Fish Hatchery Management - fisheries & aquaculture

t,.ISH HA'I'CI{ERY M ANAGL,M DN-I'00.31.0SMALL FISH SU RVIVESHORTEXPOSURE)) LETHAL IF EXPOSURE PROLONGED)E.U,Jt-JC'=z.lrlIxooUJJoC)(no2.03.04.05.0FISH SURVIVE, BUT GROWTH SLOWFOR PROLONGED EXPOSURE\ DESIRABLE RANGEFrcuRE 4. Effectsof dissolved oxygen on warm water pond fish.Milligrams/liter : parts per million. (Sourc", Swingle 196{).)concentrations near 4-5 parts per million, and these fish will die if it dropsbelow 3 parts per million. Walleye fry do not survive well in water containing3 parts per million dissolved oxygen or less. Low levels of dissolvedoxygen below 5 parts per million can cause deformities of striped bass duringembryonic development.NII'ROGENMolecular nitrogen (wz) may be fixed by some aquatic bacteria and algae,but it is biologically inert as far as fish are concerned. Dissolved nitrogenmay be ignored in fish culture so long as it remains at 100",' saturation orbelow. However, at supersaturation levels as low as 102')i it can induce gasbubble disease in fish.