Engraulidae (Teleostei, Clupeiformes) in tropical estuarine ecosystems: identification of fish larvae based on morphological analysis and molecular evidence

Fish larvae identification in estuarine environments is of major importance for fishing resources verifications, environmental monitoring, and establishment of protection areas. Species of the Engraulidae family are morphologically very similar; therefore, taxonomic characterization can be insufficient to reach a precise identification. Molecular-level analysis has become an important tool to assist on taxonomy, as it does not depend on morphological expressions that only occur in juvenile or adult stages. Fish larvae were sampled in tropical estuarine ecosystems, in a single water body, with salinities ranging between 15 and 25, using a bongo net with a 500-mu m mesh, towed obliquely from the surface. Around 73% of identified individuals are from the Engraulidae family, and are classified into nine morphotypes according to morphological characteristics. DNA analyses were performed, with the sequencing of the mitochondrial gene Cytochrome C Oxidase I. These analyses suggest the occurrence of two distinct genera: Anchoa and Lycengraulis, among the investigated specimens. The present study contributes to enriching knowledge on the morphology of larvae of the Engraulidae family, and highlights the potential of molecular analysis techniques to elucidate taxonomic issues.

Automated summary

Identification of fish larvae in estuarine environments is crucial for fishing resources verification, environmental monitoring, and protection area establishment. Species of the Engraulidae family are morphologically similar, making taxonomic characterization insufficient for precise identification. Molecular analysis is an important tool to assist in taxonomy and can overcome the limitations of morphological analysis.