Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, College of Marine Sciences, Beibu Gulf University, Qinzhou, 535011, China.
Department of Chemistry, City University of Hong Kong, Hong Kong.
J Environ Manage. 2020 Oct 1;271:110925. doi: 10.1016/j.jenvman.2020.110925. Epub 2020 Jun 28.
Estuarine structured habitats, including benthic cultivation structure, are widely cited as substantial nursery and feeding grounds for fish and macroinvertebrates. Activities such as locomotion and foraging behaviour of sediment-dwelling species, however, may be hindered in the presence of the obstacles. In this study, collected field evidence demonstrated that habitat utilization of the juvenile tri-spine horseshoe crab Tachypleus tridentatus, an iconic and endangered macroinvertebrate, was adversely affected by high-density intertidal oyster rubble zones. Despite the fact that the utilization area of individual juvenile horseshoe crabs was independent of the presence of these obstacles, the abundance and number of positional fixes of tagged juveniles in these areas were lower. The effects of these obstacles and their associated topographic changes on the movement of the juvenile horseshoe crabs was investigated in a simulated laboratory experiment. Both the simulated oyster cultches and hummocks formed between the cultches reduced the total distance and displacement of the feeding trail, and less juveniles preferred to forage on elevated, dry hummocks (dry at low tide) formed between the cultches. Our findings suggested that oyster cultches and rubbles reduced the habitat quality for juvenile horseshoe crabs. On-bottom oyster cultivation activities seeking to conserve horseshoe cabs by avoiding nursery habitats should instead consider off-bottom or offshore cultivation methods.
河口结构生境，包括底栖养殖结构，被广泛认为是鱼类和大型无脊椎动物的重要育苗和觅食场所。然而，沉积物栖息物种的运动和觅食行为等活动可能会受到障碍物的阻碍。在本研究中，实地收集的证据表明，高密度潮间带牡蛎碎石区对幼年三刺鲎（一种标志性的濒危大型无脊椎动物）的生境利用产生了不利影响。尽管个体幼年鲎的利用面积与这些障碍物的存在无关，但标记的幼年鲎在这些区域的数量和位置固定次数较少。在模拟实验室实验中研究了这些障碍物及其相关地形变化对幼年鲎移动的影响。模拟牡蛎养殖箱和养殖箱之间形成的土丘都减少了觅食轨迹的总距离和位移，并且较少的幼年鲎喜欢在养殖箱之间形成的、位于高处的、干燥的土丘（低潮时干燥）上觅食。我们的研究结果表明，牡蛎养殖箱和碎石减少了幼年鲎的栖息地质量。为了保护鲎而避免育苗生境的底栖牡蛎养殖活动，应该考虑采用底外或底外养殖方法。
