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The article discusses a study which investigated the association between improved body condition and superabundant food at catfish aquaculture facilities in American White Pelicans (Pelecanus erythrorhynchos). The study was conducted in four geographic regions in Mississippi and Louisiana. It was observed that Pelicans that foraged on catfish during spring have better physical condition.

Samples of water supply and effluent were collected from five commercial hatcheries for channel catfish Ictalurus punctatus in northwestern Mississippi. Hatcheries were visited three times at 2-week intervals during the peak of the catfish spawning season. Samples were analyzed for total suspended solids, soluble and total phosphorus, total ammonia, total nitrogen, and 5-d biochemical oxygen demand (BOD5). Net pollutant loads (effluent concentration minus inflow concentration) were low for all variables. Maximum average net loadings were 10.7 mg/L for total suspended solids, 0.13 mg/L for total phosphorus, 0.28 mg/L for total nitrogen, and 2.07 mg/L for BOD5. Because net pollutant loadings were low and groundwater supplies initially had low concentrations of solids and organic matter, effluents were of excellent quality with respect to those variables. Four of the groundwater supplies contained substantial background levels of phosphorus or nitrogen; accordingly, effluents from those hatcheries had moderate levels of those substances. The highest average effluent concentrations (ranges for all samples in parentheses) were as follows: total suspended solids, 12.3 mg/L (7-19 mg/L); soluble reactive phosphorus, 0.36 mg/L (0.007-0.390 mg/L); total phosphorus, 0.45 mg/L (0.15-0.53 mg/L); total ammonia nitrogen, 0.49 mg/L (0.13-0.57 mg/L); total nitrogen. 0.60 mg/L (0.19-0.72 mg/ L); and BOD5, 3.03 mg/L (0.85-4.03 mg/L). These concentrations are lower than the corresponding concentrations in most potential effluent-receiving streams in northwestern Mississippi, and total effluent volume from catfish hatcheries constitutes less than 0.02% of total annual streamflow in the region. It is therefore unlikely that catfish hatchery effluents will have a negative effect on receiving stream water quality. [ABSTRACT FROM AUTHOR]

We evaluated the effectiveness of weekly low-dose applications of copper sulfate (0.12 mg of Cu/L of water) for reducing the prevalence of off-flavor in channel catfish Ictalurus punctatus on commercial farms. The study was conducted over 3 years in ponds (3.2-8.4 ha) on two catfish farms in western Mississippi. Farm managers applied copper sulfate (0.5 mg of copper sulfate pentahydrate/L of water) weekly beginning in the late spring or early summer and continued until the water temperature dropped below 20°C. Water samples were collected from treated and untreated ponds approximately every 3 weeks during the application period and were monitored for levels of the musty compound 2-methylisoborneol (MIB), chlorophyll a, and phytoplankton community structure and abundance. In addition, channel catfish were caught from each study pond during the third year of the study and were checked for flavor. Levels of MIB and the abundance of the MIB-producing cyanobacterium Oscillatoria perornata were significantly lower in treated ponds than in control ponds at one farm, while numbers of green algae and diatoms at both farms were significantly higher in treated ponds than in control ponds. Also, fish flavor analysis indicated that the overall prevalence of all types of off-flavor was 50% lower in treated ponds than in control ponds. Based upon our results, weekly low-dose applications of copper sulfate appear to be beneficial in mitigating musty off-flavor problems in commercially produced channel catfish. Copper sulfate treatment reduced potential harvest delays by nearly half and reduced costs associated with off-flavor by 35%. However, the economic benefit of treatment was not statistically significant, although this result is probably attributable to the small data set used for economic analyses rather than ineffectiveness of treatment. [ABSTRACT FROM AUTHOR]