Provided below are the reponses(as of 6/5/97, 11:00 am) from
FISH-ECOLOGY subscribers to my e-mail on researching larval fish
use/fish production. I included my orignial e-mail below for
reference.
Thanks for the insightful responses!!!
ORIGINAL E-MAIL:
I an considering conducting research on larval fish use/reproduction
of freshwater fish in coastal plain stream systems (South Carolina) by
comparing stream channel habitat usage to floodplain. My first
thought is to compare the number of individuals; number of individuals
of each species; and number of species from three stream systems using
stream channel and floodplain to represent the two conditions.
Variables I consider important to sample/collect include velocity,
D.O., temperature, and habitat characteristics (such as type of
aquatic vegetation and cover, type of substrate, % vegetation cover,
water depth, etc.). I plan on sampling fall through spring to
coincide with spawning events occurring during high water periods for
a two year period, sampling one or two times/week.
I would appreciate any ideas/comments. Specific questions include:
What type of larval fish sampling devise is appropriate for both
faster moving stream channels and slower moving floodplain waters? Any
ideas on adjusting the number of individuals collected since more
water (higher water velocity) will flow through the sampling
collection devises located in the stream channels? How long should
each collection last (24 hours?)?
I do plan on thoroughly researching this topic, but would appreciate
any early advise you may have.
Thanks!!! :)
Susan Dyer
University of South Carolina and
Savannah River Site
[log in to unmask]
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RESPONSES:
Dear Dr. Dyer,
My deepest sympathy with regard to your research project! In my lab we
have some experence with sampling in a large river Danube, approx.
mean discharge 2000 m2.s-1 and a backwater system. What my colleagues,
who sampled at the main channel did was point abundance sampnig by an
electrofishing gear. They used a standard grid an two locations and
did seasonal sampling. (mai-august) Our main species are cyrinids and
their early stages usually are confined to the shall,ow shore areas.
If you use electofishing, you should be aware, that you are only
sampling approx. the first 50cm of water column. If percid species or
other fish families with more or less pleagic stages within their
ealry development are improtant in your rivers (as I suspect) I think
you have to do larval drift sampling or you might use a push-net
system, where a certain water volume is sampled by pushing a net
through the water.
In the backwater myself and two students used mainly beach-seining,
two nets, one was 1m high, the other 4 m high. The operation of the
high beach sein net was a bit tricky, but the information we got was
essential, as the deeper areas contain a completely different
asssociation. There was a seasonal shift from the shallow shore areas
to deeper areas for most species.
I agree with your set of environmental variables. Especially water
depth and vegetaion cover are crucial. Other variables I would
suggest: steepness of the shore and connectivity (distance of the
samples from upstream and downstream connection to the river). Have
fun!
best wishes
Irene
*************************************
Irene Zweimueller e-mail: [log in to unmask] Inst. of
Zoology phone: ++43 1 31 336 1337 or 1342 Dept. of
Limnology fax: ++43 1 31 336 778 Althanstr. 14
A-1090 Wien
AUSTRIA - EUROPE
************************************
Susan,
I Suggest drift nets (various horizontal and verticle positions for
each transect) in strong to moderate current and towed or pushed nets
on floodplain and in slower current, all with flowmeters to measure
volume of water. Where possible, use a variety of differnt types of
gear. In quieter waters along shore, in backwaters, and on the
floodplain, consider fine-mesh seines and dip nets (day and perhaps at
night--consider attracting fish with light before netting), pop-nets,
point electrofishing for larvae and early juveniles, and light traps.
The latter two can be quite useful for relative abundance data.
Pop-nets (effectively verticle tows) are qualitative but often suffer
from low catches. I've been particularly impressed with
quatrefoil-type light traps and can provide results of some
experiments and and field experience if you are interested.
As you research the possibilites, be sure to consult the chapter on
Fish Eggs and Larvae in the AFS Fisheries Techniques manual:
Kelso, W. E., and D. A. Rutherford. 1996. Collection, Preservation,
and
Identification of Fish Eggs and Larvae. Pages 255-302 in B. R. Murphy
and D. W. Willis, editors. Fisheries techniques, 2nd edition.
American Fisheries Society, Bethesda, Maryland.
If you have the earlier edition, check out:
Snyder, D. E. 1983. Fish eggs and larvae. Pages 165-197 in L. A.
Nielsen
and D. L. Johnson, editors. Fisheries Techniques. American Fisheries
Society, Bethesda, Maryland.
