大麻哈鱼繁殖特征及呼玛河原始产卵场生境功能验证

Reproductive Characteristics and Verification of Original Spawning Ground of Chum Salmon(Oncorhynchus keta)in Huma River

本文在研究大麻哈鱼Oncorhynchus keta卵繁殖特征同时,对呼玛河大麻哈鱼原始产卵场生境功能进行验证。2017年10月下旬,在黑龙江抚远江段采捕繁殖洄游大麻哈鱼80尾(雌、雄鱼各40尾),运至呼玛河支流—韩辉套子开展相关实验,依水深、流速、底质、泉眼数量、水草和绿藻密布等地理特征,用拦网将实验河段分为A、B、C、D 4个实验区。同年10月28日—11月9日大麻哈鱼繁殖期间,每日上午在实验区观察记录大麻哈鱼鱼巢位置、形状、规格、区域等指标,用大疆精灵Phantom 4航拍机、GoPro hero 5水下摄像机拍摄大麻哈鱼筑巢行为,回收繁殖后死亡亲鱼并测定实验水域水化学指标。2018年4月13—15日,挖掘部分浅水水域鱼巢,水下摄像观察大麻哈鱼受精卵发育情况,测定各区域水体理化因子。结果表明:大麻哈鱼在进入实验水域后约1周完成繁殖活动,其后逐渐死亡。期间共发现大麻哈鱼巢24处,主要分布于C区;大麻哈鱼由雌鱼筑巢、掩埋巢穴并守护鱼巢,鱼巢多为圆形和椭圆形,筑在流速较小、水深0.2~0.8m、河床底质为卵石、石砾的水域。统计回收亲鱼发现,参与产卵繁殖的雌性个体约占90%,受精卵经过5个月左右孵化进入卵黄囊仔鱼期,能够完成整个胚胎发育过程。推测呼玛河大麻哈鱼原始产卵场生境功能尚存。

A total of 80 samples(40 males and 40 females)of chum salmon were collected in Fuyuan section of Heilongjiang River and transported to Hanhuitaozi river,a tributary of the Huma River in late October 2017.The Hanhuitaozi reach was divided into four experimental areas A,B,C and D by net blocking according to the geographic characteristics of water depth,flow velocity,pebble sediment,spring number,and aquatic grasses and green algae.During the breeding period,from Oct.28 to Nov.9 of the same year,the water depth was determined every morning,and the nesting location,shape,size,redds site and other indicators were recorded.The nesting behavior of salmon was photographed with Phantom 4 aerial camera and GoPro Hero 5 underwater camera of Xinjiang elves.The dead chum salmon were recovered after breeding,and the water quality indicators of each water area were determined in order to study the spawning characteristics and verification the habitat function of the original spawning ground of the chum salmon in the Huma River when they migrated to the tributary of the Huma River,Hanhuitaozi river,from the Fuyuan section of Heilongjiang River in the end of October 2017 for spawning.It was found that the chum salmon completed the spawning activities about 1 week after they entered the experimental waters,and then gradually died.During the experimental period,24 redds were observed,mainly in the area C waters,and the females were responsible for nesting,burying and guarding the mostly round and oval nests which were built in the waters with small flow velocity,0.2~0.8 m in water depth,and pebble and gravel bottom of the riverbed.Statistically,90%of the spawners found in the experimental spawning ground were females,the fertilized eggs successfully hatched in about 5 months and became alevin(prelarvae with yolk sac),with complete embryonic development process.It is concluded that the habitat function of the original spawning ground of chum salmon in the Huma River is remained.