying amounts of mortality, which indicates that in some instances, the act of catching and releasing fishes is stressful. Thus, in instances where fish are stressed, but not mortally wounded, we expect to observe sub-lethal effects, such as a reduction in growth rate. In this presentation, we will (1) present results that compared growth rates for caught-and-released and un-caught largemouth bass Micropterus salmoides and rainbow trout Oncorhynchus mykiss, and (2) discuss a conceptual model of growth for fishes caught and released by anglers.

Keywords: angling growth model

Oral Presentations

Contributed Papers Session

Environmental Assessment

The 316(b) Regulation: Fisheries Biologist Right to Work Law

Heitman, J. F.*, AMERICAN AQUATICS, INC.

In July 2004 EPA finalized an updated regulation (CWA Section 316(b)) that deals with power plants with cooling water intake structures that have a design capacity of at least 50 MGD. The regulation sets performance criteria for impingement and entrainment of aquatic organisms of 60-80% and 70-90&, respectively, from a calculated baseline flow. Of particular interest to fisheries workers is that there is extensive work associated with larval fish, adult fish and fish restoration associated with this new regulation. Not since the 316 (a & b) work of the 1970’s has there been an environmental regulation that so directly impacts fisheries workers. In this presentation I will review and discuss opportunities for workers and agencies pertaining to the 316(b) regulation.

Keywords: CWA 316(b) Fisheries Biologists environmental regulations

Assessing the Ecological Recovery of the Pigeon River Using Benthic Invertebrate Surveys (B-IBI) in Cocke County, TN and Haywood County, NC (1987-2005)

Wilson, MJ *, JL Wilson and JA Coombs. University of Tennessee, Knoxville, TN.

The Pigeon River Restoration Project (PRRP) is an ongoing project to help restore the ecological integrity of the Pigeon River as is feasible while maintaining economic growth along the river. The benthic invertebrate assessment is just one aspect of a larger restoration project. Historical Benthic Index of Integrity (B-IBI) data is available for both the Tennessee and North Carolina portions of the Pigeon River. Current B-IBI samples for 2004 were collected in March and August. Additional samples will be taken in March and July of 2005. This assessment will include the creation of a database with a comprehensive species list of all aquatic invertebrates collected on the river. Improvements in the fauna are expected due to the reduction of emissions and the upgrade of equipment at Blue Ridge Paper Products mill in Canton, North Carolina. We have witnessed improvements in the fish communities, with multiple species re-colonizing the Pigeon River from its tributaries. There should be a corresponding improvement in benthic communities. I will try to assess this ecological recovery in the benthic invertebrate assemblage to aid the ongoing habitat assessment and restoration efforts on the Pigeon River. * I would also be interested in presenting a poster if there is not available space for my presentation. Thank you! Melinda

Keywords: Benthic Invertebrate Assemblage Riverine Habitat Assessment Assess Ecological Recovery of River Pigeon River Restoration Project Cocke County, Tennessee Haywood County, North Carolina

Lake bed accretion and patterns of sedimentation affect lake morphometrics and fish communities in Lake Texoma, Oklahoma

Lyday*, C. L., Patton, T. M., and Morel, J. Department of Biological Sciences, Southeastern Oklahoma State University, Durant, OK.

Lake Texoma is a 36,000 ha reservoir located in northern Texas and southern Oklahoma. It was completed in 1944, and upper reaches are now experiencing significant sedimentation and accretion, resulting in isolation of coves and a reduction of reservoir surface area. In this study, we are determining (1) the amount of reservoir surface area lost to accretion, (2) morphometric changes in areas of high sedimentation, and (3) the impacts of these processes on fish community structure. We are using GIS technology to address changes in surface area, standard limnological measurements to address morphometrics, and experimental gill nets and electrofishing to characterize the fish community. Preliminary analyses indicate that a substantial area of the reservoir has experienced accretion above the water level, shoreline development has increased, and numerous areas of the lake have lost connectivity to the main body of water. With these changes, the fish community has become fragmented, and more representative of a riverine-like community; it is likely that the relative abundance of game fish has become reduced, while the relative abundance of non-game fish has increased. These changes will likely impact the quality of the sport fishery and the local economy in this area.

Keywords: sedimentation accretion shoreline development fragmentation isolation

Assessing Macroinvertebrate Communities in Streams Impaired by Fecal Coliform in the Vicinity of Lake Anna, Virginia.

Cramer*, R. L., and C. Gowan. Environmental Studies Program, Randolph-Macon College, Ashland, VA

Citizen monitoring programs are used throughout Virginia to detect impaired aquatic ecosystems. However, one major source of contamination, fecal coliform, cannot be measured easily by citizens. About 7,726 km of the state’s rivers currently fail to meet water quality standards for fecal coliform bacteria, a result livestock, leaky sewage systems, wildlife, and pets. A simple method allowing citizens to detect fecal coliform would aid professionals in their efforts to protect Virginia rivers. The goal of this study was to determine if macroinvertebrates, already commonly used by citizen monitors, could also be used as indicators of fecal coliform. Six impaired and five unimpaired streams in the vicinity of Lake Anna were sampled using methods developed for use by citizens. Stream health scores for impaired streams were significantly lower (average = 16.5 on a scale of 0-24) than scores for unimpaired ones (average = 19.8). Streams impaired by fecal coliform had significantly more tolerant organisms and more non-insects. For impaired streams, stream health scores were negatively correlated with the percentage of time Virginia Department of Environmental Quality water samples exceeded water quality standards. This research suggests that macroinvertebrate monitoring may offer a way for citizens to detect fecal coliform impairment.

Keywords: fecal coliform stream health citizen monitoring

Reservoir Management

Striped Bass Eggs: The White Perch’s Caviar?

Harris*, J.L., and Ney, J., Virginia Polytechnic Institute and State University, Blacksburg, VA.

