The coastal zone of Los Petenes” Biosphere Reserve, is a critical breeding habitat for many species, particularly fish. Despite its low anthropic impact, development on the coastal area around the reserve is gradually increasing and fishing activities continue to grow; however, there are few studies on fish communities and the characteristics of their environment. In addition, there are no reference indexes to measure possible future impacts on the fish community. In order to obtain a baseline index, we carried out 12 monthly campaigns at 24 sampling sites between May 2013 and April 2014 in the coastal area of the reserve. Through these months we analysed water environmental variables, and calculated various diversity indexes: species richness (S), evenness (E_1/D), importance index (IV), and indexes of taxonomic distinctiveness (Δ*, Δ⁺, Ʌ⁺). There are significant environment variations through these months, but there is no evident variation between sampling sites. We identify 45 species of fish grouped into 44 genera, 20 families, 15 suborders, 13 orders, 2 subclasses and 2 classes. According to index IV (> 10), 12 species are important. Taxonomic diversity indexes are sensitive to environmental variation, mainly during the rainy season. We establish the preferred environmental characteristics of all 45 species. This study allows for the establishment of baseline index values for the state of the Reserve that can be reassessed in future research regarding the impact of developing fishing, tourism and urban activities in the region.

Los Petenes生物圈保护区沿海地区是许多物种（尤其是鱼类）的重要繁殖地。尽管人类活动影响不大，保护区周围沿海地区的开发却在逐步增加，捕捞活动继续增长；但是，关于鱼类群落及其环境特征的研究很少。此外，没有参考指标可以衡量未来可能对鱼类群落的影响。为了获得基准指数，我们于2013年5月至2014年4月在保护区沿海地区的24个采样点开展了12个月的运动。在这几个月中，我们分析了水环境变量，并计算了各种多样性指数：物种丰富度（S），均匀度（E _{1 / D}），重要性指标（IV）和分类学独特性指标（Δ*，Δ ⁺，Ʌ ⁺）。在过去的几个月中，环境有很大的变化，但采样点之间没有明显的变化。我们确定了45种鱼类，分为44属，20科，15个亚目，13个目，2个亚类和2个类。根据索引四（> 10），重要的是12种。分类学多样性指数对环境变化敏感，主要是在雨季。我们建立了所有45种物种的首选环境特征。这项研究可以为保护区的状态建立基线指标值，可以在未来有关该地区发展渔业，旅游业和城市活动的影响的研究中重新评估该基线值。