褐菖鲉养殖密度与其eDNA的相关关系探讨

研究以舟山岛礁水域优势鱼种褐菖鲉(Sebastiscus marmoratus)为研究对象, 通过与其他5种近缘鱼种COⅠ基因片段序列的比较分析, 设计了褐菖鲉特异性引物与Taqman探针; 基于K2P模型计算得到褐菖鲉与其他5种近缘鱼种在引物探针区的种间遗传距离, 褐菖鲉与日本鬼鲉遗传距离最大(0.3202), 而与同属的三色菖鲉种间遗传距离最小(0.2617)。将均重为12.46 g的褐菖鲉按2、4、8、16和32尾分别放入室内5个容积为1 m3的圆形水桶, 并在40 m×15 m×0.3 m三个养殖池内分别投放20、40和80尾褐菖鲉, 其后的0、8h、16h、1d、1.5d、2d、3d、4d、5d、6d、7d、8d及10d进行水样抽取, 测定褐菖鲉eDNA浓度。分析结果表明, 褐菖鲉eDNA浓度前后变化明显, 3d后较为稳定, 且与各自群体密度相对应, 从相关系数和拟合趋势可以看出养殖密度与其eDNA浓度之间呈线性函数相关关系, 为褐菖鲉资源eDNA监测评估奠定基础。

CORRELATION BETWEEN THE DENSITY OF CULTURED SEBASTISCUS MARMORATUS AND ITS ENVIRONMENTAL DNA

Environmental DNA (eDNA) analysis has become an important tool for biological resources research. Sebastiscus marmoratus, an important coral reef fish in Zhoushan coastal waters, has high economic value. To explore the relationship between the density of cultured Sebastiscus marmoratus and its eDNA, this study analyzed the COⅠ gene sequence of Sebastiscus marmoratus and other five relative species based on a set of specific primer and probe. Based on K2P model, the interspecific genetic distances between Sebastiscus marmoratus and other species were calculated with the maximum value of 0.3202 between Sebastiscus marmoratus and Inimicus japonicus and the minimum value of 0.2617 between Sebastiscus marmoratus and Sebastiscus tertius. 2, 4, 8, 16 and 32 individuals with average weight of 12.46 g were respectively cultured in five indoor buckets with a volume of 1 m3, and 20, 40 and 80 individuals were respectively in three outdoor ponds with a size of 40 m×15 m×0.3 m. The samples were taken at 0, 8h, 16h, 1d, 1.5d, 2d, 3d, 4d, 5d, 6d, 7d, 8d and 10d for extracting eDNA. It was concluded that eDNA reached a stable stage after 3d and 7d indoors and outdoors respectively. By fitting the linear correlation function between culture density and eDNA concentration at the stable stage, a highly significant positive correlation was found between culture density and eDNA concentration under the two culture conditions (P<0.001, R2≥0.9546). The increase in eDNA concentration was higher in all indoor groups than that in the outdoor groups. This study provides a basis for eDNA monitoring and evaluation of Sebastiscus marmoratus resources.