Intertidal molluscs are keystone species often used as biological indicators of human-driven perturbations. The increasing levels of harvesting pressure on these intertidal grazers, due to the expansion of human population on coastal areas, is known to affect negatively the exploited populations by altering population size–structure and decreasing abundances. A comparative study on the effect of harvest on the size–structureof Phorcus sauciatus populations was conducted according to the exploitation level, harvested and non-harvested, throughout the intertidal zone of mainland Portugal, Azores, Madeira, and the Canaries. The comparative analysis of the size–structure of 10,480 individuals of P. sauciatus showed that the largest individuals were recorded in the Azores and the smallest in Madeira. In harvested populations, P. sauciatus showed to be under greater harvesting pressure in the archipelago of Madeira, where the lowest mean size was observed. In the Canaries the harvesting is regulated whilst in the mainland Portugal the regulation is scarce. The Azores showed no harvesting pressure. Marine Protected Areas showed individuals with the highest mean sizes supporting their effectiveness in preserving the size–structure of this species, regardless the ecoregion and thus, the harvesting pressure. The present results highlight the importance of harvesting regulation of P. sauciatus in Madeira, as well as the implementation of management measures aiming at the sustainable exploitation and conservation of this species.

潮间带软体动物是基石物种，通常被用作人类驱动扰动的生物学指标。已知由于沿海地区人口的增加，这些潮间带放牧者的收割压力增加，这会通过改变种群的大小结构和减少丰度而对被开发种群产生负面影响。根据整个葡萄牙大陆，亚速尔群岛，马德拉群岛和加那利群岛的潮间带的采伐水平，收获的和未收获的采伐水平，对收获对梭子蟹种群规模结构的影响进行了比较研究。的10480个个体的尺寸结构的比较分析P. sauciatus结果表明，最大的个体记录在亚速尔群岛，最小的个体记录在马德拉。在收获的种群中，马尾群岛的南美白对虾在更高的收获压力下，其平均大小最低。在加那利群岛，收割受到监管，而在葡萄牙大陆，则稀少。亚速尔群岛没有收获压力。海洋保护区显示的个体平均大小最高，从而可以有效地保护该物种的大小结构，无论其生态区域如何，也不论其收获压力如何。目前的结果突出了对南美白僵菌的收获调节的重要性 在马德拉（Madeira）以及实施旨在可持续开发和保护该物种的管理措施。