中华花鳅的繁殖生物学特性研究

Reproductive Biology of Cobitis sinensis

探究中华花鳅(Cobitis sinensis)的繁殖生物学特性,可为其人工增养殖和资源保护利用提供科学依据。2017年11月至2018年5月,在贵州境内舞阳河施秉段采集中华花鳅样本381尾,以鳞片作为年龄鉴定材料,将样本解剖后进行性别鉴定和性腺分期。结果表明,舞阳河中华花鳅体长(L)为58.9~100.2 mm,体重(W)为2.0~13.7 g,年龄在1~4龄。381尾样本中,性别不可辨样本有23尾,雄248尾,雌110尾,性腺发育至IV期最多。经肉眼观察发现,中华花鳅的精巢和卵巢均可分为6期,有70尾雌鱼性腺发育达到IV期,其绝对繁殖力(F)为542~2 865粒,体长相对繁殖力(FL)为6.6~28.6粒/mm,体重相对繁殖力(FW)为99.8~490.7粒/g;绝对繁殖力(F)、体长相对繁殖力(FL)均与体长(L)、体重(W)、净体重(W0)、性腺重(W1)、成熟系数(GSI)之间具有极显著相关性(P<0.01),体重相对繁殖力(FW)与性腺重(W1)、成熟系数(GSI)之间具有极显著相关性(P<0.01)。实地调查发现,中华花鳅的产卵场主要在砂质底质、水质清新、水流较缓、水草丰富的浅水区,繁殖期为5-8月,繁殖高峰期为5月中旬至6月上旬。研究显示,中华花鳅的繁殖力较低,繁殖高峰期时间较短,低龄化严重,亟需对其进行资源保护和系统研究。

Cobitis sinensis is a popular ornamental fish because of its beauty, and a commercially important native fish species because of its good taste. In recent years, the wild population of C. sinensis in Wuyang River has sharply declined due to pollution, over fishing and hydropower development. In this study, we investigated the reproductive biology of C. sinensis and looked for biological indicators of individual fecundity using correlation and regression analysis. The objective was to provide a basic reference for artificial reproduction, genetic resource conservation and resource development of C. Sinensis populations. From November 2017 to May 2018, 381 C. sinensis specimens were collected in the Shibing section of Wuyang River, Guizhou province. Body length(L), body weight(W), net weight(W0) and gonad weight(W1) were measured. The age of each specimen was determined using scales as the age structure and egg diameter was measured with the aid of a microscope. To investigate reproductive biology, the gonad-somatic index(GSI) was calculated, absolute fecundity(F) was obtained by counting all eggs and relative fecundity per millimeter(FL) and relative fecundity per gram(FW) were calculated. The body length(L) range was 58.9-100.2 mm, the body weight(W) range was 2.0-13.7 g, and the age range was 1-4 years. Among the 381 specimens, there were 248 males, 110 females and the sex of 23 individuals were not identified. The egg diameter of C. sinensis with ovary at stage IV ranged from 1.2 mm to 1.5 mm, and eggs were adhesive, spherical and golden yellow and gray white in color. The size distribution of eggs indicates that C. sinensis spawns once each year. The range of absolute fecundity was 542-2 865 eggs, and the ranges of relative fecundity, FL and FW, were 6.6-28.6 eggs/mm and 99.8-490.7 eggs/g. The absolute fecundity(F) and body length relative fecundity(FL) of C. sinensis correlated significantly with body length, body weight, net weight, gonad weight and GSI(P<0.01). The body weight relative fecundity(FW) correlated significantly with gonad weight and GSI(P<0.01). Through field investigation, we also found that C. sinensis preferred spawning in fresh shallow water with sandy bottom, slow current and abundant aquatic plants. C. sinensis spawns from May to August, peaking from mid-May to mid-June. Our research shows that the reproductive ability of C. sinensis is poor, the spawning period is short and the trend toward younger C. sinensis is severe. Protection of the C. sinensis resource is urgently needed.