Flier Newsletter
October-December
2000
Volume 3, Number 4
Konrad Schmidt,
Editor
-----------------------------------------------------------------------------------------------------
Scientific Value of Keeping Native Fishes In Aquaria
Lawrence M. Page, Principal Scientist
Center for
Biodiversity, Illinois Natural History Survey, Champaign, IL 61820
Fishes are kept in aquaria for a variety of reasons. Most aquarists keep
fishes because they enjoy observing the tremendous diversity of body shapes,
colors, and behaviors. Others keep fishes for the explicit purpose of learning
something new about them. Keeping only a few species of fish can quickly teach
an aquarist and his/her family some valuable lessons about the natural world.
Our native fishes are quite diverse – about 800 species are found in the
freshwaters of North America – and they show a great variety of morphological
designs and behaviors.
Keeping fishes in aquaria has led to many original
observations. It is one of the best methods for making scientific discoveries
about fishes, which can be extremely difficult to study in streams and lakes. In
fact, some fishes are nearly impossible to study in detail in the bodies of
water in which they normally are found. For example, fishes that live in turbid
rivers cannot be seen by human observers who are either above or in the water.
Fishes that live in clear water can be observed from a stream bank or by someone
with a snorkel, but often they are extremely uncooperative with a person trying
to study them. In aquaria, conditions can be controlled to simulate natural
conditions and may lead to observations that otherwise would not be made.
Although sometimes difficult to observe even in aquaria, spawning
behaviors can be particularly fascinating and relevant to species protection.
Some fishes spawn by scattering eggs, some lay eggs in secluded places and guard
them, others give birth to living young. One group of native fishes on which our
knowledge of spawning behaviors has grown greatly from aquarium observations are
darters. With about 180 species, darters are one of the two most diverse groups
of North American fishes. (The other group, the minnows, contains about 250
species.) Aquarium observations on darters have revealed a variety of
reproductive behaviors. Some bury their eggs in the substrate, some attach them
to plants or the sides of rocks, and some sequester them under rocks and guard
them. We know now the breeding habits of 103 species of darters. Only 25 of
these species have been observed in nature; the other 78 have been observed only
in aquaria.
Females of some of the egg-guarding species of darters prefer
to lay eggs with males that already are guarding eggs in their nests rather than
spawn with males without eggs. They shun males at least to some degree that have
not yet demonstrated that they can successfully guard eggs. Males of these
species compete for these choosy females and, in some species, have evolved
morphological traits that can make them more attractive to females. They have
evolved structures on their fins that look very much like eggs. These egg-mimics
can attract females to nest sites even though no eggs are present. Although not
always this spectacular, other amazing behaviors are shown by North American
fishes, and many of these behaviors are known only because they have been
observed in aquarium-held fishes.
In the United States, 70 species of
fish are listed as federally threatened or endangered because of habitat loss
and other forms of environmental degradation. This depressingly large number of
endangered fishes exists because people do not care or know enough to demand
that land be developed in a way that protects habitat for our native plants and
animals. The more that we know about our native fishes, the more we will
appreciate them for their beauty and their habits, and the more we will want to
protect their environments.
Scientists make excellent use of aquarium
observations. In fact, we would know far less about our native fishes if we did
not keep them in aquaria. Aquarists enjoy keeping fishes, but our native fishes
are the more significant beneficiaries of this activity.
-----------------------------------------------------------------------------------------------------
Putting Back the Pieces II
Konrad Schmidt, Nongame Fish
Biologist
Department of Natural Resources, Box 25, 500 Lafayette Rd., St.
Paul, MN 55155
In the 1960s and 70s, Wisconsin carp control programs treated several
streams with fish toxicants which may have eliminated many non-target species.
Extirpation is difficult to verify, however, Becker (1983) reported the
suspected loss of at least 10 species from treated streams where isolated
populations would likely never be naturally reestablished (Table
1).
Table 1. Reported fish extirpations in Wisconsin (Becker
1983).
--------------------------------------------------------------------------------------------------------------------
Species
- Population
-----------------------------------------------------------------------------------------------------------------------------------------------------------
Northern
Brook Lamprey - Tomorrow and Waupaca Rivers: 50 miles of mainstem and
tribs
Redfin Shiner - Upper Rock River system: Washington and Fond du Lac
Co.
