Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River
Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River
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DOI：
10.1007/s00343-016-4303-2
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发表时间：
2016-01
影响因子：
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通讯作者：
Mingzheng Li;Z. Duan;Xin Gao;W. Cao;Huanzhang Liu
中科院分区：
文献类型：
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作者：
Mingzheng Li;Z. Duan;Xin Gao;W. Cao;Huanzhang Liu
青鱼、草鱼、草鱼、青鱼是我国四大鲤鱼，是中国重要的水产养殖品种。自三峡大坝建成以来，由于长江水流和热力状况的改变，这些鲤鱼的繁殖量已经下降。然而，关于这四个物种繁殖变化的细节尚不清楚。为了评估TGD对四种鲤鱼繁殖的影响，我们于2005-2012年在距TGD 80公里的宜都市调查了它们的卵和仔鱼。在三峡工程修建前(1997-2002年)和修建后(2003-2012年)，研究了监利段(TGD下游350公里)4种幼虫丰度的差异。根据这些观察，这四个物种的第一次产卵日期平均推迟了约25天。宜都河段的平均卵子丰度为2.49亿，仔鱼平均丰度为4.64亿，这是自20世纪80年代以来的显著下降。建坝后监利段幼虫丰度显著低于建坝前(ANCOVA，P<；0.05)。观测到的幼虫丰度只占2003年大坝首次淹没时预测值的24.66%。目前TGD至宜都河段之间的产卵场与上世纪80年代所描述的非常相似，TGD上游存在一些产卵场。为了刺激产卵和有效地保护这四个主要中国鲤鱼物种，需要在TGD上游建立大片自由流动的河段，并在下游建立人工洪水淹没的河段。
Silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), grass carp (Ctenopharyngodon idella), and black carp (Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aquaculture species in China. Reproduction of these carp has declined since the construction of the Three Gorges Dam (TGD) due to an altered water flow and thermal regime in the Changjiang (Yangtze) River. However, details of the changes in reproduction of the four species are not well understood. To assess the impact of the TGD on reproduction of the four carp, we investigated their eggs and larvae at Yidu City, which is 80 km below the TGD, during 2005–2012. We examined diff erences in larval abundance of the four species in the Jianli section (350 km downstream of the TGD) before (1997–2002) and after (2003–2012) construction of the TGD. Based on these observations, the first spawning date of the four species was delayed a mean of about 25 days after the dam was constructed. Mean egg abundance in the Yidu section of the river was 249 million and mean larval abundance was 464 million, which were significant decreases since the 1980s. Moreover, larval abundance in the Jianli section after the dam was constructed was significantly lower than that before construction (ANCOVA,P<0.05). The observed larval abundance accounted for only 24.66% of the predicted value in 2003 when the dam was first inundated. The present spawning grounds between the TGD and Yidu section of the river are very similar to those described in the 1980s, and some spawning grounds exist upstream of the TGD. Large free-flowing stretches upstream of the TGD and the creation of artificially flooded downstream reaches are needed to stimulate spawning and eff ectively conserve these four major Chinese carps species.