一、親蝦消毒方法欠妥。常規的消毒方法是用濃度為3%的de鹽yan水shui浸jin泡pao小xiao龍long蝦xia親qin蝦xia,這zhe對dui帶dai水shui運yun輸shu的de親qin蝦xia來lai說shuo是shi正zheng確que的de。但dan對dui離li水shui運yun輸shu的de親qin蝦xia而er言yan,用yong鹽yan水shui進jin行xing消xiao毒du將jiang加jia重zhong其qi脫tuo水shui症zheng狀zhuang,不bu利li於yu放fang養yang成cheng活huo率lv的de提ti高gao。建jian議yi用yong高gao錳meng酸suan鉀jia溶rong液ye替ti代dai鹽yan水shui對dui親qin蝦xia進jin行xing消xiao毒du。
二、親qin蝦xia放fang養yang時shi間jian不bu當dang。目mu前qian生sheng產chan上shang小xiao龍long蝦xia苗miao種zhong的de來lai源yuan基ji本ben是shi相xiang同tong的de,即ji投tou放fang親qin蝦xia自zi繁fan或huo購gou買mai蝦xia苗miao放fang養yang。部bu分fen養yang殖zhi戶hu在zai製zhi訂ding親qin蝦xia放fang養yang和he苗miao種zhong生sheng產chan方fang案an時shi常chang會hui出chu現xian一yi些xie不bu當dang之zhi處chu,如ru在zai上shang半ban年nian放fang養yang野ye生sheng親qin蝦xia進jin行xing蝦xia苗miao繁fan殖zhi等deng。
小龍蝦交配與產卵的適宜水溫為12-33℃,雖然3-5月份的水溫已達到產卵要求,但5月份之前的親蝦性腺尚未發育成熟,此期小龍蝦隻交配不產卵,蝦卵需經4-6個月的發育後才能進入Ⅳ期末,因此上半年放養的親蝦在下半年才能繁育蝦苗。
在自然條件下,小龍蝦的產卵和孵苗高峰期大多在9-11月,蝦卵經9-15天的孵化,即可孵出蝦苗。在華東地區80%以上的蝦苗在10-12月份孵出,因此隻要在8-10月份投放親蝦,就可以通過自然繁殖培育出供養殖所用的蝦苗。解剖小龍蝦親蝦可知,3月份有部分雌蝦的卵巢已發育至Ⅱ-Ⅲ期qi,通tong過guo投tou喂wei優you質zhi飼si料liao和he提ti升sheng越yue冬dong水shui溫wen,能neng加jia快kuai雌ci蝦xia的de性xing腺xian發fa育yu速su度du,並bing實shi現xian提ti前qian產chan卵luan和he孵fu苗miao。因yin此ci將jiang親qin蝦xia的de溫wen室shi越yue冬dong技ji術shu與yu池chi塘tang養yang殖zhi及ji稻dao田tian養yang殖zhi相xiang結jie合he,可ke形xing成cheng新xin的de養yang殖zhi模mo式shi,有you利li於yu小xiao龍long蝦xia養yang殖zhi產chan量liang和he效xiao益yi的de提ti高gao。
三、大da量liang施shi肥fei造zao成cheng水shui草cao死si亡wang。一yi些xie養yang殖zhi戶hu認ren為wei水shui草cao主zhu要yao起qi隱yin蔽bi作zuo用yong,其qi飼si料liao作zuo用yong不bu如ru浮fu遊you生sheng物wu重zhong要yao,因yin而er當dang水shui中zhong浮fu遊you生sheng物wu數shu量liang減jian少shao時shi,往wang往wang通tong過guo施shi肥fei的de方fang式shi加jia以yi調tiao節jie,池chi水shui透tou明ming度du因yin此ci大da幅fu度du下xia降jiang。當dang池chi水shui透tou明ming度du降jiang至zhi30厘(li)米(mi)以(yi)下(xia)時(shi),池(chi)中(zhong)的(de)水(shui)草(cao)因(yin)光(guang)合(he)作(zuo)用(yong)受(shou)阻(zu)而(er)難(nan)以(yi)生(sheng)存(cun)。水(shui)草(cao)死(si)亡(wang)不(bu)僅(jin)減(jian)少(shao)了(le)蝦(xia)苗(miao)的(de)飼(si)料(liao)來(lai)源(yuan),還(hai)會(hui)導(dao)致(zhi)水(shui)體(ti)自(zi)淨(jing)能(neng)力(li)下(xia)降(jiang)和(he)水(shui)環(huan)境(jing)惡(e)化(hua),最(zui)終(zhong)使(shi)生(sheng)物(wu)飼(si)料(liao)培(pei)育(yu)效(xiao)率(lv)及(ji)飼(si)料(liao)利(li)用(yong)率(lv)降(jiang)低(di)。這(zhe)種(zhong)養(yang)殖(zhi)方(fang)式(shi)不(bu)但(dan)生(sheng)態(tai)效(xiao)應(ying)差(cha),而(er)且(qie)最(zui)終(zhong)還(hai)將(jiang)影(ying)響(xiang)小(xiao)龍(long)蝦(xia)養(yang)殖(zhi)產(chan)量(liang)和(he)效(xiao)益(yi)。因(yin)此(ci)在(zai)小(xiao)龍(long)蝦(xia)養(yang)殖(zhi)過(guo)程(cheng)中(zhong)應(ying)對(dui)水(shui)草(cao)的(de)種(zhong)植(zhi)和(he)利(li)用(yong)予(yu)以(yi)足(zu)夠(gou)的(de)重(zhong)視(shi)。