Bigmouth Buffalo - a) Beaver Dam Lake: Dodge Co. b) Rock River: above
Watertown
Silver Redhorse - Waupaca River: Weyauwega to mouth Waupaca
Co.
Longear Sunfish - East Branch of Rock River: Washington
Co.
Western Sand Darter - Waupaca River: downstream of
Weyauwega
Rainbow Darter - Waupaca River: downstream to Weyauwega Waupaca
Co.
Fantail Darter - Waupaca River: downstream to Weyauwega Waupaca Co.
Least Darter - Waterloo Creek: Dane Co.
Banded Darter - Tomorrow
and Waupaca Rivers: Portage and Waupaca Co.
I suspect comparing all
available pre and post treatment surveys of these streams would delete some
species, but also add several more. Even though this nefarious list will contain
almost exclusively nongame fishes, I feel the Wisconsin Department of Natural
Resources (WDNR) and NFC, as an advocate, have a responsibility to at least
verify extirpation, and whenever possible, reintroduce species to historic
localities. Unfortunately, the reality is there will be little funding to
support such an initiative and NFC, especially members in Wisconsin, may
consider, accepting a larger role.
My proposal generally follows what I did following the 1989 reclamation of
the Upper Knife River watershed in central Minnesota (Schmidt 1990 and 1993). I
recommend the following actions be taken:
1. Organize interested
members.
2. Present proposal to the WDNR.
3. Verify and document
extirpations.
4. Identify nearest existing populations.
5. Conduct
reintroductions.
6. Monitor results.
A general inquiry outlining
objectives should be submitted to all offices within the WDNR which may become
involved with the project. This would likely include the Bureaus of Endangered
Resources, Fisheries Management, and Integrated Science Services. The WDNR will
decide whether and how to proceed. In my own experience with the Minnesota
Department of Natural Resources (MDNR), I was officially signed on as volunteer
which enabled partial reimbursement of expenses, provided unlimited access to
all survey files, and issued a permit to collect, transport and reintroduce
nongame fishes. Initially in the reintroductions, the Section of Fisheries also
assisted with the "loan" of a fish transport truck with a biologist who was
actually "double checking" my identification before finally turning me loose.
If the proposal is accepted, verifying extirpations and establishing a
final species list can be a very "dry" and tedious task, but probably the most
important phase of the project. The Bureau of Fisheries Management should be
able to provide a list of all streams which have been treated for carp control.
The Bureau of Integrated Science Services maintains a large fish distribution
database which contains survey records from approximately 50 percent of the
basins in Wisconsin (Fago 1992), and may be able to provide both a before and
after species list for the exact reach of treated stream. If no follow up
surveys have been conducted since treatment, some field sampling may be required
at historic localities. However, whenever a "target" species is found, at least
one specimen should be saved for verification and deposited in a voucher
collection. Once the species list is finalized, potential sources for
reintroduction should be identified and preferably be proximal populations in
the same basin which should be genetically similar to the extirpated population.
Again, the Integrated Science Services’ database may be able to provide a list
of candidate populations.
I would hope the WDNR will permit NFC
members to reintroduce most species with a minimal amount of supervision and
restrictions. However, I see a few problems and issues which will probably have
to be addressed at some point. On the current list of extirpated fishes (Table
1), the redfin shiner and longear sunfish are Threatened, and the western sand
darter and least darter are Special Concern in Wisconsin (Schmidt 1996). The
Bureau of Endangered Resources will probably support the intent of
reintroductions, but will require collection permits which stipulate conditions
to safeguard the "seed sources." Fisheries Management would almost certainly be
concerned with identification skills and a field proficiency exam may be
required. Finally, some species can't be collected in sufficient numbers with
gears that will likely be permitted for this project. Electrofishing is probably
the most effective method to collect bigmouth buffalo and silver redhorse which
Fisheries Management may be able to do incidentally with regularly scheduled
activities.
Seines, kick nets, and minnow traps can be very effective on
most species in their preferred habitats. During collection, I keep the catch in
a flow through minnow bucket which is tethered on a rope off my belt. In
transit, I use food coolers up to 96 quarts, avoid over crowding, and provide DC
aeration. At the reintroduction site, I temper fish with stream water and select
habitats that provide temporary cover and some protection from predators.
