Lizinga lemanti libalulekile ekufuyeni timfishi emantinilahlobile (aquaculture) eNingizimu Afrika njengoba kucinisa indzawo lephilile ngemanti kwentela timfishi.
Lizinga lelikahle lemanti lisita kukhula kwemfishi (emanti lasezingeni lelikahle = kukhula ngekushesha), kuvela kwetifo kanjalo nekuvela kanye nelibala lwetimfishi. Lizinga lemagi litfolwa ngetindlela letine:
Simo semanti
Tigaba temoya emantini
Tigaba te ammonia emantin
I-pH yemanti (tigadla te acid noma ialkaline)
Liningi lelizinga letinkinga temanti ngetimfishi letifuywa emantinilahlobile kungenca yemoya lonciphisekile, tigaba letiphakeme te ammonia noma tigaba letisetulu te pH. Letitinkinga tisedvute nalokuhlanganiswe etigabeni tetitjalo letisemantini.
Lokukhula kwaletitjalo emantini kushiyana ngelinani lemanutrients – Nitrogen (N) ne Phosphorus (P) – emantini. Lawa emanutrients angena kulelidamu nge:
Ngendlela yemanti (kungena kwemanti kulelidamu).
Kungena kwetinshwana leticinile ngesikhatsi setimvula letimatima (kugeleta).
Kudla kwetimfishi ngesikhatsi semjikelo wekukhicita.
Simo Semantic ekuFuyweni kweTimfishi
Imfishi yasemantini ikhula emkhatsini wa 14 na 18°C (16°C lowenta simo semantic) kepha emacembu lafutfumele lafana nemfishiyakati yelitinyolelicijile ikhula kahle emantini lafutfumele (20 kuya ku 30°C) futsi itilapia icolela timo temanti letiphakeme kakhulu nga 24 kuya ku 34°C.
Timfishi letihlala phansi emantini tiyincelencele kumanti lafutfumele. Simo sekushisa lesingetulu kwa 20°C singenta letimfishi kutsi time kukhula futsi kungakha letinye tinkinga tekukhicita, kufana nekukhula kwentinkinga tetifo netinkinga temoya, kuchaza Henk Stander mengeni lophetse wetebungcongcoshe te Aquaculture: Litiko Letilwane teSayensi, eNyuvesi yase Stellenbosch.
Leti tinkinga (tikhulisa ingoti yetilwane phindze kunciphise umoya) kuvame kubangwa titjalo letiningi emantini lafutfumele. Sitsi simo singafika ku 21°C nangetulu, kunakekela lokufanele kumele kwenteke khona kutovikeleka timfishi kutsi tingafi nekucala kwekuhluma kwetitjalo, titjalo tasemantini tibangwa kukhula kwesitjalo lesiluhlata sasibhakabhaka-naluhlata ngenombolo letsintfwa simo sekushisa lesiphakeme nebukhona bema nutrients. Lesitjalo sasemantini sikhulula tintfo letincane temakhemikhali fana nentfo lemantana yemhlaba-lenukako, geosmin. Loku kubanjwa timfishi nelushintjo lweluvelo lwenyama yemfishi.
Tigaba Temoya ekuFuyweni kweTimfishi
Letigaba temoya temanti ekufuyweni kwetimfishi letihlala emantinilahlobile kumele tibe ngu 5mg/L nangetulu kwaloko ngasosonkhe sikhatsi. Umangabe tigaba temoya emantini tiphansi kakhulu, letimfishi angeke tikhone kuphefumula kahle futsi titokhatsateka.
Tinkinga temoya tivame kubangwa titjalo tasemantini letincane. Leti titjalo letincane letiphotosynthesize naletikhokha umoya. Ngetigaba letijwayelwe taletitijalo tasemantini, kutobabete tinkinga.
Uma tigaba taleti titjalo tasemantini tikhula, letigaba temoya ngesikhatsi sasebusuku tingaba ngaphansi kuna 5mg/L futsi kutobabete tinkinga temoya emantini ngekusa lokulandzelako.
Kwesibili, umangabe inombolo lenkhulu yetitjalo tasemantini letincane tifa ngekushesha (ngendzaba yetimo telitulu letinemafu noma kufutfwa kwetitjalo), ligciwane lemoya likhula kakhulu kwentela kuncedza kubulala letitjalo tasemantini letifile. Lawamagciwane emoya adla umoya longehlisa tigaba temoya kumadamu ngekushesha phindze kubangge kukhatsateka etimfishini.
Tigaba te Ammonia kuManti Lamasha/Lahlobile
I-Ammonia iyincenye ye nitrogen (N) emantini. Ngaphandle kubekhona kungena kwe ammonia noma lamanti asesimeni semoya lomncane (kute kahle umoya), i-nitrogen leningi emantini itoba ngendlela ye nitrate, lekuyintfo lengasiyo lelimata timfishi.
I-Ammonia ivela ngendlela yephoyizini (i-ammonia lekhululekile) nalete-iphoyizini (ammonia lene iron) ngekwakheka kepha lokwakheka kwephoyizini ivame kubaphansi kuna 10% we ammonia lephelele. Kumanti lafutfumele (+20°C) ne pH lephakeme (8.5), iammonia yephoyizini itokhula.
Tigaba te ammonia tingeke takhe tinkinga emadamini ngaphandle nangabe ashona kakhulu (5m noma ngephansi kwaloko) kanye nemphumela lophansi ngephansi kwakunye. (‘Umphumela weMnyaka’ nguyona nombolo lapho khona lidamu leligcwele emanti ligcwaliswa yimvula noma kungena kwemanti).
I-pH yeManti eliDamu
Lamantin epH asitjela kutsi umangane lidamu line acid leningi noma ialkaline. I-pH ya 7 isemkhatsini. Emacembu etimfishi letihlala emantinilahlobile angamelana netigaba te pH ta 5 kuya ku 9.
Intfo lebalulekile lengakhulisa tigaba te pH kukukhula kwetitjalo letincane. Buningi baletitjalo letihluma emantini kungakhulisa letigaba te pH ikakhulu kumadamu lamancane emapulazini kuya etigabeni letingetulu kune pH 9 (ikakhulu emvakwemadina). Loku kungenca yekusuka kwe carbon dioxide ngesikhatsi senchubo ye photosynthesis. Lena pH lephakeme ifaka timfishi kutsi tikhatsateke.
Kunciphisa noma kutfutfukisa letitigaba, lushintjo lwemanti luyadzingeka, yengeta emantilamasha nakudzingeka. Ngaphandle kwaloko, yengeta straw lesicishe noma lekute.
Translated by Phindile Malotana