Quantitative diet analysis of four mesopredators from a coral reef

Abstract

The diets of four common mesopredator fishes were examined in the back-reef habitat of a subtropical fringing reef system during the summer months. Quantitative gut content analyses revealed that crustaceans, represented >60% of ingested prey (% mass) by the latticed sand-perch Parapercis clathrata, brown dottyback Pseudochromis fuscus and half-moon grouper Epinephelus rivulatus. Dietary analyses also provided insights into ontogenetic shifts. Juvenile P. fuscus ingested large numbers of crustaceans (amphipods and isopods); these small prey were rarely found in larger individuals (<1% of ingested mass). Fishes also made an important contribution to the diets of all three species representing 10-30% of ingested mass. Conversely, the sand lizardfish Synodus dermatogenys fed exclusively on fishes including clupeids, gobies and labrids. Differences in the gut contents of the four species recorded were not apparent using stable isotope analysis of muscle tissues. The similarity of δ(13) C values in muscle tissues suggested that carbon within prey was derived from primary producers, with comparable carbon isotope signatures to corals and macroalgae, whilst similarities in δ(15) N values indicated that all four species belonged to the same trophic level. Thus, interspecific differences between mesopredator diets were undetectable when using stable isotope analysis which suggests that detailed elucidation of trophic pathways requires gut content analyses.

Refining the invertivore: diversity and specialisation in fish predation on coral reef crustaceans

“…Nuanced differences in micro-crustacean feeding were also apparent, with different wrasses tending to specialise towards the Amphipoda, Calanoida, Harpacticoida and/or Isopoda. This suggests that there are at least two distinct crustacean-based trophic pathways on reefs and that care is needed when assessing the role of crustacean-feeding fishes in coral reef trophodynamics (Depczynski and Bellwood 2003;Graham et al 2003;Ashworth et al 2014).…”

“…Randall 1967;Ferry-Graham et al 2002;Depczynski and Bellwood 2003;Cowman et al 2009), information on this trophic group is scarce, even within well-studied families such as the Labridae (but see Bellwood et al 2006;Ashworth et al 2014).…”

Specialization within a shifting habitat mosaic underpins the seasonal abundance of a tropical fish

“…, Ashworth et al. ) of L. vaigiensis . Each transect comprised two passes: (1) all fishes greater than and equal to 10 cm TL within a 5 m wide band were recorded first, followed by a (2) return pass to record all fishes less than 10 cm TL within a 1 m wide band.…”

Trophodynamics as a Tool for Understanding Coral Reef Ecosystems

“…Due to the complexity and variability of coral reef ecosystems, simplifications are often applied. For example, global databases (e.g., Fishbase; Froese and Pauly, 2000) may be used to source available data in lieu of extensive field collection to obtain site specific data (Bauman et al, 2010;Alva-Basurto and Arias-González, 2014;Ashworth et al, 2014;Ceccarelli et al, 2014;Aguilar-Medrano and Barber, 2016). However, information within these databases is often limited to specific regions.…”