Nursery grounds for round crucian carp, Carassius auratus grandoculis, in rice paddies around Lake Biwa
Nursery grounds for round crucian carp, Carassius auratus grandoculis, in rice paddies around Lake Biwa
复制标题
琵琶湖周边稻田中的圆鲫鱼 (Carassius auratus grandoculis) 的苗圃
DOI：
10.1007/978-4-431-55330-4_10
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
T
中科院分区：
文献类型：
--
作者：
Ohtsuka;T
自21世纪初以来，日本琵琶湖周围实施了两种促进稻田用作养鱼场的手段。一种涉及养鱼：新孵化或前屈曲的幼体在水稻移栽后被释放到稻田，然后在季节中期排水之前饲养给幼体。另一项措施是安装鱼类通行证，以增加成年鱼进入稻田的机会，并鼓励它们在那里自然繁殖。这些努力主要是为了促进栖息在琵琶湖的濒危地方性亚种大眼鲫鱼(Carassius Auratus Grand Oculis)的繁殖，后者也是滋贺县特产食物福纳祖师的主要成分。这两种方法都被认为是环保的，因此得到了当地人的大力支持。然而，我们对稻田食物链的研究表明，圆形鲫鱼仔稚鱼对稻田水生生物群的影响是深远的。捕食鱼类导致枝角类极端减少，随之而来的是支角类食物种类和竞争对手的增加。通过底栖觅食，幼鱼还会导致稻田水中总磷浓度和浮游植物的增加。此外，稻田中稀少的竞争者和捕食者有助于鱼类仔稚鱼的快速生长和低死亡率。尽管利用稻田作为养鱼场可以有效地养护圆形鲫鱼，但还需要采取其他办法来加强琵琶湖周围稻田地区的整体生物多样性。
Since the turn of the twenty-first century, two means of promoting the use of rice paddies as fish nursery ground have been implemented around Lake Biwa in Japan. One involves fish culture: newly hatched or pre-flexion larvae are released into rice paddies after the rice transplantation, and then reared to juveniles before the mid-season drainage. The other involves the installation of fish passes to enhance the entry of adult fish into paddies and encourage their natural reproduction there. These efforts mainly aim to enhance the reproduction of round crucian carp (nigorobuna),Carassius auratus grandoculis, an endangered endemic subspecies inhabiting Lake Biwa, which is also the principal ingredient infuna-zushi, a specialty food of Shiga Prefecture. Both methods are regarded as environment-friendly and thus are well supported by local people. Our studies on the rice paddy food chain revealed, however, that the impact of round crucian carp larvae/juveniles on aquatic biota in rice paddies is profound. Fish predation results in an extreme reduction of Cladocera, and a concomitant increase in the food species and competitors of cladocerans. Through their benthic foraging, juvenile fish also cause a rise in total phosphorus concentration and phytoplankton in the paddy water. In addition, scarce competitors and predators in the paddies contribute to the rapid growth and low mortality of the fish larvae/juveniles. Although the employment of rice paddies as fish nursery ground may be effective for the conservation of round crucian carp, other approaches are also needed to enhance the overall biodiversity of rice paddy areas around Lake Biwa.