Publication Date:
2021-05-19
Description:
The research project have been formulated to find-out bio-technique
for raising crayfish in soil ponds by given supplementary food .
Creation new prodactive activity with potential for export , increasing
job opportunity and enhancing aquatic-products were also the
contemplated aim of the schem . The investigation time planed for a six
months period in Gilan region ( Asstanehashraphyeh ) in the year of
1999.
Culture practice have been done in two test ponds ( treatment) with
four replicates ponds each with the surface of 400 m2
. The stocking
rate were between 20, 30 ind crayfish /m2
(200000 ind/ ha).
Crayfish seedlings collected , when they have been released from
female brooders and cultivated indoor with artificial feed in a 25 days
period reaching at theird stage of juvenile with mean length of 14 mm
and weight of 100 mg , these crayfish stocked in earthen ponds.
Of course 15 days befoore stocking the ponds natural production
strengthen by manure application and live- feed reached 3-5 mg/l.
The raising crayfish in addition to natural feed , supplied with
cincentrated feed , rice bran, chopped and whole Kilka also provided
slaughter -house residue . During culture period each 45 days the
biometric data of culture crayfish were gadered , since
slaughter- house waste affected water quality in ponds every month
50% of water in ponds discharged . The 15°c
could be considered as a
temperature which crayfish start active feeding in 30°c eating
temporarily stope as the temperature get lower , again food are taken
by crayfish . Aquatic _plants in the bottom and pond,s dike function as
forage for crayfish also as refuge .
Length and weight of the raising crayfish and survival rate at the
end of culture period in different replicates are as followes : In the first and second replicate ponds , the density of stocking were
20ind/m2
mean weight 16.4 g and 15.34 g and average length 8 cm and
7.8 cm respectively. In third and fourth replicate ponds crayfish
stocked 30 ind /m2
with mean weight of 11.1 g and 13.06 g with average
length of 6.9 cm and 7 cm respectively .
Survival rate from first until fourth replicates calculated 87.675% ,
94.112% , 85.291% and 69.033% respectively . The test yield
generalized per ha and calculated as followes :
With the density of 20 ind/m2
in first and second replicated the
production calculated 2875.74 kg and 2887.34kg respectively .
With cocentratin of 30 ind /ha in third and fourth replicates the
crayfish crop computed 2840kg and 2704 kg respectively .
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Different denesity
;
Monoculture
;
Crayfish
;
Astacus leptodactylus
;
Earthen ponds
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
37pp.
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