Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), Estación de Acuicultura Marina, Puerto de San Pedro del Pinatar, 30740 Murcia, Spain.
Mar Environ Res. 2012 Mar;74:47-55. doi: 10.1016/j.marenvres.2011.12.003. Epub 2011 Dec 16.
This work concerns the monitoring of a Mediterranean maërl bed influenced by an experimental fish cage culture for eighteen months. The maërl bed showed an a priori stratified distribution with depth, which led to the selection of a stratified random sampling design that also took into account the gradient of influence by the fish cages. Maërl coverage and total biomass, macroalgae species richness and community structure as determined from semi-quantitative abundance data were assessed. The content of organic matter sediment was also considered. Sampling campaigns (performed by scuba divers) were carried out six months before the start of the culture, twice during the culture, and two months after the end of the experimental culture. Below the fish cages, the maërl community was almost completely buried and dead blackened calcareous algae were seen beneath a thin layer of sediment prior to the end of the study, and only a few specimens of Lithophyllum racemus, Flabellia petiolata, Gracilaria cylindrica and Meredithia microphylla remained alive. The influence of the experimental culture on the maërl algae community structure bed did not extend beyond the facilities, but a regression of the community was also observed close to the fish cages. Sensitivity to aquaculture activity, and the ecological benefits provided by maërl beds suggest that this community warrants further consideration when planning fish farm site selection and management.
本研究对一个受十八个月实验性鱼类养殖笼影响的地中海石莼床进行了监测。石莼床表现出与深度相关的先验分层分布，这导致采用了分层随机抽样设计，同时也考虑了养殖笼的影响梯度。评估了石莼覆盖率和总生物量、大型藻类物种丰富度和群落结构，这些数据来自半定量丰度数据。还考虑了有机物质沉积物的含量。在养殖开始前六个月、养殖期间进行了两次、实验养殖结束后两个月，由水肺潜水员进行了采样活动。在养殖笼下方，石莼群落几乎完全被掩埋，在研究结束前，可以看到死的黑色钙质藻类被一层薄薄的沉积物覆盖，研究结束后，只有少数 Lithophyllum racemus、Flabellia petiolata、Gracilaria cylindrica 和 Meredithia microphylla 标本存活。实验养殖对石莼藻类群落结构床的影响没有超出设施范围，但在养殖笼附近也观察到了群落的退化。由于对水产养殖活动的敏感性以及石莼床提供的生态效益，在规划鱼养殖场选址和管理时，有必要进一步考虑这种群落。
