Midwest Fish & Wildlife Conference 2018

AUTHORS. Scott A . Bonar, U.S. Geological Survey Arizona Cooperative Fish and Wildlife Research Unit; Norman Mercado-Silva, Universidad Autonoma del Estado de Morelos; Kevin L. Pope, U.S. Geological Survey Nebraska Cooperative Fish and Wildlife Research Unit

ABSTRACT. The American Fisheries Society developed standard methods to sample freshwater fish populations, publishing them in 2009 in the book Standard Methods for Sampling North American Freshwater Fishes. This project involved 284 scientists from 107 different organizations across Canada, Mexico and the United States. Data collected using standard methods gives biologists improved ability to compare data across regions or time. This meets increasing needs for larger regional or global scale assessments, and helps biologists to communicate and share data across political boundaries. Current research on standard methods focuses on calibration of local techniques to the North American methods, development of efficiency models for the standard techniques; development of web-based electronic means to compile and compare data collected from standardized monitoring efforts; collaboration with fisheries biologists on other continents in developing and comparing standard methodologies; completion of a 2nd edition of Standard Methods and institutionalizing a process to update AFS standard methods in the future. Standardization in industry, medicine and science has led to great advances. An overview of current research on standard fisheries sampling techniques and how AFS standard methods are being incorporated into North American fisheries management illustrates the importance of advancements in technology and communication among biologists when conserving the continent's fish populations.

AUTHORS. Martha E. Mather, U. S. Geological Survey, Kansas Cooperative Fish and Wildlife Research Unit, Division of Biology, Kansas State University; Dan Shoup, Department of Natural Resource Ecology & Management, Oklahoma State University; Quinton Phelps, Davis College of Agriculture, Natural Resources & Design, West Virginia University

ABSTRACT. Implementation of rigorous methodologies, including gear evaluation and standardization, is critically important for effective fisheries research and management.  Although few fisheries professionals disagree with the urgent need for detailed, quantitative protocols prior to data collection, challenges exist in executing representative and generalizable gear evaluations and standardizations.  Three primary areas require attention. Addressing these challenges can advance the establishment and implementation of improved sampling methodologies. As a first challenge, unless a complete census is undertaken every time resource data are collected, uncertainty about context-specific bias at the time of each individual data collection event (related to time-, place- and personnel-related sampling variation) will affect efforts to evaluate and standardize gear.  Consequently, practical and philosophical cautions about data interpretation related to the inevitable uncertainty in bias need to be integrated into the development, validation, and application of standardized data.  As a second challenge, the type of data needed and impact of specific gear bias differ with the question asked.  For example, data needed to estimate population size are quite different from those needed to quantify the impact of specific conditions on fish populations (e.g., habitat type, season, disturbances such as dams) regardless of the gear used. Thus, the question asked alters the appropriateness of the sampling design for the same and different gears.  As a third challenge, an integrated analysis of how standardized data relates to the fisheries questions asked is needed (e.g., what will be done with the standardized data once it is collected?; are the right questions being asked for the problem at hand?; will the resulting data be useful if unanticipated trends are detected?).  By addressing these challenges, fisheries professionals can develop a more balanced portfolio of tools that provide a broader context for the development, validation, and application of standardized data. 

AUTHORS. Jeff Koch, Ben Neely – Kansas Department of Wildlife, Parks, and Tourism; Michael Colvin, Mississippi State University

