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Geology topics

A.J. Mitchell

Publications and source records attributed to A.J. Mitchell.

At least 19 recordsLinked to original sources

Survival of the faucet snail after chemical disinfection, pH extremes, and heated water bath treatments

The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region and Montana. It is important to limit the spread of the faucet snail; small fisheries equipment can serve as a method of snail distribution. Treatments with chemical disinfection, pH extremes, and heated water baths were tested to determine their effectiveness as a disinfectant for small fisheries equipment. Two treatments eliminated all test snails: (1) a 24-h exposure to Hydrothol 191 at a concentration of at least 20 mg/L and (2) a treatment with 50°C heated water for 1 min or longer. Faucet snails were highly resistant to ethanol, NaCl, formalin, Lysol, potassium permanganate, copper sulfate, Baquacil, Virkon, household bleach, and pH extremes (as low as 1 and as high as 13).

Wisconsin↗

Nifurpirinol (Furanace: P-7138) related lesions on channel catfish Ictalurus punctatus (Rafinesque)

Skin lesions developed on channel catfish, Ictalurus punctatus , exposed to 0-5 mg/1 Furanace for 4 or 14 days. Lesions developed 3 days after the 4-day exposure and on the eleventh day of the 14-day exposure. The lesions continued to develop after the fish were moved to untreated water. The lesions which began as dull areas of skin, sometimes resulted in erosion of skin and muscle which exposed the vertebrae. Bacteria were not isolated from the lesions except those with severely eroded muscle. The gills possessed lesions characteristic of a response to a toxic chemical agent.

Journal of Fish Diseases↗

Toxicity and efficacy of Furanace on channel catfish Ictalurus punctatus (Rafinesque) infected experimentally with Aeromonas hydrophila

The 96-h medium tolerance limit of Furanace (nifurpirinol: P-7138) for channel catfish Ictalurus punctatus at 21°C was 0-94 mg/1. The most effective treatment level for channel catfish, experimentally infected with Aeromonas hydrophila , was 2mg/1 for 6.5 h. Furanace at 0.5 and 1.0 mg/1 in brain heart infusion agar reduced in vitro growth of A. hydrophila and at 2.0 mg/1 growth was completely.

Journal of Fish Diseases↗

Heteropolaria colisarum Foissner and Schubert, 1977 (Protozoa: Epistylididae) or North American freshwater fishes

The peritrichous ciliate ‘Epistylis sp.’ involved in the‘red-sore’ disease of various North American freshwater fishes is identified as Heteropolaria colisarum Foissner & Schubert, 1977. Its morphology is redescribed from observations of living and silver-stained organisms and biometrically analysed individuals. Extended zooids can be easily identified by their highly characteristic (elongated) body. Silver impregnations show a very high number of silverlines and a band-like, irregularly formed macronucleus. The genus Heteropolaria belongs to the family Epistylididae and is characterized by the eccentric location of the scopula of the swarmer and a peculiar myoneme in the peristomal disc that branches off the myoneme of the peristomal collar. Autochthonous occurrences of this species are known only from North America. In Europe only the related species H. lwoffi has been found. Histological sections give some evidence that the terminal platelet of the stalk is embedded in the dermal epithelium. This suggests that H. colisarum could be a parasite rather than an epizoon and that the often associated bacterium Aeromonas hydrophila is a secondary invader. However, further studies are necessary. Experiments showed a high infectivity of the ciliate and no host specificity. These characteristics are supported by the observations of other researchers. Preliminary laboratory tests showed that a single treatment with salt solution (NaCl) at a rate of 1.5% for 3h controlled H. colisarum.

Journal of Fish Diseases↗