Table_1_Spatial Management Units as an Ecosystem-Based Approach for Managing Bottom-Towed Fisheries in the Central Mediterranean Sea.docx

Marine ecosystems are being continually impacted by human activities and, among these, fisheries have been one of the most damaging. Fisheries modify the structure and functioning of food-webs through biomass removal and physical damage to the seabed, leading to loss of biodiversity and ecosystem services provided by the oceans. The ecosystem-based approach to fisheries is considered the most efficient way to achieve the goal of sustainable use of marine resources while allowing for biodiversity protection. The Strait of Sicily is a biologically important area of the central Mediterranean Sea characterized by high habitat complexity and rich biodiversity, however, due to the multispecific nature of local fisheries and weak implementation of the adopted management plans, this region is particularly vulnerable. We used fishery independent time series (1994–2016) to identify the main demersal assemblages and map their spatial distribution. The pressure of fishing effort on each of these defined assemblages was then quantified in order to evaluate the impact of bottom trawling on demersal communities. Our results showed four spatially distinct and temporally stable assemblages of the Strait of Sicily. These have a clear spatial distribution, different species composition and biodiversity values and are driven primarily by environmental gradients (i.e., mainly depth and, to a lesser extent, surface salinity). The demersal assemblages were subsequently grouped in homogeneous areas characterized by specific communities of commercial and non-commercial species and response to trawling impacts. These areas are proposed as Spatial Managements Units to evaluate and manage demersal mixed fisheries, while also considering biodiversity conservation in the central Mediterranean Sea.

海洋生态系统持续受到人类活动的影响，其中渔业活动是破坏性最强的人类活动之一。渔业通过移除海洋生物量、对海底造成物理破坏，改变食物网的结构与功能，进而导致生物多样性丧失以及海洋所提供的生态服务功能受损。基于生态系统的渔业管理方法（ecosystem-based approach to fisheries）被认为是实现海洋资源可持续利用、同时兼顾生物多样性保护的最有效途径。西西里海峡是地中海中部具有重要生物学意义的海域，其生境复杂度高、生物多样性丰富，但由于当地渔业为多物种捕捞模式，且已制定的管理计划执行力度薄弱，该区域尤为脆弱。本研究采用1994—2016年的非渔业依赖型时间序列数据（fishery independent time series），识别西西里海峡的主要底栖生物群落（demersal assemblages）并绘制其空间分布图谱；随后量化了捕捞努力量对上述各划定群落的压力，以评估底拖网捕捞（bottom trawling）对底栖生物群落的影响。研究结果显示，西西里海峡存在4个空间上独立、时间上稳定的底栖生物群落，这些群落具有清晰的空间分布特征，物种组成与生物多样性水平各不相同，其分布主要受环境梯度调控，核心影响因子为水深，次要影响因子为表层盐度。随后，研究将底栖生物群落按照物种组成（涵盖商业捕捞物种与非商业捕捞物种）及对拖网捕捞影响的响应特征，划分为多个均质区域；上述区域被提议作为空间管理单元（Spatial Management Units），用于评估和管理地中海中部的混合底栖捕捞渔业，同时兼顾该海域的生物多样性保护工作。