The distribution of non-essential trace elements in some vital organs of 11 fish species from Aiba Reservoir, Iwo, Nigeria was assessed between November 2010 and June 2011. The fish species belong to seven families; family Mormyridae, family Cyprinidae, family Hepsetidae and family Channidae each with one species; family Bagridae and family Clariidae each with two species; and family Cichlidae ...

The study assessed adoption of improved fish pond management technologies among fish growers in Benue State, Nigeria. Stratified, purposive and simple random sampling techniques were used in selecting 221 respondents. Primary data were collected using structured questionnaire. Data collected were analysed using both descriptive such as frequency distribution tables and inferential statistics su...

Figure 1. Types and distribution of electric fish. Species of electric fish can be found in freshwater rivers of Africa and South America, as well as marine environments. Marine species are depicted in blue, freshwater species in yellow. Strongly electric fish use electricity to stun their prey, while weakly electric fish use electricity for sensing and communication. The waveform above each fi...

the systematics, morphology, distribution, biology, economic importance and conservation of the spiny eel ( mastacembelus mastacembelus ) of iran are described, the species is illustrated, and a bibliography on this fish is provided. the single species is distributed in southern iranian basins, including karkheh, karun, jarrahi and helleh river basins, mostly part of the tigris river and persia...

We present a simulation of the electrosensory input of the weakly electric fish Apteronotus leptorhynchus. This fish senses its environment by producing a sinusoidal voltage difference between its body and tail sections, causing an electric field and a current distribution in the surrounding water. If an object is nearby which has different electrical conductivity from the surrounding water, th...

Geographical barriers influence species distribution and play an important role in the segregation of fish assemblages. The present study aims to test the influence of a small natural barrier on the spatial distribution of fish species in the Verde River, Upper Paraná River Basin, Brazil, considering two biotopes: upstream and downstream of the Branca Waterfall. We observed the highest species ...

Although there are a number of papers on how fish swim (Gray, 1957; Aleev, 1969; Lighthill, 1969), we have been unable to find any measurements of the pressure on the body surface measured while a fish is swimming. A preliminary calculation using the Pitot equation indicated that the pressure against the anterior surface of the fish, expressed in centimetres of water, would be approximately equ...

The transparency-gradient hypothesis argues that ultraviolet radiation (UV) is a primary determinant of the vertical distribution of zooplankton in transparent lakes with fewer fish, while fish predation is the primary driver in less transparent lakes where fish are more abundant. We measured vertical profiles of UV, photosynthetically active radiation (PAR, essentially visible light used as a ...