新疆乌伦古湖河鲈(Perca fluviatilis Linnaeus)种群的生长模型及生态参数的研究

A STUDY ON GROWTH MODEL AND ITS ECOLOGICAL PARAMETER OF PERCA FLUVIATILIS LINNAEUS IN WUBENGU LAKE

本文对新疆乌伦古湖河鲈(Perca fluviatilis Linnaeus)种群的数量生长模型和生态学参数作了计算和分析,研究结果如下: (1) 河鲈的生长模型为: L_t=53.65(1-e^(-0.15(t+0.41))…体长模型 W_t=4052.74(1-e^(-0.15(t+0.41))~3.1986…体重模型 (2) 体重增长率函数在t=2^+龄时有一拐点,此时体重增长加速度达最大值。表明2^+的河鲈体重的增长节律比之以往生命时期有了一个飞跃式上升,这时期的种群全部进入性成熟期,能量资源主要用于营养积累和性腺发育。 (3) 体重增长率函数在t=13^+时也有另外一个拐点,此时体重增长加速达最小值,说明这时的河鲈新陈代谢已达到最低点,接近衰老死亡状态,我们把这一点视为河鲈在自然界中的实际最高年龄。经推算河鲈的理论极限年龄为19.6年。 (4) 体重增长率在t=7^+龄处有极大值,此时的体重速度为零,表明河鲈的生长已达顶盛期,7^+龄以后走向衰老,增长率为一减函数,且加速度为负值。 (5) 种群最大生物量的临界年龄t_a=5.3,死亡率A=0.53,残存率S=0.47,自然死亡系数为0.43,资源利用率为0.

In this paper the growth model of Perca fluviatilis Linnaeus has been analysed and the ecological parameter which involves the special numerical value of its resources has been workked out. The result is as follows: The relationship between the weight(w) and the body length can be expressed by the equation W=0.0121L^(3.1986)… The function of the length growth is L_1=53.65(1-e^(-0.15(1+0.41)))… And that of the weight is W_1=4052.74(1-e~[-0.15(1+0.41)])^(3.1986)… The function of the W＇(t) that is weight growth rate which is also the derivative of equation(3)has two inflection points. One is at t_1=2^+(years); the other is at t_2=13^+(years). The former point means that the growth rhyth has changed qualitively and the population is growing towards sexual maturity. The Latter corresponds to the population is becoming feeble and dying. The curve of the growth rate reaches the maximum value at t=7^+ yearsold. This means that the perch is going to transit from youth to old age. The age of maximum biomass of the population is at t=5^+ years; and the limit age is 19.6 years.