Fish Hatchery Management - fisheries & aquaculture

I36FISH HATCHERY MANAGEMEN.ITeBr-n 17. coNTTNUEDSPAWN I NC;I'!-MPERA I'URIll(;(is PI]i.POT NI)l REquFrNc\OP'|I}IT]M SI'A\\'NI\(; OI }ISIILargemouth bassAnnual33 95'5 5-lr0'(i0 (irl'I 3,0(X)Smallmouth bassAnnual33 90"50 70"r;ti (i2"1J,000BluegillIntermittentil3-95 "55 lJO'(i5 80'50,(x)0Golden shinerIntermittent3 3-90"50 r]O'(i5-l.t0'7 5,(X)0GoldfishIntermittent3lJ-t)5'.15 ll0'55 80"50,0(x)American shadAnnual33 l.iO'.15 70'50 (i:r'7 0,000Common carpIntcrmittentSemi-annuallyllii 95'5.5-n0'rl5 1.i0'{i0,(xx)broodfish of this species relatively simple. Eggs can be obtained from oneyear-oldfish that have reached a size of0.7-1.0 pounds. Brood bass can beexpected to spawn satisfactorily for three to four seasons and should bebetween 3 and 4 pounds at the end of this time. It is suggested that onethirdof the broodstock be replaced each year. The food organism can bereared on the station or purchased from outside sources. As a minimumstandard, enough food should be provided to produce a weight gain in thebroodstock of 5091, per year. For largemouth bass, as an example, 5 poundsof forage food produce about I pound of fish gain, in addition to the 3Pounds of forage per pound of bass required for body maintenance. Thus, al-pound bass being held for spawning should be provided a minimum of5.5 pounds of forage fish.Fish typically lose 10-20,q0 of their body weight during the spawningseason. Much of this is due to the release of eggs and sperm, and is mostpronounced in females. Feeding may be interrupted during courtship orduring periods when the nest and fry are protected against predators. Notall species protect their young, but male largemouth bass, bluegill, and othersunfishes do. This weight loss must be regained before subsequent eggsand sperm are developed. Feeding schedules should reflect the nutritionalstatus of the fish and be tailored to their respective life histories.Close attention should be given to the quality and availability of theforage fish provided. The forage should be acceptable to the cultured fish