The maintenance of natural capital and the stability of regulation services of marine ecosystems has proved to be linked to the conservation of key species supporting the ecosystems function. Chondrichthyes are key top-predators and their removal from marine ecosystems due to fishing exploitation could lead to changes in species interactions and biomass that can negatively influence the provision of ecosystems services. The ecological role of the demersal Chondrichthyes living in the marine food web of the Calabrian area in the Northern Ionian Sea (Central Mediterranean Sea) was analysed by means of ecological indicators derived from Ecopath mass-balance food web models estimated in their stationary states during the periods 1995–1997, 2003–2005 and 2013–2015. The trophic web model was described by 57 functional groups (7 of which representing the demersal Chondrichthyes), which were described by their Biomass (t/km²), Production and Consumption rate, Diet, Landings (t/km²) e Discards (t/km²). Remarkable changes in biomass were recorded for shark and rays, as a consequence of changes in fishing patterns and oceanographic regime shift named Bimodal Oscillating Systems (BiOS).

Demersal Chondrichthyes occupy high trophic positions in the Calabria food web showing trophic levels higher than 4.1, with the D. licha identified as the main apex predators, while E. spinax and G. melastomus as meso‑predators. The pattern of the consumption flows highlighted a potential sensitivity of E. spinax and G. melastomus to the changes in deep waters circulation caused by the BiOS acting on the entire ecosystem of the Ionian Sea. D. licha was identified as the main keystone predators in all the investigated periods. The analysis of the trophic indirect and direct impacts shows the role of the demersal Chondrichthyes as beneficial predators, with positive effects on several preys. Results also showed that G. melastomus and the Shelf Elasmobranchs group (e.g. Raja asterias, Mustelus mustelus, etc.…) were overexploited in 1995 and that all groups of sharks and rays underwent to a decrease of exploitation rate over time. Chondrichthyes showed medium-low values of overlap with the fishing gears (<0.50), with the more relevant values estimated between the shelf elasmobranch group and passive nets and other gears. According to the findings of this work, the protection of Chondrichthyes could combine biodiversity conservation and fisheries management objectives. Therefore it is envisaged the implementation of appropriate spatial planning and conservation measures for these top-predators to guarantee valuable and sustainable flows of ecosystem goods and services.

事实证明，维持自然资本和海洋生态系统调节服务的稳定与保护支持生态系统功能的关键物种有关。软骨鱼类是主要的捕食者，由于捕捞而将其从海洋生态系统中捕捞可能会导致物种相互作用和生物量的变化，从而可能对生态系统服务的提供产生负面影响。利用从Ecopath质量平衡食物网模型在稳态期间估计的生态指标得出的生态指标，分析了生活在北爱奥尼亚海（地中海中部）卡拉布里亚地区海洋食物网中的软骨鱼类的生态作用。 1995-1997年，2003-2005年和2013-2015年。²），生产和消费率，饮食，着陆量（t / km ²）e丢弃物（t / km ²）。鲨鱼和rays鱼的生物量发生了显着变化，这是由于捕捞方式的变化和称为双峰振荡系统（BiOS）的海洋学制度变化的结果。

水下软骨鱼类在卡拉布里亚食物网中占据较高的营养位置，显示营养水平高于4.1，其中以D. licha被确定为主要先天捕食者，而E. spinax和G. melastomus为中消食者。消费流量的模式突显了大肠杆菌（E. spinax）和黑变菌（G. melastomus）对BiOS作用于爱奥尼亚海整个生态系统所引起的深水循环变化的潜在敏感性。荔枝在所有调查期间内被确定为主要的基石掠食者。对营养间接和直接影响的分析表明，深海软骨鱼是有益捕食者的作用，对一些猎物有积极影响。结果还表明，黑变种G. melastomus和架子Elasmobranchs组（例如Raja asterias，Mustelus mustelus等）在1995年被过度开发，所有鲨鱼和rays鱼群的使用率都随着时间的流逝而降低。软骨鱼显示出与渔具重叠的中低值（<0.50），而在架子弹bra群与被动网和其他渔具之间估计的相关性更高。根据这项工作的发现，对软骨鱼的保护可以将生物多样性保护和渔业管理目标结合起来。因此，设想为这些顶级捕食者实施适当的空间规划和保护措施，以确保生态系统产品和服务的宝贵和可持续流动。