The influence of main ecological and environmental factors on the energy budget of Schlegel's black rockfish Sebastes schlegeli

In the Maidao Ecological Laboratory of the Huanghai Sea Fisheries Research Institute in 1998~2000,the continuous flow-through method was adopted to determine the energy budget components and models of Schlegel's black rockfish under different ecological and environmental factors,such as temperature,food species,body mass and feeding level,etc.The body mass of test fish ranged from 21.2 to 224.5 g.The specific growth rate tended to invert "U" change with temperature increase.The ecological conversion efficiency showed the same trend as temperature and feeding level rise.Only the specific growth rate tended to decelerate the increment with the rise of feeding level.From the above quantitative relationships,the maximum and optimal growth temperatures could be obtained as 17.5 and 16.2℃,and the maintenance feeding rate and optimum feeding rate as 0.8% and 4.1% of the body mass.The specific growth rate and ecological conversion coefficient showed a decelerating decrease trend with body mass increment.The small-sized fish food was more advantageous to the feeding level increase in comparison with the small-sized shrimp food,which led to the increase of growth,metabolism and excretion,but had no significant influence on the ecological conversion coefficient.All of temperature,feeding level,body mass and food species can obviously change the energy budget models.The assigning rate of growth energy tended to change along the invert "U" curve with the increase of temperature and feeding level,and decrease with the body mass increase,but the assigning rates of metabolism energy and excretion energy were quite reverse.These relationships could be quantitatively described as quadratic or power function curve.If the above relationships proved true to other marine fish,the establishment of energy budget model of the same fish under different conditions can be largely simplified.