Wednesday 26th August 2015

 

The day is bright and sunny and the Tongariro is fishable.  It got up to about 80 cumecs yesterday but is down to a highly fishable 45 today. 

The Tauranga-Taupo is quite coloured but if you knew where you are going fishable ... better tomorrow.

Waimarino and Waiotaka coloured.  Waiotaka definitely fishable even with this colour.

The Firemen have reported some good fish caught with some weighing in their catches early and having to take the rest of the day off ! 

I've been super flat out in the shop to be able to concentrate on the website but have a bit of time now.

I received this email and photo yesterday thanks to Seth Fasher.  Seth writes:

Tuesday morning, rivers up and dirty !

 

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(Below) I received this email and photo this morning thanks to Phil Reid.  Phil writes:

Hi Graham

 

I have just spent several great days lake fishing in and around Turangi. The fish were generally in great condition but one which was a fat silver bullet was as white as when opened up. One theory I have heard is that these little worms are responsible for the white fish. The theory being that the Shags droppings contain these worms which the trout eat and then  they in turn suck the colour from the fish. Have you heard of this???

Many thanks

Phil Reid

Lower Hutt

 

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In the meantime Phil had received an answer from Dave Conley at the Department of Conservation.  Dave writes:

Hi Phil

This is an issue that pops up pretty regularly, and will be usually most visible as we get into late winter and spring. This is due to the parasite being most visible in the fish which have lost condition over spawning. I have attached a photo which shows the life cycle of the nematode worm which is commonly called shagworm. The reality is that quite a few birds can act as hosts, so the poor old shag gets the blame and people want to cull them, but many other birds which eat bullies and trout can also act as hosts for the worm. You would have to cull all sorts of birds to try to stop the spread of this common parasite.

 

 

 

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In lake Taupo, bullies act as the mosquito fish in the above picture, and trout act as the predator of bullies. Most birds that eat either bullies or trout can carry the worm, and complete the cycle by excreting the eggs. The presence of the worm doesn’t necessarily cause issues with the flesh quality or colour. The reason why people commonly see white fleshed trout having the worms is that the worm flourishes when a trout’s immune system is low, such as when the trout has spawned and is weak through lack of food etc. Usually these fish have the whitest flesh, as the colour of the flesh usually changes after spawning. So you will most commonly see the blisters or cysts that John describes on older fish which have spawned previously, or on slabby mending fish. Maiden fish will carry the parasite, but it is reasonably rare for the cysts to form on maidens prior to them spawning. Does that answer your collective queries? Basically, culling shags won’t do anything to stop this parasite, as other hosts like herons, bitterns and gulls will continue its life cycle. Interestingly, brown trout are much less susceptible to this parasite than rainbows. Despite having a diet which is very dependent on bullies, brown trout rarely show up with the cysts on them.

Cheers

Dave

(Below) These are some of the pictures I have taken over the years


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(Above & Below) This is the cyst on the outside of the fish before the worm eventually bursts out as Dave says above. The fish seem to still live ok and you can even see big gaping open wounds on some fish. 


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(Below) The worm usually sits just on the outside of the rib cage. Sometimes there is only a black spot to be seen like in the picture below this one with the match head. The picture below shows nice flesh colour to this fish I had caught.

 

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(Below) If you poke the black spot then the worm may wriggle out.

 

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You can still eat the fish if you wish by cutting around the effected area but ...... my suggestion would be to cook it well !!

 

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