中华绒螯蟹对苦草生境的依赖与破坏

确定浅水草型湖泊水草资源对放养中华绒螯蟹的承载量是探明水草多元功能的途径之一。本研究通过构建中华绒螯蟹栖息与生长所需的小生境,观察和分析了蟹-草之间的相互关系。试验结果显示苦草对放养中华绒螯蟹的承载量为1.08ind/100g/m~2,中华绒螯蟹的生长比速SGR(％/day)与其对苦草的拥有量Vp(g/m~2/ind)呈正相关,即SGR=0.464 0.003Vp。中华绒螯蟹特别是雄蟹对苦草的影响主要表现为破坏性,破坏率VD(g/ind/m~2/d)与雌、雄蟹的放养密度(S_F,S_m,ind/m~2)有显著的线性关系,即V_D=2.08 0.11S_F 5.83S_M。实验结果为草型湖泊渔-蟹混养生态渔业管理提供了理论依据。

REQUIREMENT FOR AND DAMAGE TO VALLISNERIA SPIRALIS BY ERIOCHEIR SINENSIS

Submerged macrophytes play an important role both in producing cash aquatic animals and keeping good quality of lake water. By transplanting Vallisneria spiralis in 8 concrete tanks to form artificial habitats for yearling Eriocheir sinensis to live in and grow up for 4 months, the mutual effects of these two species were examined. This crustacean, particularly the male crab, did damage to this submerged plant, while the plant provides defiladed habitats rather than food for the animal. A liner relationship between the damage rate (VD, g/m2/ind/d) and the crab stocking density (SF, female; SM, male, ind/m2) was found to be as VD = 2.08 0. 11SF 5.83 SM . The carrying capacity of this plant for cultur-ing crab was determined to be 1. 08 ind/100g/m2 . A model of the crab growth (SGR, %/d) with the biomass of V. spiralis (VP, g/m2) was established as SGR = 0. 464 0. 003VP. The carb would grow to their marketable size in condition that the initial standing biomass of V. spiralis exceeded 124g/m2.The above results could be used as a guide for rearing crab and keeping renewable resources of submerged aquatic weed in macrophytic lakes.