The trophic basis of fish assemblages in temperate estuarine and coastal ecosystems

Abstract

More than half of the sh biomass of coastal rocky reefs depends on zooplankton; however, the trophic basis of estuarine sh assemblages remains unknown. We quanti ed the trophic basis (i.e. basal energy sources) of sh community biomass inhabiting three habitat types (seagrass, natural reef and arti cial reef) in two estuaries, and at two coastal rocky reef sites. Estuarine sh assemblages were surveyed with Baited Remote Underwater Video (BRUVs). Species abundance, richness and biomass of sh were classi ed into 9 functional feeding groups (3 elasmobranch and 6 teleost). Comparable metrics for coastal sh assemblages were obtained from published surveys using BRUV, remote underwater video and visual census survey methods. Using the functional feeding group biomass and the group-speci c diet composition, the breakdown of energy sources was calculated using a food web analysis. Estuarine reef habitats had different species and different functional feeding group composition than seagrass habitat. The majority of sh biomass in the seagrass habitat was supported by detritus (51% at one estuary) or macrophytes (58% at the other estuary). In contrast, zooplankton supported most sh biomass (45-59%) at the coastal reef locations, and in reef habitat in one estuary (35-43%), but not the other estuary (33-34%). The trophic basis of estuarine and coastal sh assemblages reveals their potential response to urbanisation including changes to habitat, nutrient supply and current ow.

A deep dive into the ecology of Gamay (Botany Bay, Australia): current knowledge and future priorities for this highly modified coastal waterway

“…Since then, a further 200 reef balls have been deployed west of Bare Island. Reef balls have been deployed in multiple NSW estuaries, and associated fish communities have been found to differ among estuaries, (Folpp et al 2020;Goddard et al 2022), largely owing to the proximity of the deployment location to the estuary entrance. In Gamay, nearly half of fish biomass associated with reefs balls is based on plankton (the rest on algal or benthic production), which is similar to the adjacent coastal rocky reefs (Truong et al 2017;Holland et al 2020).…”

Size-selective predation by three estuarine zooplanktivorous fish species

“…Zooplanktivorous fish are a key trophic link between abundant zooplankton and larger predators. On temperate rocky reefs, zooplankton can support over 50% of the fish community biomass, with much of this flowing through small zooplanktivorous fish (Truong et al 2017;Goddard et al 2022). The foraging strategy of zooplanktivorous fish presents an interesting test of optimal foraging theory.…”

DIET COMPOSITION, CONDITION FACTOR AND INTESTINAL COEFFICIENT OF THE FISH Astyanax lineatus REFLECT THE ANTHROPOGENIC EFFECTS ON STREAMS IN CENTRAL BRAZIL

“…The analysis of diet in fishes has constituted an important source of information for greater insights into the processes that regulate tropical aquatic ecosystems (Manna et al 2019, Soe et al 2021, Goddard et al 2022. Also, it provides essential data on the ecology and biology of the species that cohabitate, with evidence about the role of each species in the ecosystem (Teixeira 1989, Zavala-Camin 1996, Manna et al 2012, Peressin et al 2018, Alonso et al 2019.…”