牙鲆年龄和生长的研究

STUDY ON AGE AND GROWTH OF THE BASTARD HALIBUTS, PARALICHTHYS OLIVACEUS OF THE NORTHERN CHINA SEA

本文根据1980—1986年间连续逐月牙鲆生物学测定和耳石观察资料,确认其年轮形成期在3—5月,主要在4月。经标准von Bertalanffy生长方程拟合,鱼体体长(mm)年间生长规律为: ♀:L_t=800.10[1-e^(-0.2323(t-0.0254))] (?):L_t=690.62[1-e^(-0.2557(t+0.1211))]依体长与体重间相关关系计算渐近体重和最大生长速度,雌鱼分别为8370.43g和865g/a;雄鱼分别为4867.15g和554g/a。对低龄鱼(0—Ⅲ)生长特征模拟结果表明,雄鱼体长生长的季节变动幅度(C=1.07,k=0.5925)明显大于雌鱼;当年生雄鱼在7—9月的生长速度为年内最大。

Age and growth of the bastard halibuts, Paralichthys olivaceus (T. & S.), were carried out by saggita reading of 8 173 fish taken from several biological investiga-tion for enhancement of fisheries resources in the northern China Sea during the period from June 1980 to June 1986, where the population mostly pervaded. In order to explicate the population successive law and develop multispecies biology theoretically and practically, some life historical parameters have been given as follows;1. The external features of a saggita pair of this fish are two subelliptical, laterally compressed and distally concave forms with long axis oriented in an anterior-posterior direction. The morphological differences of saggitae in lagena are comparatively observed that there were rounded or scuted crenulations around the posterior side and that the core or kernal position inclined to posterior on upper saggita (left). So, the regular lower ones (right) were used as an indicator for age identification and measurement for ring length and radius without grinding or sectioning.2. Monthly changes of the marginal increment of saggitae showed that the time of ring formation mostly occurred once a year in breeding season between February and May, largely from April to May (Fig. 1). Sexually, transformation stage from opque to hyaline zone happened earlier in male (February to April) than female (March to May).3. By analyzing the measured body length (Lb:mm), versus radius (R: number of graduation on eyemicrometer enlarged 20 times), the increment of body length with radius was in exponential curve form;(1) Female: Lb = 2.955 9R2.2666 (r2 = 0.994 4,s= 0.042 9,n = 210 9,N = 65)(2) Male:Lb = 3.285 9R1.233 8 (r2 = 0.996 6,s= 0.030 8,n=272 5,N = 53)(3) All: Lb = 3.314 9R1.2375 (r2 = 0.995 8,s = 0.040 9,n= 552 3,N = 68)It has been shown that the regression function is rather significant for either female or male and that by using t-test for standard variation of equation 1 and 2, slightly difference has become visible based on that the ratio of standard dev- iation of female to that of male is 1.940 1 larger than critical value 1.921 1.4. By modelling von Bertalanffy growth equation with back-calculated length (Fig. 2), the growth patterns can be represented by;(4) Female: Lt = 800.10[1 - e-0.2323(t-0.0254)](5) Male: Lt = 670.62[1 -e-0.2557(t+0.1214)](6) All: Lt = 796.56[1 -e-0.2123(t+0.1021)]5. The relationship between body length and weight is closely related to power function curve:(7)Female: W = 1.8568×10-5L2.9809 b (r2= 0.997 0,s= 0.092 5,N = 65)(8)Male: W = 1.923 8×10-5L2.9730 b (r2 = 0.999 2,s= 0.046 7,N= 55)(9) All: W = 2.114 1×10-5L2.9857 b (r2 = 0.998 0,s= 0.089 1 ,N=69) Statistically test of the regression gradient and intercept shows there were nodistinct diversity between sexes. Under α =0.001, the values of observed and estimated by equation 7-8, expressed as standard deviation, have noticed aparent to the some extent.6. Translating body length growth parameters (equation 4-6) by equation 7-9 into weight parameters, increment of weight with age(10) Female: Wt= 8 370.43[1 -[1 - e-0.2323(t-0.0254)] 2.9809(11)Male: Wt= 4 867.15[1 - e-0.2557 (t+0.1214)]2.9730(12)All: Wt=8 108.88[1-e-0.2123(t+0.1021)]2.95877. By using expanded growth equation, seasonal characteristics have been elucidated at the major aspects of the younger ones (under 3 years old), considering that growth changes of O-group fish seemed more complicated than over 4 years old, and that body length of male fish during August and September increased faster than that of female.The results mentioned above have been manifested that body length of this fish grows faster at initial years (1-4) than older (6-10). However, the growth of weight against age displayed a typical asymmetric sigmoid type, correspoding to maximum growth rate at 4.138 4 years for male and 4.727 2 years for female with body length and weight as well as maximum growing rate of 532 mm, 2 476 g and 865 g/a for female and 441 mm 1 438 g and 554 g/a for male respectively. There are obvious differences in body