Non-native mud sleeper Butis koilomatodon (Bleecker, 1849) (Perciformes: Eleotridae) in Eastern Amazon Coastal region: an additional occurrence for the Brazilian coast and urgency for ecological assessment

Since 1989, specimens of the non-native mud sleeper Butis koilomatodon (Bleeker, 1849) (Perciformes: Eleotridae) have been collected off of the Brazilian coastline. The species has the potential to invade marine and estuarine systems, and outcompete native fish. The present study reports an additional occurrence of B. koilomatodon in the intertidal zone of Maranhao state, eastern Amazon coastal region of northeastern Brazil. Detailed environmental data was obtained at the site of specimen collection, and B. koilomatodon behavior in situ was documented. Ten individuals were sampled from three different mediolittoral tide pools at Panaquatira beach. Predominant substrate, percentage of algae coverage, surface area, tide pool volume and depth, roughness, pH, salinity, water temperature and dissolved oxygen were also documented. Ecological plasticity of analyzed individuals, associated with port handling behavior in neighboring bays of the studied area, suggest that the B. koilomatodon route of introduction was ship-mediated. High shipping intensity in this region may have favored introduction and possible invasive process of the species nearshore due to satisfactory propagule pressure. Nevertheless, more data are needed to comprehend the invasive potential of B. koilomatodon in Brazilian waters.