Fish Ecology

Ecosystem of designed artificial reefs

A food web based on plankton may sustain the multi-million dollar fishing industry around designed artificial reefs, but the key drivers of this ecosystem remain unknown. This project aims to compare the fish assemblage and recreational fishing effort around different designs and locations of artificial reefs, using an innovative combination of oceanographic, acoustic and radar technologies. We will reveal the dietary fingerprint of zooplankton in key trophic groups, including the harvested fish. The diet and residency of forage fish will indicate if the estimated catch is balanced by fish production. The expected outcomes include a general ecosystem model to assess these reefs as they proliferate around urbanised coastlines of Australia.

Designed artificial reefs are deployed to enhance recreational fishing – a significant part of a $10 billion pa economy based around Australia’s vast temperate reef ecosystem. This fishery may be sustained by a food web based on plankton as it drifts across the structure. This project aims to determine the various reef designs, environmental conditions, ecosystems and fishing effort, which optimise the fishing outcomes and determine the risk of locally unsustainable fishing. Globally there is still a lack of scientific direction for managing these significant investments. This project provides a scientific basis for managing future deployments and for their social, economic and environmental legitimacy.


ARC-LP150100923 (Suthers et al. 2015-2019)

“Surplus baitfish? The consumption and bioenergetics of a predatory fish”

The ecosystem demand by predatory fish is not understood, because it fails to include the considerable impact of juvenile fish, especially when they reside in an estuary. Our aim is to determine the diet and the size- and temperature-dependent growth and biogenetics of a species, from juvenile to adult; from estuary to the open sea. This study is also significant for fisheries management of economically important baitfish, by incorporating the size-based metabolism of a representative predator. The project is innovative by implanting acoustic transmitters, calibrated in a flume, to discover bioenergetic rates in the field. The outcomes include an ecosystem synthesis of related pelagic fish predators from catchment to coast.

Small pelagic fish have great economic potential but they also sustain coastal ecosystems. The consumption of baitfish by a recreationally important species will be estimated, from juvenile to adult and from estuary to the open coast. The juveniles of this representative fish can be reliably sampled, to discover the ecological requirements during the first year. This research will reveal the lifetime schedule of energetic needs, and provide a new basis for managing marine resources.

ARC-LP160100162 (Jonsen et al. 2016-2019)

“Resolving the warming East Australian Current’s impact on a marine food web”

Warming waters due to strengthening western boundary currents have unknown consequences for coastal marine food webs. This project aims to integrate data on oceanographic conditions and fish distribution with the foraging patterns and breeding success of seabirds. The project is significant for understanding the effects of climate change on marine food webs, from plankton production to predation by iconic marine fauna. Innovative prey capture signatures from accelerometers, together with advanced movement models from satellite locations will be used to show how fish schools are located and preyed upon by predators. The outcome will be new insight into how changing resource availability in the oceans affects ecosystem resilience.This project will improve predictions of the impact of climate change on coastal marine food webs. It will give much needed insight into the future viability of important industries for coastal regions, such as pelagic finfish fisheries, recreational game fishing, and ecotourism relating to marine wildlife. Information from this study will be used to develop ecosystem-based conservation management strategies that will benefit declining populations of seabirds.