近海双壳类筏式养殖对大型底栖动物群落影响综述

Review on the effect of coastal bivalve raft mariculture on macrobenthic assemblages

近海的双壳类筏式养殖,通过对海域水文、物理、化学条件的改变,从在对海岸带水域的生态系统产生影响。滤食性双壳类能够摄食有机质颗粒和浮游植物,产生的粪便或假粪能够加剧生物沉降,造成有机质在海底表面的大量聚集,造成养殖海域的有机质污染。养殖设施也会引起当地水文状况和海流的改变。双壳类养殖筏架对大型底上动物来说,可起到人工鱼礁相似的作用,为众多生物提供了栖息场所和庇护场所,增加了大型无脊椎动物和底层鱼类可利用的饵料数量,保护底上动物免受渔业捕捞等强烈扰动的影响,提高底栖鱼类和大型无脊椎动物的丰度和生产力。而对于底内动物来说,双壳类养殖对底栖群落的结构和组成的影响与海流的强度呈负相关,当养殖海域的海流强度达到一定程度,大量有机质将会被带走,对底内群落的影响将可以忽略不计,但在海流能量较小的情况下,有机质的富集将会造成底栖群落多样性和丰度的降低。正确的养殖选址结合科学的生态容量评估,以及多营养层次的综合养殖是维持双壳类养殖健康可持续发展的重要保证。

Coastal bivalve mariculture can exert adverse or positive effect to the coastal ecosystem through changing the hydrological, physical and chemical conditions of coastal area. Suspension feeding bivalves can feed the organic particulate and phytoplankton, and enhance the deposition of organic matter on the sea floor through the excretion of feces and pseudofeces. Meanwhile the mariculture structure can also affect the local hydrodynamics and current flow. The mariculture structure can act as artificial reef which provides various habitats and refugees and more available food to the epifauna. The demersal fishes and macroinvertebrates under the mariculture structure will benefit from it and have higher abundance and productivity with the protection from the fishery trawling. The effect of the bivalve mariculture on the structure and composition of the macrobethic infauna is negatively correlated to the current or tidal flow strength. The negligible effect of the bivalve culture on the endobenthic community will occur with stronger current whilst the organic enrichment will result in the degradation of benthic diversity and abundance with slow current velocity. The suitable farm site selection, the evaluation of ecological carrying capacity and the integrated multi-trophic polyculture would be crucial to the healthy and sustainable development of bivalve mariculture.