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MEPS prepress abstract   -  DOI:

Foraging behaviour and movements of an ambush predator reveal benthopelagic coupling on artificial reefs

Aaron C. Puckeridge*, Alistair Becker, Matthew D. Taylor, Michael B. Lowry, James McLeod, Hayden T. Schilling, Iain M. Suthers

*Corresponding author:

ABSTRACT: The behaviour of coastal fishes to new habitats and trophic opportunities provided by artificial reefs may reveal the key processes which sustain fish production at these reefs. We quantified the trophic link between the benthic predators and pelagic forage fish, from the movement and foraging behaviour of an ambush predator, bluespotted flathead Platycephalus caeruleopunctatus, around an artificial reef in relation to schools of small pelagic fish. We used a network of acoustic receivers to monitor the fine-scale movements of 48 acoustically tagged flathead, around five groups of artificial reef modules for eight months in conjunction with acoustic surveys of pelagic baitfish and sustained monitoring of current speed and direction. Flathead were highly associated with the artificial reef, with 44% of standardised detections within 10 m of the modules. Flathead had a considerable degree of fidelity to the reef system with an average residency period of 84 d yr–1 (residency index = 0.23, standard deviation = 24 d). The low activity recorded by accelerometers indicated that the artificial reefs were a foraging ground for these ambush predators, especially in daytime, and where schools of planktivorous fish typically occurred upstream of the reef modules. These forage fish were found in the predatory fish stomachs. Artificial reefs with high vertical relief allow planktivores to feed through more of the water column, fixing more pelagic biomass into the system. Defining the residency and the trophic connectivity of fish at artificial reefs is critical to clarify the production-attraction debate and the sustainability of fishing at artificial reefs.