| ligictaluridus michaelalicea n. sp. (monogenea: dactylogyridae) from flathead catfish (pylodictis olivaris) in the upper mississippi river, including remarks on taxonomy influencing monogenean treatment regulation in the united states. | ligictaluridus michaelalicea n. sp. (monogenea: dactylogyridae, ancyrocephalinae) is described from the gills of pylodictis olivaris (siluriformes: ictaluridae) from wisconsin and iowa portions of the upper mississippi river. diagnostic features include a relatively large, strongly curved tubular cirrus with minor terminal flare; an accessory piece with a prominent basal lobe and a simple, thick terminal limb featuring a thin lateral flange and blunt distal tip devoid of recurved hooks. the sini ... | 2018 | 29362870 |
| seasonal concentrations of dieldrin in water, channel catfish, and catfish-food organisms, des moines river, iowa--1971-73. | concentrations of dieldrin in aquatic insects, crayfish, minnows, and small carpsuckers, and muscle tissue of channel catfish (ictalurus punctatus) were compared with the dieldrin content of des moines river water in 1971-73. monthly mean concentrations of dieldrin in river water and most aquatic organisms were highest in june and july, soon after aldrin had been applied to corn land in the watershed. several groups of aquatic organisms also exhibited high dieldrin levels in the fall when the di ... | 1976 | 1264575 |
| variations in ddt concentration in muscle tissue of channel catfish, ictalurus punctatus, from the des moines river, 1971. | concentrations of ddt in muscle tissue of channel catfish, ictalurus punctatus, from the des moines river, iowa, were compared in relation to length, age, sex, and fat content. residue concentrations were not correlated with sex. although residue concentrations were significantly correlated with size-related factors and fat content, they varied widely. therefore, predictions of ddt concentrations in individual catfish on the basis of length, age, or muscle fat content may be grossly inaccurate. | 1978 | 673660 |
| persistence of dieldrin water and channel catfish from the des moines river, iowa, 1971-73 and 1978. | this study was conducted to determine if dieldrin concentrations in water and fish of the des moines river, iowa, decreased after registration of the compound was withdrawn by the environmental protection agency in 1975. mean june concentrations of dieldrin in river water decreased from 50 ppt in 1971 to 11 ppt in 1978. average daily transport of dieldrin was 156 g in 1971 and 70 g in 1978. july levels in channel catfish muscle were 75 ppb in 1973 and 46 ppb in 1978. dieldrin was still present i ... | 1981 | 7312556 |