CAGE BREEDING OF WARM WATER FRESHWATER FISH SPECIES

Abstract

Sedamdesetih godina prošlog stoljeća i Hrvatska se aktivno uključila u suvremene europske trendove uzgoja riba u plutajućim kavezima. Osim s raznim vrstama morskih riba pokušalo se i s uzgojem pastrva, šarana, soma, ozimica i lososa. Od svih navedenih slatkovodnih vrsta uspostavljeni su čvrsti standardi samo za kavezni uzgoj kalifornijske pastrve. Uzgoj ostalih slatkovodnih vrsta riba u kavezima zadržao se na razini sporadičnih pokušaja više eksperimentalnog nego profitabilno komercijalnog tipa. Uporna nastojanja da se ovlada i tehnikom uzgoja toplovodnih vrsta slatkovodnih riba u kavezima proizlaze iz zapaženih prednosti takvog uzgoja poput jednostavnosti provedbe tehnoloških mjera, lakše uspostave uzgojnog sustava, jednostavnije manipulacije, mogućnosti gušćeg nasada na jedinicu volumena uz visoku razinu proizvodnje, lakše prilagodbe zahtjevima tržišta i manje početne investicije u objekte. Unatoč brojnih prednosti kao značajniji razlozi izostanka masovnije primjene tehnologije kaveznog uzgoja toplovodnih vrsta slatkovodnih riba navode se problemi u kontinuiranom osiguranju i nabavi odgovarajućih kategorija i količina zdrave mlađi za nasad, specifičnosti i promjenjivosti fizikalno kemijskih karakteristika recipijenta te ljudske pogreške. Valorizirajući nedostatke i prednosti konačna prosudba o opravdanosti uzgoja pojedinih slatkovodnih vrsta toplovodnih riba u kavezima mora se bazirati i na biološkim i na ekonomskim čimbenicima. Temeljem dosadašnjih spoznaja za uzgoj u kavezima, a pravilo vrijedi za gotovo sve sustave intenzivnog uzgoja, povoljna je samo ona vrsta riba za kojom postoji potražnja na tržištu i koja ima visoku cijenu. Tehnologija koja zahtjeva prehranu visokokoncentriranim hranidbenim smjesama uz ostale troškove proizvodnje je skupa te je s jeftinijim vrstama riba nemoguće postići rentabilnost. Pored toga proizvodnja mora biti marketinški orijentira tj. prije početka proizvodnje neophodno je provesti odgovarajuće mjere istraživanja tržišta (mogućnost plasmana) i ekonomske ili gospodarske promidžbe.In the 1970s, Croatia became actively involved in the contemporary trend of breeding fish in floating cages. In addition to various species of marine fishes, breeding was attempted with trout, carp, catfish, cisco and salmon. Of the above freshwater fish species, specific standards were established only for the cage breeding of rainbow trout. Cage breeding of the remaining species remained at the level of occasional attempts, with more of an experimental than a commercial character. The regular attempts to master this technique for cage breeding of warm water freshwater fish species were aimed at achieving the known benefits of such breeding, such as simplicity of implementing technological measures, easier establishment of the breeding system, simpler manipulation, the possibility of denser colonies per unit volume with a high level of production, easier adaptations to market conditions and fewer initial structural investments. Despite the many advantages, the main reasons for the lack of greater implementation of the cage breeding technology for warm water species of freshwater fish include problems in obtaining the appropriate category and quantity of healthy fry, the specificity and applicability of physical and chemical properties of the recipients and human error. In evaluating the advantages and disadvantages, the final decision on the justification of cage breeding for individual warm water freshwater species must be based on both biological and economic factors. Based on the knowledge of cage breeding acquired to date, the rule for virtually all intensive breeding systems is that it is only recommended for those species with high market demand and a high market price. The technology that demands nutrition with highly concentrated feed and other production expenditures is costly, and is therefore not profitable with less expensive fish species. Furthermore, production must be market oriented, i.e. the appropriate market research measures, and economic promotion, must be implemented prior to starting production

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