Abstract：
Uca maracoani is a fiddler crab found in estuaries along the western Atlantic coast, with a notable preference for euhaline environments. This study aimed to analyze the population structure and dynamics of this species in an estuary on the North Coast of Brazil, specifically in an area of the upper estuary where seasonal rainfall fluctuations result in significant changes in salinity. Monthly crab samples were taken from December 2013 to November 2015, together with measurements of environmental variables, such as water and climate parameters. The population maintains a balanced sex ratio; however, males are generally larger, with lower mortality rates and longer lifespans than females. Reproduction is continuous but mainly takes place in the dry season when salinity levels are higher (above 12‰). Higher crab densities have been observed during the rainy season when, despite lower salinity levels (below 10‰), the conditions for survival (food availability and milder climate) seem to be more favorable. The estimated average annual biomass and production for the population were 2.62 g AFDM m-2 and 5.43 g AFDM m-2 year-1, respectively, characterized by a high turnover rate (P/B = 2.10 year-1). Our results suggest that U. maracoani has thriving populations in the Amazon coast\'s mangroves, benefiting from the vast muddy intertidal zone and the high organic content delivered by the estuaries.
摘要：
Ucamaracoani是一种在大西洋西部沿岸河口发现的提琴蟹，与一个显着偏好的环境。这项研究旨在分析该物种在巴西北海岸河口的种群结构和动态，特别是在上河口地区，季节性降雨波动会导致盐度发生重大变化。从2013年12月至2015年11月采集每月螃蟹样本，并测量环境变量，如水和气候参数。人口保持均衡的性别比例；然而，雄性通常较大，与女性相比，死亡率更低，寿命更长。繁殖是连续的，但主要发生在盐度较高（12‰以上）的旱季。在雨季观察到更高的螃蟹密度，尽管盐度水平较低(低于10‰)，生存条件(食物供应和温和的气候)似乎更有利。该种群的年平均生物量和产量分别为2.62gAFDMm-2和5.43gAFDMm-2year-1，特点是高周转率(市盈率=2.10year-1)。我们的结果表明，美国马拉科尼在亚马逊海岸的红树林中拥有蓬勃发展的种群，受益于广阔的泥泞潮间带和河口提供的高有机物含量。
