Santos T, Schorer M, Dos Santos J, Pelli A, Pedreira M. 2019. The light intensity in growth, behavior and skin pigmentation of juvenile catfish Lophiosilurus alexandri (Steindachner). Lat. Am. J. Aquat. Res.. 47(3): 416-422. Available from: doi:10.3856/vol47-issue3-fulltext-3 [Accessed 13 Jul. 2019].
ABSTRACT
The survival of several fish species in captivity depends on their adaptation to the environmental conditions and the biological characteristics. The objective of the study was to evaluate the influence of different light intensity levels in growth, behavior and skin pigmentation in juvenile of
. Fishes were exposed to the following luminosities: 0, 218, 278, and 459 lux. The experiment was conducted for 75 days, in a water recirculation system with controlled temperatures and aeration. Catfish juvenile were distributed in 35 L aquariums, at the density of 0.28 ind L-1. In order to evaluate fish growth, weight, standard-total length, weight gain, food consumption, food conversion, biomass, specific growth rate and survival were measured twice times a month. Also, swimming behavior, skin pigmentation and plasma cortisol levels were evaluated. Light influences L. alexandri feed consumption, food conversion, behavior and plasma cortisol levels. Environments with low light are recommended for the L. alexandri growth.
While I realize one would like to measure the growth on a regular basis - after all, it could be that all differences are found in the first half of the study, I wonder what the effects of this biweekly measurements are.
Had I done this study, I would have introduced another control group: One with the same light and so on as another group, but without this biweekly measurements.
Any differences between the two groups with same light conditions wouldt be the result of stress due to the measurements.