White perch (Morone americana) were introduced into Kerr Reservoir, Virginia in the late 1980’s and have subsequently become very abundant. There is concern that the perch are affecting recruitment of sportfishes, especially the self-sustaining striped bass (Morone saxatilis), by eating their eggs and larvae. To address ovivory, white perch of all sizes were collected in 2004 from the Roanoke River, the major spawning tributary of striped bass in Kerr Reservoir, and their stomach contents were examined for sportfish eggs and larvae. Perch collection took place in early May at multiple locations on the Roanoke River coinciding with the peak striped bass spawn. First-year results showed that white perch ate primarily chironomids and ephemeropterans, but egg predation did occur. Much of the predation was on white perch eggs (as high as 7.2 % by weight), but striped bass eggs (never above 2 % by weight) did appear in the perch’s diets at certain locations. Larval striped bass were not found in white perch diets. To determine if white perch egg predation affects striped bass recruitment, the fraction of eggs consumed must be determined.

Keywords: White Perch Striped Bass Kerr Reservoir

Environmental and Genetic Influences to Hatching Timing of Florida and Intergrade Largemouth Bass

Rogers, M.W., and Allen, M. S. University of Florida, Department of Fisheries and Aquatic Sciences Porak, W. Florida Fish and Wildlife Conservation Commission

We evaluated the relative contribution of genetic versus environmental factors to the timing of largemouth bass reproduction. Florida strain broodstock from Lake Okeechobee, FL and intergrade broodstock from Lake Seminole, FL were allowed to spawn in experimental ponds located in central Florida (i.e., keeping environmental conditions similar prior to spawning). We compared pond results to observed hatching distributions at Lakes Okeechobee and Seminole during the same year. First hatching and median hatch dates were earlier for Florida-strain fish (prior to February 13th in all ponds, median hatch date February 28th) than for intergrade largemouth bass (all after February 24th, median hatch date March 11th) in experimental ponds . Water temperatures at median hatch date were generally similar for Florida and intergrade fish (14-19^o C). Florida largemouth bass had longer hatching duration than intergrade fish in experimental ponds (16-72 days and 7-11 days, respectively). Similar to our pond results, age-0 fish at Lake Okeechobee exhibited earlier hatching, earlier median hatch date, and longer hatching duration than fish at Lake Seminole, and water temperatures at median hatch date were similar. Our results suggest that intergrade largemouth bass genetics may facilitate punctuated spawning, thus maximizing the growing season for the majority of offspring.

Keywords: largemouth bass, hatching timing, hatching duration

Temporal and spatial variability in trace element signatures of juvenile striped bass otoliths.

Schaffler*, J.J., and Winkelman, D.L. Oklahoma State University, Stillwater, OK

The elemental composition of fish otoliths represents a permanent record of the environmental conditions an individual has experienced as trace elements, incorporated into the growing surface of the otolith, reflects the physical and chemical characteristics of the ambient water. We tested the utility of trace element signatures in otoliths as natural tags of the river of origin of juvenile striped bass collected from the Red and Washita River arms of Lake Texoma. We were able to detect 17 elements in otoliths of juvenile striped bass during all three years. All otoliths were standardized to 40% Calcium. Phosphorus was the strongest predictor of river of origin in during 2002; however, phosphorus is biologically unstable. Strontium (Sr₈₈) was the next strongest predictor. During 2002, our classification rate was 83%. During 2003, Lanthanum, Copper, and Strontium were all useful in predicting the river of origin. During 2003, our classification rate was 84%. During 2004, Rubidium, Neodymium, Phosphorus, Vanadium, and Strontium (Sr₈₆) were all useful in predicting the river of origin. During 2004, our classification rate was 88%.

Keywords: striped bass otolith trace element analysis

First-year Contribution to the Year Class and Growth of Largemouth Bass Stocked at 50 mm and 100 mm into the Arkansas River

Heitman*, E., Racey, C., and Lochmann, S. University of Arkansas at Pine Bluff.

Few evaluations of largemouth bass stockings have been conducted in rivers. Oxytetracycline-marked largemouth bass Micropterus salmoides, averaging 50 or 100 mm TL, were stocked into backwater areas of pool 4 of the Arkansas River in the summer of 2003 at densities of 309 and 62 fish/ha, respectively. Contributions to the year class of 50-mm (13.2%) and 100-mm (13.8%) stocked largemouth bass were not significantly different in fall 2003. Stocking contributions of 50-mm (17.6%) and 100-mm (17.2%) largemouth bass were also not significantly different in spring 2004. Contributions were not significantly different between seasons. Mean (SD) total lengths for 50-mm stocked, 100-mm stocked, and wild fish were 164 (38), 172 (39), and 162 (43) mm, respectively, in fall 2003, and 187 (37), 185 (43), and 179 (44) mm, respectively in spring 2004. There were no significant differences among mean lengths for stocked or wild fish in either season. Stocking five times as many 50-mm as 100-mm largemouth bass yielded similar contributions. Largemouth bass stocked into the Arkansas River had one-year stocking contributions similar to largemouth bass stocked into reservoirs and lakes.

Keywords: largemouth bass, supplemental stocking, rivers, contribution

Exploitation of Nile Tilapia in a Closed System, Public Fishing Reservoir in Northern Arkansas

Henry*, S.D. and Barkley, S.W. Arkansas Game and Fish Commission (AG&FC), Jonesboro, AR. Johnson, R.L. Department of Biological Sciences, Arkansas State University, State University. AR.

Nile tilapia, Oreochromis niloticus, have been stocked as a forage species annually since 2001 in Lake Hogue of Northeast Arkansas, a 101 ha., closed system public fishing reservoir. A mail-in tag study was implemented in 2003 to determine total estimated harvest, contribution of tilapia to the lakes sportfish fishery and impact of angler harvest on tilapia reproduction. Estimates of harvest were corrected for tag loss, tag-induced mortality and non-reporting of tags by anglers. Angler hours were compared for anglers targeting and not targeting tilapia. Sportsmen harvested an estimated 82% of the stocked tilapia using traditional fishing methods and with dip-nets. Anglers primarily targeting Nile tilapia fished significantly longer than individuals who incidentally caught tilapia while fishing for other species. Analysis of the economic impacts of stocking Nile tilapia demonstrated a cost/benefit ratio of 0.38. Harvest of Nile tilapia did not apparently interfere with the management goal of serving as a forage species for gamefishes. Tag return data strongly suggested that anglers harvested Nile tilapia over the traditional panfish species (e.g., bluegill, redear sunfish) at mid-day during the hot summer months, when fishing pressure had been traditionally low.