ABSTRACT. We evaluated the precision of samples and the number of stock-length fish collected by means of standard methods used for sampling North American freshwater fishes from 2010 to 2013 in Kansas. Median RSE of electrofishing samples was generally less than 25% for Largemouth Bass in all sizes of reservoirs and for Channel Catfish in medium (251–1,000 acres) and large reservoirs (greater than 1,000 acres). The RSE estimates were generally >25% for Bluegill and crappies collected in trap nets and palmetto bass and Walleye sampled in gill nets. With few exceptions, 100 stock-length individuals of all target species (e.g., Largemouth Bass, Bluegill, crappies, palmetto bass, Channel Catfish, Walleye) were not sampled at current levels of effort. Resampling procedures indicated that fewer than 20 deployments were usually needed to obtain an RSE 25% and 100 stock-length fish for Largemouth Bass in smaller impoundments; however, more than 20 deployments were needed in larger impoundments. The median effort needed to achieve an RSE 25% for Bluegills and crappies in trap nets varied and may exceed what some biologists find practical. Our results indicate that more samples than are currently prescribed are generally needed to precisely sample sport fishes by means of standardized protocols in Kansas reservoirs. We also used multiple linear regression to determine the relationships between the biological, chemical, and physical characteristics of reservoirs and the number of gear deployments needed to reach two sample objectives.  Recent CPE was identified in N100 models for six target species and in RSE25 models for five. Conversely, reservoir surface area was identified in only one model for N100 and two for RSE25. These results suggest that reservoir characteristics other than surface area, particularly recent CPE, should be considered when developing minimum sample sizes for objective-based fish sampling protocols.

AUTHORS. Sandra J. Clark-Kolaks, Indiana Department of Natural Resources; Andrew Bueltmann, Indiana Department of Natural Resources

ABSTRACT. Reservoir community sampling in Indiana has been standardized for many years but sampling frequency was not. In 2016 Indiana moved to revisit the reservoir sampling protocol and develop a sampling schedule to better monitor long-term status and trends. The new protocol strived to strike a balance between sampling efforts adequate to obtain a representative sample while allowing biologist to sample more lakes each year. A total of 95 reservoirs greater than 15 acres were included in the program with 16 reservoirs being sampled statewide each year.  Sampling is conducted from May 1 to June 15th and includes a combination of boat DC electrofishing, experimental gill nets and trap nets. The majority of lakes (less than 1000 acres) receive a combination of two 15 minute DC electrofishing stations, two experimental gill net sets and two trap net sets. Lakes between 1000 acres and 5000 acres are sampled with four 15 minute DC electrofishing stations, four experimental gill net sets and four trap net sets.  Reservoirs greater than 5000 acres are sampled with eight 15 minute DC electrofishing stations, four experimental gill net sets and four trap net sets. Total length, weight, and aging structures are taken from game species. A Tier II vegetation survey is conducted between July 15th and August 31st. Since the program began in 2016, 33 reservoirs have been sampled with 20,273 fish collected. Bluegill was the most common species collected (31%) followed by Gizzard Shad (23%) and Largemouth Bass (11%). This new protocol has allowed biologists to sample more lakes at a greater frequency while allowing for comparison of abundance, growth, and condition across reservoirs.

AUTHORS. Jake Allman, Zach Ford, Dave Woods, Andy Turner - Missouri Department of Conservation

ABSTRACT. Electrofishing has been a common fisheries tool in Missouri since the early 1970s. While electrofishing is a common tool, there has been little done in Missouri to standardize our fleet so consistent results are achieved. Two state-wide projects sampling smallmouth bass and big river catfish led to researchers attempting to standardize methods and equipment to hopefully standardize survey results. This effort led to a realization of deficiencies in our other equipment’s ability to replicate sampling results, operate safely, and even document the actual electrofishing settings in use during collections. In 2014, a committee was formed to address electrofishing equipment and safety and the committee decided that an attempt at standardization of equipment was appropriate at this time as well. The resulting electrofishing manual provides recommendations for control box and backpack shocker brands, wiring configuration, safety standards and anode resistance goals. The committee has also developed training to help biologists standardize their equipment, map their electrical fields, inspect boats for safety issues, and calculate anode resistance. Biologists are also provided information on power goals based on conductivity for consistent power usage to collect fish. Additional work is being conducted to determine electrofishing power thresholds for smallmouth bass, blue catfish and flathead catfish.

