Fish Hatchery Management - fisheries & aquaculture

HATCHERY REqL. TRL,NIENTSl5TABLE 2. sriccLS lL,D cHFrMrcAL vAr.LrF,s F()R HAi ctu,rRy wA.t t,.R sLrppt-n.rs. coNct,rNTRATION ARE IN pARTS pF-R t\4 Il.t.tuN lppMl ls()URClt: H()!\iAu.t) N. LARsuN. LtNpLrBLISHED.]VARIAI]I,IDissolved oxygenCarbon dioxideTotal alkalinity (as CaCOr)'1,'as phenolphthalein'rLras methyl orange"', as ppm hydroxide1rl,as PPm carbonate1i, as PPm bicarbonatepH'fotal hardness (as CaCOq)Calciu mMagnesiumManganescIron (total.)lerrous ionl'erric ionPhosphorousN itrateZincHydrogen sulfide5 saturation0 l0I0.10002575 l0002575 100(i.5 lt.0l0 .100,1 I(t0Needed for buffer systcm0 0.0I0 0.15(,0.50.01 3.00 lJ.00 0.050\{.\R\1 \\'l t uR5 saturation0 1550 .1(X)0..1060 I (X)00 ,107r 100(i.5 1).050 .100I0 I(t00 0.0I0 0.500 0.ri0.0l 3.00 lJ.0same0ponds. It also restricts light penetration, thereby limiting photosynthesisand the production of desirable plankton in earthen ponds.PesticidesMany pesticides are extremely toxic to fish in the low parts-per-billionrange. Acute toxicity values for many commonly used insecticides rangefrom 5 to 100 microgram/liter. Much lower concentrations may be toxicupon extended exposure. Even if adult fish are not killed outright, longtermdamage to fish populations may occur in environments contaminatedwith pesticides. The abundance of food organisms may decrease, fry andeggs may die, and growth rates of fish may decline. Pesticides sprayed ontofields may drift over considerable areas, and reach ponds and streams. Ifwatersheds receive heavy applications of pesticides, ponds usually are notsuitable for fish production.Suggested water quality criteria for salmonid and warmwater fishes arepresented in Tables I and 2.