Keywords: Exploitation Nile tilapia Reward tag study Estimated 82% harvest

Contribution of Stocked Fingerling Walleyes in Lake James

Besler*, D.A. North Carolina Wildlife Resources Commission

Approximately 30,000 walleye Sander vitreus fingerlings were marked with oxytetracycline hydrochloride (OTC) and stocked in Lake James in May 2000–2002 to measure the contribution of stocked fingerlings to the sport fishery. Gillnetting was conducted during October–November in 2001–2003. Total catch of age-1 walleyes varied between years (range, 51–94). The percent of marked age-1 walleyes was consistently low and ranged from 2.1–3.7%. The proportionate contribution reported for all years was substantially below the criteria used to determine stocking success. It is recommended that fingerling walleye should not be stocked in Lake James.

Keywords: Walleye OTC Stocking

Using an Angler Mail Survey to Assist in Evaluating a Slot-length Limit on a Texas Reservoir.

Bonds*, C.C., and Magnelia, S.J. Texas Parks and Wildlife Department, San Marcos, TX.

Changes in a largemouth bass population were evaluated in Georgetown Reservoir, Texas, following the implementation of a 356- to 457-mm slot length limit in 1993. The largemouth bass population was surveyed by electrofishing semi-annually from 1988 through 2004. An angler creel survey, followed by a mail survey, was conducted in 2004 to gather angler catch statistics and opinions concerning support for this length limit. Size structure, electrofishing catch per effort, and angler catch rates for largemouth bass greater than 356 mm increased moderately, but only after six years post regulation change. Evidenced by survey responses, most angler opinions were neutral concerning improvements in fishing quality (50%; N = 40) and support for the slot length limit (33%; N = 24). More tenured bass anglers (i.e., fished Georgetown Reservoir > 10 years) agreed (28%; N = 7) than disagreed (12%; N = 3) fishing for largemouth bass improved after the slot. More respondents disagreed (47%; N = 20) than agreed (28%; N = 12) when asked if they would support rescinding the slot length limit in favor of a 356 mm minimum length limit if fisheries data showed improvement in the largemouth bass population. Because fisheries and angler opinion data were largely neutral, we believe allowing a minority constituent component to share in the decision to retain the slot length limit positively influenced our agency’s credibility among Georgetown Reservoir anglers.

Keywords: largemouth bass management mail survey slot length limit

Changes in Walleye Recruitment and Growth Following a Blueback Herring Invasion

Wheeler*, A.P., C.S. Loftis, D. L. Yow. North Carolina Wildlife Resources Commission

Blueback herring Alosa aestivalis were first collected from Hiwassee reservoir in 1998. Their recent appearance has raised concerns due to negative impacts of a similar species, alewife A. pseudoharengus, on walleye Sander vitreus recruitment in Tennessee reservoirs We began monitoring the Hiwassee Reservoir walleye population with annual bottom-set gillnet surveys in the fall of 2000, and aged all walleye collected using sagittal otoliths. The successive annual surveys allowed us to track recruitment, mortality, and growth of walleye year classes since the blueback herring invasion. In addition, we used catch curves to back-calculate pre-blueback estimates of walleye recruitment. Due to low catch rates of recent year classes and sampling variability, estimates of annual mortality rates could only be calculated for the 1996-1998 cohorts and ranged from 32-43%. Total length at age has increased for each consecutive year class. Walleye recruitment declined and then nearly ceased following the blueback herring invasion. The 1996 cohort was approximately four times larger than the 1997-1999 cohorts, and recruitment has essentially failed since 2000. In response to recruitment failure, we began stocking OTC marked fingerling walleye in Hiwassee Reservoir in 2004.

Keywords: Walleye Recruitment Blueback Herring Invasion

Increases in voluntary release rate of largemouth bass of legally-harvestable size from Texas creel surveys over 1985-1999

Taylor, J.B, and Myers, R.A. Texas Parks and Wildlife

Concurrent with a large increase of popular interest in bass angling over the past few decades, anecdotal evidence indicates a strong catch and release ethic has also become more prevalent among largemouth bass (LMB) anglers. However, documentation of long-term changes in LMB voluntary release rates is lacking. Texas Parks and Wildlife conducted annual creels on five reservoirs managed with minimum-length limits for LMB (Canyon, Conroe, Palestine, Sam Rayburn ,and Toledo Bend) and two managed with protected slot limits (Lake Fork and Monticello) over varying time spans of 12-15 years from 1985-99. Voluntary release rates of LMB in legally-harvestable sizes increased significantly over time in each of the seven reservoirs, with correlation coefficients ranging from 0.62-0.96. Analysis of covariance indicated the slope of the relationship between voluntary release rate and time for Lake Fork to be significantly lower than for the other six reservoirs, and Lake Fork also had the highest voluntary release rates observed. Lake Fork has had a reputation as an exceptional fishery for trophy bass since the mid-80s, and anglers there have consistently demonstrated a high propensity to voluntarily release LMB of harvestable size. By 1999, voluntary release rates ranged from 52-98% in creels from all reservoirs examined.

Keywords: largemouth bass voluntary release creel

Otolith Ageing techniques for an invasive population of white perch Morone americana in an Oklahoma reservoir.

Kurt E. Kuklinski*, Oklahoma Department of Wildlife Conservation (ODWC), Norman, OK.

White perch (Morone americana) entered Oklahoma via the Arkansas River system and were first discovered in Kaw Reservoir in 2000. In order to determine the age structure of the invasive population, 161 white perch have been aged using annulus counts on the saggital otoliths. Whole view otolith ageing was effective for age-0 and age-1+ white perch as confirmed by sectioned view ageing (97.9% and 97.1% respectively). Whole view otolith ageing of age-2+ and older white perch was not accurate, with only 13.5% confirmed by sectioned view for age-2+ and just 25% confirmed by sectioned view for age-3+ fish. The age structure of the Kaw white perch population consists of mainly age-0 and age-1+ white perch, with few fish older than age-2+ in fall samples. Both adult and age-0 white perch were found in Keystone Reservoir, downstream of Kaw Reservoir, in fall 2004 gillnet samples.

