Université Côte d'Azur, CNRS, ECOMERS, Nice, 06108, France.
Sorbonne Universités, UPMC Univ Paris 06, INSU-CNRS, UMR 7093 Laboratoire d'Océanographie de Villefranche (LOV), Villefranche sur mer, 06230, France.
Sci Rep. 2017 Jul 20;7(1):6012. doi: 10.1038/s41598-017-06394-7.
Canopy-forming algae are declining globally due to multiple disturbances. This decline has recently been on the increase due to the spread of some tropical herbivorous fishes. This new phenomenon has drawn attention to the effects of fish herbivory in temperate areas, which have been assumed to be negligible compared to that of invertebrates, such as sea urchins. In this study, the impact of a Mediterranean native herbivorous fish (Sarpa salpa, salema) was assessed on the canopy-forming seaweed Cystoseira amentacea var. stricta. Cystoseira amentacea forms belts in the infralittoral fringe of wave-exposed shores, which has so far been considered a refuge from fish herbivory. To test the effects of salema feeding on natural C. amentacea belts, an innovative herbivore deterrent device was conceived. Salema had a significant effect on C. amentacea by decreasing algal size, biomass and fertility, by up to 97%. The results suggest that the contribution of salema feeding to the loss of Cystoseira forests in the Mediterranean may have been overlooked. In addition, the analysis of temporal and spatial patterns of salema landings in the Mediterranean Sea suggests that salema abundance may have increased recently. Thus, along with invertebrate herbivory and anthropogenic stressors, fish herbivory may also represent a potential threat to algal forests in temperate areas.
由于多种干扰，全球的冠层藻类正在减少。由于一些热带草食性鱼类的传播，这种减少最近一直在增加。这种新现象引起了人们对温带地区鱼类食草作用的关注，与海胆等无脊椎动物相比，人们认为这种作用可以忽略不计。在这项研究中，评估了一种地中海本地草食性鱼类（Sarpa salpa，salema）对冠层形成海藻 Cystoseira amentacea var. stricta 的影响。Cystoseira amentacea 形成了暴露于波浪的近岸带的带状物，迄今为止，这些带状物被认为是免受鱼类食草作用的避难所。为了测试 salema 摄食对天然 C. amentacea 带的影响，设计了一种创新的食草动物驱避装置。salema 通过将藻类的大小、生物量和繁殖力降低多达 97%，对 C. amentacea 产生了显著影响。研究结果表明，salema 摄食对地中海 Cystoseira 森林的损失可能被忽视了。此外，对地中海 salema 登陆的时间和空间模式的分析表明，salema 的数量最近可能有所增加。因此，除了无脊椎动物食草作用和人为压力外，鱼类食草作用也可能对温带地区的藻类森林构成潜在威胁。
