On the Acclimatization of Pelagic Fish Species Juveniles in a Closed Environment: An Atlantic Horse Mackerel Case Study

Understanding how fish species acclimatize to a new environment may help to improve aquatic/fisheries resource management. Further, baseline information specific to behavior patterns of (pelagic) fish species juveniles particularly during acclimatization appears unreported to best of our knowledge. Therefore, the current study was goaled to examine the acclimatization of pelagic fish species juveniles in a closed environment using Trachurus trachurus as a case reference. Eighteen Trachurus fish juveniles were maintained in well-kept seawater-filled aquarium under laboratory/room conditions of controlled temperature. The characteristic observations of fish aggregation, fish-to-feed movement and fish-feed selection that varied across begin (days 1-5), middle (days 6-15) and end (days 16-20) phases provided substantiations about either how and when Trachurus spp. juveniles started, increased and or achieved complete/full acclimatization behavior. The initial peak (laboratory/room = ~18°C; water = ~20°C) temperatures of 20-day acclimatization period would stabilize with time. Along with the abovementioned characteristic observations, water temperatures seemed to fluctuate more compared to laboratory/room. Overall, the current study provides noteworthy baseline knowledge about pelagic fish juveniles’ behavior(s)/pattern(s) in closed environment and useful reference for future acclimatization studies.