Subject: Freshwater lice on brown trout

From: Philip M Jones <[email-masked]>
Date: Sat, 7 Dec 1996 21:39:18 +0000

Can anyone provide any info on the louse, known as Argulus apparently,
which sometimes infests brown trout in freshwater?  What might cause an
increase in their numbers?  Effects?

Mail to [email-masked] would be appreciated.

-- 
Phil Jones

Turnpike evaluation. For information, see http://www.turnpike.com/

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From: [email-masked](brett rowley)
Date: 9 Dec 1996 14:38:36 GMT

In <[email-masked]> Philip M Jones
>Mail to [email-masked] would be appreciated.

I'm not sure about Argulus in cold water, but we get them on warmwater
fish in our lakes.  They are not much of a problem in low numbers, but
can get to be a problem, especially in aquaculture ponds or hobby
ponds.  We use different insecticides to control them in ponds.  I'm
sure this would not work well in a stream.  Do the fish seem to be
severly hurt by them?

Brett Rowley
Fisheries Biologist
Great Lakes Sportfishing Resort and Koi Breeding Farm
West Columbia, Texas

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From: [email-masked] (Stephen Walker)
Date: Thu, 12 Dec 1996 16:22:47

In article <[email-masked]> [email-masked](brett rowley) writes:
>From: [email-masked](brett rowley)
>Subject: Re: Freshwater lice on brown trout
>Date: 9 Dec 1996 14:38:36 GMT

>sure this would not work well in a stream.  Do the fish seem to be

If I remember rightly, Argulus are suspected vectors for some fish viruses.

Steve

-- 
Steve [email-masked]| My opinion only.
>From  where I'm sitting, you lot don't all pass the Turing test.
Remove first '.' when replying by mail.

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From: "james a. mackie" <[email-masked]>
Date: Thu, 12 Dec 1996 20:11:20 +0000

In article <[email-masked]>, Philip M Jones
<[email-masked]> writes
>In article <[email-masked]>, brett rowley
><[email-masked]> writes
>>
>Brett
>Thanks for your interest.
>
>Haven't seen them on my local river previously, but this September I
>caught a few fish (approx 11") that were heavily infested (couple of
>dozen lice each) and which were in very poor condition (thin and dark,
>instead of bursting with health after a summer on the feed).  Other
>anglers reported the same but not all fish were affected.  I've seen
>them on fish in other rivers in the past but then they were limited to a
>couple on each fish and there appeared to be no ill effects.
>
>I think you're right about use of insecticides in a stream / river being
>difficult.  Anyway, what effects would insecticide have on the insects
>which the trout feed on?  Presumably it would 'cide 'em - I don't think
>we want that!
>
>I can find very little about the little buggers in any of my books, so
>if anyone could draw my attention to something on the subject I'd be
>grateful.
>
FRESH WATER ARGULUS attack all fish species.      Spread is often  by
birds and anglers.   In trout fisheries they will jump host fish when
the fish is caught on a hook.    Normally they are only present in still
waters not fast running streams.    They have a life cycle that includes
an egg and free swiming stage.    Eggs attach to branches etc.   Removal
of all branches, grass stems etc will slow down egg settlement.    On
the other hand an old chinese method of treatment is to plasce straw
bales in the pond and remove them on a regular basis and burn them.
Pesticides have been used to treast them but they are often toxic to
fish and will kill all insect life in the water course  ( eg spillage of
pesticides from sheep dip tanks).   

Lice are a major problem in salmon farming and last year I came across a
site that had problems with a marine argulus on farmed summer flounder
in New Hampshire.     I have commercial experience of treating sea lice
on farmed salmon with "Salartect FLT " formulastion of hydrogen peroxide
>from  Brenntag UK Ltd, 45c High Street, Hampton Wick, Kingston-upon-
Thames, Surrey, UK. tel 0181 977 3200.

Dr Christine Sommervillie of Stirling University is a leading researcher
into fish parasites and it may be worth contacting her on 01786 473171.

I am currently undertaking studies into the use of hydrogen peroxide in
fresh water fisheries and would like to speak to anyone with this
problem who would like to carryout small trials.

Jim Mackie,
James A Mackie (Agricultural), 3 Braehead, Lornshill Park, Alloa,
Clackmannanshire. UK FK10 2EW  Tel  01259 215136   Fax 01259 211053 
-- 
james a. mackie

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From: Philip M Jones <[email-masked]>
Date: Mon, 9 Dec 1996 19:10:27 +0000

Brett

-- 
Phil Jones
Swansea, South Wales, UK