Issue 96, 24 July 2003

Victoria Introduces Annual Closed Season for Murray Crayfish
A closed season has been introduced for Murray crayfish effectively prohibiting their harvest north of the Great Divide, from 1st September each year to the 30th April the following year inclusive. The closed season will contribute to the sustainable management of Victorian Murray crayfish populations by:

• providing additional protection to legal size female Murray crayfish to maintain their long-term breeding capacity,
• avoiding the transference of angling effort to Victoria. New South Wales anglers, barred from the Murray itself by the NSW closed season, were crossing the border to fish for crayfish in Victorian waters. Matching closed seasons for this species will stop this pressure on Victorian stocks.

The closed season also has the benefit of improving compliance capacity between NSW and Victoria for this species.
The closed season does not apply to the Gippsland crayfish nor the Glenelg crayfish given that both species are found south of the Great Dividing Range.
These regulatory changes will be included in the 2003/2004 Victorian Recreational Fishing Guide and publicised widely.

Waranga Basin Temporarily Closed to the Harvest of Murray Crayfish

A temporary ban on the recreational harvest of Murray crayfish from Waranga Basin has been introduced.

Waranga Basin, near Rushworth, is currently experiencing very low water levels. Consequently, the reservoir’s Murray crayfish population is vulnerable to excessive harvest during the cooler months when they are most often targeted by recreational anglers.

Although bag and size limits currently restrict the recreational harvest of Murray crayfish from inland waters, including Waranga Basin, there is concern that these measures will not adequately protect the lake’s population at this time.

The temporary ban will be lifted when Waranga’s water level improves significantly.

MAFRI Trout Research – Rubicon River

The Rubicon River is a relatively small tributary stream of the Goulburn River, supporting self-sustaining populations of brown and rainbow trout.

It is a popular recreational fishing destination. Recently, however anglers have raised concerns that the Rubicon does not maintain acceptable catch rates throughout the trout season and have suggested these low catch rates reflect too much angling pressure.

Some anglers would like to see alterations made to the fishing regulations covering this river, imposing more restrictive bag limits or possibly making it a catch and release only fishery. However, too much fishing is not always the cause of declining catch rates. A study in the USA found that increasing water temperatures were responsible for declining catches and increased angler dissatisfaction rather than the over-harvesting of the fish stock.

Before any consideration is given to changing the current regulations in the Rubicon River, resource managers from Fisheries Victoria need to be certain that the reported decline in trout numbers in the Rubicon was real and then, determine which factors or combinations of factors were causing the problem. Indeed if, like the American example, environmental factors are the cause of lower catch rates, then changing fishery regulations would not necessarily improve the situation.

Fisheries Victoria through its research arm MAFRI is nearing completion of a 2 year study of the trout fishery in the Rubicon River.

The principle aims of the study are to determine if any changes in the abundance and structure of the trout population occurs during the open trout season, and whether any detected change is related to angler harvest. The study is also investigating angler catch rates and how they relate to the angling experience.

Preliminary results suggest:

• In the first year of the study, there was no marked decline in either the total number of trout or the number of larger fish (>25cm) in the Rubicon River during the trout angling season;
• To date, nearly three quarters of the trout caught by anglers fishing the Rubicon River were subsequently released;
• None of the anglers interviewed to date, harvested (caught & retained) the maximum daily bag limit of 5 trout per person of which no more than 2 may be 35cm or greater;
• To date, approximately half of the anglers were fly fishing only, one quarter were bait fishing only and the remainder were lure fishing only or using combinations of fly/lure/bait;
• To date, anglers who fish the Rubicon River actively (>3 times/month) have higher success rates than those who only fish the river occasionally (few times/year);
• To date, approximately three quarters of anglers fishing the Rubicon River did not catch any trout during their fishing session;
• In the first year of the study, angler numbers on the more accessible section of the river, such as the Tumbling Waters area, decline around one month after the trout season opens.
  

A more detailed report on this research, for consideration by fisheries managers, will be produced later this year. For further information about this project please contact John Douglas at MAFRI on 5770 8025.

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