嘉陵江渠化对主要经济鱼类产卵场的影响

为探究嘉陵江渠化对主要经济鱼类产卵场的影响，2019年3-4月，采用历史资料搜集、访问调查和实地勘察的方法，并结合DNA条形码技术鉴定野外采集的样品。结果显示，原有60个主要经济鱼类产卵场中，41个已经消失，14个存在但已经发生改变，只有5个基本未改变；从产卵场数量、类型和规模来看，均呈减少趋势，仍存在的主要为鲤（Cyprinus carpio）、鲫（Carassius auratus）产卵场。共鉴定鱼卵1 362粒、鱼苗539尾，隶属2目2科12种。鱼卵仅3种，其中，鲤1039粒，占比76.28%；鲫312粒，占比22.91%；红鳍原鲌（Cultrichthys erythropterus）11粒，占比0.81%。鱼苗11种，包括鲤、鲫、马口鱼（Opsariichthys bidens）、麦穗鱼（Pseudorasbora parva）、峨眉鱊（Acheilognathus omeiensis）、大鳍鱊（Acheilognathus macropterus）、兴凯鱊（Acheilognathus chankaensis）、?（Hemiculter leucisculus）、短须颌须鮈（Gnathopogon imberbis）、子陵吻虾虎鱼（Rhinogobius giurinus）、粘皮鲻虾虎鱼（Mugilogobius myxodermus）；其中，兴凯鱊最多，有372尾，占比69.02%；其次为鲫59尾，占比10.95%；鲤57尾，占比10.58%；其他占比仅9.46%。研究表明，产卵场的改变主要集中在水文情势、河床底质和水生植物等方面，梯级水电站开发和采砂作业等导致河道变宽、水位上升、流速降低、卵石漫滩等生境消失、水生植物生物量减少，是原有产卵场消失或改变的主要原因。

Effects of Channelizing Jialing River on the Spawning Grounds of Major Commercial Fish Species

At the end of the 20th century, channelization of the Jialing River officially began. Currently, 15 hydropower stations are in operation, basically channelizing the entire river. From March to April 2019, the effects of channelizing the Jialing River on the spawning grounds of major commercial fish species were investigated using historical data, interviews, surveys, and field investigations. DNA barcoding was used to identify specimens collected in the field. Results show that among the original 60 primary spawning grounds of commercial fish species, 41 spawning grounds had disappeared, 14 spawning grounds were altered, and 5 remained basically unchanged. This represents a serious decrease in the number, type, and size of spawning grounds. The spawning grounds of Cyprinus carpio and Carassius auratus still exist. During the investigation, a total of 1 362 fish eggs and 539 fry were identified, belonging to 12 species, 2 families and 2 orders. There were only 3 kinds of fish eggs, consisting of 1039 Cyprinus carpio eggs, 312 Carassius auratus eggs and 11 Cultrichthys erythropterus eggs, accounting respectively for 76.28%, 22.91% and 0.81% of the total eggs. There were 11 species of fish fry identified, including Cyprinus carpio, Carassius auratus, Opsariichthys bidens, Pseudorasbora parva, Acheilognathus omeiensis, Acheilogn Macropterus, Acheilognathus chankaensis, Hemiculter leucisculus, Gnathopogon Imberbis, Rhinogobi Giurinus and Mugilogobius myxodermus. A total of 372 Acheilognathus chankaensis fry were collected, accounting for 69.02% of the fry collected, followed by Carassius auratus (59 fry, 10.95%) and Cyprinus carpio (57 fry, 10.58%). Other species, together, accounted for only 9.46%. The changes in spawning grounds result primarily from alterations in hydrological regime, riverbed substrate and aquatic plants. The development of cascaded hydropower stations and sand excavation have led to wider river channels, rising water levels, decreased flow velocity, disappearance of cobblestone floodplain and decreased aquatic plant biomass, and these changes are the primary factors leading to the disappearance and alteration of the original spawning grounds.