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Want to know what flies are working best here at Fisherwick Trout Lake?

Have you ever wanted to tie your own flies but were unsure about what materials and equipment you need? Or how to tie the best patterns?

Fisherwick member, Al Stewart, shares his thoughts on flies and the tying thereof, and anything else that comes to mind in the noble pursuit of fly fishing.

 

A 'lousey' time to fish

by Al Stewart - 10:07 on 21 October 2015

A lot of you will no doubt be frustrated, to say the least, that you are not catching recently.

The Trout Lake has suffered from high algae blooms over the summer due mainly to the higher temperatures and mild winter, but the actual water quality has remained good. There are plenty of sticklebacks, snails and shrimps thriving in the lake and the weed on the bottom looks healthy.

What has caused the recent lack of catch is an outbreak of the fish louse Argulus foliaceus.

Argulus is a crustacean parasite, commonly known as the “fish louse”. In trout fisheries heavy infections cause a rapid loss of condition and even death. Even moderate Argulus infections can reduce rod catches, cause distress to the trout and threaten the economic viability of fisheries.

Argulus can cause considerable damage to trout through their aggressive attachment and feeding behaviour. They feed by inserting a long spine-like structure into the skin, which breaks down tissues through the secretion of enzymes. The repeated puncturing of the skin, combined with activity of the parasites’ serrated mouth-parts, can cause substantial damage and irritation.

Healthy trout will tolerate light parasite burdens with few adverse affects. However, heavily infested fish can harbour many hundreds of parasites and quickly become debilitated. Trout suffering from Argulus infestations often show signs of irritation, such as repeated jumping. They may shoal tightly together or congregate at the fishery margins or in areas of high water movement, such as an inlet. Individuals may stop feeding, become lethargic, lose condition and darken in colour.

Infected trout

 

 

 

 

 

 

 

Argulus follow a seasonal cycle of reproduction and development. Egg laying usually begins when temperatures exceed 10°C and cease during winter. Populations typically increase throughout the year, being at their greatest toward the end of the summer. Parasite numbers decline with the onset of winter, although all developmental stages (including egg strings) can over-winter.

Studies have shown that Argulus prefer to lay their eggs on hard surfaces within the top metre of water and usually in the mornings. As there are no rocks or hard surfaces around the margins of the lake (with the exception of the rocks at the base of the water inlet waterfall). Pete Jackson and I have embarked on a plan to try and eradicate this pest by the introduction of surfaces for argulus females to lay their eggs on which will be inspected every two weeks.

On Tuesday (20 October 2015) Pete and I inserted four one-metre square corrugated tin boards around the lake and will be trialling various other methods including floating boards and smaller submerged boards. Please do not tamper with any stakes that have rope attached to them.

We apologise if this looks unsightly or interferes with your fishing, but we have to do whatever we can to rid the fishery of this pest.

As a precaution please ensure that you disinfect all nets and equipment after use.

Al


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