江西鳈年轮、摄食及长重关系研究

通过对浉河流域采集到的江西鳈的观察,发现江西鳈鳞片前区轮纹比侧区密,侧区的年轮较为清晰,后区由于被放射沟所截而不易分辨.其主要食物中硅藻类占65.7%、水生昆虫占48.6%;充塞度在2～3级所占比例为60%.用于表示长重关系的a值为0.043,b值为2.665.结果表明:江西鳈属于杂食性,具有切割型年轮,属等速生长鱼类.

Studies of Sarcocheilichthys Kiangsiensis Nichols on Annuli Characters,Feeding and the Relation between Length and Weight

Based on the observations of Sarcocheilichthys kiangsiensis Nichols sampled from the Shihe River,the round lines of the scales of Sarcocheilichthys kiangsiensis Nichols situated at the front area(proparea) was found much denser than the lateral area,and annual rings in the lateral area compared with other areas are relatively clear,while the back area are hard to distinguish due to the cutting off by the radial groove.Sarcocheilichthys kiangsiensis Nichols feeds primarily on diatom which accounts for 65.7%,and aquatic insects about 48.6%.Sixty percent fishes has the ratio of cram degrees(density) ranking from level 2 to 3.Two valuses,used as an indication of the relationship between length and weight were measued with a equal to 0.043 and b equal to 2.665.The results showed that Sarcocheilichthys kiangsiensis Nichols is a kind of isauxesis fish and belongs to ominivorefish with the cutting style of annual rings.