The direct-proportion method was used to estimate fish populations in
Areas 1, 3 and 6. Reliable results could not be obtained for all species
because of scarcity, mortality in handling, mobility, or other factors.
A high rate of mortality due to handling was observed in Area 1 for the
red shiner and in Area 6 for river carpsucker (young-of-the-year),
sucker-mouthed minnows, red-finned shiner, red shiner, blunt-nosed
minnow, and stoneroller. In Area 3, in contrast, there was little
mortality in the same species during the twelve-hour interval that fish
were held in traps prior to release as marked individuals.
The following species were common in at least one area, but probably are
sufficiently mobile (see page 416) to invalidate estimates of static
populations in small areas: red shiner, red-finned shiner, and channel
catfish (yearlings and older). Other species were rare and are indicated
as "T" in Table 13.
Those species for which population-estimates seem warranted include:
golden redhorse, sucker-mouthed minnow, red shiner, sand shiner,
fat-headed minnow, stoneroller, stonecat, channel catfish
(young-of-the-year), green sunfish, long-eared sunfish, slender-headed
darter, and orange-throated darter. I consider the estimate valid if a
high percentage of the marked fish is recaptured. Results are presented
in Table 15, and ordinarily will not be referred to in the following
discussion of the population in each of the three areas.
_Area 1_
The order of abundance at Area 1, in terms of the estimated population
per 500 square feet, was as follows: stoneroller (47.6), stonecat
(29.4), channel catfish (young-of-the-year) (20.6), green sunfish
(19.4), red shiner (18.2), long-eared sunfish (9.4), channel catfish
(yearlings and older) (6.5), golden redhorse (1.2). Insufficient data
make inclusion of other species unreliable.
A comparison of the order of abundance between the estimated total
population and the percentage composition in the first collection from
each area shows significant correlations. The percentage-composition of
the fish fauna at Area 1 was calculated as follows: stoneroller (27.7%),
red shiner (18.2%), green sunfish (11.2%), stonecat (10.3%), channel
catfish (young-of-the-year) (9.5%), channel catfish (yearlings and
older) (5.8%), long-eared sunfish (5.4%), golden redhorse (0.8%). It can
be seen that the stoneroller, green sunfish, long-eared sunfish and
golden redhorse follow each other in the same order in both
calculations. The stonecat is shown to be more common than channel
catfish (young-of-the-year) in both calculations, but both species
appear to be more abundant than green sunfish and red shiner in
calculations of the total population and less abundant in the
percentage-composition in the first collection. I think that the order
of abundance as shown by percentage-composition is the more accurate
figure for Area 1. The abundance of the red shiner is known to have been
affected by mortality in collecting. Furthermore, as will be shown
later, the species is so mobile that its abundance often changes
markedly in a short time. Therefore, it is not surprising to find the
red shiner in widely varying positions of relative and absolute
abundance. However, the green sunfish maintains stable populations and
should remain in about the same position of abundance in relation to
other species (such as the stonecat and channel catfish
young-of-the-year) that also maintain stable populations. The
differences in order of abundance obtained by the two methods for green
sunfish and channel catfish young-of-the-year are not great. However, in
the estimation of total population the abundance of the stonecat seems
significantly greater, in relation to other species, than in the
calculation of percentage-composition. I believe that this difference
can be attributed to the relatively low number of marked fish
recaptured, which is probably due to a slow rate of dispersal from the
point of release. Stonecats were released in relatively quiet water, and
if they remained there they might be missed in subsequent collections,
because they lack air-bladders and tend to remain on the bottom when
shocked. Therefore, the calculated total population of the stonecat in
Area 1 may be too high.
TABLE 15. DATA USED IN ESTIMATING TOTAL POPULATIONS, BY DIRECT
PROPORTIONS, IN AREAS 1, 3, AND 6 AT THE UPPER NEOSHO STATIONS.