Keywords: white perch, non-native species, age and growth, otolith

Relation between fish assemblages and native and non-native aquatic plants at Lake Izabal, Guatemala

Christian Barrientos* and Mike S. Allen Department of Fisheries and Aquatic Sciences, University of Florida, 7922 Northwest 71st Street, Gainesville, Florida 32653, USA.

We compared the abundance and community composition of fishes among five species of aquatic plants at Lake Izabal, Guatemala. Lake Izabal is the largest lake in Guatemala, Central America, and was recently invaded by a non-native aquatic weed Hydrilla verticillata. Fish were sampled with block nets (0.01 ha) using rotenone in June-July of 2004. Hydrilla had higher aquatic plant biomass than eel grass Vallisneria americana and bulrush Scirpus spp. of the same coverage area. Total fish biomass was positively related to plant biomass across all plant types. Fishes of the family Cichlidae were the most abundant in species richness and showed the highest biomass across all habitats sampled. The most common fish collected fish in all habitats and areas with no plants was the silverside Atherinella spp. Mojarra Vieja maculicauda support the primary fisheries in the lake, and we found that areas with high hydrilla coverage contained high densities and biomass of this species. Hydrilla in littoral areas of Lake Izabal is suitable habitat for fishes, containing high species richness, density, and biomass compared to other plant species present.

Keywords: Aquatic plants native Hydrilla Fish habitat Cichlidae Guatemala Izabal

VARIABILITY IN EGG CHARACTERISTICS AMONG FEMALE WHITE BASS Morone chrysops AND THE RELATIONSHIP BETWEEN EGG VOLUME AND YOLK-SAC FRY LENGTH OF SUNSHINE BASS

Lochmann*, S.E., Racey, C.R., Goodwin, K.J., and Green, C.C. Aquaculture/Fisheries Center, UAPB, Pine Bluff, AR.

Domesticated white bass Morone chrysops make possible selective breeding programs to produce sunshine bass. Besides fast growth or favorable feed conversion, selection could be based on favorable egg or fry characteristics. Eggs from 12 white bass, used to produce sunshine bass fry, were individually photographed and incubated. Average egg volume ranged from 0.316 to 0.422 mm3 and varied significantly among females (P<0.0001). Hatch rates ranged from 49% to 96%, but there was no relationship between hatch rate and egg volume. Total lipids varied from 4.03% to 6.17%. There was no relationship between egg volume and percent total lipids. The yolk-sac fry hatched from these eggs were also photographed within 3 h of hatching. Standard lengths of yolk-sac fry were less variable than egg volumes (CV=6.3%) and ranged from 2.35 to 3.62 mm. Average standard length ranged from 2.89 to 3.08 mm and also varied among females (P<0.0001). Specific female and time to hatch explained 60% of the variability in yolk-sac fry SL. Some females had egg and fry characteristics more suitable to increasing survival and

fingerling production. Selection for these characteristics in brood stock white bass females could lead to improved production of sunshine bass fingerlings.

Keywords: sunshine bass, egg volume, fry length

The demographics of retirement among state agency fisheries personnel: challenges and opportunities presented by retiring Baby Boomers.

McMullin, S.L. Department of Fisheries and Wildlife Sciences, Virginia Tech

Aging of the Baby Boomer generation has created concern among public agency administrators and policy makers that significant institutional memory and leadership ability may be lost as Baby Boomers approach retirement age. For fisheries personnel in state fish and wildlife agencies, that concern is amplified by the fact that many people were hired during the “Environmental Decade” of the 1970s and those employees now have 25 to 30 years of service. I conducted a nationwide, Internet-based survey of state fish and wildlife agency personnel to quantify the demographics of retirement and professional development needs. Twenty-five percent of fisheries professionals nationwide plan to retire by 2010 and 43% plan to retire by 2015. Forty-six percent of fisheries professionals in leadership positions plan to retire by 2010 and 77% will retire by 2015. This large turnover of fisheries professionals will challenge agencies to replace the institutional memory that will go with retiring personnel. It also offers an opportunity for agencies to address the lack of diversity in their work forces.

Keywords: Retirement, fisheries professionals, diversity

Investigation of the Effect of Size-Selective Fishing on Growth Rates in Wisconsin Bluegill Populations

Leonard,*D.M., and J.J. Ney

Both commercial and sport fishing are biased toward harvest of large specimens. Intense size-selective harvest that removes fast-growing specimens can cause genetic stunting in the population, as has occurred in marine commercial fisheries. Can sportfish harvest be both sufficiently intense and selective to depress growth potential? We addressed this question for bluegill sunfish populations in northern Wisconsin lakes, where harvest-oriented bluegill fisheries are subject to restrictive bag limits, by comparing growth in spatial and temporal data sets. Bluegills were 10-15% longer at ages 5-9 in a lightly-fished lake versus an adjacent lake with public access. Length at age 3 declined 15-45% in 10 of 15 heavily fished lakes between 1970 and 2000. These growth dynamics provide initial support for the genetic stunting hypothesis for Wisconsin bluegill populations. More such comparisons plus controlled experiments are required for confirmation.

Keywords: size-selective fishing; genetic stunting; growth rate; bluegill sunfish

The Evolution of Competitive Bass Fishing

Gene Gilliland*, Oklahoma FIshery Research Lab, Oklahoma Dept. of Wildlife Conservation, Norman, OK

Competitive bass fishing began with amateur anglers testing their skills against their fishing buddies. Seemingly limitless quantities of fish were available from our waters. Fishery mangers felt that little harm could come to these renewable resources. Early tournaments were catch-weigh-and-fillet. Then in the mid-1970s, fishery managers, tournament organizers and competitors began to embrace the concept of catch-and-release. As tournament fishing evolved into an increasingly complex sport complete with professional anglers, corporate sponsors and prime-time television coverage, so too did the care given tournament-caught bass. Using a time-line approach, I describe changes in equipment and fish-care techniques over the past 30 years which have dramatically improved the survival of bass released following tournaments, and areas needing further research and refinement. Note to Program Chair: This can be an oral presentation or a poster, whichever best fits your program.

