First, 2 basic generalities that I always hear in crayfish presentations by my
colleagues at the Missouri Department of Conservation (they've worked with
them a lot longer than I):
1: Crayfish eat everything, everything eats crayfish. Mine had spaghetti for
breakfast today! They also eat blood worms, ground beef, tomato, tortilla,
grass, hot dogs...
2: Crayfish do not play well together. - I've seen a crayfish remove all the
legs from his tank-mate (they have regenerated since I isolated them), and
another crayfish dismantle and consume one added to his tank in less than 10
minutes. I also have 2 that have been in the same tank together with little
cover for 7 months and are doing fine. So, I guess it depends on the species
and/or individuals involved.
Keeping burrowers:
As far as burrowing species, I have not had any trouble keeping them just like
I do the stream species. I use the crayfish to set up displays at earth day
type events, so they are kept in pretty Spartan quarters - bare 10-gal tanks,
a 1/2 section of PVC pipe, maybe a few rocks or mussel shells. I have found
that it is very important with some species to securely cover the tank or they
will leave! Now that I have no openings larger than a pencil, I haven't had
any more go AWOL.
Digging Burrows:
To capture the burrowing crayfish, I often use a brute force method similar to
what Bruce described. The only difference is that I try to be as "low impact"
as possible. I try to keep clods from falling into the hole and carefully dig
down to the water level and make a shelf about 2" under water. Then I agitate
the water violently with my hand for a few seconds and sit back to watch.
Half the time I'll see antennae brushing the surface, then I nab him!
Burrow Traps:
I also tried out an alternate method this spring in my neighbor's back yard
(my yard is too far up hill for crayfish, unless they want to burrow 30 feet
through sand, clay and rock). I made 24 "burrow traps": a 12" long piece of
PVC pipe taped to a wire rod (or tent stake) with a 1-way aluminum flap midway
up so they can go up the pipe but not down. A soda can with the top cut out
is just the right size to cover the top so the crayfish can't climb on out.
(I'll be talking about crayfish at the NANFA Convention next year, and will
bring examples of these traps.)
To set the traps, first remove the chimney (the biggest problem I've had with
these is the flap getting stuck open with mud, which is almost sure to happen
if the chimney is nor removed). Then push the stake in the ground beside the
hole so that the hole leads straight into the pipe and cover the top with the
soda can. Lift the cans to check if the trap has caught anything, preferably
every morning.
Remember that this is a passive capture method - you won't catch him unless he
comes out. On the best nights I still caught crayfish in less than 1/4 of the
traps. These guys are most active on warm, wet, Spring nights. They have
complex burrows with multiple exits - my daughter (and main crayfish trap
checker) found that clustering traps to cover all the holes for a single
burrow complex and moving to another area after catching one, greatly improved
the catch rate.
Hand Capture:
The easiest method, which I have yet to accomplish, is going out with a
flashlight on these warm, wet, Spring nights and picking them up off the
ground - we've even had a kid discover a new species this way while walking
their dog!
Hope this helps - let me know if you have any more questions,
Brian Wagner
Nongame Aquatics Biologist
Arkansas Game & Fish Commission
915 East Sevier Street
Benton, AR 72015
(877)847-2690
bkwagner_at_agfc.state.ar.us
-----Original Message-----
------------------------------
Date: Wed, 20 Aug 2003 17:17:46 -0400
From: "Bob Muller" <michiganfish_at_wideopenwest.com>
Subject: NANFA-- crawfish
Can anyone tell me how to catch crawfish urt of their chimneys (burrows)?
Bob Muller
-
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------------------------------
Date: Wed, 20 Aug 2003 18:15:55 EDT
From: BR0630_at_aol.com
Subject: Re: NANFA-- crawfish
In a message dated 8/20/03 3:09:55 PM Mountain Daylight Time,
michiganfish_at_wideopenwest.com writes:
> Can anyone tell me how to catch crawfish urt of their chimneys (burrows)?
>
> Bob Muller
>
I use a really crude, Neanderthal man sort of method. I remove the chimney,
then I dig the top of their hole out big enough that I can put my hand with my
fingers squeezed together into the hole as far as possible and then I pull my
hand out suddenly. This creates a suciton action and either all of the
commotion it makes or the change in pressure seems to cause at least half of
the
crawfish to come to the surface of their hole to investigate. Generally, I
make
a little shelf, if possible, at the top of the water column in their hole, so
when they come to the surface [usually, all you'll see are their antanae] it
gives me a place to get my hand to pin them down. Often, if you only get
their pinchers in your grasp, they will shuck them and you're left with
pinchers
but no crawfish. It takes patience, sometimes maybe even a couple of minutes,
although most of the time they appear within 30-40 seconds if they're inclined
to being curious. Hope this helps.
Bruce Scott
Meridian, Idaho
------------------------------
Date: Wed, 20 Aug 2003 21:08:09 EDT
From: Gastropodmania_at_aol.com
Subject: Re: NANFA-- crawfish
Chimney crayfish won't really do well in captivity, unless you provide them
with enough mud to make their chimneys. I recommend free-living crayfish.
You
should be able to catch them with any good net. They also may come to a
baited minnow trap.
------------------------------
End of nanfa V1 #1747
*********************
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/-----------------------------------------------------------------------------
/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ Association"
/ This is the discussion list of the North American Native Fishes Association
/ nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ nanfa-request_at_aquaria.net. For a digest version, send the command to
/ nanfa-digest-request_at_aquaria.net instead.
/ For more information about NANFA, visit our web page, http://www.nanfa.org