_Electrical Fishing Gear_
The principal collecting-device used was a portable (600-watt, 110-volt,
A. C.) electric shocker carried in a 12-foot aluminum boat. Two 2 x
2-inch wooden booms, each ten feet long, were attached to the front of
the boat in a "V" position so they normally were two feet above the
surface of the water. A nylon rope attached to the tips of the booms
held them ten feet apart. Electrodes, six feet long, were suspended from
the tip and center of each boom, and two electrodes were suspended from
the nylon rope. The electrodes extended approximately four feet into the
water. Of various materials used for electrodes, the most satisfactory
was a neoprene-core, shielded hydraulic hose in sections two feet long.
These lengths could be screwed together, permitting adjustment of the
length of the electrodes with minimum effort. At night, a sealed-beam
automobile headlight was plugged into a six-volt D. C. outlet in the
generating unit and a Coleman lantern was mounted on each gunwale to
illuminate the area around the bow and along the sides of the boat (Pl.
3a). In late summer, 1959, a 230-volt, 1500-watt generating unit,
composed of a 115-volt, 1500-watt Homelite generator was used. It was
attached to a step-up transformer that converted the current to 230
volts. The same booms described above were used with the 230-volt unit,
with single electrodes at the tip of each boom.
A 5.5-horsepower motor propelled the boat, and the stunned fish were
collected by means of scap nets. Fishes seen and identified but not
captured also were recorded. On several occasions fishes were collected
by placing a 25-foot seine in the current and shocking toward the seine
from upstream.
The shocker was used in daylight at all six stations in the three years,
1957-'59. Collections were made at night in 1958 and 1959 at the middle
Neosho station and in 1959 at the lower Neosho station.
_Seines_
Seines of various lengths (4, 6, 12, 15, 25 and 60 feet), with
mesh-sizes varying from bobbinet to one-half inch, were used. The
4-, 12-, and 25-foot seines were used in the estimation of relative
abundance by taking ten hauls with each seine, recording all species
captured in each haul, and making a total count of all fish captured in
two of the ten hauls. The two hauls to be counted were chosen prior to
each collection from a table of random numbers. Additional selective
seining was done to ascertain the habitats occupied by different
species.
_Trap, Hoop, and Fyke Nets._--Limited use was made of unbaited trapping
devices: wire traps 2.5 feet in diameter, six feet long, covered with
one-inch-mesh chicken wire; hoop nets 1.5 feet to three feet in
diameter at the first hoop with a pot-mesh of one inch; and a fyke net
three feet in diameter at the first hoop, pot-mesh of one inch with
wings three feet in length. All of these were set parallel to the
current with the mouths downstream. The use of trapping devices was
abated because data obtained were not sufficient to justify the effort
expended.
_Gill Nets_
Gill-netting was done mostly in 1959 at the lower Neosho station. Use of
gill nets was limited because frequent slight rises in the river caused
nets to collect excessive debris, with damage to the nets.
Gill nets used were 125 feet long, six feet deep, with mesh sizes of
3/4 inch to 2-1/2 inches. Nets, weighted to sink, were placed at right
angles to the current and attached at the banks with rope.
_Sodium Cyanide_
Pellets of sodium cyanide were used infrequently to collect fish from a
moderately fast riffle over gravel bottom that was overgrown with
willows, making seining impossible. The pellets were dissolved in a
small amount of water, a seine was held in place, and the cyanide
solution was introduced into the water a short distance upstream from
the seine, causing incapacitated fish to drift into the seine. Most of
these fish that were placed in uncontaminated water revived.
_Rotenone_
Rotenone was used in a few small pools in efforts to capture complete
populations. This method was used to check the validity of other
methods, and to reduce the possibility that rare species would go
undetected. Rotenone was applied by hand, and applications were
occasionally supplemented by placing rotenone in a container that was
punctured with a small hole and suspended over the water at the head of
a riffle draining into the area being poisoned. This maintained a toxic
concentration in the pool for sufficient time to obtain the desired
kill. Rotenone acts more slowly than cyanide, allowing more of the
distressed fish to rise to the surface.
_Dyes_
Bismark Brown Y was used primarily at the upper Neosho station to stain
large numbers of small fish. The dye was used at a dilution of 1:20,000.
Fishes were placed in the dye-solution for three hours, then
transferred to a live-box in midstream for variable periods (ten minutes
to twelve hours) before release.
_Determination of Abundance_
In the accounts of species that follow, the relative terms "abundant,"
"common," and "rare" are used. Assignment of one of these terms to each
species was based on analysis of data that are presented in Tables 9-16,
(pages 402, 403, 404, 405, 408, 410, 411, 414-415, and 416). The number
of fish caught per unit of effort with the shocker (Table 10) and with
seines (Table 11) constitute the main basis for statements about the
abundance of each species at all stations except the upper Neosho
station. Species listed in each Table (10 and 11) are those that were
taken consistently by the method specified in the caption of the table;
erratically, but in large numbers at least once, by that method; and
those taken by the method specified but not the other method.
For the species listed in Table 10, the following usually applies:
abundant=more than three fish caught per hour; common=one to three fish
caught per hour; rare=less than one fish caught per hour.
Tables 12-16 list all fish obtained at the upper Neosho station by means
of the shocker, seines, and rotenone.
_Names of Fishes_
Technical names of fishes are those that seem to qualify under the
International Rules of Zoological Nomenclature. Vernacular names are
those in Special Publication No. 2 (1960) of the American Fisheries
Society, with grammatical modifications required for use in the
University of Kansas Publications, Museum of Natural History.