Results for “migrate”

In the Mekong, it has been observed to migrate upstream from Phnom Penh to Khone Falls between November and February, returning downstream between May and August. The downstream migration ends in the Mekong delta area in Vietnam, where the fish remain until the floods reach their peak in October and November. These lower Mekong migrations mostly comprise juveniles and sub-adults, whereas above Khone Falls...

A 2003 phylogenetic study by Hrbek and Meyer showed that in genetic terms specimens of A. fasciatus collected from different localities do not vary as much as with other members of the genus. The latter tend to exist in geographically separated populations and exhibit localised differentiation. While A. fasciatus does show certain disparities in appearance depending on locality it is thought that periodic migration events have restricted the development of genetic diversity within the species to...

Found in a number of habitat-types, though rarely in smaller tributaries, generally preferring deeper, flowing channels through which it travels for considerable distances at certain times of year. Like other large, migratory pimelodids these movements are typically associated with nutrient-rich, white water drainages rather than nutrient-poor black waters.

Study of B. rousseauxii has revealed that sexually mature adults are found only in the western Amazon, with no mature individual ever recorded east of Manaus despite the intensive commercial fishery operating there. The total distance covered by some populations during migration from the delta was as much as 5500 km, making it the longest known in any freshwater fish species.

This rich feeding ground is exploited until the sea water returns, at which point the catfishes begin to migrate upstream in massive numbers, moving up the Amazon and its tributaries. Sexually mature individuals are not normally recorded during these events so they're thought related to feeding and dispersal rather than spawning. The fish are subject to intensive capture by commercial and artisanal fishing operations during this upstream movement.

The Brycon genus is large, at present containing over 50 species. A number of these are very similar, a couple of which (B. rubricauda and B. orbignyanus) resemble B. cephalus quite closely. However this one is the most common in nature and is likely to be the species seen on sale most often. Commonly known as the matrinxã in Brazil, it has an interesting life cycle, migrating twice per year over large distances according to the season. The first movement occurs at the start of...

H. armatus should probably not be considered a home aquarium subject at all given its eventual size and migratory natural behaviour. Unfortunately, juveniles are seen for sale quite regularly, most often without adequate information regarding their long-term care, and it's common to see them being maintained in medium-sized aquaria with no possibility of achieving their potential.

This species is migratory on a seasonal basis; during the dry season it can be found in larger river channels, whereas during drier months it moves into smaller tributaries and flooded forests. Apparently displays a preference for rocky habitats and is not known to adapt to reservoirs or other artificial impoundments.

Some wild populations have evolved a complex amphidromous breeding strategy in which adults live and spawn in freshwater or brackish streams and the pelagic post-hatch larvae are washed downstream to the sea where the post-larval fry spend the first part of their life developing in estuarine nursery zones under brackish to full marine conditions. Once they reach a certain stage of development they begin to migrate upstream with some mov...

Semaprochilodus are one of the most common and widespread shoaling fish found in South America. Over a dozen species have been described but most are never imported. They are used as food fish in their native countries. It makes a stunning addition to a community of larger fish. Along with some congeners, S. insignis is commonly known as the Jaraqui in Brazil. It is an interesting species both ecologically and biologically. In nature it migrates over large distances in huge shoals according ...