AUTHORS. Brian G. Blackwell, South Dakota Department of Game Fish and Parks; Bradley J. Smith, U.S. Fish & Wildlife Service

ABSTRACT. The first step in standardizing fish sampling in South Dakota was a gear comparison between the South Dakota Department of Game, Fish and Parks (SDGFP) standard gill nets and modified fyke nets and the recommended North American (NA) equivalent nets. Gill net catch per unit effort (CPUE) was higher for the longer SDGFP nets than the NA nets and modified fyke net catches were similar. Conversion factors were calculated that allow for continued use of historic CPUE data. Species richness and diversity were not found to differ between the SDGFP and NA nets. Additional research found that modified fyke nets with restricted throats retained fish better than non-restricted throats resulting in higher CPUE. Selectivity curves for common species were developed for mesh sizes contained within the NA gill nets. No difference in CPUE was found between random and non-random modified fyke net locations in small waters. The comparisons between the gears and supplemental research provided the necessary information to allow South Dakota to make the transition from SDGFP standard nets to the NA nets. South Dakota began using the NA nets statewide in 2017. In addition to using the NA nets, net locations are now randomized and the number of gill nets used in a standard survey is double the previous number. Concerns with the changes have included that fewer fish are being collected per gill net, portion of sampling period occurs outside the recommended sampling times, and random net placement has resulted in longer boat travel times. Overall, few issues have occurred during the standardization with the NA nets.

AUTHORS. Joseph D. Conroy, Jeremy J. Pritt, Stephen M. Tyszko, Chris G. French, Richard D. Zweifel - Ohio Department of Natural Resources, Division of Wildlife

ABSTRACT. From minimizing bias of individual samples to facilitating data sharing, standard sampling approaches have many benefits for fisheries management and research. However, accepted methods may not always be directly transferable from one situation to another, requiring additional development work to allow application. Further, whereas most standard methods have clear criteria for sampling (i.e., time of year, gear used, site selection, etc.), they often lack a direct assessment or validation of what the method actually indexes relative to the fish population of interest. Finally, applying standard methods over long periods provide high-quality datasets on which to evaluate existing programs, regulations, and research questions. Here, we illustrate approaches to development, validation, and application of standard methods using the Inland Management System, the planned, iterative, priority-based approach to standard assessment of reservoir sport fish populations used by the Ohio Department of Natural Resources, Division of Wildlife. Specifically, we describe (1) developing a low-frequency electrofishing approach to assess recently-stocked Blue Catfish Ictalurus furcatus populations; (2) validating catch per unit effort (# caught/h) from shoreline boat electrofishing as an index of Largemouth Bass Micropterus salmoides density; and, (3) applying fall shoreline electrofishing as an index of Sander spp. stocking success to inform management programs and research projects. By developing standard assessments that build on existing ones, validating commonly used standard methods, and systematically applying standard methods fisheries managers learn more about managed sport fish populations in addition to the methods used to assess them.

AUTHORS. Stephen M. Tyszko, Jeremy J. Pritt, Joseph D. Conroy, Kevin S. Page, Richard R. Budnik - Ohio Department of Natural Resources, Division of Wildlife

ABSTRACT. The Ohio Department of Natural Resources, Division of Wildlife seeks to develop a standard method to index Channel Catfish Ictalurus punctatus density and size structure in reservoirs, and tandem hoop net sets most effectively catch Channel Catfish.  We estimated the catchability of Channel Catfish with tandem hoop net sets in Ohio reservoirs and compared statistical power to detect differences in density as well as false positive rate.  We estimated catchability and density during mark-recapture experiments that included two recapture events per week during May–July in Dillon Lake (2016) and Burr Oak Lake (2017).  Catchability (q) was greatest in June and July and was similar for our two study reservoir populations (Burr Oak Lake q, 95 % confidence limits [CL]: 0.041, 0.031–0.050; Dillon Lake: 0.035, 0.032–0.037).  Channel Catfish density estimates differed, however (Burr Oak Lake: 21 catfish/ha, 95% CL 20–22; Dillon Lake: 49 catfish/ha, 47–51).  When including data from the entire sampling period (May–July), the probability of detecting a difference in Channel Catfish density increased from 39% to 94% as sample size increased from 5 net sets to 20 net sets.  The probability of detecting differences in density increased, however, when including data only from a restricted June–July period.  At the reservoir with low Channel Catfish density, false positive rate (detecting a difference in density when one did not exist) was similar for data collected during the entire sampling period and during the restricted period.  At the reservoir with the high density population, false positive rate was greater when sampling during the entire period but decreased when sampling during a restricted period.  Results will be used to design a standard sampling program for Ohio reservoir Channel Catfish populations, sampling during a period that maximizes catchability and minimizes its variability.  

