David M.V. Coombes, Sr. Fisheries Inventory Technician, Aquatic
Inventory Branch
B.C. Environment, 1106 Cook St. Victoria B.C. CANADA V8V 1X4
Voice 604-387-9563:::Fax 604-356-1202
e-mail <dcoombes@fwhdept.env.gov.bc.ca>
**Words from Peter T.***
Hello everyone;
I've had opportunity to try a number of different methods in situations
where
electrofishing was simply ineffective. The most difficult situation I
have
encountered was in the Queen Charlotte Islands in winter in conditions
that
varied from cold temperatures plus low flows (e.g., -2 to 4 degrees C)
to
elevated flows and moderate temps. occurring after typical winter rains.
Throughout the range of conditions, we (Shawn Hamilton and I) found that
the
best method was Gee traps plus salted fish roe. We obtained salted
salmon roe
readily from Arctic Seafood Products Ltd, 3777 Kieth Street, South
Burnaby, BC
V5J 3B9.
A small portion of the roe skein was all taht was needed to attract
coho, Dolly
Varden and Steelhead (ages 1 to 6). This method was especially
effective in
cold weather. We marked hundreds of coho and steelhead by using cold
brands
specific to different reaches of several streams. There were numerous
instances
where electrofished pools/logjams, riffles, and glides generated no
catch. Gee
traps left overnight (this was necessary given that we were attempting
to
quantify population densities and distributions) in the same sites
frequently
contained dozens of fish by mid-morning.
We were able to attract coho to shallow pools without any sort of
overhead cover
from their hiding places eslewhere. These pools were readily surveyed
visually
and contained no coho prior to trapping. We were able to recover
substantial
proportions of the originally-marked populations by this method by
distributing
our traps primarily in pools at bank undercuts, 4 - 6 traps in and
around major
logjam pools, along cutbanks in glides and riffles. The trap density in
the
glides and riffles was roughly 1 per 10 lineal metres of stream. The
streams
were main channels and side channels within watersheds varying from
about 10 -
50 km2. These results were repeated in Carnation creek in the same
study. I
have longed to publish this stuff; however, the data rests with my grad
student
(Shawn) who is presently busy with WRP.
I have not found baits other than fish roe to be especially effective.
In
Carnation Creek, catches of coho in Gee traps baited with sardines, dog
food,
etc. were astonishingly low. I rejected these methods in that
particular
situation when I was doing my PhD thesis back at the turn of the
century.
Thats all for now. Hope this has been helpful.
P.S. I now am on MS Exchange for e-mail and my new address is Peter.Tschaplinski@gems4.gov.bc.ca
>From Gordon Hass:
As my previous comments indicate, I have had the same experience although I am not sure I would attribute it to the same reasons as he did. However, that does not really matter. I can also add that Dana and I marked thousands of coho fry in upper Thompson tributaries in December with the water very near zero and that we caught these fish repetitively by trapping. Our choice of traps though was based on not wanting to repetitively shock the fish and because it enabled us to cover more ground and do more work. Hope this helps.
Cheers,
Gordon
ps. The additional problem here is the salmonid bias. **more from Gordon Hass***
Here are some comments, but let me know if they are not what you wanted or need. I am just guessing based on what you forwarded me (and do not necessarily guess very well....).
2 - Bait makes a huge difference as already noted. I know of no real experiments (but a literature search might find some) but I have wasted more than one sunny afternoon watching my traps and have noticed the following. Firstly, baited traps catch more fish and the type of bait does matter in terms of species caught. Roe works very well for salmonids/sculpins/"predatory fish" but less well for other species. We usually use processed cheese slices because they can be purchased anywhere cheaply and the frightening part is they do not dissolve in water. The best solution I can offer up is to bait all the traps with more than one type of bait. The only other consideration here is within-trap predation but there is not much you can do about that except to modify the G-Trap entrance size which does work but is starting to perhaps get too complicated. The other thing to note here is that the thing that catches the most fish is fish in the trap. You have probably noticed that when you collect traps, some traps have lots of fish and others do not - if you watch traps, as soon as one fish enters a whole bunch more follow for reasons not known - we have even "tested" this using traps baited with fish (sticklebacks in our case and we wanted to trap sticklebacks).
