Long-term changes in the abundance of Jesogammarus annandalei (Tattersall) in Lake Biwa
Long-term changes in the abundance of Jesogammarus annandalei (Tattersall) in Lake Biwa
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DOI：
10.4319/lo.2004.49.5.1840
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发表时间：
2004-09-01
影响因子：
4.5
通讯作者：
Urabe, J
中科院分区：
文献类型：
--
作者：
Ishikawa, T;Narita, T;Urabe, J
从1966年到1999年，研究了栖息在琵琶湖深水区的特有端足类Jesogammarus annandalei丰度的变化。20世纪80年代中期，安氏圆蚧的丰度突然增加，此后一直保持在1980年以前的7倍水平。与20世纪60年代的片足类动物相比，20世纪90年代成熟个体的窝卵和体型都有所下降，这表明人均食物供应量有所下降。因此，J. annandalei丰度的增加似乎主要是由于它们存活率的增加，而不是它们的生长或繁殖率。在片足类丰富度增加的雅阁下，在深海区占优势并以这种片足类为主要食物的特有的虎鱼鱼种的渔业捕获量在1980年代中期急剧下降。这些结果表明，长期变化的J.annandalei在琵琶湖的丰度主要是由鱼类捕食，而不是由食物供应调节。
Changes in the abundance of an endemic amphipod, Jesogammarus annandalei, that inhabits the profundal zone of Lake Biwa were examined from 1966 to 1999. The abundance of J. annandalei increased suddenly during the mid 1980s and thereafter stayed at a level that was sevenfold higher than that before 1980. Compared with the amphipod in the 1960s, both the clutch and body size of the matured individuals decreased during the 1990s, which suggests that per capita food supply decreased. Thus, the increase in the abundance of J. annandalei appeared to be due largely to an increase in their survival rate and not their growth or reproduction rates. In accord with the increase in amphipod abundance, the fishery catch of an endemic gobiid fish species that is dominant in the profundal zone and preys on this amphipod as a major food, decreased dramatically during the mid 1980s. These results suggest that long-term changes in abundance of J. annandalei in Lake Biwa are mainly regulated by fish predation rather than by food supply.