======================================================================
| Number | Number | Number
| captured first | marked and |captured second
SPECIES | collection | released | collection
+----+-----+-----+----+----+----+----+-----+----
| 1 | 3 | 6 | 1 | 3 | 6 | 1 | 3 | 6
----------------------+----+-----+-----+----+----+----+----+-----+----
Golden Redhorse | 2 | 5 | 0 | 2 | 5 | 0 | 2 | 5 | 0
Sucker-mouthed Minnow | 0 | 54 | 31 | 0 | 51 | 15 | 0 | 42 | 12
Red Shiner | 44 | 116 | 186 | 22 |106 | 86 | 7 | 165 | 202
Sand Shiner | 0 | 25 | 10 | 0 | 25 | 7 | 0 | 35 | 10
Blunt-nosed Minnow | 0 | 4 | 108 | 0 | 3 | 28 | 0 | 10 | 91
Fat-headed Minnow | 1 | 1 | 112 | 1 | 1 |101 | 0 | 2 | 156
Stoneroller | 67 | 84 | 54 | 58 | 79 | 33 | 39 | 107 | 67
Channel Catfish(j)[I] | 14 | 37 | 3 | 9 | 32 | 3 | 7 | 16 | 1
Channel Catfish(yy)[J]| 3 | 34 | 40 | 22 | 33 | 39 | 16 | 34 | 23
Stonecat | 25 | 7 | 0 | 25 | 7 | 0 | 8 | 7 | 0
Green Sunfish | 27 |[K]--| 62 | 27 | -- | 62 | 17 | -- | 62
Long-eared Sunfish | 13 | 6 | 10 | 13 | 6 | 10 | 12 | 3 | 22
----------------------+----+-----+-----+----+----+----+----+-----+----
======================================================================
Number of | Estimated | Percent of | Number
marked fish | total | marked fish | per 500
recaptured | population | recovered | square feet
----+----+----+----+-----+------+-----+-----+----+------+------+------
1 | 3 | 6 | 1 | 3 | 6 | 1 | 3 | 6 | 1 | 3 | 6
----+----+----+----+-----+------+-----+-----+----+------+------+------
2 | 5 | 0 | 2 | 5 | 0 | 100 | 100 | -- | 1.2 | .4 | 0
0 | 17 | 0 | 0 | 126 | -- | -- | 33 | 0 | 0 | 10.0 | --
5 | 18 | 14 | 31 | 972 | 1284 | 23 | 17 | 11 | 18.2 | 77.1 | 64
-- | 12 | 1 | 0 | 73 | -- | -- | 48 | -- | 0 | 5.8 | --
0 | 1 | 8 | 0 | -- | 319 | -- | 33 | 28 | 0 | -- | 16
0 | 0 | 19 | -- | -- | 830 | 0 | 0 | 19 | -- | -- | 41.5
28 | 35 | 8 | 81 | 242 | 276 | 48 | 44 | 24 | 47.6 | 19.2 | 13.8
6 | 13 | 0 | 11 | 39 | -- | 67 | 41 | 0 | 6.5 | 3.1 | --
10 | 11 | 1 | 35 | 102 | -- | 45 | 33 | 3 | 20.6 | 8.1 | --
4 | 1 | -- | 50 | -- | 0 | 16 | 14 | -- | 29.4 | -- | 0
14 | -- | 22 | 33 | -- | 175 | 52 | -- | 35 | 19.4 | -- | 8.8
10 | 3 | 6 | 16 | 6 | 37 | 76 | 50 | 60 | 9.4 | .5 | 1.9
----+----+----+----+-----+------+-----+-----+----+------+------+------
[I] (j) Denotes juveniles only.
[J] (yy) Denotes young-of-year only.
[K] A dash denotes incomplete or insufficient data.
_Area 3_
The order of abundance of the species at Area 3, in terms of the
estimated population per 500 square feet, was as follows: red shiner
(77.1), stoneroller (19.2), sucker-mouthed minnow (10.0), channel
catfish (young-of-the-year) (8.1), sand shiner (5.8), channel catfish
(yearlings and older) (3.1), long-eared sunfish (0.5), golden redhorse
(0.4). Insufficient data make inclusion of other species unreliable.
For comparison with the estimates of total population, the
percentage-composition in the first collection gives the following
results: red shiner (24.0%), stoneroller (17.4%), sucker-mouthed minnow
(11.2%), channel catfish (yearlings and older) (7.6%), channel catfish
(young-of-the-year) (7.0%), long-eared sunfish (6.0%), sand shiner
(5.2%), and golden redhorse (1.0%).
For the most part, the species have the same order of abundance in both
methods of analysis. Those that are apparently out of order are channel
catfish (yearlings and older) and long-eared sunfish. The first species
is mobile (excepting young-of-the-year) and commonly fluctuates widely
in numbers in the same area; the second species was treated differently
in that only adults were considered in the population-estimation
whereas both young and adults were considered in calculating
percentage-composition. (I found that I could not confidently
distinguish between young-of-the-year of green sunfish, long-eared
sunfish and orange-spotted sunfish after staining.)
_Area 6_
The order of abundance of the species at Area 6, in terms of the
estimated population per 500 square feet, was as follows: red shiner
(64.0), fat-headed minnow (41.5), blunt-nosed minnow (16.0), stoneroller
(13.8), green sunfish (8.8), long-eared sunfish (1.9). Insufficient data
make inclusion of other species unreliable.
Calculations of percentage-composition give the following results: red
shiner (20.1%), long-eared sunfish (14.6%), green sunfish (12.2%),
fat-headed minnow (12.1%), blunt-nosed minnow (11.7%), stoneroller
(5.8%). The two species of sunfish form a more significant part of the
population in the latter analysis because young are included. Only
adults were considered in the estimation of total population.
The fact that estimates of the total population and the
percentage-composition agree in most respects lends support to the
validity of both methods of analysis. It should be re-emphasized that
differences in the order of abundance in the various areas reflect the
ability of each species to utilize each particular kind of habitat.