闽东北海域假长缝拟对虾种群分布格局强度

以负二项参数、Mrisita指数、平均拥挤度、聚块指数和扩散系数为种群分布格局强度指标,分析了闽东北海域假长缝拟对虾(Parapenaeus fissuroides Crosnier)种群分布格局强度,探讨了种群分布格局强度生态学意义及其影响因子。结果显示:假长缝拟对虾种群聚集强度和聚块性夏季最强,其余依次为秋季、春季和冬季,平均拥挤度夏季最大,其次是秋季、冬季,春季最小,扩散程度春季最大,其次是冬季、秋季,夏季最小。负二项参数和Mrisita指数表征种群聚集强度,聚块指数体现种群斑块的组成形式,个体平均拥挤度指数反映平均个体实际的拥挤程度,扩散系数反映种群扩散程度。饵料浮游动物是影响假长缝拟对虾种群聚集强度的主要因子,种内竞争是影响假长缝拟对虾种群扩散程度的主要因子。

Pattern intensity of Parapenaeus fissuroides Crosnier in sea area in the northeast of Fujian

In the current study, we analyzed the aggregation pattern of Parapenaeus fissuroides Crosnier in sea area in the northeast of Fujian based on pattern intensity index of the negative binomial parameter, Morisita index, mean crowding, poly block index, and diffusion coefficient. We also discuss the factors that affect pattern intensity and ecological significance of the pattern intensity indices. The aim of the study was to explore new aspects in the protection of the fishery resources for P. fissuroides Crosnier. In spring, its population primarily consisted of twelve patches, which showed dispersed population distribution and the second smallest poly block index. The population in spring had the smallest mean crowding, the largest average distance between individuals, and the biggest diffusion coefficient compared to that in other seasons. In summer, the population mainly consisted of four patches with most concentrated population distribution. The biggest poly block index, biggest mean crowding, smallest average distance between individuals, and smallest diffusion coefficient were observed. In autumn, the population primarily consisted of five patches with moderately concentrated population distribution. The second largest poly block index and mean crowding as well as the second smallest average distance between the individual diffusion coefficient were explored. In winter, the population primarily consisted of fourteen patches with highly dispersed population distribution, the smallest poly block index, the second smallest mean crowding, and the second largest average distance between individuals and diffusion coefficient. The negative binomial parameter and Morisita index were employed to characterize the aggregation intensity. When the Morisita index is greater and the negative binomial parameter is smaller, the aggregation intensity is stronger, and vice versa. Mean crowding provided a more actual representation of the average individual crowding degree compared with the average density. Mean crowding reflected the average individual crowded degree. When mean crowding was large, the inter-specific competition was intense,and average distance between individuals was smallest. The poly block index revealed the constitution of the population patches. When the poly block index was big, the population primarily consisted of a few patches, and vice versa. The diffusion coefficient reflected the diffusion degree. The bigger the diffusion coefficient, the greater was the significant spread of the population. The food zooplankton was the major factor influencing the pattern intensity, and the inter-specific competition was the major factor mediating diffusion degree of the Parapenaeus fissuroides Crosnier in the sea area northeast of Fujian. In this study, the population distribution pattern intensity simplified the research of school behavior, which reflect the aggregation intensity, poly block, mean crowding, inter-specific competition degree, and diffusion degree to meet the school behavior inherent law.