Rachel V. Beecham

Using Portable Lactate and Glucose Meters for Catfish Research: Acceptable Alternatives to Established Laboratory Methods?

Abstract Simple and portable methods for assessing the physiological state of channel catfish Ictalurus punctatus would be valuable tools in field situations where problems with blood storage and transportation occur. This study compared the use of handheld lactate and glucose meters with established laboratory methods in stressed (fatigued) and unstressed (control) channel catfish fingerlings. The results obtained from the Accutrend (Roche Diagnostics Corp.) lactate meter and the Accu-Chek Advantage (Roche Diagnostics) glucose meter were consistently lower (P < 0.05) than those obtained with the laboratory reference method. However, significant differences (P < 0.0001) were found between the control and fatigued fish for both lactate and glucose, regardless of the method of analysis. Both handheld meters were found to be reliable and suitable for use in field or laboratory situations where relative measurements are acceptable. The costs associated with using the handheld meters were higher than those ass...

Effects of Loading Density on Golden Shiner Survival during and after Hauling

Abstract Four hauling trips of approximately 6 h each were conducted to investigate effects of loading density on survival of golden shiners Notemigonus crysoleucas. Commercially graded golden shiners (mean weight ± SE, 3.3 ± 0.04 g) were transported at densities of 120, 180, and 240 g of fish/L of water in insulated hauling tanks that were filled with fresh well water, chilled with unchlorinated block ice, and aerated with pure oxygen. The criterion for determining success or failure was golden shiner survival. Transportation at a given density was deemed successful if survival both at trips end and at 18 h postdelivery was at least 99%. At all three hauling densities evaluated, survival exceeded 99% both at trips end and at 18 h postdelivery. Furthermore, increasing loading density had no effect on whole-body cortisol concentrations, demonstrating that no significant stress response occurred. Un-ionized ammonia concentration increased with loading density (range, 0.05–0.46 mg/L) but had no effect on f...

The Effects of Harvesting and Hauling on the Blood Physiology and Fillet Quality of Market-Size Channel Catfish

Abstract Commercially produced, food-size channel catfish Ictalurus punctatus that were harvested using routine procedures had significant elevations in plasma cortisol, glucose, and lactate compared with preharvest fish captured from open ponds. Blood samples were taken from 10 fish in each of two treatments (liquid oxygen diffuser- and paddlewheel-aerated holding socks) and four sampling periods (before harvest, after socking, before loading, and before unloading) during each of 10 harvest events. Water column temperatures averaged approximately 27°C during the study. Ten fillet samples were taken from fish held overnight in paddlewheel- and liquid oxygen-aerated holding socks during some harvest events. Mean plasma cortisol levels averaged 3.02 ng/mL before harvest, 84.38 ng/mL immediately after socking, 135.22 ng/mL after 18 h in the sock (i.e., before loading onto the truck), and 128.54 ng/mL after 2–3 h on the truck (i.e., before unloading). Mean plasma glucose levels averaged 34.7 mg/dL before harv...

The Effects of Proliferative Gill Disease on the Blood Physiology of Channel Catfish, Blue Catfish, and Channel Catfish × Blue Catfish Hybrid Fingerlings

Abstract This study was conducted to gain a better understanding of the effect of exposure to the myxozoan Henneguya ictaluri (the agent of proliferative gill disease [PGD]) on host physiology by measuring the variation in selected blood characteristics in three differently affected host taxa (channel catfish Ictalurus punctatus, blue catfish I. furcatus, and blue catfish × channel catfish hybrid fingerlings). Forty-five fish of each host taxon were exposed to PGD, and 10 fish of each host taxon were sampled at 24, 96, and 168 h. Fish were weighed, blood was collected and analyzed for a suite of physiological variables, and wet mount preparations of gill clips were examined grossly for the presence of cartilage breaks. The results of this study are consistent with the current knowledge regarding H. ictaluri infections in blue catfish, channel catfish, and blue catfish × channel catfish hybrids. Chondrocytic lysis was observed in channel catfish and hybrid catfish at 96 and 168 h but was not observed in bl...