However, I recommend the Kelso and Rutherford revision and update for
the latest info and recommendations.
Darrel
At 02:20 PM 6/3/97 -0400, you wrote:
> I an considering conducting research on larval fish
use/reproduction
> of freshwater fish in coastal plain stream systems (South
Carolina) by > comparing stream channel habitat usage to
floodplain. My first
> thought is to compare the number of individuals; number of
individuals > of each species; and number of species from three
stream systems using > stream channel and floodplain to represent
the two conditions.
> Variables I consider important to sample/collect include
velocity, > D.O., temperature, and habitat characteristics (such
as type of
> aquatic vegetation and cover, type of substrate, % vegetation
cover, > water depth, etc.). I plan on sampling fall through
spring to
> coincide with spawning events occurring during high water
periods for > a two year period, sampling one or two times/week.
>
> I would appreciate any ideas/comments. Specific questions
include: > What type of larval fish sampling devise is appropriate
for both
> faster moving stream channels and slower moving floodplain
waters?
> Any ideas on adjusting the number of individuals collected since
more > water (higher water velocity) will flow through the
sampling
> collection devises located in the stream channels? How long
should > each collection last (24 hours?)?
>
> I do plan on thoroughly researching this topic, but would
appreciate > any early advise you may have.
>
> Thanks!!! :)
>
> Susan Dyer
> University of South Carolina and the Savannah River Site >
[log in to unmask]
*****************************************************************
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, CO 80523-1474 E-mail:
[log in to unmask] ______ WEB-
http://www.CNR.ColoState.edu/~desnyder/desnyder.htm _______
For information on the Larval Fish Laboratory, check out our web page
__________ http://www.CNR.Colostate.edu/~desnyder/lfl97.htm
___________
I would appreciate any ideas/comments. Specific questions include:
What type of larval fish sampling devise is appropriate for both
faster moving stream channels and slower moving floodplain waters? Any
ideas on adjusting the number of individuals collected since more
water (higher water velocity) will flow through the sampling
collection devises located in the stream channels? How long should
each collection last (24 hours?)?
Susan,
First of all, I would recommend that you read the chapter on
"Collection preservation, and identification of fish eggs and larvae"
by W. E. Kelso and D. A. Rutherford in Fisheries Techniques, 2nd
edition. I would suggest that you use some sort of a push net in the
fast water; however, this will probably not be as effective in slower
moving waters. You
can also equip a flow meter in the mouth of the net to estimate the
amount of water sampled, allowing you to calculate CPUE as larvae per
unit of water sampled. In the slower moving waters, you may consider
light traps or a seine. Here are a couple citations of papers that
you'll probably be interested in:
Scheidegger & Bain. Larval fish distribution and microhabitat use in
free-flowing and regulated rivers. Copeia 1995:125-135.
Brown & Armstrong. 1985. Propensity to drift downstream among various
species of fish. Journal of Freshwater Ecology 3:3-17.
Thayer et al. 1983. Estimates of larval-fish abundances: diurnal
variation and influences of sampling gear towing speeds. Transactions
of the American Fisheries Society 112:272-279.
Flyod et al. 1984. Chronology of appearances of habitat partitioning
by stream laral fishes. Transactions of the American Fisheries
Society 113:217-223.
I hope this information is useful.
***********************************
Carl R. Ruetz III
Graduate Research Assistant
D. B. Warnell School of Forest Resources University of Georgia
Athens, GA 30602
Phone: (706) 542-1159
e-mail: [log in to unmask]
***********************************
Susan,
I have been doing some work on larval/early juvenile fish on the
Kissimmee River-floodplain system in central Florida. Our littoral and
floodplain region is heavily vegetated with limited or no flow. We
have used paired bongo push nets in
the river channel and light traps in vegetated littoral and open water
habitats.
What type of vegetation is on the floodplain at your research sites?
If they are vegetated you might consider using a modified quatrefoil
light trap after Floyd et al 1984. Trans Am Fish Soc. 113:217-223.
I have not begun to analyze our samples, but there appears
to be variation based on presence/absence of vegetation, type of
vegetation, distance from vegetation, depth, flow, DO, and sample
method.
Be careful not to collect 10,000,000 samples when you only have the
time to analyze 1,000.
Hope these limited comments help. Best of luck, D. Albrey Arrington
Kissimmee River Restoration Division South Florida Water Management
District
Hi Susan,
I read your post to FISH-ECOLOGY. I've done a little bit of work on
fish communities in the coastal plain of North Carolina and it sounds
like your project will help answer some important questions.
