Einfluss unterschiedlicher Kohlendioxid-Konzentrationen auf das Wachstum desSteinbutts (Scophthalmus maximus( L.)) = influence of varying carbon dioxide concentrations on growth of turbot (Scophthalmus maximus (L.))

• Main Author: Gronemeier, Marina
• Format: Thesis
• Language: German
• Published: 2012
• Subjects: Scophthalmus maximus; Turbot
• Online Access: https://oceanrep.geomar.de/id/eprint/54619/; https://oceanrep.geomar.de/id/eprint/54619/1/Dipl.%202012%20Gronemeier,%20M.pdf

Turbot (Scophthabnus maximus) is a highly marketable and therefore increasingly important aquaculture species. C02 enrichment in aquaculture, often resulting from high biomass and poor water quality, can have negative effects on fish health and growth. In the present study, the effects of C02 enrichment on growth performance of turbot in a recirculating aquaculture system were investigated. Fish were subjected to three different C02 treatments: high C02 concentrations of 32.15 ± 0.949 mg/1, medium concentrations of 19.11 ± 1.306 mg/1 and low concentrations of 4.08 ± 0.889 mg/1. C02 concentrations were determined once a week via alkalinity measming and fish weight, length and width was recorded once every two weeks. Oxygen saturation (minimum 7,09 ± 9.94 mg/I,), salinity (20-21) and temperature (17.8-18. l 0C) were monitored constantly during the experiment. Oxygen uptake rate (OUR), growth rates, condition factor, weight gain, food intake rate (FIR) and feeding ration were as well calculated as NH4 + excretion and O:N ratio for each treatment. There was a significant decrease in weight gain, growth rates, OUR and condition factor for increasing C02 levels. FIR decreased slightly for higher C02 concentrations, while at the same time a minor elevation in feeding ratio for these groups could be observed. O:N ratio was lower with higher C02 suggesting a change in metabolism due to C02. Apart from one fish in the high C02 treatment, that supposedly died from handling stress during measuring, no m011ality due to high C02 levels could be observed in this study. Based on this results, further examination of acclimatisation processes to long-term elevated C02 concentrations in turbot are recommended.