3 - In terms of stream sizes and protocols, I can be less helpful. We usually set traps simply to cover ground as it permits us to collect fish while doing something else. Obviously and as already stated, large rivers do not necessarily trap well but they do for juveniles in backwaters and so on. If someone wants to talk about specifics, I would be willing to listen but at this point I could just go on forever. I will leave it at this for now then.
4 - Certain species do seem to be better trapped than electroshocked but this seems to usually be due to habitat and stream type/structure rather than the species per se. If you can electrofish a stream well and you have a decent crew, you really should not miss anything that would otherwise turn up in the traps unless you are talking about fish which are moving a lot , are very capable of avoiding the electrofisher, or are deeply embedded in the substrate. In the latter cases except for the substrate species, you do sometimes trap fish that were not electrofished, and for some species particularly at night. In terms of substrate species, I have found that I often collected species on a "second pass" while electroshocking particularly when the water is cold. What I mean is I walked up a stream electrofishing and caught nothing or very little, and then as I walked back to the truck in the stream I kept electrofishing and picked up a bunch of benthic species. What I think happens is these fish are deeply embedded for the winter in the substrate and the first pass moved them up a little and the second pass brought them out. This was not so much of a problem in warmer water.
In the past we have ordered all our traps from
Cuba Specialty Manufacturing Co.
Fillmore, NY
P.O. Box 195
USA 14735
1-716-567-4176
Hope this helps. Have a good weekend.
Cheers,
Gordon
****Now, for Scot***
I'm not sure what a G trap is but heres a abstract from minnow traps
and
dolly varden.
Bloom, Arthur M. 1976. Evaluation of minnow traps for estimating populations of juvenile Coho Salmon and Dolly Varden. Progressive Fish-Culturist. 38:2 99-101
Abstract:
Minnow traps baited with preserved salmon eggs have been used for
capturing juvenile coho salmon (O. kisutch) and dolly varden (S. malma)
for several years (Blackett 1968). Interest in the use of these traps
has increased because they are easy to use, highly portable, and require
no maintenance. In remote locations these features are attractive,
especially when compared to electrofishing, which requires that a source
of electricity be available and that equipment be in good working order.
However, no evaluations has yet been made to determine whether the trap
catches provide sound estimates of population size, species composition,
and length-frequency distributions. The purpose of this investigation
was to determine which attributes of a fish population could be
accurately estimated on the basis of trap catch data alone. The study
was conducted in tributary streams in the Kandashan watershed on
Chichagof Island, Alaska. These streams average less than 3 m wide and
provide rearing habitat for coho salmon and dolly varden.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Scott D. Craig craigs@CWU.EDU
***Mario***
Dear David,
from my personnal experience, I can tell you that dry food for dog like
Purina Puppy chow does work for several minnows, perch and crayfish. I
don't
really know for larger species but I think that also could work. It is
easy
to use, cheap and the fish caught could even be eaten.
Mario
50 av. de Verdun, B.P. 53
33612 CESTAS cedex
FRANCE
Tel: (33) 05 57.89.08.10
Fax: (33) 05 57.89.08.01
e-mail: Mario.Lepage@bordeaux.cemagref.fr
****Darrel****
What is a G trap? <the ordinary metal mesh bucket type, more properly
Gee traps- D.C. Sorry, I did not realize that was'n the common name for
them> Also, you might find light traps more effective than the
breder fry trap; we've been very happy with a quatrefoil design produced
by
Southern Concepts of Birmingham, Alabama.
Darrel E. Snyder Research Associate
Larval Fish Laboratory Curator, LFL Collection
33J Wagar Building Telephone: (970)491-5295
Colorado State University Fax: (970)491-5091
Fort Collins, Colorado 80523 E-mail: DESnyder@picea.CNR.ColoState.edu
WEB: http://www.CNR.ColoState.edu/~desnyder/desnyder.html
Darrel again:
Thanks, I'm familar with the metal mesh minnow trap, just not the name
"gee"
applied to it.
Requested address for manufacturer of floating quatrefoil-style light
traps:
Southern Concepts
c/o Ed Tyberghein
4822 Caldwell Mill Lane
Birmingham, Alabama 35242
Phone: 205-980-9105
Best Wishes,
Darrel E. Snyder Research Associate
Thank you all who responded.
David C.
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