I don't really have any great insights on how you should structure
your design for sampling larval fish - I'd be *really* interested in
reading the replies you get. Please summarize them and post them to
the list.
One thought I have is that perhaps it would be a good idea to include
distance from the main channel as one of the "habitat" variables you
keep track of for each of your traps. I believe that Ross and Baker
(1983) indicated that some species tended to move further, and more
aggressively, into the floodplain than others. Could the spatial
distribution of larval fish serve a resource-partitioning function?
You might be able to aquire data that would shed some light on the
possibility.
You also mentioned that you will be recording water depth as one of
your habitat variables. Have you thought about trying to construct
flood-duration curves for your sampling locations? If you set up a
water-level recorder at a known elevation and then survey the relative
elevations of your sampling locations you could figure out how long
each location was under x centimeters of water. This kind of
information might really be helpful if you run into drastically
different flow regimes during your two sampling years. I'm wondering
whether there is a critical hydroperiod for effective utilization of
floodplain areas, and what it might be. The answer might be important
for evaluating the "functionality" of wetlands for protection,
mitigation, and restoration.
Have fun!
Peter M. Ruhl
U.S. Geological Survey
3916 Sunset Ridge Road
Raleigh, NC 27622
phone: 919-571-4026
fax: 919-571-4041
email: [log in to unmask]
Susan,
Saw your request on Fish-Ecology. You might contact Harvey Walsh here
at the Beaufort Lab, NMFS. [log in to unmask]
He has a study on larval anadromus clupeids in the Roanoke River in NC
and has considerable insight into collecting in streams and rivers.
I have experience in sampling larval fish around inlets, but that may
not help you much.
William Hettler
National Marine Fisheries Service
101 Pivers Island Rd.
Beaufort, North Carolina 28516-9722 USA Tel:919-728-8770
Fax:919-728-8784 e-mail: [log in to unmask]
[log in to unmask] wrote:
> My first
> thought is to compare the number of individuals; number of
individuals > of each species; and number of species from three
stream systems using > stream channel and floodplain to represent
the two conditions.
Some larval fish captured in stream channels will have certainly been
produced in floodplain backwaters. If you simply seek to compare
abundances between channels and other floodplain aquatic areas, how
will you know where those fish were actually produced? Will that open
question thwart your objectives?
> I would appreciate any ideas/comments. Specific questions
include: > What type of larval fish sampling devise is
appropriate for both
> faster moving stream channels and slower moving floodplain
waters?
> Any ideas on adjusting the number of individuals collected
since more > water (higher water velocity) will flow through the
sampling
> collection devises located in the stream channels?
Try a 0.5-m plankton net with a flow meter mounted in the mouth. That
will allow you to measure the volume of water strained by the net.
We use General Oceanics' flow meters. They have a Web page (sorry, I
don't have the URL), so you can locate them with a search on their
name.
> How long should
> each collection last (24 hours?)?
You should do some preliminary sampling. The answer depends on
abundance. We rarely tow a plankton net longer than 15 min, but we're
using 1-m nets (0.5-m nets will permit you to tow in shallower water).
> I do plan on thoroughly researching this topic, but would
appreciate > any early advise you may have.
Yes, do a lit review. I can give you a start by providing a lit
review on early life history stages of fishes that was posted on the
net two years ago. The .zip file is larger than 1-MB, and is too
large to mail. If you have ftp let me know and I'll copy the file to
my anonymous ftp directory, give you my domain name and
a time you can pick up the file. For security reasons, my computer is
not available to ftp at night.
-Steve
----------------------------------------------------------------------
| Steve Gutreuter, Ph.D. Upper Mississippi Science Center
| | U.S. Geological
Survey | | TEL: (608) 781-6222 2630 Fanta
Reed Road | | FAX: (608) 783-6066 La Crosse, WI
54603-1223 USA |
----------------------------------------------------------------------
"Science may be described as the art of systematic
over-simplification."
- Karl Popper
Susan:
The Shad Foundation would be very interested in any finding you have
regarding larval American shad. We are a non-profit organization which
publishes a quarterly newsletter on current shad research. It is
distributed world-wide to researchers who are interested in the
preservation of shad species.
Thanks
Richard Hinrichsen
President
The Shad Foundation
PO BOX 21748
Seattle, WA 98111-3748
(206) 616-7449
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|
