An investigation on the effects of juvenile rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) monoculture and duo-culture farming in freshwater and seawater on growth performance

The objective of this study was to compare growth performance and feed conversion ratios of rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) juveniles in monoculture and duo-culture in freshwater and seawater under aquarium conditions. The fish were about ۲-months old hatchery-reared brook and rainbow trout with initial weights of ۰.۹۳۴±۰.۰۳۳ (n=۳۶۰) and ۱.۰۱۴±۰.۰۱۹ (n=۳۶۰) g, respectively. The juveniles were kept in ۱۰ L aquaria. Each aquarium contained ۴۰ fish: ۴۰ fish from each species for monoculture, ۲۰+۲۰ (rainbow trout+brook trout) fish from each species for duo-culture. The fish were in ۳ groups with three replicates in freshwater and seawater and ۱۸ aquaria were used. At the end of the ۴۵ day study; mean live weights of brook trout were ۲.۷۳۵±۰.۱۵۳ g, rainbow trout ۲.۹۲۵±۰.۲۶۲ g in monoculture and brook trout ۲.۳۵۴±۰.۱۸۶ g, rainbow trout ۳.۸۸۲±۰.۴۹۴ g in duo-culture in seawater, brook trout ۳.۰۸۸±۰.۰۸۵, rainbow trout ۳.۳۶۴±۰.۰۹۳ g in monoculture and brook trout ۲.۱۶۴±۰.۱۶۹, rainbow trout ۳.۹۴۸±۰.۱۲۴ g in duo-culture in fresh water. While there were similarities between brook trout and rainbow trout in monoculture groups in sea water and fresh water, some differences were realized in duo-culture (p<۰.۰۰۱).

Keywords:

Rainbow trout , Oncorhynchus mykiss , Brook trout , Salvelinus fontinalis , Polyculture , Growth Performance , Feed conversion ratio