Study On Fishery Biology Of Nibea Coibor In Arafura Sea Of Indonesia

Nibea coibor is the second largest economy fish species in the fishery resources of Arafura sea, accounted for about 40% of the total fish objects. It is bigger, tender and it is very delicious .Its swimming bladder is superior Chinese herbal medicine. So it will have the high development prospects and use value in the future. There are only aquaculture and molecular aspects of research on Nibea coibor at present. But the study on fishery biology of Nibea coibor in Arafura sea of Indonesia has not been reported at present. So this paper studies will provide the first-hand theory materials for developing the fish resources in the future.Based on the data of the Nibea coibor from single trawler by investigated in the Arafura sea of Indonesia form July to September in 2009, the fishery biology of Nibea coibor in the Arafura sea were studied. The investigation included the population distribution, the relationship analysis between morphometric attributes and body weight, the division of population structure, the reproductive characteristics and the feeding characteristics. The result indicated the following content.1176 individuals were randomly sampled in investigating period in Arafura sea of Indonesia. The result indicated the body length varied between 10.5 and 51.5 cm, the average of body length is 22.71cm, the dominant length varied between 12 and 20 cm and 22 and 30cm, there was no difference between months in 2009.The length distribution has no large difference between female and male respectively by ANOVA. The body weight ranged from 0.025 to 1.715 kg, the average of body weight is 0.27kg. There was no difference among months and between female and male respectively by ANOVA. As time continued there has slow uptrend on body length from July to September in 2009. The body length distribution along the longitude and latitude direction had a marked difference. The difference is more and more obvious from west to east and from south to north.In order to study the effects of morphometric characters on the body weight in Nibea coibor, the attributes measured in this study include body length(X1),trunk length(X2),caudal(X3),head length(X4),body high(X5),maximum body circumference(X6) , body weight(Y).The correlation coefficient between every two metric traits were constructed by correlation analysis . The path and determination coefficient in which the body length were used as the dependent variable and other attributes were used as independent variables were calculated by path analysis. The result showed that the correlation coefficient of each morphological trait to body weight were all at extremely significant level(P<0.01) in female and male Nibea coibor.The path coefficient of body length, maximum body circumference ,body high, caudal length and trunk length to body weight all reach at extremely significant level(P<0.01) in female Nibea coibor and the path coefficient of body length, maximum body circumference, head length, caudal length and trunk length to body weight all reach at extremely significant level(P<0.01) in male Nibea coibor.The analysis result of determination coefficient show that the body length and maximum body circumference are the most important determination morphological traits to body weight in female Nibea coibor, the maximum body circumference and trunk length are the most important determination morphological traits to body weight in male Nibea coibor. The multiple regression equation was established by multiple analysis after eliminated the morphological traits on body weight which are not significant. Y雌=-131.239+9.655X1-3.530X2-2.564X3-1.742X5+9.851X6(R2=0.941) Y雄=-132.739-0.628X1+5.595X2+3.527X3-2.601X4+13.572X6 (R2=0.967) .The female Nibea coibor had three populations, the body length of population 1 varied between 14.12 and 17.58 cm; the body length of population 2 varied between 22.24 and 32.22 cm; the body length of population 3 varied between 39.07 and 45.13cm. The male Nibea coibor had three populations too, the body length of population 1 ranged from 14.1 to 18.5 cm; the body length of population 2 ranged from 20.52 to 32.28 cm; the body length of population 3 ranged from 48.81 to 51.51 cm. The morphological index along three populations had a marked difference by C.D in female and male Nibea coibor. But the coefficient of variation is less than 1.28, so they will belong to the same population.The sex ratio remained 1.10. The sex ratio corresponded to 1:1 by in the temporal sequence. Maturity atⅡ,ⅢandⅢof the gonad are dominant from July to September.The feeding grade for 2009 and 2010 were both dominated by grade1, grade 2 and grade 3.The average length had a marked difference among months and the average length of female is longer than males basically. The length of the first sexual maturity is 38.29cm in female and the length of the first sexual maturity is 30.02cm in male. There had positive correlation between body length and GIS.The stomach plumpness index was less than 0.04, accounted for 89%.The distribution of the stomach plumpness index had no great difference among three months. The feeding grade was dominated by grade1and grade3, accounted for 45.22% and 24.06% respectively. The individuals of grade0and grade4 in the minority, accounted for 7.24% and 2.61% respectively. The empty stomach rate of Nibea coibor was 7.49% in 1185 individuals. The empty stomach rate had reduced from July to September as time continued. The empty stomach rate of female was less than male individuals. The empty stomach rate of female was 5.36% in July, 3.39% in August and 4.62% in September. The empty stomach rate of male was 7.84% in July, 12.07% in August and 7.41% in September.