珠江口鱼类浮游生物种类组成与数量分布

江门位于珠江口西南部，其近海海域是多种小型鱼类的产卵场和育幼场。以珠江口江门海域春季采集到的鱼卵为研究对象，基于DNA条形码技术分析鉴定了鱼卵种类，描述了鱼卵的形态特征，并初步研究了其形态分类。共采获13种鱼卵，分属于3目10科，其中4种鉴定至种水平，分别为眶棘双边鱼 (Ambassis gymnocephalus)、缘边银鲈 (Gerres limbatus)、多鳞 (Sillago sihama) 和斑头舌鳎 (Cynoglossus puncticeps)；8种鉴定至属水平，分别为沙丁鱼属、小公鱼属、棘鲷属、副叶鲹属、叫姑鱼属、属和舌鳎属；1种鉴定至科水平，为鲾科。结果发现，江门海域大部分鱼卵可通过形状与大小、卵周隙宽窄、油球数量和色素分布等形态特征进行分类；对于胚体发育良好的鱼卵，胚体上色素胞颜色、数量及分布也是种类鉴定的重要依据。然而相近种类难以通过单一发育阶段形态特征进行准确区分，更深入的形态学研究尚待开展。

Morphology of pelagic fish eggs identified using mitochondrial DNA and their distribution in waters west of the Mariana Islands

Jiangmen is located in the southwest of the Pearl River Estuary. It is the spawning ground and nursery ground for various small fish. We identified the species of fish eggs from Jiangmen coastal waters of the Pearl River Estuary in sping based on DNA barcoding analysis, then described and preliminarily classified the morphological characteristics of fish eggs. We acquired a total of 13 taxa, which belonged to three orders and ten families. Four and eight taxa were identified to species and genus levels, respectively (Ambassis gymnocephalus, Gerres limbatus, Sillago sihama, Cynoglossus puncticeps, Sardinella sp., Stolephorus sp., Acanthopagrus sp., Alepes sp., Johnius sp., Sillago sp. and Cynoglossus sp.). One taxon was identified in family (Leiognathidae sp.). The results demonstrate that most fish eggs collected in the survey area can be classified by morphological characteristics such as shape, fish eggs size, perivitelline space, number and pigment distribution of oil globules. In addition, the colour, amount and distribution of pigments of the embryo are also important in species identification when the embryo is well developed. However, it is difficult to distinguish the closely related species only by the morphological characteristics of a single developmental stage. Further morphological studies should be conducted in the future.