SERUM OSMOREGULATION IN 2 SPECIES OF ESTUARINE BLENNIOID FISH, ANOPLARCHUS-PURPURESCENS AND PHOLIS-ORNATA

1. 1. Blood serum osmoregulatory capacities were assessed for two species of estuarine blennioid fish exposed to a range of environmental salinities. 2. 2. Exposure to a range of environmental osmolality of 1800 mOsm/l resulted in a 300 mOsm/l. change in blood serum. Both species were similar in ranges of osmoregulation. 3. 3. Both species showed partial recovery of normal serum osmolalities after three days exposure to 56 ppt and are considered most efficient osmoregulators. 4. 4. It was concluded that a greater tolerance to osmotic stress than that observed for open coast littoral species enables inhabitation of more dilute estuarine habitats by these two blennioids. © 1979.