Midwest Fish & Wildlife Conference 2019

AUTHORS: Cory Becher, The Ohio State University, Aquatic Ecology Laboratory, EEOB; Stephen M. Tyszko, Ohio Department of Natural Resources-Division of Wildlife; Dr. John Olesik, The Ohio State University, Trace Elements Research Laboratory; Dr. Stuart A Ludsin, The Ohio State University, Aquatic Ecology Laboratory, EEOB

ABSTRACT: Stocking is a key management tool used to establish or enhance fisheries in reservoir ecosystems. Quantifying the contribution that stocked individuals make to the fishable population should be an essential component of any stocking program. However, such post-stocking assessment is oftentimes neglected, likely owing to difficulties associated with using conventional (i.e., artificial) tags to discern stocked individuals from wild-produced ones. To help the Ohio Division of Wildlife (DOW) better assess its Channel Catfish (Ictalurus punctatus) reservoir stocking program, we have been evaluating the use of otolith microchemistry—quantified using laser-ablation plasma-mass spectrometry—as a natural tag to discriminate between stocked and wild-produced individuals. Herein, we first present results from predictive quadratic discriminate function (QDF) models that were developed for three reservoirs, which we used to differentiate wild-produced individuals from hatchery-reared individuals. These models were built using known signatures from the hatchery and reservoirs. We used core and edge chemistry of hatchery-reared broodstock and juveniles, as well as the recent edge chemistry of individuals captured in the three reservoirs. Afterwards, we present findings from our predictive analyses, which used the QDF models to classify reservoir individuals unknown core signatures as either stocked (hatchery origin) or wild-produced. Our preliminary findings indicate that otolith microchemistry can be used as a tool to identify the natal origin of wild-caught fish in our study reservoirs, with stocked fish comprising less than half of the population at large in each reservoir. We ultimately discuss the value of this approach for helping management agencies such as the Ohio DOW assess the effectiveness of their channel catfish stocking programs.

AUTHORS: Ernesto Flores, Kansas Department of Wildlife, Parks, and Tourism; William J. Stark, Fort Hays State University

ABSTRACT: Age information is a management tool used by fisheries biologists to characterize populations. The Blue Catfish (Ictaluris furcatus) is a riverine species that grow to trophy lengths and have been introduced into Kansas Reservoirs. Blue Catfish were introduced into Wilson Reservoir in 2006 and Lovewell Reservoir in 2010 with a common management objective, establishing a trophy fishery. Standard sampling protocol (SSP) has misrepresented the Blue Catfish population status in both reservoirs; a targeted sampling effort was conducted in the summer of 2016 in Lovewell Reservoir using low-pulse electrofishing and in 2017 using float-lines to gain insight on the population structure. A total 170 fish were collected from Wilson Reservoir with a TL ranging 210-860 mm. We sampled Lovewell Reservoir and collected 146 individuals ranging from 220-860 mm. Pectoral spines were collected from each individual and used for aging. Annual stockings were scheduled for Lovewell reservoir from 2010-2014 approximately at 1 fish/acre excluding the year 2013 stocking at 0.33 fish/acre. Age 6 fish comprised 52% of the sample, 2% at age 5, 13% age 4, 3% age 3, 23% age 2, and 4% age 1. Wilson Blue Catfish stocking rates were conducted at 2 fish/acre in 2006 and 2008; stocking rates were 1 fish/acre in 2007, 2010, 2011, 2012, 2013, 2014, and 2016. Age 11 fish made up 13% of the sample, age 10 at 49%, 36% were age 9, and 7% age 1. Age classes 2, 3, 4, 5, 6, and 7 were not represented in the sample. Detection of these missing year classes may have been caused by low lake levels during this time period.

