上海大莲湖春季鲫鱼生境选择

Habitat Selection of Spring Carassius auratus in Dalian Lake of Shanghai

为研究天然淡水湖泊中春季鲫鱼对环境因素的选择性,于2009年3个时间段(4月11日至19日、4月27日至5月8日、5月20日至29日),用同一种型号的鱼笼对上海大连湖的鲫鱼进行定点重复捕捉.结果表明,3个时间段,藻类生境中鲫鱼捕获量一直较高,芦苇和菰生境中捕获量依次下降,而藻类和无草区生境中捕获量依次上升;3个时间段,水深大于等于2m生境中鲫鱼捕获量低于水深小于1m和介于1～2m的生境中的捕获量.在水深介于1～2m的生境中,鲫鱼捕获量在3个时间段内依次上升.有藻类等大型沉水植物、浅滩和缓慢流动的水体环境,是天然淡水湖泊中春季鲫鱼偏爱的生境,但芦苇和深水生境则对春季鲫鱼的繁殖不利.

For better understanding the habitat selection of Carassius auratus in natural freshwater lake in spring, a method of repeat capture in a fixed site was used with the same type of fish cages in Shanghai Dalian Lake in three time periods in 2009, from Apr. 11 to Apr. 19, Apr. 27 to May 8, and May 20 to May 29 separately. The results indicated that the numbers of Carassius auratus captured in the three periods were all at a high level in alga, the numbers declined in reed and wild rice shoots, but increased in alga and non-grass grown site. The numbers were lower in water depth ≥2 m than those in water depth 〈1 m and 1 to 2 m. The numbers increased in the water depth of 1 to 2 m along the period. The ecological environment with submerged macrophytes such as alga, and shallow water and low speed water were the preferred habitats for Carassius auratus, but the environment with reed and deep water were not the better site for Carassius auratus to breed in spring in natural freshwater lake.