垂钓强度对鲫幼鱼易钓性和生长的影响

EFFECT OF ANGLING INTENSITY ON THE VULNERABILITY TO ANGLING AND GROWTH OF JUVENILE CRUCIAN CARP

  • 摘要: 为考察不同垂钓强度对鲤科鱼类易钓性和生长的影响, 研究以鲫(Carassius auratus)幼鱼为实验对象, 在实验(26.9±0.1)℃条件下对大小相近和机体健康的3个处理组高强度组(1d垂钓1次)、中强度组(2d垂钓1次)和低强度组(4d垂钓1次)进行垂钓实验; 每个垂钓处理组均设3个平行组, 每个平行组包括40尾鱼, 每个组在垂钓10h后则停止该组的垂钓活动, 记录成功垂钓每尾鱼的时间、序号和电子标签信息, 计算垂钓比例、单尾被钓时间、平均垂钓序号、变异系数和实验期间(9d)的生长率。研究发现: 3个垂钓强度组的垂钓比例均随着垂钓次数的增加而呈现下降的变化趋势, 单尾被钓时间呈现增加的变化趋势, 导致垂钓比例与单尾被钓时间呈负相关。除低强度组外, 高、中垂钓强度组的平均垂钓序号随着被钓次数的增加均呈现减小的变化趋势, 并且该2个强度组平均垂钓序号的变异系数随着被钓次数的增多均呈增大的变化趋势; 3个垂钓强度组的平均垂钓序号与其变异系数呈负相关。3个垂钓强度组在实验期间的特定生长率均出现负值情况, 但3个组之间无差异。研究表明: 高强度的垂钓活动会降低鲫幼鱼的易钓性, 并且导致个体生长表现出一定的负面效应, 表明高强度垂钓活动可能影响鱼类野外种群易钓性及其相关的其他表型的进化轨迹。

     

    Abstract: The vulnerability to angling refers to the stable difference in the probability of being caught among individuals within a fish species, which is easy to be affected by various environmental factors. Fish in nature are affected by human angling activities, but the characteristics of the effects of different angling intensities on the vulnerability to angling and growth of the Cyprinidae fishes are not clear. In order to investigate the effects of different angling intensities on the vulnerability to angling and growth performance of the Cyprinidae fishes in the Yangtze River, the juvenile crucian carp (Carassius auratus) was used as the experimental object in this study under the condition of the laboratory (26.9±0.1)℃, angling with different intensities for three treatment groups that have similar size and physical fitness, three treatment groups high frequency group (angling once a day), medium frequency group (angling once every two days) and low frequency group (angling once every four days); three parallel groups were set up in each angling treatment group, including 40 fishes in each parallel group. After 10 hours of angling in each repetition, the angling activities of the group were stopped. The angling time, angling serial number and electronic information of each fish successfully fished were recorded. The angling ratio, individual fish angling interval, average angling serial number and its coefficient variation as well as the specific growth rate of fish during the experimental period (9d) were all calculated. The results showed that the angling proportion of the three angling intensity groups decreased with the increase of angling times, and the individual angling interval showed an increasing trend with angling time increased, which results in a negative correlation between angling proportion and individual angling interval. Except for the low intensity treatment, the average angling serial number of both the high and medium angling intensity treatments showed a decreasing trend with the increase of the angling times, and the coefficient variation of the average angling serial number of the two intensity treatments increased with the increase of the angling times. The average angling serial number of the three treatment treatments was negatively correlated with its variation coefficient. The specific growth rates of the three angling intensity treatments were all negative during the experiment, but there was no significant difference among the three groups. Our results suggested that high intensity angling activities can reduce vulnerability to angling of the juvenile crucian carp, and it can lead to obvious negative angling effect of individual growth, which shows that high-intensity fishing activities may affect vulnerability to angling and evolutionary trajectory of other related phenotypes of the wild fish populations.

     

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