Jeff D. Koch

A Technique for Preparing Fin Rays and Spines for Age and Growth Analysis

Abstract Fin rays and spines are becoming more popular for age and growth analysis. A protocol for processing structures is first to mount the structure in epoxy, then to use a low-speed saw or handsaw to section the structure, and finally to estimate age from the resulting section. Unfortunately, scientists are often unaware of efficient techniques for mounting structures for such analyses. We describe a simple technique for mounting fin rays and spines in epoxy in preparation for sectioning. The advantages of this method include minimal preparation time, low cost, and little or no damage to hard structures. We have used this technique extensively to estimate age from the fin rays and spines of shovelnose sturgeon Scaphirhynchus platorynchus, catostomids, cyprinids, and ictalurids; however, this technique is useful for any species for which fin rays or spines are used in age and growth analyses. In addition, the technique is not limited to fin rays and spines; it can also be used to prepare a variety of ...

Assessment of Hatchery-Reared Pallid Sturgeon Survival in the Lower Missouri River

Abstract The population of pallid sturgeon Scaphirhynchus albus in the lower Missouri River between Gavins Point Dam (river kilometer [rkm] 1,305.2) and the confluence with the Mississippi River (rkm 0.0) remains imperiled, little to no natural recruitment occurring. Artificial propagation and subsequent population augmentation (i.e., stocking) may be the only viable option for maintaining pallid sturgeon populations in the lower Missouri River in the near term. Because relatively little is known about the ability of hatchery-reared pallid sturgeon to survive, the objective of this study was to quantify survival estimates for hatchery-reared pallid sturgeon stocked into the lower Missouri River. We used stock–recapture data collected from 1994 to 2008 to derive survival estimates based on the Cormack–Jolly–Seber model within program MARK. Since 1994, a total of 78,244 hatchery-reared pallid sturgeon have been released and 1% of these have been recaptured. Recapture numbers by size at stocking were as foll...

Effects of commercial harvest on shovelnose sturgeon populations in the upper Mississippi River

Shovelnose sturgeon Scaphirhynchus platorynchus have become an increasingly important commercial species in the upper Mississippi River (UMR) because of the collapse of foreign sturgeon (family Acipenseridae) populations and bans on imported caviar. In response to concerns about the sustainability of the commercial shovelnose sturgeon fishery in the UMR, we undertook this study to describe the demographics of the shovelnose sturgeon population and evaluate the influence of commercial harvest on shovelnose sturgeon populations in the UMR. A total of 1,682 shovelnose sturgeon were collected from eight study pools in 2006 and 2007 (Pools 4, 7, 9, 11, 13, 14, 16, and 18). Shovelnose sturgeon from upstream pools generally had greater lengths, weights, and ages than those from downstream pools. Additionally, mortality estimates were lower in upstream pools (Pools 4, 7, 9, and 11) than in downstream pools (Pools 13, 14, 16, and 18). Linear regression suggested that the slower growth of shovelnose sturgeon is a consequence of commercial harvest in the UMR. Modeling of potential management scenarios suggested that a 685-mm minimum length limit is necessary to prevent growth and recruitment overfishing of shovelnose sturgeon in the UMR.

Evaluation of Precision and Sample Sizes Using Standardized Sampling in Kansas Reservoirs

AbstractWe 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. Additionally, we used resampling procedures to determine the number of gear deployments needed to achieve a relative standard error (RSE) of 25% for the CPUE and collect 100 stock-length individuals. Median RSE of electrofishing samples was generally less than 25% for Largemouth Bass Micropterus salmoides in all sizes of reservoirs and for Channel Catfish Ictalurus punctatus in medium (251–1,000 acres) and large reservoirs (greater than 1,000 acres). The RSE estimates were generally >25% for Bluegill Lepomis macrochirus and crappies Pomoxis spp. collected in trap nets and palmetto bass (female Striped Bass Morone saxatilis × male White Bass M. chrysops) and Walleye Sander vitreus sampled in gill nets. With few exceptions, 100 stock-length individuals of all target species (e.g., Largemouth Bass, Bluegill, cr...

