13种鲟形目鱼类线粒体DNA的PCR-RFLP分析

以白鲟科和鲟科的13种鲟鱼为研究对象，设计7对特异引物，利用PCR技术扩增鲟形目(Acipenseriformes)鱼类线粒体DNA(mtDNA)，扩增片段大小在2～3kb，总长度约为整个mtDNA的97％。同时利用3个限制性内切酶，即Mbo、CfoⅠ和HaeⅢ对13种鲟形目鱼类进行限制性酶切片段长度多态性(RFLP)分析。结果总共检出233条电泳带，其中209条有多态现象，表明鲟形目鱼类mtDNA存在广泛变异。但是各个扩增片段的变异程度并不相同，其中NADH脱氢酶亚基基因的RFLP多态性较丰富，其次是细胞色素c氧化酶亚基基因，而两个rRNA基因最贫乏。说明在鲟形目鱼类mtDNA的进化中NADH脱氢酶亚基基因速率最快，细胞色素c氧化酶亚基基因次之，rRNA基因最慢。分子系统分析结果显示，鲟科的6种鱼与匙吻鲟和白鲟分成两大支；鲟科中两种鳇鱼没有聚到一起，支持了鳇鱼不能作独立分类单元的观点。本研究旨为鲟形目鱼类遗传和进化研究提供科学依据。     

鲟形目鱼类和渔业

本文论述了国内外鲟形目鱼类和渔业.包括三部分:1.鲟形目的种类和分布:2.鲟形目的生物学特征;3.世界上鲟鱼和白鲟渔业,并着重讨论该鱼类资源在我国的开发和利用.     

Status, trends and management of sturgeon and paddlefish fisheries

The 27 extant species of sturgeons and paddlefishes (Order Acipenseriformes) represent a unique and relict lineage of fishes. Producers of coveted black caviar, sturgeons are one of the most valuable wildlife commodities on earth. The group is among the most endangered fishes with all species listed under Convention on International Trade in Endangered Species (CITES) Appendix I (two species) or II (25 species), only two species considered Lower Risk by IUCN, four of the nine US taxa and one Caspian species protected under the Endangered Species Act, and local extinctions recorded for 19 of 27 species. Despite their well‐publicized imperilled status, commercial pressure on 15 species persists. Here, after reviewing the biological characteristics of sturgeons and paddlefishes and their commercial use, an overview of global fisheries is presented. The synopsis demonstrates that, with few exceptions, sturgeon and paddlefish are imperilled across the globe and long‐term survival in the wild is in jeopardy. All major sturgeon fisheries have surpassed peak productivity levels, with 70% of major fisheries posting recent harvests <15% of historic peak catches and 35% of the fisheries examined crashing within 7–20 years of inception. Even in Caspian Sea fisheries, the most important globally, present catches are below 10% of historic peak landings. Improved domestic and international fisheries management and attention to habitat and species restoration is now needed. Although captive rearing offers promise for caviar alternatives and endangered species restoration, it must advance cautiously to avoid environmental harm. To ensure a continued supply of caviar and the survival of these unique fishes we offer recommendations for priority conservation action for the future.