Reproduction of external fertilizing vertebrates is typically constrained to either fresh or salt water, not both. For all studied amphibians and fishes, this constraint includes immotile sperm that are activated after ejaculation only by the specific chemistry of the fertilizing medium in which the species evolved (fresh, brackish, or salt water). No amphibians can reproduce in the sea. Althou...

BACKGROUND Management and conservation of biodiversity requires adequate species inventories. The Yasuní National Park is one of the most diverse regions on Earth and recent studies of terrestrial vertebrates, based on genetic evidence, have shown high levels of cryptic and undescribed diversity. Few genetic studies have been carried out in freshwater fishes from western Amazonia. Thus, in cont...

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...

Collections of 'Echinorhynchus salmonis' from Britain and Ireland deposited in The Natural History Museum, London (1921.7.19.3-12 and 1952.10.30.122-127) were re-identified as Acanthocephalus clavula and Acanthocephalus lucii respectively. The amphipod, Pontoporeia affinis, European intermediate host of E. salmonis, does not occur in the British Isles, so it is concluded that E. salmonis is abs...

The purpose of this toxicity test was to determine the reliability and comparability of Cu++ toxicity on Gammarus fasciatus. The study was conducted to compare toxicity results for Rainbow trout, Salmo ~airdneri Richardson, another coldwater poikilotherm. Since G. fasciatus comprises a major portion of the diet of many freshwater fishes, it can be stated to be an "important" species (PATRICK et...

Systematic comparisons of the ecology between functionally similar fish species from freshwater and marine aquatic systems are surprisingly rare. Here, we discuss commonalities and differences in evolutionary history, population genetics, reproduction and life history, ecological interactions, behavioural ecology and physiological ecology of temperate and Arctic freshwater coregonids (vendace a...

Teleost fishes, living in fresh water, engage in active ion uptake to maintain ion homeostasis. Current models for NaCl uptake involve Na(+) uptake via an apical amiloride-sensitive epithelial Na(+) channel (ENaC), energized by an apical vacuolar-type proton pump (V-ATPase) or alternatively by an amiloride-sensitive Na(+)/H(+) exchange (NHE) protein, and apical Cl(-) uptake mediated by an elect...

Previous studies have recorded Spironucleus torosus Poynton et Morrison, 1990 from several species of gadoid fishes, including the only freshwater gadoid, the burbot Lota lota (L.). Two morphologically different isolates of S. torosus have been described (elongate and pyriform). Both have been found in saltwater, while only the elongate has been found in freshwater. To address the conspecificit...

The present work is part of a process to create a Catalogue of the Freshwater Fishes of Colombia and consisted in the depuration and updating of the taxonomic and geographic components of the checklist of the freshwater fishes of Colombia. An exhaustive revision of the 1435 species recorded in 2008 was necessary to: 1. Add new species described since 2009 and species originally described from C...

Euryhaline fishes, such as the red drum (Sciaenops ocellatus), must quickly transition between hyperosmotic and hypoosmotic physiological strategies. When freshwater individuals transition to seawater they are exposed to increased diffusive water loss and ion gain. To maintain osmoregulatory balance these animals must drink and absorb seawater through the intestine, followed by ion excretion at...