Keywords: competitive bass tournament mortality fish-care

Effects of Livewell Conditions and Largemouth Bass Virus on Mortality of Largemouth Bass Caught in Summer Tournaments

Schramm, H.L., Jr. USGS Mississippi Cooperative Fish and Wildlief Research Unit, Mail Stop 9691, Mississippi State, Mississippi 39762 Walters, A.R. Department of Wildlife and Fisheries, Mississippi State University, Mississippi State, Mississippi 39762 Grizzle, J.M., and Beck, B.H., Southeastern Cooperative Fish Disease Project, Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, Alabama 36849 Hanson, L.A. and Rees, S.B., College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762 USA

This study evaluates the effect of improved livewell conditions on mortality and the interaction of tournament stress and largemouth bass virus (LMBV) for largemouth bass Micropterus salmoides caught in 12 summer tournaments. Improving livewell conditions by cooling water about 2-5¢ªC, adding uniodized salt (NaCl), and continuous aeration reduced initial mortality of largemouth bass from 7% to 3%. However, post-release mortality of fish held for 5 d in net pens or raceways was not reduced by the improved livewell conditions and averaged 76% for all tournament fish. The percentage of angler-caught fish infected with LMBV at the end of tournaments (14%) was significantly higher than population levels (7%). The percentage of tournament-caught fish infected with LMBV increased after capture and during the post-tournament retention period, but was significantly lower for fish from livewells with improved conditions (63%) compared to fish from control livewells (70%). Many of the fish also had bacterial diseases during the post-tournament period, so the effect of LMBV on mortality could not be determined. However, the higher mortality of both tournament and reference fish in our study compared to previous tournaments on lakes presumed free of LMBV suggests that this newly discovered pathogen influences measurement of post-tournament mortality.

Keywords: Largemouth bass, tournament mortality, livewell conditions, largemouth bass virus

Smallmouth bass tournament mortality on middle Tennessee reservoirs

Kaintz*, M.A., and Bettoli, P.W. Tennessee Cooperative Fishery Research Unit, Tennessee Technological University, Cookeville, TN (MAK); U.S. Geological Survey/Biological Resources Division, Tennessee Cooperative Fishery Research Unit, Cookeville, TN (PWB)

Few tournament mortality studies have distinguished mortality rates among black bass species; however, recent studies have found that black bass species respond differently to tournament angling. In particular, smallmouth bass are thought to be more susceptible to tournament mortality than largemouth bass. In addition, when initial mortality rates are low there is a common misconception among anglers and organizers that total tournament mortality is also low. Providing information on delayed mortality will allow for a more accurate assessment of the impact of tournament fishing on smallmouth bass. This study was designed to measure initial mortality resulting from tournaments on Center Hill and Percy Priest reservoirs in middle Tennessee and measure delayed mortality of smallmouth bass on Dale Hollow Reservoir under simulated tournament conditions. Smallmouth bass captured with conventional hook-and-line tackle were held and monitored in a large net pen or externally tagged with an ultrasonic tag and float assembly and released immediately after a simulated weigh-in. Initial mortality of all three black bass species on Center Hill and Percy Priest reservoirs ranged from 0-16% and 0-23%, respectively. Delayed mortality of smallmouth bass at Dale Hollow Reservoir ranged from 0-27% at water temperatures ranging from 9-27 ºC.

Keywords: smallmouth bass, tournament, mortality

Instream Flow

An Analysis of Fish Abundance and Flow Patterns in the North Anna River, Virginia

Fowler, D. L., Virginia Department of Game & Inland Fisheries, Richmond, VA.

In order to evaluate whether additional flow reductions in the North Anna River downstream from Lake Anna would have a measurable impact on resident fish, an analysis of historical flow patterns and fish abundance in this river was undertaken. Historical electrofishing data (1981-2002) collected by Dominion Virginia Power were compared with river flow data. At least 55 fish species were collected in the North Anna River during the study period. The abundance of numerous species appeared to be influenced by river flows. Flow during spawning and early life history stages was directly correlated with the abundance of eight species during subsequent years, whereas it was inversely correlated with that of two others. Numerous other significant relationships are discussed. Results suggest that reductions in flow during spawning and early life stages, and during dry periods that generally occur from July-October, will have a negative effect on the abundance of numerous fish species found in the North Anna River. The recent reduction in the minimum release requirement at the Lake Anna Dam from 40 to 20 cfs may have already had such effects.

Keywords: fish abundance spawning flow river

Fish habitat use and community structure in regulated and unregulated reaches of a large southeastern warmwater stream.

Shea*, C., and Peterson, J.T., US Geological Survey, Georgia Cooperative Fish & Wildlife Unit, Warnell School of Forest Resources, University of Georgia, Athens, GA

River regulation and development are the foremost problems threatening fishes and other aquatic biota in the Southeastern US. Dams-- primarily constructed for power generation and water use-- have impounded more than half of the mainstem rivers in the Southeast, destroying and fragmenting critical riverine habitat. Dam operation also can influence both habitat availability and environmental stability in downstream areas. Minimum stream flow regulations are often used to protect the former. However, previous studies have shown that the flow regime can influence fish community structure and that species interactions can influence habitat use. We evaluated the fish community structure and habitat use at unregulated and hydropower regulated reaches of the Flint River in southwest GA. Daily discharge downstream of the regulated reach varied by as much as 35% of the maximum daily flow within a 24-hour period. We examined overall and seasonal species richness among and between study sites. We found significant differences in fish community structure between sites with more species occurring in the unregulated reach. Habitat use patterns at the unregulated and regulated sites also differed for small-bodied species and juvenile fishes representing various genera. These differences were presumably related to the effects of hydropower regulation on the species pool and its effect on species interactions and habitat use patterns.

Keywords: Flow regulation Fish habitat use Fish community structure

Long-Term Impacts of Bridge and Culvert Construction on Fish Communities within West Tennessee

Melville*, M.J., and Combs, D.

Currently there are close to 17,000 bridges and culverts constructed throughout Tennessee, and many are in need of repair. Bridges and culverts have many potential negative impacts on streams, including increased sedimentation, stream bank erosion, channelization, and changes in stream chemistry. The effects of bridge and culvert construction were studied on 48 streams in west Tennessee. Two 100-m stream reaches above and two 100-m reaches below were sampled at each bridge or culvert. Each of the four reaches had a 50-m buffer zone separating the reach. Instream habitat, woody debris, water quality parameters, and riparian zones were measured for each of the four reaches. Streams were sampled once by single pass techniques using a backpack electrofishing unit. Fish diversity, abundance, and richness were then compared upstream and downstream from the bridge or culvert. Based on preliminary analysis, fish communities did not appear to be negatively impacted in this study.

