Influence of temperature conditions on the mobile fish hatchery efficency

The demand for angling native fish species and their conservation value are steadily increasing nowadays. Mobile fish hatchery developed by the Department of Aquaculture at MATE AKI allows for immediate on-site propagation after capturing the broodstock. Several experiments have demonstrated the usefulness of the system, but there are certain aspects changing dynamically such as temperature conditions due to the small size of system and environmental exposure, which require further investigation. In this study, applicability of mobile hatchery was compared with a closed recirculation hatchery system. Model species used in the experiments was the chub (Squalius cephalus L.). Results show the difference in daily heat input and average temperature between differently positioned Zuger jars in mobile hatchery; however, it does not affect hatching rate, larval mortality rate or body length of freshly hatched larvae. The closed recirculation system had a higher proportion of deformed larvae than the mobile hatchery; in addition, the hatching rate was positive in all Zuger jars. Based on statistical analysis, no statistically significant difference was detected in body length between Zuger. Body length of freshly hatched larvae in the closed recirculation system was significantly smaller than in case of groups incubated in Zuger jars 1 (P < 0.05) and 2 (P < 0.05). Results show that water temperature of mobile hatchery is affected by the temperature outside, but hatchery units provide optimal temperature for developing eggs even at low air temperatures.