Eric Fisher - AIMS@JCU

Eric Fisher

College of Science and Engineering

Eric Fisher

College of Science and Engineering
The biological and physical drivers influencing coral reef fish aggregations

Eric grew up in North Queensland and after graduating with honors at JCU Townsville in Marine Biology travelled for a decade overseas. On return to Cairns, Eric started work as a Marine Biologist for a tourism operator 13 years ago. At present still with the company working full time in managing a team of biologist in charge or our reef interpretation, reef monitoring, reef management and research. Currently Eric lives happily in Cairns with my wife and two daughters while also trying to complete my PhD part time.

The biological and physical drivers influencing coral reef fish aggregations

2017 to 2022

Project Description

To investigate the physical and biological processes influencing coral reef fish forming aggregations at a coral reef pass. The four goals of this project are:
1) To evaluate the fine scale water circulation patterns of a reef pass on a temporal scale ranging from hours to years.
2) To examine the extent to which key features of the hydrodynamic environment predicted the occurrence of 10 fish species from five families at a fish aggregation site over a six-year period.
3) Produce case studies assessing the ecological importance of three individual coral reef fish species that utilize a fish aggregation site to forage and or reproduce.
4) Quantify large piscivore abundance and species richness patterns at a fish aggregation site at a temporal scale ranging from hours to years.

Project Importance

Previous research on coral reef fish aggregations has focused on fish forming spawning aggregations and the ecological consequences of overfishing these aggregations. Spawning aggregation are important to the replenishment of fish populations. Although on coral reefs, fish aggregations are usually multispecies and often tight interactions develop between species. Some fish species also aggregate to forage at these locations thus incorporating primary production from both benthic and pelagic sources into coral reef systems. The importance of Eric’s research is to substantiate that fish form foraging and reproductive aggregations at the same site and often same time and that these aggregations are of equal ecological importance.

Project Methods

To investigate the fish aggregation site, the project will incorporate a variety of methodologies, including 1) using several types of novel marine instruments developed by JCU to illustrate current patterns, 2) using multivariate regression trees and indicator species of a long term data set of fish abundance in relation to temporal hydrodynamic variables, 3) using a swimmable stereo video rig (provided by AIMS) while towing a GPS to provide reliable estimates on size structure, spatial distribution and behaviour of aggregating fish, 4) using fixed video cameras to quantify large piscivore predator presence and behaviour of aggregating fish species.

Project Results

A Small reef pass has a configuration in which the hydrodynamic processes are influenced by tides. Flood tides produce a separation point at the mouth of the pass created through tidal jet phenomenon. Consequently, the separation point is the area of the fish aggregation site and flood tides are the principle driver underlying fish forming fish aggregations at the pass regardless of their trophic classification. Eric can predict four out of ten times the occurrence of all ten species of large coral reef fish at the aggregation site at the temporal scale ranging from hours to years.


Climate change,
Coral reefs,
Field based,
Marine planning,
Ocean warming,
Quantitative marine science,
Sharks / Rays,
Temporal change,