Evaluation of a Diffused Oxygen Aeration System under On-Farm Harvest Conditions

Abstract The aeration effectiveness of a diffused oxygen system was compared with that of a tractor-powered paddlewheel during eight harvests of channel catfish Ictalurus punctatus at Top Cat II Fishery in Chicot County, Arkansas. Dissolved oxygen and water temperature data were collected from a grading net aerated by the diffused oxygen system, from a grading net aerated by a paddlewheel, and from the open culture pond between the two grading nets and were not significantly different. However, comparison of estimated oxygen consumption by the biomass confined in each grading net indicated that the aeration effectiveness of the diffused oxygen system equaled or exceeded that of a paddlewheel during six field trials. An informal cost comparison indicated that a diffused oxygen system can be placed in service for a smaller capital investment than a tractor-powered paddlewheel and that the hourly operating expense of the diffused oxygen system is comparable to that of the paddlewheel. Results of the study in...

Comparative Swimming Performance of Juvenile Blue Catfish and Hybrid Catfish

Abstract We compared the swimming performance of juvenile blue catfish Ictalurus furcatus and hybrid catfish (female channel catfish I. punctatus × male blue catfish) using a protocol in which fish were forced to swim at a fixed velocity and their time to fatigue recorded at speeds of 30–120 cm/s. Hybrid catfish swam significantly longer than blue catfish at all of the speeds tested except 30 and 40 cm/s. The maximum sustained swimming speed (no fatigue in times ≥200 min) was 30 and 40 cm/s for blue catfish and hybrid catfish, respectively. The maximum prolonged swimming speed (fatigue in times >20 s but <200 min) was 100 cm/s for blue catfish and 120 cm/s for hybrid catfish. The burst swimming speed (fatigue in times <20 s) for blue catfish was 110 cm/s. The burst swimming speed for hybrid catfish was not determined; however, it is higher than its maximum prolonged swimming speed of 120 cm/s (highest speed tested). Hybrid catfish were able to swim longer before fatiguing than were blue catfish at 50 cm/s...

Biomass assessment in commercial catfish ponds

With increasing seafood demand aquaculture is poised to become a major growth industry in the United States in the 21st century. In particular channel catfish represent an approximately

Swimming Performance and Metabolism of Cultured Golden Shiners

260 million industry in Mississippi with strong growth potential. A major portion of the costs associated with raising channel catfish are related to the cost of feed and aeration which are directly related to the total number of fish being raised in each pond. Crop insurance and bank loans are also contingent upon accurate population estimates. A high frequency, horizontally scanning, active pulse echo sonar system, the Aquascanner, has been developed to estimate pond populations. Commercial catfish ponds are typically 2 to 10 acres and, unlike many offshore fisheries, have fairly shallow depths of 1 to 2 m. The system components and its use will be presented along with results from field tests. [Work supported by US Dept. of Agriculture.]

Estimating Liquid Oxygen Requirements for Aeration of Fasted Channel Catfish

Abstract Swimming performance and metabolism of golden shiners Notemigonus crysoleucas were examined by use of swim tunnel respirometry. The oxygen consumption and tail beat frequency (TBF) at various swimming speeds, an estimation of the standard metabolic rate (SMR), and the critical swimming speed (U crit) were determined for golden shiners that were tested in 10 groups of 5 individuals each. Oxygen consumption and TBF both increased as swimming speed increased. The mean U crit for the first, second, and third individual to fatigue in each group was 38.0, 41.7, and 47.2 cm/s, respectively. The SMR was estimated at 131 mg O2·kg−1·h−1 for fish averaging 5.3 g. The active metabolic rate averaged 150 ± 14 mg O2·kg−1·h−1 (mean ± SE) at 10 cm/s, increased to 163 ± 20 mg O2·kg−1·h−1 at 30 cm/s, and peaked at 177 ± 19 mg O2·kg−1·h−1 at 50 cm/s. Total aerobic cost of transport (0.36 cal·g−1·km−1; i.e., the metabolic cost of swimming) and net cost of transport (0.08 cal·g−1·km−1) were lowest between 30 and 40 cm/s.

The development and use of a high frequency horizontal sonar to monitor channel catfish in shallow water commercial aquaculture ponds

Abstract A review of the scientific literature concerning the respiration of channel catfish Ictalurus punctatus resulted in development of a Microsoft Excel spreadsheet for estimating the volume of oxygen consumed by a given fasted channel catfish biomass. Channel catfish farmers and live haulers using diffused oxygen aeration systems can use computed estimates of oxygen consumption as a guide for setting flow rates for diffusers placed in grading nets and haul tanks. Entry of eight variables into the spreadsheet provides estimates of oxygen gas consumption with respect to time and biomass, the liquid oxygen equivalent of that volume, liquid oxygen expense, and the ratio of liquid oxygen expense to gross revenue.