AUTHORS. Zach Morris, University of Missouri; Craig Paukert, U.S. Geological Survey, Missouri Cooperative Fish & Wildlife Research Unit; Zach Ford, Missouri Department of Conservation; Andy Turner, Missouri Department of Conservation; Jan Dean, Dean Electrofishing, LLC

ABSTRACT. Standardized sampling is essential to monitor Smallmouth Bass populations. Our objective was to evaluate the effectiveness of different electrofishing settings for collecting Smallmouth Bass by measuring immobilization response thresholds. We compared immobilization thresholds for 12 pulsed DC waveforms (30 to 120 pulses per second (Hz), duty cycles of 15 - 40%), including a commonly used waveform to collect Smallmouth Bass (60Hz/25%). A total of 310 Smallmouth Bass from two size groups (18-28; 35-43 cm) and three temperatures: 11 – 14°C, 17 – 20°C, and 22 – 26°C were collected via electrofishing, rested in a pen for >1 hr, and placed in a tank attached to a backpack electrofisher. Voltage was increased from one volt until immobilization was observed. Preliminary analysis using a 3-way anova testing if immobilization threshold differed by waveform, temperature, and fish size revealed two-way interactions with temperature and size (P=0.01) and temperature and waveform (P=0.071). For the coolest water temperature, the lowest immobilization thresholds were generally with 30 Hz waveforms but did not differ from the commonly used 60Hz/25% waveform (P For the warm water temperature, there was interaction between waveform and size class (P=0.031). Immobilization threshold tended to be the lowest for 60Hz/25% and 120Hz/30% waveforms for small fish (P=0.074) and 60Hz/25% was the lowest for larger fish (P=0.007). A standard waveform commonly used to collect Smallmouth Bass (60Hz/25%) was typically grouped with the waveforms that had the lowest voltage gradients. These results reflect preliminary analysis that will be finalized in 2018.

AUTHORS. Benjamin J. Schall, South Dakota Game, Fish and Parks / University of Nebraska Kearney; Keith D. Koupal, Nebraska Game and Parks Commission; Casey W. Schoenebeck, Minnesota Department of Natural Resources / University of Nebraska Kearney

ABSTRACT. Effective standardized sampling protocols can be difficult to establish, particularly in large reservoirs exhibiting a gradient of available habitats. Research on the impact of seasonal fish distribution on population dynamics information can be limited. Therefore, developing a better understanding of fish aggregation patterns can assist managers in sample design and the interpretation of potential influences on sampling data. Lake McConaughy is a large irrigation and hydroelectric reservoir over 35 km in length located in western Nebraska and covers more than 14,000 hectares. Investigation of spatial and seasonal distribution of two common sportfish species was performed to determine potential biases related to sampling design. Significant seasonal differences in distribution occurred in catch per gill net night and mean total length (mm). Results of population dynamics assessments also indicated seasonal differences in age (years), projected growth, and mortality, which has the potential to impact management objectives. However, trends were not consistent for Walleye (Sander vitreus) and Channel Catfish (Ictalurus punctatus). The information obtained from this research indicates that a stratified sampling approach may be necessary in large reservoirs, and sample timing should reflect research or management objectives.

