- Arkansas River largemouth bass study
Mike Eggleton and Ben Batten
Recently, the Arkansas Game and Fish Commission (AGFC) has
become concerned about declining abundances of large largemouth
bass in the Arkansas River. Although the decline to date is
based largely on tournament data and has not been statistically
significant, there is some concern that declines could be real
and possibly related to levels of river off-channel or
“backwater” habitats. Although data are lacking, it is also
perceived that these habitats have declined in quantity and
quality since the McKellan-Kerr Navigation System was completed
in the early 1970s. Once the Arkansas River became a series of
impounded pools, these habitats suffered from influences of
river regulation: accelerated sedimentation, reduced connectance
with the river, and eventual terrestrialization.
To address these concerns, UAPB has initiated a 2-year stock
assessment of largemouth bass populations in the lower 11 pools
of the Arkansas River. Stock assessments will encompass
quantifying abundance, size/age structure, growth, and mortality
of largemouth bass populations throughout the lower Arkansas
River within Arkansas. Working in collaboration with researchers
at Mississippi State University, we also plan to quantify the
quantity and quality the river’s present-day backwater habitats
as well as the rate of change in those habitats over the past 35
years. Regression analyses will then be used to examine possible
relationships between largemouth bass population metrics and
backwater habitat characteristics. This research should provide
a status report of the Arkansas River’s largemouth bass fishery
and provide useful information on the roles that backwater
habitats in large river fisheries.
Year 1 field sampling was conducted during June/July 2004 and
October/November 2004. Similar collections are planned for
spring and fall 2005 (Year 2). Results pending.
Study duration: 2004-2006.
- Relation of floodplain lake fish communities and river
connectivity in the lower White River, Arkansas
Sandra J. Clark, John R. Jackson, and Steve E. Lochmann
A river and its floodplain can be considered one interacting
unit termed the “river-floodplain ecosystem” (RFE). The
flood-pulse concept is the major paradigm used to describe
ecological processes of many RFEs. Ecological integrity of RFEs
is maintained by connectivity, the connection between the
floodplain and main river channel operating across a range of
spatio-temporal scales. This concept is based on tropical RFEs
and its application in temperate RFEs has not been adequately
tested due, in part, to lack of unaltered temperate RFEs. The
lower White River, Arkansas provides such an opportunity. Our
study was conducted within the White River National Wildlife
Refuge located in the lower portion of the River that has
connection to over 65,000 ha of bottomland hardwoods. The goal
of our research is to provide an understanding of
river-floodplain linkages for relatively unaltered temperate
RFEs that can be used as a template for floodplain lake
restoration. We will accomplish this by comparing fish
assemblages in 1) 35 floodplain lakes during river disconnection
assessing whether empirical relationships between
physical/environmental conditions and species composition
exists, 2) 12 lakes during periods river connection and
disconnection exploring temporal fish use of floodplain lakes,
and 3) four lakes over a three-year period to assess annual
variations. Boat electrofishing, experimental gill nets,
paddlefish gill nets, mini-fyke nets, and shoreline seining will
be used to sample fish populations. Fish assemblages will be
described using Shannon Wiener species diversity, species
richness, and relative abundance.
- Assessment of impacts of proposed navigation and water
withdrawal on fishes in the lower White River, Arkansas
Mike Eggleton, Hal Schramm, John Jackson, and Steve E.
Lochmann
The value of the natural resources of the White River Basin is
recognized by the area’s designation as a “Wetland of
International Importance”. The Basin constitutes one of the
Nation’s largest remaining forested wetland landscapes. It
supports the North American continent’s largest concentration of
over-wintering mallard ducks, a productive big river fishery,
and several threatened and endangered species. The continued
viability of this floodplain-river ecosystem depends on the
suitability of the hydrologic environment to the resident flora
and fauna. The imminent construction of an irrigation pumping
plant at De Wal’s Bluff is causing concern in some natural
resource agencies and in some private NGOs. In spite of the
enormous stakes involved, there have been no studies relating
fish and wildlife resource responses to past and future
cumulative hydrologic alterations in the Basin.
We developed a Bayesian belief network for 80 taxa or groups of
river fishes of the White River ecosystem. This model identifies
key components that affect ecosystem structure and function,
predicts impacts of habitat change, and, through sensitivity
analyses, prioritizes management and research activities. The
model is based on current and future habitat conditions and
synthesis of existing life history, distribution, and abundance
information for fishes and mussels. The model is being reviewed
by a number of fish ecology experts and will be revised
according to comments from those reviewers. The model will aid
state and federal natural resource managers in determining risks
to habitat changes and in prioritizing research needs.
- First-year contribution to the year class and growth of
largemouth bass stocked at 50 mm and 100 mm into the Arkansas
River, Arkansas
Liz Heitman, Chris Racey and Steve E. Lochmann
Oxytetracycline-marked largemouth bass Micropterus salmoides,
averaging 50 or 100 mm TL, were stocked into backwater areas of
pool 4 of the Arkansas River in the summer of 2003 at densities
of 309 and 62 fish/ha, respectively. Contributions to the year
class of 50-mm (13.2%) and 100-mm (13.8%) stocked largemouth
bass were not significantly different in fall 2003. Stocking
contributions of 50-mm (17.6%) and 100-mm (17.2%) largemouth
bass were also not significantly different in spring 2004.
