Size-dependent effects of daily thermal fluctuations on the growth and size heterogeneity of Nile tilapia Oreochromis niloticus

作者：Azaza M S^*; Legendre M; Kraiem M M; Baras E

来源：Journal of Fish Biology, 2010, 76(3): 669-683.

DOI：10.1111/j.1095-8649.2009.02524.x

• cycling thermal regimes
• growth dispersion
• optimum temperature

The growth of Nile tilapia Oreochromis niloticus (0.02-20.00 g) was measured when fed to excess during the hours of light, following their exposure to five thermal regimes fluctuating around the thermal optimum for growth (T(opt) = 30 degrees C) over the diel cycle of day (light, L) and night (dark, N), i.e. 27 degrees C(L):33 degrees C(N), 28.5 degrees C(L):31.5 degrees C(N), 30 degrees C(L):30 degrees C(N), 31.5 degrees C(L):28.5 degrees C(N) and 33 degrees C(L):27 degrees C(N) (two replicates per treatment, six weeks' rearing, growth measurements at weekly intervals).A model constructed with a stepwise multiple-regression analysis accounted for 87.4% of the variation of the specific growth rate (G, % M day(-1)) from the variations of wet mass (M), the extent of the thermal fluctuation (FT) and their interactions, i.e.log10 G = 1.7686-0.2136 log(10) M + 0.0806 [log(10) M x log(10) (1 + F(T))]-0.0394 [log(10) M x log(10) (1 + F(T))](2). Based on this model, the thermal fluctuation that produces the fastest growth (F(Topt),degrees C) decreases in a curvilinear way, from 5.1 degrees C at 20 mg to c.0.7 degrees C at 20 g.Thermal regimes that produce the slowest growth also produce the highest size heterogeneity.Functional hypotheses behind the size-dependent effects of thermal fluctuations are discussed, together with their implications in natural habitats and aquaculture systems with in different contexts of food availability.

• 出版日期2010-2