Environmental stimuli improve learning capability in striped knifejaw juveniles: the stage-specific effect of environmental enrichment and the comparison between wild and hatchery-reared fish

• Published in: Fisheries science Vol. 81; no. 6; pp. 1035 - 1042
• Main Authors: Makino, Hirona, Masuda, Reiji, Tanaka, Masaru
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.11.2015; Springer Nature B.V
• Subjects: Analysis; Animal behavior; Biomedical and Life Sciences; bricks; Environmental effects; environmental enrichment; Experiments; Fish; Fish & Wildlife Biology & Management; Fish hatcheries; Fisheries; Fisheries management; Food Science; Freshwater & Marine Ecology; Habitats; juveniles; learning; Life Sciences; Marine; Oplegnathus fasciatus; Original Article; plastic pipes; rearing; Science education; seagrasses; Studies; tanks; viability; wild fish; Stock enhancement; Habitat complexity; Environmental enrichment; Critical period; Behavioral ontogeny; Reward conditioning; Y-maze
• ISSN: 0919-9268; 1444-2906
• DOI: 10.1007/s12562-015-0917-0

Hatchery-reared fish often show different behavioral traits from their wild counterparts, possibly due to the lack of environmental stimuli. Here, we aimed to reveal the stage-specific effect of environmental stimuli on the development of learning capability in striped knifejaw Oplegnathus fasciatus. The fish were raised for 15 days (50–65 days post-hatch) or 30 days (50–80 or 90–120 days post-hatch) in either conventional rearing tanks (control) or in a structurally enriched tank containing bricks, artificial sea grass, and plastic pipes (enriched environment), and were examined for learning capability using Y-maze reward conditioning. The learning capability of wild juveniles was also examined, and their scores were compared with those of hatchery-reared fish (which we previously reported). Only fish in the 50–80 days post-hatch enriched-rearing group showed significantly better scores than those in the control group, and wild fish performed better than hatchery-reared ones. The present results indicate that, although the learning capability of hatchery-reared fish is inferior to that of wild fish, exposure to a highly structured environment at an appropriate stage promotes the development of learning capability. Such environmental enrichment can potentially improve the viability of hatchery-reared fish when they are released into the wild.