AUTHORS. Troy Zorn, Todd Wills, Jan-Michael Hessenauer, Danielle Forsyth Kilijanczyk - Michigan Department of Natural Resources Fisheries Division; Joel Lenz, Michigan State University; Ed Bissell, Michigan State University; Ashley DePottey, Esri; Anila Francis, Michigan Department of Technology, Management, and Budget; Henry Quinlan, U.S. Fish & Wildlife Service; Brett Fessell, Natural Resources Department of Grand Traverse Band of Ottawa and Chippewa Indians

ABSTRACT. Building upon insights from fishery managers and multi-decadal studies on trout populations, the state of Michigan embarked on a statewide program to monitor trends in wild trout populations and to characterize (i.e., assess the status of) fish assemblages and habitats in all streams. Initiated in 2002, the Status and Trends Program is providing a rich set of information from standardized surveys across Michigan. Data from this program support public-facing tools which inform stakeholders (biologists, anglers, various publics) of trends in highly-valued trout populations and provide a scientific, quantitative basis for making management decisions on individual stream reaches. Launched in 2014, the Fish Population Trend Viewer Trend Viewer allows users to assess trends in wild trout abundance, growth, and survival using data from index sites scattered across the state. A companion tool for evaluating fish assemblage and habitat characteristics for streams is scheduled for release in 2017. The Michigan Stream Evaluator will compare conditions at an individual site with benchmarks computed from surveys in streams having user-specified size, temperature, channel gradient, and geographic location attributes. Both tools are refreshed annually with additional stream survey data collected for the Status and Trends Program.

AUTHORS. Anthony R. Sindt, Minnesota Department of Natural Resources

ABSTRACT. Fisheries managers desire efficient sampling methods with sufficient precision for monitoring catfish populations.  We conducted single unbaited hoop net surveys in the Minnesota River to evaluate efficacy of simultaneously assessing stock size (= 280 mm) Channel Catfish Ictalurus punctatus and quality size (= 510 mm) Flathead Catfish Pylodictis olivaris populations.  We compared catch rates and length distributions among months, and used resampling procedures to estimate the number of hoop net samples needed to achieve desirable precision (i.e., RSE = 25 and RSE = 15) of catch rate estimates and adequate statistical power (= 0.80 with a = 0.10) to detect simulated reductions in mean catch rates with two-tailed t-tests.  We observed mean ± SE catch rates of 2.1 ± 0.3 Channel Catfish/net-night and 0.8 ± 0.1 Flathead Catfish/net-night.  Resampling procedures demonstrated a minimum of 68 hoop net samples during August are needed to achieve desirable precision (RSE = 25) and adequate statistical power to detect 50% reductions in mean catch rates of both species.  Unbaited hoop nets are effective for simultaneously assessing Channel Catfish and Flathead Catfish populations in the Minnesota River and conducting surveys during August provides the best balance between catch rate and precision while minimizing perceived environmental and behavior biases.  We expect the same could be true for other rivers with moderate–high density Channel Catfish and Flathead Catfish populations, but the best time of year for conducting surveys likely varies regionally.  However, the amount of sampling effort needed to detect small population changes (

AUTHORS. David Rowe, Daniel Oele, Joanna Griffin - Wisconsin Department of Natural Resources

ABSTRACT. There have been large increases in the abundance of Brown Trout Salmo trutta in Wisconsin in the past 50 years. Several changes may have led to these increases including: improved agricultural practices and land use, stream habitat improvements, wild trout propagation, fishing regulations, and angler attitudes. This study used Wisconsin DNR standard sampling protocols and a modification of a baseline monitoring rotation schedule to evaluate the current reproductive classification and need for continued stocking of streams in the Mill Creek watershed, Richland County Wisconsin. The baseline monitoring schedule was adjusted so that stream surveys were grouped by watershed. This allowed for the suspension of all stocking within the watershed the year prior to evaluation. We assumed that any yearling fish sampled the following year were the result of natural recruitment. A total of 35 sites on 14 streams were sampled between June 17 and August 20 in 2013. Levels of natural recruitment, measured by abundance of yearling trout, levels of natural reproduction, measured by abundance of young of the year trout, and adult trout abundance, were assessed using standard WDNR single pass electrofishing survey protocols. Comparisons of size specific relative abundance were made using all stream surveys from 2007-2014 collected using standard protocols and recorded in the WDNR Fisheries Management Database. Catch rate distributions were constructed for statewide and regional comparisons. Many of the Class 2 sites showed higher recruitment than Class 1 sites. However several of these sites also had no evidence of natural reproduction. Two streams showed low recruitment and reproduction but did have above average adult abundance. One stream had high reproduction, but no yearlings or adults. We discuss these results and the implications for trout stream reproductive classification criteria, standard sampling protocols, and use of baseline rotation sampling to answer targeted management questions.