Keywords: bridges culverts fish communities

Influence of seasonally discontinuous surface flow on stream fishes of the Interior Highlands

Girondo*, N.M., and Gagen, C.J. Arkansas Tech University, Russellville, AR.

Relationships between discontinuity of surface streamflow and the fish communities within the Interior Highlands of Arkansas were investigated during 2004. Fish were sampled and marked during June while surface flow was continuous in nine streams draining ~2800 ha watersheds distributed among three ecoregions. Fish were sampled again during August when streams were drying and in October when continuous flow had resumed. Stream dryness was not observed for the Ouachita Mountains, but dry reaches were measured for the remaining six streams (ranging from 0 to 83 % of a 2 km study section). Species richness was similar among ecoregions. Fish densities in the Boston Mountains (driest streams) and Ozark Highlands were lower in October after surface flow resumed; whereas densities of fish in the Ouachita Mountains (no dry reaches) increased with each sample. Documented fish movement was greater in the Ouachita Mountains (mean = 188 m) than the Ozark Highlands (mean = 152 m) or Boston Mountains (mean = 135 m) (x2 40.7, p = 0.03). Recapture rates were higher in the Ouachita Mountains (6.2%) than the Boston Mountains (1.8%). Thus, dry reaches during the growing season were associated with increased mortality and decreased movement without substantial effects on species richness. We argue that habitat assessments in these types of ecoregions should include measures of stream dryness.

Keywords: stream flow dryness drying discontinuity community movement

Paddlefish Biology

Assessment of Overfishing in a Commercial Paddlefish Fishery

Scholten*, G.B. Tennessee Wildlife Resources Agency, Nashville, TN Bettoli, P.W. Tennessee Cooperative Fishery Research Unit, Tennessee Technological University, Cookeville, TN

Paddlefish Polyodon spathula were collected from Kentucky Lake, KY-TN, in 2003-2004 to assess population characteristics and the likelihood of commercial overfishing. Size and age structure have been reduced and annual mortality has trebled since the most recent study in 1991. Thirty-seven percent of fish collected in 1991 were older than the maximum age we observed (age 11) and annual mortality for age 7 and older paddlefish in 2003 was high (A = 68%). Estimates of total annual mortality were negatively related to river discharge in the years preceding each estimate. The number of paddlefish harvested since 1999 was also negatively related to river discharge during the fishing season because gill nets cannot be easily deployed when discharge exceeds ~ 850 m³/sec. Large females spawn annually because all females longer than 1,034 mm eye to fork length (EFL) were gravid. No mature females were protected by the current 864 mm minimum EFL limit. Simulation modeling indicated growth overfishing was likely occurring and spawning potential ratios were below minimum levels suggested for freshwater fish populations. Recruitment overfishing probably occurs during droughts; however, variations in rainfall and river discharges have prevented the population from being exploited at unsustainable rates over long periods.

Keywords: Paddlefish overfishing

Abstract Number: 100250

Bycatch Mortality and Gillnet Size Selectivity in a Paddlefish Fishery

Bettoli*, P.W. Tennessee Cooperative Fishery Research Unit, Tennessee Technological University, Cookeville, TN Scholten, George, B. Tennessee Wildlife Resource Agency, Nashville, TN

Paddlefish Polyodon spathula in Kentucky Lake, KY/TN, were sampled using experimental gillnets and the ability of mesh size restrictions to increase spawning escapements was investigated. Factors influencing bycatch mortality were also described. Following the standards of commercial gear used in that fishery, nets were tied-down or “hobbled” (128 x 3.6 m nets were hobbled to 2.4 m; 91 x 9.1 m nets were hobbled to 7.6 m). Mean lengths of captured fish were similar among most meshes and bycatch rates of sublegal fish (< 864 mm eye-fork length) did not vary with mesh size. The range of fish girth:mesh perimeter ratios for paddlefish captured in each mesh was broad. It is unclear whether the lack of size selectivity was due to the fact that gillnets were hobbled, the unique morphology of paddlefish, or a combination of those two factors. Netting material, water temperature, and soak time were all significant predictors in a logistic regression model of initial mortality. Fish died at a higher rate in monofilament nets and observed mortality exceeded 70% at water temperatures > 20 C; most ( > 85%) paddlefish were alive when nets were retrieved in cold (< 14 C) water.

Keywords: Paddlefish gillnets mesh selectivity bycatch mortality

Zooplankton density and taxonomic composition in the Tennessee-Tombigbee Waterway: Implications for paddlefish restoration

OKeefe, D. M., OKeefe, J. C., and Jackson, D. C.

The paddlefish is a long-lived planktivorous species which has declined in many areas of former abundance. In the Tennessee-Tombigbee Waterway and its tributaries, paddlefish have disappeared from upstream impoundments and persisted in the most downstream impoundment: Demopolis Lake, Alabama. Reintroduction of paddlefish into an upstream impoundment (Columbus Lake, Mississippi) began with the translocation of eight radio-tagged adult paddlefish from Demopolis Lake during May, 2004. Zooplankton samples were taken from tailrace areas and radio-tagged paddlefish locations weekly during summer in Demopolis and Columbus lakes. Density, abundance, and taxonomic composition of zooplankton in the two lakes were compared to evaluate the quality of Columbus Lake food resources relative to a similar area that is known to support a high density of paddlefish. Three introduced zooplankters were identified in samples: Daphnia lumholtzi, Leptodora kindtii, and Mysis relicta. D. lumholtzi has larger helmet and tail spines than native cladocerans and may be less vulnerable to larval paddlefish predation. The other two species are large predators which may reduce zooplankton biomass or alter species composition. An introduced planktivorous fish, bighead carp, was also recorded during sampling. Changes in zooplankton community structure should be monitored to evaluate effects of exotics and implications for paddlefish.

