Effect of Age and Rearing Environment in Route Learning of Climbing Perch, (Anabas Testudineus Bloch, 1792)

This study examines spatial learning ability of lab reared climbing perch in a complex environment and effect of critical age on learning. We reared climbing perch larvae in four different environments varying in complexity and tested their spatial learning ability at juvenile and adult stage (ieat 2^ndand 10^thmonth of rearing). Climbing perch reared in native tanks with wire mesh barrier at the bottom, middle or upper level of water column showed marked difference in route learning ability. The larvae reared in tanks with wire mesh barriers at the middle of the water column exhibited highest learning capacity, as compared to fish from other three rearing groups. This suggests that a single change in rearing environment can trigger differential cognitive abilities, probably for the lifetime. The present study also supports the idea that spatial learning ability shifts during ontogeny i.e. as the age increases learning ability also increases, possibly due to life experiences and enhanced neurogensis. Thus spatial learning ability may vary considerably in response to varying environment experienced by the fish during early life. The possible role of native habitat complexity in the route learning ability, which is critical for location based navigation of fish, is discussed. The results highlight the need to consider enrichment strategies when designing captive rearing of fish for conservation and replenishing of diminishing fish stock.