Publication Date:
2021-07-12
Description:
Survival of C. gariepinus hatchlings from different sizes of brood stocks and separation of the hatchlings from egg shells and unhatched eggs using incubating net hapas were examined under indoor hatchery condition in glass aquaria tanks using well water. The net hapas were constructed using net with mesh size 1 mm which with held normal size or fully grown fish egg but allowed hatchlings from the eggs to pass out of the hapa into the incubating tank. The hapa facilitated easy separation of hatchlings from egg shells and dead eggs, only small undeveloped eggs passes through the hapa because they were smaller than the mesh size. The use of incubating net hapa with kakabans inside did not have any effect on incubation period, hatching and survival of the hatchlings. The eggs hatched normally within 24 hours at temperature range of 26 27degreesC. About 98% hatching and separation of the hatchlings from egg shells was achieved. Survival of hatchlings was enhanced because pollution due to decaying eggshells and unhatched eggs was eliminated. The same experiment was used to test survival of hatchlings from broodstocks of varying sizes (500gm, 350gm and 250gm). The survival and mortality rate of hatchlings from the three different brood stock sizes were 77.3% mortality, 22.7% survival, 75.9% mortality, 24.1% survival and 68.1% mortality, 31.9% survival for 500gm ,350gm and 250gm broodstocks respectively. Statistically, there was no significant difference (P〉0.05) in survival and mortality rate of hatchlings from different sizes of broodstocks. Fecundity obtained from the brood stocks were 42,972; 50,925 and 80,878 for 250g, 350g and 500g broodstocks, respectively.
Description:
Includes:- 4 tables.;1 plate.;11 rfs.
Keywords:
Aquaculture
;
Clarias gariepinus
;
Nigeria
;
freshwater environment
;
Fish culture
;
Hatching
;
Eggs
;
Hatcheries
;
Incubators
;
Floating cages
;
Survival
;
Length-weight relationships
Repository Name:
AquaDocs
Type:
conference_item
,
TRUE
Format:
application/pdf
Format:
application/pdf
Format:
224 - 228
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