长江中游黄石江段三种不同类型河道中仔鱼空间分布研究

2016年6月10-15日对长江中游黄石江段三种不同类型河道(分汊型、顺直型和弯曲型)中仔鱼的空间格局进行了研究。共采集仔鱼12 331尾,隶属于5目7科25种,优势种为贝氏(Hemiculter bleekeri)(占仔鱼总数的89.4%)、鳊(Parabramis pekinensis)(占4.6%)和吻虾虎鱼属(Rhinogobius sp.)(占1.6%)。弯曲型河道仔鱼平均密度最大,为(2.34±1.10)ind/m~3;分汊型河道次之,为(1.97±2.03)ind/m~3,顺直型河道最低,为(1.79±1.19)ind/m~3。三种河道类型的仔鱼总体空间分布特征相似,在水平分布上,近岸处仔鱼密度最高(3.06±1.54)ind/m~3,江心最低(1.16±0.94)ind/m~3;垂直分布上,仔鱼密度表层(3.20±2.51)ind/m~3最高,其次为中层(1.69±1.35)ind/m~3,底层最低(1.20±1.20)ind/m~3。不同发育阶段的仔鱼分布呈现一定规律,总体上仔鱼从卵黄吸尽期开始倾向于分布在近岸处浅水区。本研究表明分汊型和弯曲型河道中的近岸水域是鱼类育幼场的主要分布区,在航道整治等涉水工程的建设中应该予以重点保护。

Studies on spatial distribution of fish larvae in three channel patterns in the Huangshi section of middle Yangtze River

Spatial distribution of fish larvae were compared among three watercourses with different patterns as meander,bifurcation and straight in the Huangshi section of the Middle Yangtze River.A total of 12 331 fish larvae were collected from June 10 to 15 in 2016,and identified to 25 species,7 families,5 orders.The dominant species were Hemiculter bleekeri (accounted for 89.4％ of the total numbers),Parabramis pekinensis (4.6％) and Rhinogobius sp.(1.6％).The average highest density of larvae was observed in the meander watercourse (2.34 ± 1.10 ind/m3),and then in the bifurcation (1.97 ± 2.03 ind/m3) and the straight (1.79 ± 1.19 ind/m3) watercourse.The characteristics of the spatial distribution for fish larvae in the three watercourse were similar,which the nearshore had the highest density of larvae whereas the middle had the lowest in horizontal distribution,and the sufface water layers had the highest whereas underlying the lowest in vertical distribution.The distributions of larvae with different development stages across the river and water layers were also analysed,and indicated that larvae of the yolk exhausting stage preferred to live around the shallow water in the near shore.The results showed that the inshore waters of the meander and bifurcation watercourse were the main distribution areas of fish larvae in the Yangtze River,and protection problems should be carefully considered for near-shore project in fish breeding season.