AUTHORS. Kristopher Maxson, University of Illinois; Levi Solomon, University of Illinois; Rob Maher, Illinois Department of Natural Resources; Andy Casper, University of Illinois

ABSTRACT. Long term monitoring of fishes and other biota can be incredibly valuable when assessing the health of a population, giving us the ability to observe trends over an extended period of time that can encompass various disturbances or extreme weather events.  One example of long term monitoring is the Upper Mississippi River Restoration (UMRR) Program’s Long Term Resource Monitoring element (LTRM).   Beginning in 1993, the LTRM element monitors fish and water quality in six reaches along the Upper Mississippi River System (UMRS). Study methods are standardized across the six reaches and employ a stratified random sampling (SRS) design. This standardized design allows comparisons among the six reaches and can help inform management decisions. For example, buffalo (Ictiobus sp.) are one of the most important commercially harvested species on the UMR. Despite this, little work has been done to assess buffalo populations. This study seeks to use Smallmouth Buffalo (Ictiobus bubalus) catch data collected from 1993-current to track trends in Smallmouth Buffalo populations.  Using catch data from hoop nets and day electrofishing, we calculated the catch per unit effort (CPUE) for Smallmouth Buffalo in each of the six LTRM reaches. CPUE data for the six LTRM reaches indicate a downward trend for Smallmouth Buffalo populations since the program’s inception. In contrast to the trends in LTRM data, Illinois commercial harvest levels of buffalo sp. have remained relatively stable since the 1950s. Future efforts will examine otoliths collected from Smallmouth Buffalo in 2017 to determine the age structure of the fish in each LTRM study reach. Data from this study can be used to help inform management of the Smallmouth Buffalo commercial fishery on the UMRS.

AUTHORS. Jason DeBoer, Illinois Natural History Survey; Martin Thoms, University of New England, Australia; Andrew Casper, John G. Shedd Aquarium

ABSTRACT. Large rivers are among the most-regulated and highly modified ecosystems, globally. More than 65% of the world’s large rivers are fragmented by dams, experience hydrological regulation, and are controlled for navigation purposes. Large rivers are increasingly modified by multiple drivers that cumulatively influence these ecosystems. However, few studies explicitly explore the effects of, or responses to, multiple drivers. Furthermore, our understanding of how system-wide drivers overlap in space or time and interact with each other is lacking. The question remains: do highly modified large-river systems maintain the ability to respond to additional cumulative anthropogenic drivers in a significant and substantial way, and if so, how are these responses manifested? To improve our knowledge of the influence of anthropogenic drivers in large rivers, we need to investigate ecosystem response at broad spatial and temporal scales, whereas most studies focus on single drivers and small scales. This study utilizes a 60-year, river-wide dataset to determine if fish community diversity in the Illinois River changed in response to two major, system-wide anthropogenic drivers: the Clean Water Act (1972) and the Asian carp invasion (2000). We analyzed diversity changes for the entire river system, between distinct geomorphic zones, and among functional feeding guilds.