Contributions were not significantly different between seasons.
Mean (SD) total lengths for 50-mm stocked, 100-mm stocked, and
wild fish were 164 (38), 172 (39), and 162 (43) mm,
respectively, in fall 2003, and 187 (37), 185 (43), and 179 (44)
mm, respectively in spring 2004. There were no significant
differences among mean lengths for stocked or wild fish in
either season. Stocking five times as many 50-mm as 100-mm
largemouth bass yielded similar contributions. Largemouth bass
stocked into the Arkansas River had one-year stocking
contributions similar to largemouth bass stocked into reservoirs
and lakes. Costs were determined to raise and stock 50-mm and
100-mm fingerlings to guide future management decisions. The
cost of raising 100-mm fingerlings appears to be more than five
times the cost of raising 50-mm fingerlings, so the differences
in stocking densities, the similarity in contribution to the
year class, and the differences in cost suggest that in this
case, 50-mm fingerlings are more economical to stock.
Variability in egg characteristics among white bass and the egg
volume: larval standard length relation in sunshine bass
Steve E. Lochmann*, Christopher R. Racey, Kelly J. Goodwin, and
Christopher C. Green
Besides fast growth or favorable feed conversion, selection of
white bass Morone chrysops brood stock could be based on
favorable egg or fry characteristics. Eggs from 12 white bass,
used to produce sunshine bass fry, were individually
photographed and incubated. Average egg volume ranged from 0.316
to 0.422 mm3 and varied significantly among females (P<0.0001).
Hatch rates ranged from 49% to 96%, but there was no
relationship between hatch rate and egg volume. Total lipids
varied from 4.03% to 6.17%, and n-3 HUFAs comprised more than 3%
of lipids in eggs from all females. There was no relationship
between egg volume and lipid levels. Yolk-sac fry were also
photographed within 3 h of hatching. Standard lengths of
yolk-sac fry were less variable than egg volumes (CV=6.3%) and
ranged from 2.35 to 3.62 mm. Average standard length ranged from
2.89 to 3.08 mm and also varied among females (P<0.0001).
Specific female and time to hatch explained 60% of the
variability in yolk-sac fry SL. Some females had egg and fry
characteristics more suitable to increasing survival and
fingerling production. Selection for these characteristics in
brood stock white bass females could lead to improved production
of sunshine bass fingerlings.
- Fluctuating asymmetry and condition in golden shiner and
channel catfish reared in sublethal concentrations of isopropyl
methylphosphonic acid
Chris C. Green and Steve E. Lochmann
Fluctuating asymmetry, small random differences between the left
and right sides of a bilateral character, has been related to
embryological stress during development. Some populations
exhibit positive relations between FA and exposure to toxicants
during development The United States has agreed to demilitarize
chemical warfare agents in accordance with the Chemical Weapons
Convention Treaty. Isopropyl methylphosphonic acid (IMPA), the
main hydrolysis product of Sarin, could be accidentally
introduced into the environment during demilitarization. This
study examined the use of fluctuating asymmetry as a biomarker
of developmental stress due to sub-lethal exposures to IMPA. A
suite of morphometric and meristic traits were measured in two
fish species exposed to IMPA. Significant differences were found
in composite FA among groups of channel catfish (Ictalurus
punctatus) exposed to sub-lethal concentrations of IMPA during
development. No differences were found in composite FA among
groups of golden shiner (Notemigonus crysoleucas) exposed to
IMPA. There was no relation between individual relative
condition and FA in channel catfish or golden shiner.
- Larval fish and zooplankton abundances in oxbow lakes of
the lower White River, Arkansas
Chris Racey and Steve E. Lochmann
The White River National Wildlife Refuge (NWR) is a 160,000 acre
bottomland hardwood forest with more than 350 oxbow lakes and 90
miles of the White River. The White River supports a highly
diverse fish community with nearly 100 different species. Fish
populations within individual oxbow lakes have not been well
researched. Similarly, the interactions between fish spawning
and natural zooplankton abundances have not been examined. We
sampled larval fish during the spring using bilateral plankton
tows with 0.5 m x 2 m townets in six oxbow lakes to estimate
larval fish abundances. We also used a Wisconsin plankton
sampler to estimate spring zooplankton abundances in the same
oxbow lakes. All samples were conducted weekly for all lakes.
Clupeids were highly abundant throughout the spring in all
lakes, while crappie abundances generally increased over time. A
variety of other fish appeared in varying abundances throughout
the spring. Cladocerans and adult copepods were virtually
nonexistent in oxbow lakes, while rotifers increased in
abundance as the spring progressed. Copepod nauplii were
found in low abundances throughout the spring in all lakes.
Oxbow lakes in the White River NWR are important for fish
spawning and nursery habitat.
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