Reefs re-open to fishing for Effects of Line Fishing Experiment

The re-opening of four reefs to fishing on 6 March 2005 marks the final phase of the Effects of Line Fishing (ELF) Experiment, one of the most important research projects being undertaken by the Fishing and Fisheries team from the CRC Reef Research Centre. This large-scale fisheries experiment is helping to determine how reef fish populations respond to different levels of line fishing. The information from the ELF Experiment has been vital to discussions on management of the Great Barrier Reef line fishery in recent years.

The ELF Experiment is carefully monitoring reef fish populations during controlled changes to fishing pressure (by opening and closing reefs to fishing). This provides important information about how fish populations respond to line fishing and an insight about the effects of past and future fishing pressure.

Map of Queensland showing approximate location of reefs that will re-open to fishing on 6 March 2005 as part of the Effects of Line Fishing Experiment. Please note that Fork Reef (18-083) and Unnamed reef (21-139) will only be opened temporarily from 6 March 2005 until 30 November 2005, when they become Green Zones under the GBRMP zoning.

In order to change fishing pressure on individual reefs for the experiment, CRC Reef sought the assistance of the Great Barrier Reef Marine Park Authority (GRBMPA) to temporarily change the zoning status of several reefs in the Great Barrier Reef Marine Park. Since March 1997, eight ‘no-take’ (green) reefs have opened to fishing for one year each, and eight ‘open’ (blue) reefs closed to fishing for five years each as part of the ELF Experiment. The last of these zoning changes occurs on 6 March 2005 when four reefs re-open to fishing after being closed since 2000. Importantly, this includes two reefs that are now zoned green ‘no-take’ areas under the GBRMP Zoning Plan (2003). These reefs will only be opened temporarily until 30 November 2005 to complete the ELF Experiment.

Reefs to re-open on 6 March 2005

Unnamed reef (14-133), near Lizard Island
Fork Reef (18-083), off Townsville
Boulton Reef (20-146), off Mackay
Unnamed reef (21-139), near Storm Cay

Please see the map for locations of these reefs or visit GBRMPA for exact co-ordinates.

Fork Reef (18-083) and Unnamed reef (21-139) are Green Zones in the GBRMP Zoning Plan (2003), but are designated Fisheries Experimental Areas that will be opened temporarily from 6 March 2005 until 30 November 2005 inclusive.

What does the ELF experiment tell us?

ELF researchers have been monitoring how fish stocks on these reefs have reacted to varying levels of fishing pressure and protection from fishing over the last 10 years. The experiment is providing important information about the effectiveness of green zones and other management strategies. This will help managers understand how we might expect to see fish stocks change in the future, following the implementation of the GBRMPA Zoning Plan (2003) and the Queensland Coral Reef Fin Fish Management Plan (2003).

Analysis of information from the ELF Experiment up to 2000 shows that reefs closed to fishing can have more and larger coral trout and red throat emperor than reefs that are open to fishing, with this pattern most obvious in areas south of Townsville. There were rapid declines in fish numbers on reefs opened to fishing, which strongly indicated that without protection from fishing, these reefs would have fish populations that are similar to the open reefs around them. In contrast, the research found that fish stocks recovered following closure of reefs to fishing. Also, larger fish populations on closed reefs will most likely have greater spawning capacity than those on surrounding open reefs. This adds support to the argument that green zones are an effective conservation and fisheries management tool.

The research results also show that reducing the level of fishing effort is the strategy most likely to see improvements in a number of indicators of fishery health (such as commercial catch rates and size of fish taken on reefs open to fishing). Effort restrictions and area closures are required to achieve both conservation of fish and satisfactory fishery performance leading to ecological sustainability.

The ELF Experiment is also allowing researchers to accumulate an enormous amount of information on the biology of a variety of important reef fish species. This has been essential in recent consideration of legal size limits and other management arrangements for the reef line fishery.

Find out more about the ELF experiment.