四、對dui魚yu蝦xia混hun養yang的de互hu利li作zuo用yong認ren識shi不bu足zu。小xiao龍long蝦xia與yu魚yu混hun養yang是shi一yi種zhong值zhi得de推tui廣guang的de養yang殖zhi模mo式shi,這zhe是shi因yin為wei魚yu蝦xia混hun養yang可ke以yi互hu利li共gong存cun,魚yu吃chi剩sheng的de殘can餌er和he排pai泄xie物wu均jun可ke被bei小xiao龍long蝦xia利li用yong,減jian少shao飼si料liao浪lang費fei,不bu僅jin降jiang低di生sheng產chan成cheng本ben,而er且qie可ke以yi減jian少shao對dui水shui體ti的de汙wu染ran。因yin此ci利li用yong小xiao龍long蝦xia的de攝she食shi特te性xing開kai展zhan魚yu蝦xia混hun養yang,可ke以yi達da到dao互hu利li共gong生sheng的de目mu的de,同tong時shi也ye有you利li於yu養yang殖zhi效xiao益yi的de提ti高gao。
五、對dui小xiao龍long蝦xia自zi相xiang殘can殺sha特te性xing認ren識shi不bu足zu。小xiao龍long蝦xia的de自zi相xiang殘can殺sha特te性xing是shi阻zu礙ai養yang殖zhi產chan量liang提ti高gao的de重zhong要yao原yuan因yin之zhi一yi。試shi驗yan表biao明ming,親qin蝦xia對dui幼you體ti和he幼you蝦xia的de殘can食shi率lv較jiao低di,這zhe與yu親qin蝦xia具ju有you護hu幼you特te性xing有you關guan,而er親qin蝦xia對dui大da規gui格ge蝦xia苗miao的de殘can殺sha率lv則ze較jiao高gao。除chu此ci之zhi外wai,幼you蝦xia之zhi間jian的de自zi相xiang殘can殺sha率lv遠yuan高gao於yu成cheng蝦xia對dui幼you蝦xia的de殘can殺sha,尤you其qi是shi大da規gui格ge蝦xia苗miao對dui幼you蝦xia的de殘can食shi率lv高gao達da60%以上。因此大規格蝦苗及幼蝦間的自相殘殺行為是影響蝦苗成活率提高的主要因素。生產中應重視人工隱蔽物的設置,如投放水草、石棉瓦、塑料管和竹筒等供蝦苗和成蝦棲息與隱蔽,可起到降低自相殘殺率和提高養殖產量的作用。
六、盲(mang)目(mu)施(shi)肥(fei)造(zao)成(cheng)水(shui)質(zhi)惡(e)化(hua)。目(mu)前(qian)小(xiao)龍(long)蝦(xia)養(yang)殖(zhi)大(da)多(duo)采(cai)用(yong)肥(fei)水(shui)的(de)方(fang)式(shi)培(pei)育(yu)浮(fu)遊(you)生(sheng)物(wu)飼(si)料(liao),所(suo)施(shi)的(de)肥(fei)料(liao)以(yi)有(you)機(ji)肥(fei)和(he)複(fu)合(he)肥(fei)居(ju)多(duo)。但(dan)施(shi)肥(fei)後(hou)水(shui)體(ti)極(ji)易(yi)缺(que)氧(yang),同(tong)時(shi)水(shui)體(ti)透(tou)明(ming)度(du)的(de)下(xia)降(jiang)導(dao)致(zhi)水(shui)草(cao)死(si)亡(wang)和(he)腐(fu)爛(lan),並(bing)導(dao)致(zhi)水(shui)域(yu)生(sheng)態(tai)環(huan)境(jing)進(jin)一(yi)步(bu)惡(e)化(hua)。合(he)理(li)的(de)施(shi)肥(fei)方(fang)式(shi)是(shi)將(jiang)有(you)機(ji)肥(fei)埋(mai)入(ru)底(di)泥(ni)中(zhong),並(bing)在(zai)池(chi)坡(po)適(shi)量(liang)堆(dui)肥(fei),這(zhe)樣(yang)可(ke)培(pei)育(yu)出(chu)大(da)量(liang)底(di)棲(qi)生(sheng)物(wu)供(gong)親(qin)蝦(xia)和(he)蝦(xia)苗(miao)攝(she)食(shi)。水(shui)體(ti)要(yao)求(qiu)肥(fei)度(du)適(shi)中(zhong),透(tou)明(ming)度(du)為(wei)30-40厘米。當水草生長旺盛時,透明度可提高至60厘米以上。夏季水溫較高,合理施肥可防止蝦苗缺氧和養殖環境惡化,因此目前全池潑灑的施肥方式應當予以改變。
七、不bu注zhu意yi及ji時shi換huan水shui。一yi些xie養yang殖zhi戶hu認ren為wei小xiao龍long蝦xia可ke以yi在zai汙wu水shui溝gou中zhong生sheng存cun,對dui水shui質zhi要yao求qiu不bu高gao。事shi實shi上shang,在zai人ren工gong養yang殖zhi條tiao件jian下xia,水shui質zhi汙wu染ran是shi小xiao龍long蝦xia大da批pi死si亡wang的de主zhu要yao原yuan因yin之zhi一yi,適shi量liang換huan水shui不bu但dan有you利li於yu改gai善shan水shui質zhi,而er且qie可ke以yi刺ci激ji小xiao龍long蝦xia蛻tui殼ke,有you利li於yu加jia快kuai生sheng長chang速su度du和he提ti高gao產chan量liang。但dan過guo於yu頻pin繁fan的de換huan水shui也ye會hui增zeng加jia電dian費fei或huo油you費fei支zhi出chu。合he理li的de方fang法fa是shi:高溫季節每半個月換水1-2次,每次換水1/4左右。若水質狀況較差,可以施生物有機肥替代普通有機肥。
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