AUTHORS. Rebecca M. Krogman, Iowa Department of Natural Resources

ABSTRACT. Modified fyke nets are used across the U.S. for panfish sampling in lentic waters, including lakes and reservoirs in Iowa.  However, modified fyke net designs in Iowa, like many states, differed substantially from the standard set forth by the American Fisheries Society (AFS).   Traditional modified fyke nets in Iowa differed from the AFS standard in two primary ways: throat opening design and number of throats.  Given the historical datasets derived from traditional nets and the reticence to convert to a net with lesser performance, an evaluation of net designs was needed.  Four combinations of throat design (open or crowfoot-style) and number of throats (one or two) were examined in this study.  The objective was to identify the modified fyke net design with the highest catch and retention rates of target species, including crappies Pomoxis spp., Bluegill Lepomis macrochirus, and Redear Sunfish L. microlophus.  For retention, nets were stocked with marked target fish and set overnight, then checked for retained fish the following morning.  Fish escapement by net type and species was analyzed using Cochran-Mantel-Haenszel tests and relative risk.  For catch efficiency, nets that were not pre-stocked with fish were deployed concurrently according to standard protocol.  Catch rates from these net sets were compared using generalized linear mixed models predicting catch with net design as a fixed effect and site nested within lake as a random effect.  Net design was a significant factor affecting both retention and catch efficiency, with the traditional Iowa net outperforming all other designs.  Modeling was then used to estimate the number of net sets needed for adequate sampling power using the recommended net design.  Standard modified fyke net sampling in Iowa will be adjusted according to these recommendations and should be considered elsewhere.

AUTHORS. Robert D. Hunter, Kim T. Scribner - Michigan State University; Edward F. Roseman, Robin DeBruyne - US Geological Survey, Great Lakes Science Center

ABSTRACT. Lake Sturgeon (Acipencer fulvescens) is an economically and culturally important species endemic to the Great Lakes region.  Once historically abundant, lake sturgeon populations have been extirpated or are estimated at less than one percent of their historic abundance.  As a result of documenting habitat modification, spawning habitat availability has been identified as a limiting factor in lake sturgeon recruitment in the St. Clair-Detroit River system.  Since 2004, largescale efforts have been under way to mitigate the loss of spawning habitat for lithophilic spawners such as lake sturgeon through construction of artificial spawning reefs.  To assess the effectiveness of artificial reefs in meeting lake sturgeon restoration goals, eggs and larvae were collected on and above two reefs in 2015 using benthic d-frame nets, egg mats, and vertically stratified conical nets.  Samples (N = 700) were genotyped using microsatellite loci and genetic pedigree analysis was used to estimate juvenile full- and half-sibling groups and estimate the number of breeding adults.  Comparisons of juvenile relatedness allow for estimation of the number of adult spawners contributing offspring at one or more reefs, in one or more spawning events, individual spawning success and larval dispersal.  Sampling in large river systems is difficult and resource intensive.  Data also identify the most effective sampling regime for assessment of spawning area use by adult lake sturgeon in large riverine systems.  These data are critical to assess and inform future aquatic habitat restoration efforts for lake sturgeon throughout the Great Lakes. 

AUTHORS. Rebecca A. Dillon, The Ohio State University; Joseph D. Conroy, Ohio Department of Natural Resources, Division of Wildlife; Stuart A. Ludsin, The Ohio State University

ABSTRACT. To best inform management decisions (e.g., harvest quotas, and stocking levels), accurate and precise estimates of fish abundance are needed. Toward improving our ability to estimate fish abundance in shallow freshwater ecosystems, we determined how aspects of a hydroacoustics processing protocol developed for the North American Great Lakes (i.e., Great Lakes Standard Operating Procedure, GL-SOP) influenced estimates of prey-fish density and target strength in five Ohio reservoirs sampled during August 2016. Specifically, we quantified how prey-fish density estimates were influenced by consideration of three key aspects of the GL-SOP: 1) removal of background noise; 2) a lower maximum beam compensation (MBC) setting; and 3) application of the Sawada index (Nv) to identify and replace biased in situ cell-specific target strength (TS). These estimates were made using the existing Ohio Division of Wildlife SOP for processing hydroacoustics data, as well as procedures that included the three GL-SLOP recommendations in isolation and in combination. Our analyses showed that the removal of background noise had little effect (-1.3 to 0.0% change), while changing the MBC from 12 to 6 dB had a large potential effect (21.4 to 64.9% increase in density). The effect of using the Sawada index was intermediate, and highly inconsistent (-24.3 to 9.8%). W.hen all three GL-SOP recommendations were simultaneously applied, prey-fish density estimates increased by 12.9 to 23.6%. Our findings indicate the need for the Ohio Division of Wildlife to consider altering its current hydroacoustic processing SOP for reservoirs, as well as to reassess past estimates of prey-fish abundance. Our results suggest the need for agencies to periodically re-evaluate their SOPs, to ensure that their estimates of prey-fish abundance are as robust as possible. Doing so will maximize the ability of agencies to make informed management decisions.