Ideally, reintroduction stock should be pre-spawn fish collected during cool
spring temperatures which will reduce stress and minimize mortality. Finally,
follow up surveys should be done every year or two which will confirm whether or
not the stockings were a success. Again, at least one “trophy” should be saved
for bragging rights, and more importantly, provide the "body of evidence" as
proof the reintroduction efforts were successful.
If there is interest
within NFC and the WDNR to pursue this project, I would be available
intermittently to serve as a consultant and participate with reintroductions and
follow up surveys. However, I'm not going to mislead any one by saying this
isn't hard and time consuming work which does demand commitment. On the other
hand, I also can't express the reward in once again finding fish that I was
responsible for "resurrecting."
Literature Cited
Becker, G.C. 1983. Fishes of Wisconsin. University of Wisconsin Press,
Madison. 1053 pp.
Fago, D. 1992. Distribution and relative abundance of
fishes in Wisconsin VIII. summary report. Technical Bulletin No. 175. Wisconsin
Dept. of Natural Resources. 378 pp.
Schmidt, K.P. 1990. Fishes of the
Knife Lake watershed in Kanabec and Mille Lacs counties of Minnesota. Minnesota
Nongame Wildlife Program. 13 pp.
Schmidt, K.P. 1993. Putting back the
pieces. North American Native Fishes Association. American Currents: Spring pp.
22-26.
Schmidt, K.P. 1996. Endangered, threatened, and special status
fishes of North American fourth edition. North American Native Fishes
Association. 65 pp.
-----------------------------------------------------------------------------------------------------
Habitat Preferences Exhibited by
the Gravel Chub (Erimystax
x-punctatus)
Lucia Yess, Winona (MN) Middle School Science
Project.
Editor’s Note: Anytime our youth (and tomorrow’s future) expresses an
interest in nongame fishes, I am at first impressed with insight far behind
their years. I am also always happy to help guide and encourage their pursuits.
In this case, my part was small, enjoyable, and cost me but one Saturday helping
collect specimens. Through the process, I believe Lucia gained an appreciation
for our little known fishes, their plight, and launched her light years ahead of
her peers. In the future, I hope this learning experience will prove beneficial
in her chosen professional, as an informed citizen, and of course, voter.
Introduction
Our rivers and streams are an important part of our environment producing
beauty, recreation, transportation, and food among other things. However, a
small change can effect the ecosystem, particularly to the little known members
like the minnows and other nongame fishes. I think it is important to study
these fishes because most people who work with fish generally do not know a
great deal about nongame species. In addition, many of these poorly known
species are having problems with their habitat in the wild. I became interested
in this project because my dad is a fisheries biologist with the U.S. Fish and
Wildlife Service and I have always been fascinated in his work.
I tested
one minnow and two darters: the gravel chub (Erimystax x-punctatus),
rainbow darter (Etheostoma caeruleum), and banded darter (E.
zonale). These fishes were selected because they are all having difficulties
with their habitat and were accessible to me. The purpose of my project was to
determine the position in the creek these fishes prefer. Habitats studied to
determine preferences included: wing dams, a rock piles, and box dams. The
habitats were constructed in a simulated creek which used a pump to provide
flow.
The gravel chub has been found in four streams in Wisconsin where
it has been listed endangered since 1979 (Wisconsin DNR 1999). It prefers to
live in streams with permanent flow and eats periphyton (detritus, diatomaceous
algae, and bacteria), Triehoptera, plant material, Ephemeroptera, gastropods,
and miscellaneous aquatic insects. Gravel chubs grow to slightly over three
inches long and have silver sides (Becker 1983). The DNR believes the gravel
chub has declined because of fertilizers running off from farm fields which
impacts this species habitats and water quality. The nutrients cause abundant
aquatic plant growth and muddy waters (Becker, 1983). In Canada, the gravel chub
has had similar problems. Canada listed it as endangered in 1985 but removed it
from the endangered list in 1987 (www. gravelchub.com). Canadian gravel chubs
look exactly like the Wisconsin gravel chub because it is the same species. They
are found in only one river in Canada but are hard to collect so it is possible
they could be in more streams. The gravel chub prefers streams with permanent
flow, clean water, and bottoms free of clay and mud.
