The influence of salinity and temperature change on the functioning of the urinary bladder in the early larval stages of the atlantic herring Clupea harengus L.

Major changes in the morphology of the urinary bladder were observed during the transition from yolk-sac to feeding larval stages of herring, in particular bladder volume increased almost sixfold. Initially, the urine flowed into the hindgut, but within days of hatching a separate urinary duct, leading to the exterior, had formed. Micturation was intermittent but quite regular.

Inducibility of metallothionein mRNA expression and cadmium tolerance in larvae of a marine teleost, the turbot (Scophthalmus maximus).

An acute (48-hr) lethal toxicity study of turbot at various stages from hatch to juveniles showed that prior to first exogenous feeding, larvae of turbot were an order of magnitude more sensitive to cadmium toxicity than later developmental stages (LC50 of 0.18-0.23 ppm Cd versus 2-5 ppm Cd).

Hypoosmoregulation of larvae of the turbot, Scophthalamus maximus: drinking and gut function in relation to environmental salinity.

Measurement of blood osmolarity of pre-metamorphic turbot larvae demonstrated that hypoosmoregulation is well established in larvae 6 days post-hatch (121 degree-days) and older. Blood osmolarity of 121-420 degree-day larvae reared in 100% seawater was significantly greater than blood osmolarity of larvae reared in 50% seawater. Hypoosmoregulation involved drinking, but instantaneous drinking rates of 340 degree-day larvae reared in 100% seawater were only slightly more than those of similarly aged larvae reared in 50% seawater.

Morphology of the pronephros of the juvenile brown trout, Salmo trutta.

The pronephros in juvenile brown trout (Salmo trutta) consists of a large ovoid renal corpuscle and a pair of tubules. The corpuscle is retained for 11 months, after which the glomerulus regresses. The glomerular arteries come directly from the dorsal aorta.

The structure of the head kidney in the mudskipper, Periophthalmus koelreuteri (pallas).

The head kidneys of adult Periophthalamus koelreuteri contain many functional glomerular nephorns which on the basis of this histochemical study, are indistinguishable from those of the typical opistonephros of marine teleosts. The anterior lobes resemble, in location and in the presence of intertubular erythropoeitic tissue, the pronephros in other species. The single nephron found there, however, does not differ significantly from the other nephrons of the head kidney.