| Popis: |
Istraživanje je provedeno u razdoblju svibanj 2020. - srpanj 2021. godine na uzgajalištu lubina (Dicentrarchus labrax) i orade (Sparus aurata) u uvali Veli Bok, Cres. Od faze nasađivanja mlađi u kaveze praćeni su relevantni pokazatelji rasta obje vrste. Temperatura, koncentracija kisika i postotak zasićenosti mora kisikom redovito su mjereni. Uzorkovanje mora za mikrobiološku analizu obavljano je na kontrolnoj postaji i uzgajalištu na četiri dubine. Tijekom perioda istraživanja lubin je dosegao 187 g, a orada 196 g. Faktor konverzije hrane kod lubina kretao se od 0,21 do 1,53, a kod orade od 0,41 do 1,38. Indeks kondicije lubina bio je u rasponu od 1,78 do 3,22, a orade 1,74 do 2,75. Do kraja razdoblja istraživanja preživljavanje lubina iznosilo je 98,27 %, dok je kod orada bilo 87,8 %. Tijekom istraživanja nije zabilježena bolest koja bi uzrokovala mortalitet. Utvrđene vrijednosti E. coli i enterokoka na obje postaje uzorkovanja bile su manje od 10 MPN/100mL. Od potencijalno patogenih bakterija iz roda Vibrio, na uzgajalištu i kontrolnoj točki utvrđen je V. harveyi, dok je V. alginolyticus utvrđen samo na uzgajalištu. Do pojave bolesti tijekom perioda istraživanja najvjerojatnije nije došlo zbog male koncentracije bakterija u uzorcima i uravnoteženog uzgoja bez stresa. The research was conducted in the period May 2020 - July 2021 at the cage farm of sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) in the Veli Bok mariculture, Cres. Relevant growth indicators of both species were monitored since the settlement phase. Sea temperature, oxygen concentration and percentage of oxygen saturation were measured weekly. Sea water sampling for microbiological analysis was performed at the control station and farm at four depths. During the study period, sea bass reached 187 g, and gilthead sea bream 196 g. The food conversion factor in sea bass ranged from 0,21 to 1,53, and in sea bream from 0,41 to 1,38. The sea bass condition index ranged from 1,78 to 3,22, and sea bream from 1,74 to 2,75. By the end of the study period, the survival of sea bass was 98,27 %, while for sea bream it was 87,8 %. No disease was reported during the study that would cause mortality. Measured values of E. coli and enterococci at both sampling stations were lower than 10 MPN/100mL. Of the potentially pathogenic bacteria of the genus Vibrio, V. harveyi was identified at the farm and control site, while V. alginolyticus was identified only at the farm. Fish diseases during the study period did not occur most likely due to the low concentration of bacteria in the samples and balanced stress-free farming technology. |
