Understanding the effects of environmental drivers on fish distribution is of primary importance for designing effective conservation measures to protect endangered species. In this study, we investigated which habitat and spatial predictors enhance the abundance and biomass of the parrotfish Sparisoma frondosum in tropical rocky reefs from a Southwest Atlantic insular complex. Besides more than 170 islands, the Ilha Grande Bay (IGB) also harbors one of the most threatened Brazilian Marine Protected Area (MPA), the Ecological Station of Tamoios (ESEC–Tamoios). This no-take MPA became an emblematic area of the systematic dismantling of Brazilian environmental laws ongoing since the beginning of 2019 when the current government has declared intentions to recategorize and reduce the ESEC-Tamoios protection status. Our results revealed that distance from the coast and depth better explained the distribution of the iconic and vulnerable S. frondosum, regardless the presence of the no-take areas. An overall trend of increasing abundance and biomass with distance and depth was observed, except for sites with high cover of invasive coral Tubastraea spp. We also discuss the ESEC-Tamoios effectiveness and its current panorama to the Southwest Atlantic rocky reef's conservation. Finally, we identify strategies to protect parrotfishes and expand the ecological benefit of this MPA to adjacent areas.

了解环境驱动因素对鱼类分布的影响，对于设计有效的保护措施以保护濒临灭绝的物种至关重要。在这项研究中，我们调查了哪些栖息地和空间预测因子可提高鹦嘴鱼Sparisoma frondosum的丰度和生物量来自西南大西洋岛屿复合体的热带岩石礁中。除了170多个岛屿外，格兰德湾（IGB）还拥有受威胁最大的巴西海洋保护区（MPA）之一，塔莫奥斯生态站（ESEC–Tamoios）。自2019年初以来，现任政府宣布有意重新分类并降低ESEC-Tamoios的保护地位，这项禁止的MPA成为自2019年初以来系统废除巴西环境法律的标志性领域。我们的结果表明，与海岸的距离和深度更好地解释了标志性脆弱脆弱链球菌的分布，无论是否存在禁区。观察到总的趋势是，随着距离和深度的增加，丰度和生物量都有增加的趋势，除了侵入性珊瑚金龟子属植物的高覆盖度的地点以外。我们还将讨论ESEC-Tamoios的有效性及其对西南大西洋礁石保护的当前全景。最后，我们确定保护鹦嘴鱼的策略，并将该MPA的生态效益扩展到邻近地区。