Large tropical fishes and their use of the nearshore littoral, intertidal and subtidal habitat mosaic

Abstract

Shallow-coastal habitats are highly productive environments supporting a diverse community of fishes. Historical research suggests these habitats primarily function to support and nurture juvenile fishes; however, contemporary research indicates large and mature fishes also utilise these habitats. Moreover, few studies have considered the continuous cross-shore nature (i.e. extending seaward) of shallow-coastal habitats consisting of conjoined littoral, intertidal and subtidal habitats. To investigate the community of large-bodied fishes (>200mm) and how they distribute themselves across a mosaic of littoral, intertidal and subtidal habitats, seasonal sampling was conducted over 1 year in north-eastern Australia. A total of 1119 individuals from 26 families and 36 species were sampled, though four families accounted for 79.1% of the total sample (Latidae, Polynemidae, Ariidae and Carcharhinidae). The littoral and subtidal communities differed significantly from each other, whereas the intertidal community shared some species-specific characteristics with both adjacent fish communities. Teleosts were the dominant group in the littoral and intertidal habitats, whereas sharks dominated the subtidal. These patterns are likely driven by a combination of biological and ecological processes; however, further research is necessary to better understand the role of these processes on shaping the large-bodied fish communities of shallow-coastal waters.