浙江沿岸产卵场春、夏季鱼类资源密度和群落多样性研究

根据2015年4月(春季)和7月(夏季)在浙江沿岸产卵场进行的渔业资源底拖网调查资料, 采用多重比较(LSD)和分类回归树(CART)方法研究了浙江沿岸产卵场春、夏季群落多样性和鱼类资源的变化, 以及多样性与诸多环境因子(生物和非生物)的关系, 结果表明: (1)该水域春季共捕获鱼类92种, 隶属17目50科77属, 夏季捕获鱼类114种, 隶属16目59科92属; (2)春季全区生物量平均为434.40 kg/km2, 中部和南部生物量差异极显著(P=0.005), 全区尾数密度平均为58.42千尾/km2, 不同区域差异不显著; 夏季全区生物量平均为1532.73 kg/km2, 北部生物量与中部差异极显著(P=0.000), 与南部差异显著(P=0.017), 全区尾数密度平均为205.50千尾/km2, 北部尾数密度与南部差异显著(P=0.034), 其他区域间差异不显著; (3)春季H′平均值为1.52, D平均值为2.18, 北部和南部D差异显著(P=0.048), 其他区域间H′和D差异均不显著; 夏季H′平均值为1.34, D平均值为1.81, 中部和北部H′差异极显著(P=0.000), 和南部差异接近极显著(P=0.01), 北部和中部D差异显著(P=0.039), 其他区域间差异不显著; (4)CART分析表明, 影响春季多样性和丰富度的主要因素有水深、浊度和溶氧; 秋季多样性水平主要受的水深、桡足类、温度和浊度的影响; (5)从空间和时间上与其他水域的多样性水平相比较得出, 在空间上, 纬度与H′并不存在简单的线性关系, 但当纬度跨度比较大时, 低纬度水域的H′值明显高于高纬度水域的H′值; 在时间上, 多样性水平较2008年明显升高, 但与2011年的调查结果相近, 表明产卵场(南部)近几年渔业生态环境处于相对较稳定的状态。

STUDY ON FISH RESOURCES AND COMMUNITY DIVERSITY DURING SPRING AND SUMMER IN THE COASTAL SPAWNING GROUND OF ZHEJIANG PROVINCE,CHINA

The fish resources and community diversity, and their relationships with the biotic and abiotic environmental factors in spawning ground of Zhejiang province (China) were studied. In this research, data were collected from bottom trawl surveys in spring and summer of 2015 by the least square deviation (LSD) and classification and regression tree. In spring, a total of 92 fish species were sampled in the survey, belonging to 77 genera, 54 families, and 17 orders. In summer, a total of 115 fish species were captured, belonging to 92 genera, 62 families, and 16 orders. In spring, the average value of biomass was 434.40 kg/km2 in the whole spawning ground, and the difference of biomass between middle and southern region was statistically significant (P=0.032). The average value of abundance density was 58.42 kg/km2 in the whole region, and the difference between northern and southern region was statistically significant (P=0.040). In summer, the average value of biomass was 1532.73 kg/km2 in the whole spawning ground, and a significant difference was found between northern and middle region (P=0.010), between northern and southern region was significant (P=0.026). The average value of abundance density was 205.50 kg/km2 in the whole region, and the differences between northern and middle region, as well as northern and southern region were both significant (P=0.041, P=0.011). The average values of H′ and D were 1.52 and 2.18 in Spring, correspondingly, the average values of H′ and D were 1.34 and 1.81 in summer, respectively. The classification and regression tree indicated that the main factors affecting the diversity and richness index were depth and turbidity in spring, while the main factors affecting the community diversity level were depth, copepods, temperature, and turbidity in summer. On space, no simple linear relationship was found between latitude and H′, however, H′ value in low latitude waters was significantly higher than that in the high latitude waters when the latitude span was very large. Once, the diversity level was remarkably improved compared with 2008, however, that was closed to the corresponding level in 2011, which indicated that the ecological and environmental factors on the coastal spawning ground of Zhejiang province was relatively stable in recent years.