Surf-zone fish assemblage structure and its diel variability in an ocean beach of Espírito Santo (Central Brazilian coast)

We characterized the surf-zone fish assemblage structure of an ocean beach on the central coast of Brazil (Guriri Beach, Espírito Santo) and assessed its diel variability. Like the entire Espírito Santo coast, Guriri Beach was also affected by ore tailings from the Fundão dam, which collapsed on November 5, 2015. Monthly samplings were carried out before the dam collapse along a year cycle (May 2013-April 2014), during the day and night in the neap tide, using a beach seine. A total of 2217 specimens were caught (1017 during the day and 1200 at night), distributed in 36 fish species and 20 families. Juveniles of the kingcroaker Menticirrhus spp., great pompano Trachinotus goodei, Florida pompano Trachinotus carolinus, littlescale threadfin Polydactylus oligodon, and Atlantic sabretooth anchovy Lycengraulis grossidens dominated the fish fauna, accounting for 84% of the total capture. The fish assemblage structure changed irregularly between day and night throughout the year. P. oligodon and Menticirrhus spp. were more abundant at night, whereas T. carolinus and L. grossidens were more abundant during the day. In most cases, no significant change was detected in fish abundance and richness between the day and night; when significant differences were detected, abundance and richness were higher at night. Our findings could support a monitoring program of the local surf-zone fish fauna and serve as before-impact data, allowing more accurate quantification of the ore tailings' impacts on the local fish biodiversity.