| heal.abstract |
Increased structural complexity (e.g. gravel, sand, pebbles, and plants) of fish rearing environment may enhance the cognitive abilities of fish and act as a means of environmental enrichment by improving the biological functioning and welfare of the fish. The rearing environment in intensive aquaculture usually does not contain any environmental modifications. The present study aimed at investigating whether the presence of substrate in tanks of a seawater recirculating system may act as a means of environmental enrichment for gilthead seabream Sparus aurata. Juveniles (68.3 ± 0.50. g) were reared for 84. days in groups of 18 individuals. In the enriched tanks, a uniform layer of single color glass gravel was used as substrate (Blue, Red-Brown and Green substrate, or BS, RBS and GS, respectively). Control tanks (C) had no gravel on the bottom (glass bottom). Growth performance, physiological status, fillet quality and fish behavior were measured. The BS and RBS fish grew significantly better (final mass, specific growth rate, mass gain, food conversion ratio) and were less aggressive compared to GS and C fish. During the first rearing week more BS and RBS fish swam near the bottom compared to the rest of the period and showed more fish-bottom interactions than the GS and C fish. The BS fish had higher condition factor and better fillet quality (higher amount of eicosapentaenoic acid-EPA. +. docosahexaenoic acid-DHA) than the other groups. The overall performance of the GS fish was hardly differentiated from C treatment. Present results indicate that the presence of Blue and Red-Brown substrates can be considered as a means of environmental enrichment for gilthead seabream. It is considered encouraging that a rather simple improvement of the fish rearing environment (as the substrate used) may have multiple beneficial aspects for fish and producers. © 2012 Elsevier B.V. |
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