AUTHORS. Olivea M. Mendenhall; Daniel K. Gibson-Reinemer - Illinois River Biological Station, Illinois Natural History Survey; Andrew F. Casper, Daniel P. Haerther - Center for Conservation and Research, John G. Shedd Aquarium

ABSTRACT. Emiquon Nature Preserve (Emiquon) is a restored backwater floodplain in the Illinois River Valley that provides 6,700-acres of habitat for waterfowl, plants, and fish communities. As part of the restoration process, fish assemblages have been monitored from 2007-2017, tracking changes in fish communities over a decade of restoration efforts. Fish community composition has been assessed using Upper Mississippi River Restoration Program, Long Term Resource Monitoring programs (LTRM) methods and protocols of mini-fyke nets, fyke nets, and electrofishing. Sampling is conducted April through October with four replicates taken with each gear type (i.e., three random and one fixed site) each month. Here we focus on the status of three highly valued sportfish in Emiquon, largemouth bass, bluegill, and black crappie tracking trends and size distribution, then compare the La Grange reach of the Illinois River by assessing size distributions. In Emiquon, the largemouth bass population is stable but skewed to larger size classes, bluegill populations are rising and increasing in size, black crappie populations are stable and represent all size classes. The La Grange supports a smaller size class of largemouth bass and bluegill. The sportfish of Emiquon are abundant and represent most all year classes for the selected species, making this backwater a highly productive system that benefits the Illinois River fish community when it is connected through added nutrients and fish. 

AUTHORS. Jeremy J. Pritt, Kevin S. Page, Joseph D. Conroy, Stephen M. Tyszko, Richard D. Zweifel -Ohio Department of Natural Resources

ABSTRACT. Fisheries managers implement minimum length limits (MLL) and bag limits to improve size structure of crappie Pomoxis spp. populations throughout the Midwest and Southeast USA. The success of these regulations has been mixed, including both successful implementations that have met management objectives and others that have resulted in slow growth and stunting of crappies and ultimately regulation removal. Further, evaluations of regulations on crappie fisheries have been limited by narrow time frames at few locations. Consequently, it is unclear whether MLLs and bag limits should be used to improve crappie size structure or where. Ohio implemented a 229-mm MLL and a 30-fish daily bag limit to improve the size structure of reservoir crappie fisheries beginning in 1998 with a single reservoir, expanding to six reservoirs in 2001 and to a total of 43 reservoirs in 2010. Using an extensive, state-wide, standardized population assessment dataset, we sought to determine (1) the response of crappie population abundance (CPE), growth (length at age-2), size structure (PSD), and condition (Wr) to the regulation and (2) whether reservoir surface area and/or productivity mediated the responses. We found that in general, the regulation had a positive effect on population abundance but negative effects on length at age-2, PSD, and Wr. However, the regulation had positive interactions with both reservoir surface area and productivity, such that in large (> 1,000 ha) and productive (total P concentrations > 100 µg/L) reservoirs, crappie length at age-2, PSD, and Wr increased in response to the regulation. These results indicate that the MLL and bag limit could be beneficial in reservoirs with high productivity but counterproductive in small, unproductive reservoirs. Our approach highlights the benefits of extensive, long-term, standardized sampling as we integrated data across years and reservoirs to make comparisons on a state-wide scale.