The IXth and the Xth cranial nerves in Anguilla anguilla were transected, and the effects upon ion and water balance were studied in fresh water and sea water, and during transfer from fresh water and vice versa. In fresh water there is a slow demineralization due to an excess loss of Na and Cl ions. During freshwater to seawater transfer the eel survives only for 4-5 days. The fish do not drin...

Non-native aquatic species can be introduced in new areas through emptying of the ballast tanks, with a high impact on health, economy and environment. This is considered by the International Maritime Organization (IMO): (i) in 2004, the IMO adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments (BMW Convention) in orde...

1. Internal as well as external factors affecting water ingestion in the eel were analysed using oesophagus-cannulated eels. 2. Acute withdrawal of the blood induced an immediate drinking response in the freshwater eel, whereas infusion of a large amount of hypertonic saline interrupted the copious drinking observed in the seawater eel. 3. The freshwater eel responded to slow infusion of hypert...

Potassium turnover was studied in rainbow trout, Salmo gairdneri Richardson, adapted to fresh water or 22 %o sea water using K and Rb. Potassium space of the whole body increased with time and was about 5 mmol kg" after 20h, while Rb space under the same conditions was only about 0-5 mmol kg", indicating slow penetration of body K by Rb + , especially in muscle and red blood cells. Potassium in...

Micropuncture techniques have been used to investigate kidney function in lampreys adapted to hyperosmotic media. Plasma electrolyte concentrations were maintained well below corresponding concentrations in the external environment. Urine composition was variable, but generally showed high concentrations of magnesium, sulphate and chloride ions. Lampreys in 50% sea water produced urine which wa...

in the recent years, rapid growth of the world’s population and overutilization of fresh water resources have caused fresh water shortage crisis in the world. in spite of the agricultural activities in the northern beaches of iran and also severe decrease of the ground water level, it still has not taken any effective measures to desalinate caspian sea water in large scale. in this research, de...

Recent studies of the fluxes of sodium and chloride across euryhaline teleost fish have shown that acclimation to fresh water involves a sharp reduction in the flux of both ions (Evans, 1967 c, 1969; Motais, 1967; Maetz et al. 1967 a, b; Potts & Evans, 1967; Ports et al. 1967). It has been shown, at least in Fundulus heteroclitus (Potts & Evans, 1967), Tilapia mossambica (Potts et al. 1967), Xi...

To examine the functional differentiation of chloride cells in the yolk-sac membrane of tilapia (Oreochromis mossambicus) embryos, we developed a 'yolk-ball' incubation system in which the yolk sac was separated from the embryonic body and subjected to incubation in vitro. The yolk-ball preparation consists of the yolk and the covering yolk-sac membrane, which contains a rich population of chlo...

Preliminary experiments have been carried out to determine the main features of salt balance in adult salmon immediately following transfer to fresh waters, both neutral and acidic. The processes of adaptation from hypo-osmotic regulation in sea water to hyperosmotic regulation in fresh water must involve many rapid adaptations of the gills, kidneys and endocrine systems. From the practical poi...