高温季节池塘种植水葫芦对河蟹生长及水质调控的影响

Effects of Eichhornia crassipes planting in crab ponds on the growth of Eriocheir sinensis and water quality regulation in high temperature season

摘要:

持续高温往往会造成蟹塘内的伊乐藻等水草衰亡,不利于河蟹的生长发育。为探明高温季节池塘种植水葫芦对河蟹生长及水质调控的影响,对养殖“诺亚1号”河蟹的池塘设置3组不同的水草种植模式,即无草塘补种水葫芦组(EI)、有草塘无处理组(EL)和有草塘补种水葫芦组(EIL)进行了为期3个月的试验,比较各组试验塘的水质、水草长势情况以及河蟹的体质量、产量、残蟹率、回捕率等。试验结果显示:EIL组的伊乐藻保存较好,且在高温季节池塘水温低于其他两组；EI组河蟹的体质量、产量、回捕率显著低于EIL组(P＜0.05),残蟹率显著高于EIL组(P＜0.05),但EI组各项指标与EL组相比没有显著差异(P＞0.05)。水质调控方面,EIL组NH₄⁺-N、NO₂^--N、TN、TP等水质指标均优于其他两组；8月份EL组的NH₄⁺-N质量浓度显著低于EI组(P＜0.05),9月份以后,EL组的NO₂^--N、TN质量浓度均显著高于EI组(P＜0.05)。结果表明,高温季节在无草蟹塘适当补种水葫芦对河蟹生长有积极作用,沉水性+浮水性水生植物的组合型水草种植模式可有效提高河蟹产量,改善池塘水质。

Abstract:

The continuous high temperature always causes the decline of the existing waterweed in adult Eriocheir sinensis culture ponds,which is detrimental to the growth and development of crabs.To explore the effects of water hyacinth (Eichhornia crassipes) planting on adult E. sinensis culture performance and water quality during the high temperature season,a culture experiment was carried out on “Noah 1” crab mono-sex(female) culture ponds with three experimental treatments,including reseeding water hyacinth in grassless pond(EI), unseeded grass pond(EL) and reseeding water hyacinth in grass pond(EIL).The results showed that the EIL treatment had better preservation of waterweed and lower water temperature than other treatments during the high temperature season.Crabs in EIL treatment also exhibited significantly higher average body weights,output and recapture rate,as well as significantly lower residual rate,than the EI treatment(P＜0.05).In terms of water quality,the levels of NH₄⁺-N,NO₂^--N,TN and TP in the EIL treatment were better than other two treatments.The mass concentration of NH₄⁺-N in EL group was better than that in EI group in August,but the concentrations of NO₂^--N and TN in the EL group were significantly higher than those in the EI group after September(P＜0.05).Above all,water hyacinth planting in grassless ponds has a positive effect on growth performance of E. sinensis during high temperature season,and the combined planting of submergent and floating water plants can effectively increase crab output and improve water quality.This research can provide effective emergency measures and theoretical basis for E. sinensis farming during the high temperature seasons.