In the present study, the female Clarias batrachus, held under long photoperiod (13L:11D), were exposed to high water temperature either constantly (24 h) and/or in form of thermopulse of 6 h and 12 h durations, separately, at different times of the day/night cycle for six weeks during the early post-spawning and late post-spawning phases of its reproductive cycle. The effects of high water tem...

For modeling the electric organ discharge of Malapterurus electricus catfish we have set up the electromechanical scheme of the catfish as an electric dipole the charges of which are linked by a spring of stiffness k. We call this particular system of charges an oscillating electric dipole. Taking into account the main forces applied to this dipole and applying the Newton’s second law of motion...

A study on the fish assemblage of the Ipanema River, a small affluent of the Tietê River basin in southeastern Brazil, was performed aiming to look for structural patterns of species diversity in small lowland lotic environments. Fish samplings were performed every two months from June 2003 to April 2004 at four sample sites located on the lower stretch of the river. Local assemblage showed to ...

Following study of the external morphology and its unmatched variability throughout ontogeny and a re-examination of selected morphological characters based on many specimens of diplomystids from Central and South Chile, we revised and emended previous specific diagnoses and consider Diplomystes chilensis, D. nahuelbutaensis, D. camposensis, and Olivaichthys viedmensis (Baker River) to be valid...

1Universidade Federal de São Carlos, Departamento de Genética e Evolução. Rodovia Washington Luís (SP 310) Km 235, 13565-905 São Carlos, SP, Brazil. 2Universidade Estadual do Oeste do Paraná, Centro de Ciências Biológicas e da Saúde. Rua Universitária 2069, 85819-110 Cascavel, PR, Brazil. [email protected] 3Universidade Federal do Mato Grosso, Instituto de Ciências Biológicas e da ...

Phylogeographic relationships, the timing of clade diversification, and the potential for cryptic diversity in the Slender Madtom, Noturus exilis, was investigated using mitochondrial Cyt b, nuclear RAG2, shape analysis, and meristic and pigmentation data. Three well-supported and deeply divergent clades were recovered from analyses of genetic data: Little Red River (White River drainage) clade...

Lactate (LDH) and malate dehydrogenase (MDH) of white skeletal muscle of fishes acclimated to 20, 25 and 30 degrees C and thereafter submitted to hypoxia were studied in different substrate concentrations. Significant differences for LDH and MDH of white muscle enzyme activities are described here for the first time in Rhinelepis strigosa of fishes acclimated to 20 degrees C and submitted to hy...

The concentration of six heavy metals in channel catfish (Ietalurus punctatus) fillets from seven watersheds In Nebraska have been measured. With the exception of mercury, in no instance did levels exceed limits set by regulatory agents. Also, with the exception of mercury, concentrations of heavy metals did not differ significantly in the agricultural and industrial areas. Trans. Kansas Acad. ...

Between August 2000 and August 2001, 12,216 fish of 73 species were purchased from several local markets in Nakhon Nayok Province, Thailand, and examined for the presence of Gnathostoma larvae. Almost all species were fresh-water fish that had grown naturally, rather than raised commercially. Eight species were found to be infected with gnathostome larvae. The overall prevalence was 5.1% (626/1...

The fish may experience periods of food deprivation or starvation which produce metabolic changes. In this study, adult Rhamdia quelen males were subjected to fasting periods of 1, 7, 14, and 21 days and of refeeding 2, 4, 6, and 12 days. The results demonstrated that liver protein was depleted after 1 day of fasting, but recovered after 6 days of refeeding. After 14 days of fasting, mobilizati...