Keywords: zooplankton paddlefish Tombigbee

Population characteristics and commercial exploitation of paddlefish in the Arkansas River.

Quinn,* J.W., Limbird, R.L., and F.J. Leone. Arkansas Game and Fish Commission.

We studied population characteristics of paddlefish in the Ozark Pool of the Arkansas River during a commercial fishing moratorium, and we documented harvest during a special 5-day commercial fishing season with a check station. We used large-mesh gill nets (5- and 6-inch bar mesh) to sample paddlefish during the winter months for two consecutive years. Fish captured were measured for eye-to-fork length and marked with individually numbered jaw tags. Median growth of fish recaptured after 1 year at large was 20 mm. Mark-recapture estimators suggest the adult population of paddlefish susceptible to gill nets was 5,000 fish. The Cormack-Jolly-Seber model estimated apparent survival as 1 during the commercial fishing moratorium. High survival of adult paddlefish was supported by a concurrent telemetry study. Commercial fishermen harvested 1072 paddlefish during a 5-day special season held during February 2004. Exploitation of fish greater than the 914-mm minimum length limit was 16%, and 70% of the harvest was gravid females.

Keywords: paddlefish

Sampling Techniques

Standardized Sampling in Lentic Systems: A Florida Perspective.

Bonvechio*, K. I. Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Eustis, FL.

Standardized sampling protocols are gaining widespread consideration among fishery biologists at the state agency level. Florida contains over a million acres of fresh water and is home to a diversity of inland systems including natural lakes, impoundments, rivers, and canals. The Florida Fish and Wildlife Conservation Commission (FWC) is developing standardized sampling protocols for all inland waters in an effort to improve the statistical value of data collected, to construct a statewide database, and to encourage data sharing within FWC and among other state and federal agencies. We consulted published literature and obtained standardized sampling protocols from state agencies throughout the Southeast. Over half of the surveyed agencies had formal standardized sampling protocols, and three were currently under construction. The objectives, sampling designs, and methods varied widely among these agencies, but most were organized by gear type. We discuss these differences in reference to standards being proposed for Florida’s lentic systems and offer justifications and considerations that ultimately led to the formation of these standards.

Keywords: standardized sampling

Evaluation of seining and hoop netting for collecting fishes in Oklahomas large prairie rivers

Utrup, N.J.*, Oklahoma Cooperative Fish and Wildlife Research Unit, and Department of Zoology, Oklahoma State University, Stillwater, OK. Fisher, W.L., U.S. Geological Survey, Oklahoma Cooperative Fish and Wildlife Research Unit, and Department of Zoology, Oklahoma State University, Stillwater

Our objective was to evaluate seining and hoop netting for detecting fish species in large prairie rivers in the central and western part of Oklahoma. To evaluate these gear types, we first determined the types and proportion of habitats that needed to sampled, the amount of effort needed at a site, and the effectiveness of each gear type at detecting fish species. Three habitat types: shallow water (< 0.75 m), deep water (> 0.75 m), and backwater (< 0.01 m/s) were visually identified on aerial photos, and samples were allocated to each type. Sampling efficiency evaluations showed that seining detected, on average, 54.2% of the available species in shallow water habitats and 57.7% in backwater habitats. Hoop net efficiency evaluations in deep water habitats revealed that small hoop nets detected significantly more fish than large hoop nets and large hoop nets detected significantly larger fish than small hoop nets; however, there was no significant difference in the number of species detected between the two. For all species; catch per unit effort for the seine was 2.16 species per seine haul, 0.78 species per net for the small hoop net, and 0.80 species per net for the large hoop net.

Keywords: river seine hoopnet Oklahoma sampling

Evaluation of shoreline seining and mini-fyke nets in floodplain lakes

Clark*, S.C., Jackson, J.R., Lochmann, S. (SJC) Arkansas Tech University, Russellville, AR. (JRJ) Arkansas Tech University, Russellville, AR. (SL) University of Arkansas-Pine Bluff, Pine Bluff, AR.

Mini-fyke nets (MFN) were compared with shoreline seining (SS) to assess their relative abilities to describe littoral fish assemblages in 14 White River, AR floodplain lakes. Lakes ranged in size from 1 ha to 48 ha. Lakes greater than 2.4 ha were sampled using three MFN, while those smaller than 2.4 ha were sampled using two MFN. MFN were set for a 24-hour period. SS effort depended on the amount of open shoreline with a minimum of one seine haul and a maximum of 30 seine hauls conducted per lake. MFN were deployable in all of the 14 sample lakes; whereas SS could only be used in10 lakes due to woody vegetation. MFN collected more fish (3148) than SS (777). Overall, MFN species richness was 42 with 18 unique species. SS species richness was 25 with one unique species. In lakes sampled using both gears, Cyprinidae (42%), Centrarchidae (31%), and Clupeidae (9%) were most commonly caught in MFN whereas Poeciliidae (43%), Centrarchidae (30%), Cyprinidae (12%) were most commonly caught in SS. MFN were more efficient at sampling littoral fish assemblages than SS, required less manpower, and were fishable in all lakes.

Keywords: mini-fyke net shoreline seining floodplain lake

Utility of Absolute Abundance Estimates in Largemouth bass, Micropterus salmoides, Management

Michaelson*, D.P. and DiCenzo, V.J. Virginia Department of Game and Inland Fisheries (VDGIF), Farmville, VA.

Population estimates used to expand our knowledge about largemouth bass populations in small reservoirs (<1000 acres) of south-central Virginia included the Petersen and Schnabel mark-recapture techniques and the Leslie depletion method. Objectives of this work were to develop a qualitative hierarchy for bass lakes based on population densities, use population estimates to determine electrofishing efficiency, and to use correlation and regression analysis to develop equations to estimate population size from catch-per-unit-effort (CPUE) estimates. Categories of population size broke out as high (> 36 bass/acre), medium (16-35 bass/acre) and low (< 15 bass/acre). Electrofishing efficiency (percent of largemouth bass actually sampled) ranged from 11-48% and averaged 29%. Correlation analysis revealed that CPUE and absolute abundance estimates were highly correlated for the total population (r = 0.83) as well as for preferred size (>380 mm) bass (r=0.90). The Leslie depletion technique worked best on larger reservoirs with adequate numbers of definable coves where one cove per day could be depleted. The Petersen and Schnabel techniques were well suited when the entire shoreline could be sampled daily. Absolute abundance estimates have shown great utility in a basic understanding of bass population dynamics, population models for regulation review, and in dealing with constituents.