Population Characteristics of Northern Pike in a Southern Kansas Impoundment

Northern pike, Esox lucius, were historically stocked throughout Kansas; however, lack of suitable habitat generally led to the senescence of these populations. Currently, Kingman State Fishing Lake (SFL) is the only public fishery in Kansas that still supports a self-sustaining northern pike population. Due to the extreme habitat conditions on the far southern edge of the northern pikes range, traditional sampling methods (e.g., fall trap nets and gill nets, spring electrofishmg) generally cause excessive mortality or are not effective at capturing northern pike. As such, data regarding the only Kansas northern pike fishery are lacking. Northern pike were sampled with trap nets during February and March 2011, to estimate population charactensties such as recruitment, growth, mortality, and population size. Kingman SFL northern pike grew quickly, generally lived less than 10 years, and exhibited annual recruitment. Total annual mortality was 44%. Population estimates obtained from mark-recapture data suggest the population density is approximately four to nine adult northern pike per surface hectare.

Utility of Reservoir Characteristics to Determine Minimum Sampling Effort Needed to Assess Sport Fish Populations in Kansas Reservoirs

AbstractEffective reservoir fisheries management requires fish samples suitable for addressing objectives. These samples are typically attained with fish sampling gears using standardized protocols. Some standardized protocols for sampling reservoir fishes promote objective-based sampling, and many include a minimum number of gear deployments. This minimum number is often a function of reservoir surface area. However, reservoir size may not adequately predict the number of gear deployments needed to reach sample objectives. We 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: (1) collecting 100 stock-length fish (N100), and (2) attaining relative SE of stock-length catch per effort (CPE) ≤25% (RSE25). These analyses were conducted using data from 34 Kansas reservoirs and six fish species. We used Akaike model averaging from a confidence model s...

Freeze Brand Retention in Channel Catfish and Channel Catfish × Blue Catfish Hybrids

AbstractWe evaluated freeze brands on Channel Catfish Ictalurus punctatus and hybrid catfish (female Channel Catfish × male Blue Catfish I. furcatus) to determine suitability of the technique for identification of year-class on ictalurid catfishes. Freeze brands were applied to fish in a hatchery setting, and adipose fins were removed as a secondary mark. Marked fish were stocked into two Kansas reservoirs within 3 d after marking. Fish were sampled with a suite of gear types for 3 years after the initial stocking in 2013. All captured catfish were observed for the presence of a freeze brand and an adipose fin. A logistic regression model estimated 80% brand retention for Channel Catfish through 460 d. The logistic regression model for hybrid catfish brand retention as a function of days at large was not significant, but retention remained near 80% throughout the 3-year study period. Results suggest that freeze brands are suitable for marking Channel Catfish and hybrid catfish in natural systems when mark...

Influence of Supplemental Feeding on the Channel Catfish Fishery in a Kansas Impoundment

Supplemental feeding has been used in attempts to improve sportfish populations; however, few studies have evaluated efficacy of this practice. I evaluated channel catfish, Ictalurus punctatus, growth, condition, size structure, and angler catch in McPherson State Fishing Lake during three multi-year periods of supplemental feeding rates (i.e., no feeding, 84 kg·ha·yr, and 336 kg·ha·yr). Growth of channel catfish was greater during years when supplemental feeding rate was low compared to years during high feeding rates. Condition of channel catfish was greater during years of high feeding rate, although contribution to the fishery that was attributed to increased condition was low. Inferences regarding size structure were unclear because of variable stocking rates and fishing regulations. Trends in angler harvest of channel catfish were variable; although, average size of harvested channel catfish was generally highest during years of supplemental feeding. These results indicate that overall effects of supplemental feeding were variable, and the funds associated with high feeding rates could be utilized to purchase commercially-grown fish approximately equal to channel catfish biomass harvested from the fishery in a given year.