Poisoning the Gudgeon,will it affect the birds!! (1 Viewer)

christineredgate · Feb 28, 2005

An item on the news today,re poisoning the Gudgeon fish in a lake near Kendal.Apparently an organic poison is going to be used to kill off these fish(they are overstocked ).Will the poison harm any birds who may be catching fish in this particular tarn?.

Dimitris · Feb 28, 2005

christineredgate said:
An item on the news today,re poisoning the Gudgeon fish in a lake near Kendal.Apparently an organic poison is going to be used to kill off these fish(they are overstocked ).Will the poison harm any birds who may be catching fish in this particular tarn?.

It depends on the poison.

If it's not biodegradable yes it will harm the birds in oneor another.

If it is biodegradable(and this seems to be the case) there is no serious(if at all) threat..

Dimitris

Dimitris · Feb 28, 2005

4rgot to mention that the biodegradable poison must desolve fast...

KnockerNorton · Mar 1, 2005

I think they'll have done a risk assessment....

alan_rymer · Mar 1, 2005

How were they overstocked?. have people been putting them in the lake?.

Keithec · Mar 1, 2005

christineredgate said:
An item on the news today,re poisoning the Gudgeon fish in a lake near Kendal.Apparently an organic poison is going to be used to kill off these fish(they are overstocked ).Will the poison harm any birds who may be catching fish in this particular tarn?.

I would be very interested to have a link to this news item or more information. What does overstocked mean in this context. This is a native species and as it is small will not be at the top of a food chain. I would be very interested to know who feels that these fish should be killed.

Keith

Keithec · Mar 1, 2005

Dimitris said:
It depends on the poison.

If it's not biodegradable yes it will harm the birds in oneor another.

If it is biodegradable(and this seems to be the case) there is no serious(if at all) threat..

Dimitris

Except to the fish!!!!!

KnockerNorton · Mar 1, 2005

It's an asian species. Link http://news.bbc.co.uk/1/hi/england/cumbria/4283919.stm

Keithec · Mar 1, 2005

Offord said:
It's an asian species. Link http://news.bbc.co.uk/1/hi/england/cumbria/4283919.stm

Ah! That's a different matter then. Thanks very much for the link.

Keith

Andrew · Mar 1, 2005

Overstocked? I doubt they would actually stock Gudgeon in Kendal unless it is a commercial pleasure fishing lake. So sounds like it is natural population explosion, if so they should leave it to settle of it's own accord. Part of evolution, roll with the punches.

KnockerNorton · Mar 1, 2005

Read the link. It's a tarn (which are natural) and tarns have interesting fauna that can do without asian gudgeon eating them.

Touty · Mar 1, 2005

Dimitris said:
It depends on the poison.

If it's not biodegradable yes it will harm the birds in oneor another.

If it is biodegradable(and this seems to be the case) there is no serious(if at all) threat..

Dimitris

The poison is almost certainly Rotenone:

http://www.chm.bris.ac.uk/motm/rotenone/piscicideh.html

It's made, IIRR, from a type of African chrysanthemum. It is a "natural" insecticide with fish (and amphibian) killing properties. I think you can even use it in 'organic farming' in some countries in Europe (daft if you ask me... a poison is a poison). If you do the 'rotenoneing' in winter the amphibians and insect larvae are dormant and unaffected. It's used to rid important amphibian ponds of released goldfish and mosquitofish (Gambusia holbrooki) in Europe.

http://www.amonline.net.au/fishes/fishfacts/fish/gholbrooki.htm

I don't know about these gudgeon, but ecology doesn't 'roll with the punch' and many amphibians are wiped out by goldfish and mosquitofish being introduced to their ponds.

Andrew · Mar 1, 2005

Ah, I see now. With it being an alien it makes sense. I was thinking of our native Gudgeon which are no trouble at all.

Touty · Mar 1, 2005

Andrew said:
Ah, I see now. With it being an alien it makes sense. I was thinking of our native Gudgeon which are no trouble at all.

My impression (at least here in Italy) is that things are much more screwed up below the water surface of lakes and rivers than above. In some Italian rivers 20% of the species and 80% of the fish biomass are aliens. Apart from the Topmouth gudgeon, Rainbow Trout, Goldfish and Mosquitofish we've got Wels catfish, Pumpkinseed (Lepomis gibbosus), Nase (Chondrostoma nasus), Common Bream (Abramis brama)... non-native, Grass Carp (Ctenopharyngodon idellus), Silver & Big-head Carps (Hypophtalmichthys molitrix and H. nobilis)... the list goes on and on. Imagine a day out birding where 20% of the birds you saw and 80% by weight were aliens... it'd be like New Zealand.

alcedo.atthis · Mar 1, 2005

"An item on the news today,re poisoning the Gudgeon fish in a lake near Kendal."

My solution would be instead of shooting Cormorants and sawbills, catch them, pinion the wings, relocate them to the lake, and watch nature at it's best.

Regards

Malky

James Blake · Mar 1, 2005

Touty said:
In some Italian rivers 20% of the species and 80% of the fish biomass are aliens.

Which shows that while angling has some positive effects environmentally there are also negatives.

simon · Mar 1, 2005

But what about the birdlife? Is it likely to cause problems especially as the reort states it is likely for the poison to take weeks to be effective

Touty · Mar 1, 2005

simon said:
But what about the birdlife? Is it likely to cause problems especially as the reort states it is likely for the poison to take weeks to be effective

No, rotenone (aka Derris on Gardeners' Question Time) is not absorbed effectively if you don't have gills (fish) tracheae (insects) or permeable skin (amphibians). African fishermen use rotenone (which they extract from plants) for fishing and cook and eat he fish immediately without any ill-effects. I guess there might be hungry grebes. Would they have chicks already in the Lake District?

http://www.pan-uk.org/pestnews/Actives/rotenone.htm

christineredgate · Mar 1, 2005

No,Touty,I don't think the Grebes have started nesting yet,but I think it is worrying that poison has to be put into a tarn where birds are likely to catch fish.I do know the anglers are complaining.
I do not think that pinioning the Cormorants wings is a good idea!!!.Shame on you Malky!!!.

alcedo.atthis · Mar 2, 2005

"I do not think that pinioning the Cormorants wings is a good idea!!!.Shame on you Malky!!!."

Why not. They would just fly away elswhere and get shot. Better a live bird on/in the lake than a dead bird in the tip!!

Regards

Malky, not taking life too seriously!!:flyaway:

Poisoning the Gudgeon,will it affect the birds!! (1 Viewer)

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