Keywords: Largemouth bass, absolute abundance

Conservation Biology

PREDICTIVE HABITAT MODELS FOR CONSERVATION OF THE FEDERALLY THREATENED BLACKSIDE DACE PHOXINUS CUMBERLANDENSIS

Jones*, B.K., and Mattingly, H.T. Tennessee Tech University (TTU), Cookeville, TN

The U.S. Fish and Wildlife Service listed the cyprinid Phoxinus cumberlandensis (blackside dace) as a threatened species in 1987. Identification of environmental attributes which affect the distribution of this fish may assist natural resource managers in the preservation and recovery of the species. Field-collected and map-produced habitat variables were gathered at 72 stream sites at a 200-meter-long reach scale and at 92 streams at a headwaters-to-mouth stream scale. Spearman correlation analyses at the reach scale showed significant (p < 0.05) correlations between the presence of blackside dace and water temperature (-), turbidity (-), conductivity (-), variation in average maximum water depth (+) and several other fish species (+ and -). Logistic regression models were constructed to relate the probability of the presence of blackside dace to water temperature, conductivity, and link magnitude at the reach scale. An additional logistic regression model was constructed relating dace presence to gradient at the stream scale. These models indicate that dace are more likely to be present in streams which have a gradient between one and six percent and in reaches with a link magnitude between three and six, a conductivity below 240 µs, and a summer temperature between 15^o and 19^o C.

Keywords: habitat model logistic regression blackside dace endangered species

Characterizing habitats and threats for species of conservation concern

Miller*, S.A. Virginia Department of Game and Inland Fisheries (VDGIF), Richmond, VA

As a part of the Comprehensive Wildlife Conservation Strategy required by all states, Virginia is developing habitat maps for all species identified as species of critical conservation need (SCCN). Habitats have been characterized using an attributed hydrography. The reaches known to contain the SCCN were pulled out and compared for patterns in the habitat attributes. For example, the habitat characterization used for the Roanoke logperch, (Percina rex), was small streams to small rivers with very low or low gradient and, in the Roanoke drainage, a reach elevation range between 175 and 500 m. These data were used to highlight reaches as potential Roanoke logperch habitats. After characterizing SCCN habitats, we assessed habitat quality and specific threats to the species. This was done using GIS analyses and expert meetings. The percentage of habitat in waters rated as “impaired” by the Virginia Department of Environmental Quality and the amount of habitat in disturbed land use were determined. The experts identified habitat loss and sediment load alteration from agriculture and urban land use as two of the factors affecting Roanoke logperch. The experts provided additional information on the scope and severity of all threats and the conservation actions needed for all species.

Keywords: conservation threats habitat

Assumptions, evolution, and application of conceptual models of Roanoke logperch population dynamics

Roberts*, J.H., and Angermeier, P.L. Department of Fisheries and Wildlife Sciences and U.S. Geological Survey, Virginia Cooperative Fish and Wildlife Research Unit, Virginia Tech, Blacksburg, VA.

Conceptual models of fish dynamics are built upon theory, empirical evidence, and expert judgment, all of which have embedded assumptions. Expert judgment is especially prominent in models for rare species, for which data are often lacking. Herein we draw from our monitoring of endangered Roanoke logperch to illustrate the assumptions, evolution, and application of conceptual models of fish population dynamics. The original, implicit model of logperch dynamics, based largely on expert judgment, assumed stable abundance, deterministic regulation, and a strong connection between abundance and habitat availability. Based on this model, flood-control construction on the Roanoke River was expected to reduce logperch abundance by decreasing availability of silt-free habitat, and this population reduction was assumed detectable. Subsequent data collection and analyses revealed high, stochastic variation in pre-construction abundance, and weak relationships between abundance and habitat. This new knowledge led to refinement of our conceptual model and modification of monitoring and construction procedures. Based on our experiences, we suggest that scientists need to 1) explicate conceptual models and uncertainties, 2) seek opportunities to test key assumptions, 3) expect models to change as more data become available, and 4) work closely with managers to incorporate new knowledge into actions and policies.

Keywords: conceptual model population dynamics assumptions uncertainty expert judgment

Pigeon River Re-introduction Efforts Update: 2004

Coombs*, J.A., and Wilson, J.L. University of Tennessee, Department of Forestry, Wildlife and Fisheries Burr, J.E. Tennessee Department of Environment and Conservation, Office of Water Pollution Control

Since its inception in 2001, the Pigeon River Recovery Project has re-introduced 12 fish species totaling 8,257 individuals as well as substantial numbers of snails and mussels. During the past three years, fish have been collected from tributaries to the Pigeon River, reference streams within the French Broad basin, and from the upper reaches of the Pigeon River itself. Visible implant fluorescent elastomer (VIE) was employed to tag darter species only. In 2004, re-introductions of four targeted species began in the North Carolina reach: saffron shiner (Notropis rubricroceus), mirror shiner (N. spectrunculus), telescope shiner (N. telescopus), and silver shiner (N. photogenis). Limited snorkeling surveys in the Tennessee reach located surviving mussels, thousands of common snails, and the first sighting of a blueside darter (Etheostoma jessiae). Tagged and untagged gilt daters were also observed at the re-introduction site and further downstream. September brought back-to-back 100-year floods from two hurricanes that inundated western North Carolina and eastern Tennessee, cutting the field season short and, raising concerns for the survival of the recently transplanted shiners. An attempt to propagate the tangerine darter (Percina aurantiaca) at Conservation Fisheries, Inc., began this year with the goal of re-introducing it into North Carolina and Tennessee.

Keywords: Re-introduction Pigeon River Visible implant fluorescent elastomer (VIE) Non-game fish species Gilt Darter Snails Mussels Tennessee North Carolina

The Digital Atlas of Oklahoma Fishes: Development of an Internet-based Geographic Information System to Manage Museum Databases

Freund*, J.G., and Fisher, W.L., Oklahoma Cooperative Fish and Wildlife