Current knowledge of the presence of microplastics (MP) in marine species in tropical areas is still limited. The presence of MP was examined in the gastrointestinal content of 30 filter feeders of the herring Opisthonema complex (Clupeiformes: Clupeidae) from the Central Pacific of Costa Rica. MP were detected in 100% of the individuals with an average of 36.7 pieces per fish, of which 79.5% were fibers and 20.5% particles. No direct association between biometric variables or sex and the amount of microplastic was found. Different physicochemical analyses were carried out to determine the composition and characteristics of the microplastics. Most of the fibers were classified as polypropylene. Remarkably, some plastic particles turned out to be composed exclusively of minerals. This study demonstrates the high presence of MP in planktivorous fishes of the Pacific coast of Central America. Also, we propose the Opisthonema complex as a model for biomonitoring microplastic pollution in the Tropical Eastern Pacific due to its wide distribution, biometric homogeneity of the schools, non-selective feeding type, and its crucial position in the marine food webs.

目前关于热带地区海洋物​​种中微塑料（MP）的存在的知识仍然有限。在鲱鱼牙长青霉的30个滤嘴中，检查了肠胃中MP的含量哥斯达黎加中部太平洋的复杂（Clupeiformes：Clupeidae）。在100％的个体中检测到MP，平均每条鱼36.7条，其中纤维占79.5％，颗粒占20.5％。没有发现生物统计学变量或性别与微塑性的数量之间有直接关联。进行了不同的理化分析以确定微塑料的组成和特征。大多数纤维被分类为聚丙烯。值得注意的是，一些塑料颗粒原来完全是由矿物组成的。这项研究证明了中美洲太平洋沿岸浮游鱼类中MP的高度存在。此外，我们提出了Opisthonema 由于其分布广泛，学校的生物识别均一性，非选择性喂养方式及其在海洋食物网中的关键地位，因此该复合物可作为热带东太平洋地区微生物监测生物污染的模型。