AUTHORS: Michael Mounce, Division of Fisheries, Illinois Department of Natural Resources

ABSTRACT: Anglers want quality fishing opportunities and a growing body of literature indicates that active bluegill management can maintain or increase angling quality in bluegill fisheries. Panfish anglers are a very important part of the angling community, but often ignored in developing quality fisheries due to stereotyped as being primarily harvest-oriented. In 1999, as part of a state-wide bluegill management study, a 203 mm minimum length limit and 10 bluegill/day harvest limit were applied to Walnut Point Lake (21 ha). Initial results looked promising, but bluegill soon stockpiled below the minimum length limit, which is typical in fish populations with good recruitment and average growth. In 2007, a maximum length limit was applied allowing the harvest of 15 bluegill/day, of which, only 5 could be > 203 mm. Age structure and the number of large bluegill collected improved. In 2013, concerns regarding body condition and potentially growth prompted liberalization of the limit to 20 bluegill/day (still allowing 5 fish > 203 mm). Body condition and the number of large bluegill collected improved. Under the maximum length limit the average proportion of large bluegill (> 203 mm) collected in surveys is significantly higher (P< 0.02) than in pre-regulation years (< 1999). The application and tailoring of this regulation, coupled with angler education, has demonstrated biological and sociological benefits in this bluegill fishery for eleven consecutive years. Resource-appropriate regulations, similarly tailored, could provide long-term angling quality benefits in other bluegill and panfish fisheries while maintaining harvest opportunities.

AUTHORS: Ben C. Neely, Jeff D. Koch, Connor J. Chance-Ossowski – Kansas Department of Wildlife, Parks, and Tourism

ABSTRACT: Bluegill Lepomis macrochirus contribute to unique fisheries in Kansas where they fill many niches. One niche that has been gaining recent attention from anglers is pursuit of large individuals. These efforts typically occur during the Bluegill spawn in May and June when anglers can visually target nest-guarding fish. A combination of being visually evident and aggressively defending nests makes Bluegill especially susceptible to angler harvest during this time. There is concern that harvest of nest-tending Bluegill may remove the fastest growing individuals from the population and ultimately results in populations that do not support quality Bluegill fisheries. To this end, Bluegill were sampled from 14 Kansas impoundments with both fall electrofishing at random shoreline locations and spring angling for nest-tending individuals in 2017 and 2018. Total length was recorded from all captured individuals and otoliths were collected from up to five individuals per centimeter group for age and growth estimation. In all impoundments, length distribution of sampled bluegill differed between gears with angled fish shifted toward larger individuals. Similarly, angled fish exhibited more rapid growth than randomly sampled individuals in some populations. These results highlight the vulnerability of the fastest growing individuals in bluegill populations to angler harvest while preparing and guarding spawning sites. Further, these results suggest that instituting some level of protection to nest-guarding Bluegill might result in increased size structure and promote development and maintenance of quality Bluegill fisheries.

AUTHORS: Erin Haws, Iowa Department of Natural Resources

ABSTRACT: Freshwater ecosystems provide a diverse and extensive supply of resources to fauna and flora living within, to surrounding ecosystems, and human economies. As bodies of water evolve, so do the methods used to protect and restore them. Over the past decade, emphasis on sustaining freshwater ecosystems has led to a large expansion in the development of protective policies and restoration programs aiming to improve aquatic habitat. A recurring challenge to fish habitat restoration lies in defining impairment factors, their scale and the rate at which they are occurring in a system. Comprehensive assessments are therefore needed to identify impairments, prioritize waterbodies in need of restoration, and provide improved methods to measure local fish habitat using feasible metrics. This study provides an expansive look into lake and reservoir fish habitat in Iowa based on a survey reporting on all significant publicly owned lakes recognized by the Iowa Department of Natural Resources (DNR). The survey asked Iowa DNR Fisheries Biologists to report the degree of impairment of a set of variables for each individual waterbody in their management area. Multivariate factors were classified using the methods of Krogman and Miranda (2016), characterizing twelve broad constructs of fish habitat impairment. Study objectives include describing fish habitat impairment trends and identifying differences across lake type, watershed location, and status in the Lake Restoration Program. Future research plans aim to quantify relationships between fish habitat impairment constructs and measured water quality, physical, and biological parameters within existing datasets to evaluate the resources available to adequately measure fish habitat.