The rainbow darter
is commonly found in central Wisconsin and prefers clear, shallow water. In one
study, 60% of the rainbows were found in pools and 40% in riffles. Rainbow
darters are found in streambeds made up of sand, boulders, or gravel. Streams
are generally twelve to twenty-four meters wide. They can also live in streams
as small as three meters to as large as one hundred meters wide. Rainbow
darter’s habitat changes depending on age and if they are male or female. Adult
males remain in fast flowing, large, rocky riffles during the winter and after
the reproductive period. Adult females like the same habitat as males in the
winter. However, before and after the spawning periods, females and young are
found in raceways and pools. The young will also stay in the raceways and pools
during the winter. The rainbow darter's population has declined due to pollution
(sewage) and siltation (Becker, 1983).
Banded darters prefer clear, swift
flowing streams with gravel, sand, or rubble. In one study, 50% of the banded
darters were found in riffles and 43% in pools. They prefer depths from three to
four and a half feet. The banded darter has been found in small streams in
southern Wisconsin. Like the gravel chub, they are not found in streams with
abundant vegetation (Becker, 1983).
Before collecting the fish, I obtained a
special permit from the Minnesota Department of Natural Resources to obtain,
transport and possess the fish for study.
Hypothesis
I hypothesized the gravel chub would prefer the wing dam over the box dam and
the rock pile because I collected them from a habitat which appeared very
similar. I thought the wing dam’s deflecting flow would help the gravel chub not
waste as much energy trying to stay in one spot.
I believed the banded
and rainbow darters would both prefer the box dam because they also would not
waste energy remaining stationery in the stream. The box dam had three sides
which would provide some shelter from downstream and cross
flows.
Methods
A simulated creek was constructed and waterproofed with marine paint. Water
was collected from a river and maintained at a temperature of 61 degrees (F).
For each test, the same habitat structure (e.g., wing dams) was placed at three
equally spaced positions along the length of the simulated stream. A filter and
a pump was used to maintain water quality and provide current.
Fish were
collected from the North Branch of the Root River (Olmsted Co.) with the
assistance of a DNR fish biologist and placed in coolers filled with river water
for transport. They were then placed in the creek. Nine tests were done with the
wing dam structure, one per day for nine days. A test consisted of blocking fish
with dividers in a wing dam area for counting. The rocks in the wing dams were
removed and the number of fish were counted. This was repeated for the remaining
two wing dams. After nine tests with the wing dam, this procedure was repeated
with the box dam and rock pile structures for a total of 27
tests.
Literature Cited
Becker, G.C. 1983. Fishes of Wisconsin. University of Wisconsin Press,
Madison. 1053 pp.
Results
Gravel chub visits at habitat structures and
locations.
Wing
Dam
Location-Visits
1-3
2-19
3-2
Rock
Pile
Location-Visits
1-1
2-6
3-15
Box Dam
Location-Visits
1-9
2-3
3-2
Rainbow darter visits at
habitat structures and locations.
Wing
Dam
Location-Visits
1-45
2-92
3-16
Rock
Pile
Location-Visits
1-29
2-67
3-53
Box
Dam
Location-Visits
1-46
2-82
3-25
Banded darter visits at habitat structures and
locations.
Wing
Dam
Location-Visits
1-30
2-14
3-4
Rock
Pile
Location-Visits
1-15
2-20
3-14
Box Dam
Location-Visits
1-25
2-15
3-8
Species averages at habitat structures and
locations.
Gravel Chub
Location-Visits
wing dam
1-0.3
wing dam 2-2.1
wing dam3-0.2
rock pile 1-0.1
rock pile 2
-0.7
rock pile 3-1.7
box dam 1-1.0
box dam 2-1.4
box dam 3-0.2
Rainbow Darter
Location-Visits
wing dam
1-5.0
wing dam 2-10.2
wing dam 3-1.8
rock pile 1-3.2
rock pile
2-7.4
rock pile 3-5.9
box dam 1-5.1
box dam 2-9.1
box dam 3-2.8
Banded Darter
Location-Visits
wing dam
1-3.3
wing dam 2-1.6
wing dam 3-0.4
rock pile 1-1.7
rock pile
2-2.2
rock pile 3-1.6
box dam 1-2.8
box dam 2-1.7
box dam 3-0.9