拉萨河鱼类调查及保护

INVESTIGATION AND PROTECTION STRATEGIES OF FISHES OF LHASA RIVER

拉萨河是雅鲁藏布江最大的支流,其鱼类区系为隶属于裂腹鱼亚科、条鳅亚科和科的13种鱼类以及裂腹鱼属的一个自然杂交种。最近十几年,由于人类活动的影响,导致了大量的外来鱼类进入拉萨河水体。文章介绍了2004年至2006年对拉萨河鱼类进行采样调查的情况。目前在拉萨河,鱼类组成包括以往记录的14种鱼类:拉萨裂腹鱼Schizothorax waltoni(Regan)、异齿裂腹鱼S.o'connori(Lloyd)、巨须裂腹鱼S.macropogon(Regan)、双须叶须鱼Ptychobarbus dipogon(Regan)、尖裸鲤Oxygymnocypris stewartii(Lloyd)、拉萨裸裂尻鱼Schizopygopsis younghusbandi younghusbandi Regan、异齿裂腹鱼和拉萨裂腹鱼的一个自然杂交种、异尾高原鳅Triplophysa stewartii(Hora)、细尾高原鳅T.stenura(Herzenstein)、西藏高原鳅T.tibetana(Regan)、东方高原鳅T.orientalis(Herzenstein)、斯氏高原鳅T.stoliczkae(Steindachner)、短尾高原鳅T.brevicauda(Herzenstein)、黑斑原Glyptosternum maculatum(Regan);8种外来鱼类:鲫Carassius auratus(Linnaeus)、麦穗鱼Pseudorasbora parva(Temminck et Schlegel)、泥鳅Misgurnus anguillicaudatus(Cantor)、黄黝鱼Hypseleotris swinhonis(Gunther)、鲤Cyprinus(C.)caupio Linnaeus、草鱼Ctenopharyngodon idellus(Cuvier et Valenciennes)、银鲫Carassius auratus gibelio(Bloch)、鲇Silurus asotus Linnaeus;2个未定种。调查结果表明拉萨河鱼类资源面临的两个主要问题是过度捕捞导致鱼类资源的减少和小型化以及外来鱼类入侵。文章针对这些情况作了分析和探讨,并对土著鱼类的保护与合理利用提出了一些建议:合理捕捞、严格禁渔期、控制外来鱼类、保护栖息地等。

Lhasa River is the biggest tributary of Yarlung Zangbo River. Its fish fauna comprise 13 fish species and a natural bastard, belonging to Schizothoracinae, Nemacheilinae and Sisoridae. Disturbed by human activities, plenty of exotic fishes have been found in Lhasa River in recent decades. Moreover, the fish resources of Lhasa River are under overfishing. Most of the endemic fishes grow slowly and mature late, so they are very vulnerable to invasions of the exotic fishes and overfishing, and the populations can not be replenished easily if depleted. So the investigation and protection strategies of fishes of Lhasa River are very important and urgent works. We roundly investigated the fish resources of Lhasa River with floating net, gill net and set net during Apr. to Jun. in 2004, Sep. in 2004 to Jan. in 2005, Mar to Apr. in 2005, May to Sep. in 2006. This paper introduced the result of our investigation. It was found that there were 8 exotic fish species （Carassius auratus （Linnaeus）, Pseudorasbora parva （Temminck et Schlegel）, Misgurnus anguillicaudatus （Cantor）, Hypseleotris swinhonis （Gunther）, Cyprinus （C.） caupio Linnaeus, Ctenopharyngodon idellus （Cuvier et Valenciennes）, Carassius auratus gibelio （Bloch）, Silurus asotus Linnaeus, and 2 species indeterminate, and 14 fish species （Schizothorax waltoni （Regan）, S. o’connori （Lloyd）, S. macropogon （Regan）, Ptychobarbus dipogon （Regan）, Oxygymnocypris stewartii （Lloyd）, Schizopygopsis younghusbandi younghusbandi Regan, Triplophysa stewar-tii （Hora）, T. stenura （Herzenstein）, T. tibetana （Regan）, T. orientalis （Herzenstein）, T. stoliczkae （Steindachner）, T. bre-vicauda （Herzenstein）, Glyptosternum maculatum （Regan）, and a natural bastard of S. waltoni and S. o’connori）. These 14 fish species were also found by previous researchers. As to the species indeterminate, species indeterminate A looked like O. stewartii and also looked like S. y. younghusbandi, so it might be omitted by the former investigator; species indeterminate B was very rare and it had many medial morphological characters of species indeterminate A and O. stewartii, so it might be omitted by the former investigator or a new natural bastard. We analyzed the distribution of economic fishes of Lhasa River. S. y. younghusbandi and P. dipogon were dominant species in Lhasa River, especially in the upstream; O. stewartii mainly distributed in the downstream; S. o’connori was rare in winter; S. waltoni and S. macropogon were rare in Lhasa River. We inferred that S. o’connori, S. waltoni and S. macropogon mainly inhabited in Yarlung Zangpo River and migrated to Lhasa River to spawn during spawning season. As to the exotic fishes, C. auratus, P. parva and M. anguillicaudatus were majority and distributed widely; C. （Cyp.） caupio and H. swinhonis increased quickly in amount; C. idellus, C. auratus gibelio and S. asotus were rare. We also pointed out that the two main threats to the fish resources of Lhasa River were decrease and miniaturization caused by overexploitation and invasion by alien fishes. In this paper, we analyzed and discussed the phenomenon and presented a series of strategies on how to protect and reasonably use of fish resources of Lhasa River： reasonable fishing, constituting fishing ban period, controlling alien fishes, protecting habitant of fishes and so on.