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| Effects of Snails Feeding Rates on Size, Yield and Survival of Chinese Mitten Crab Eriocheir sinensis |
| DONG Jiang-shui,CHEN Hong-jun,WANG Xin-hua |
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Abstract Juvenile (140 individuals/kg) Chinese mitten crab Eriocheir sinensis were randomly stocked into seven ponds of each 0.67 hm~2 with depth of 1.5 m at Cangxi 2814 fish farm in Gaochun county at a rate of 6000 ind/hm~2, and fed snails with feeding rate of 750, 1070, 2250, 4500, 5440, 5630 and 6750 kg/hm~2 to evaluate the effects of feeding rates on size, yield and survival of the crab. The test ponds were also polycultured with freshwater shrimp (Macrobrachium japonicum), mandarinfish (Siniperca chuatsi) and a few silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) juveniles. The results showed that the relationship between the crab yield (Z) and snail amounts (x) was expressed as Z=528.138+0.228x-0.000029x~2 (R~2=0.959) (P<0.05);the relationship between the crab size (Y) and snail amount (x) was expressed as Y=155.368+0.014x-0.0000017x~2(R~2=0.934)(P<0.05);the relationship between the crab survival (L) and snail feeding rate (x) was equated as L=52.208+0.018x-0.0000023x~2(R~2=0.957)(P<0.05). The optimal snail feeding rate was suggested to be 4500 kg/hm~2.
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Received: 25 November 2009
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