Effects of sediment on aquatic life

EFFECTS OF SEDTMF:.'T OV AQUATIC LIFE

Prepared by

Richard E. Sparks

Illinois Natural History Survey

River Research I,^boratory

Havana, Illinois 62644

Revised June 18, 1977

for the

Subcommittee on Soil Erosion and Sedimentation

Illinois Task Force on Agriculture I'onpoint Sources of Pollution

Reduction of Light Penetration

Primary production is the production of organic material from carbon
dioxide and water by green plants and is the basis for all food chains in
both aquatic and terrestrial environnents. Primary production is the re-
sult of a process called photosynthesis, which is dependent on sunlight.
In aquatic environments, primary production occurs only in the euphotic
zone, as the result of photosynthesis by both floating and attached algae
and by higher plants. Below the euphotic zone, there is not enough
light to permit green plants to produce more food by photosynthesis than
they consume in the process of respiration, so there is no primary pro-
duction. The euphotic zone extends down to the depth at which the light
intensity is approximately 1 percent of what it is at the surface. In a
shallow lake, the entire lake may lie within the euphotic zone. One effect
of suspended sediment is to reduce the euphotic zone, thereby reducing
primary production. Claffey (1955: 24) used a spectrophotometer to
measure light penetration in waters of various turbidities. In water
having a turbidity of 25 JTU, only 24.9 percent of the original light

of the red wave lengths (the most penetrating) was visible at a depth

of 4 inches; at 50 JTU, only 6.3 percent; and at 150 JTU, no light was

available at a depth of A inches.

In farm ponds, lakes, and large J-mpoi'ndments primary production within

the water itself can be the major source of food for the entire aquatic

ecosystem. Waterfowl feed directly on many species of aquatic macro-

phytes. Few species of fish feed directly on phytoplankton or raacrophytes.

Some fish, such as gizzard shad, feed on the zooplankters (microscopic

animals) which in turn feed on phytoplankton. Many of the garaefish

consume zooplankton when they are small, then graduate to insects and forage

fish as they become larger. The effect of turbidity on plankton was

measured by Claffey (1955: 43), who used .i Wisconsin-type plankton

net with No. 25 mesh silk bolting cloth to sample 20 farm ponds of varying

turbidity in Oklahoma. Zooplankton probably com.prised the bulk of the

material collected by the net. Turbid ponds contained much less plankton

in the surface waters (0 to 2 feet) than clear ponds:

Volume (ml of plankton Reduction of plankton, in
Turbidity Class per liter of water) comparison to clear water

Clear ( 25 JTU) 0.0187

Intermediate (25-50 JTU) 0.0037 80%

Muddy (51-350 JTU) 0.0019 90%

Primary production can be a nuisance when it is in the form of algal
blooms which are unsightly or cause taste and odor problems in drinking water.
Suspended sediment can limit or prevent such blooms by reducing light penetra-
tion and adsorbing nutrients, such as phosphorous, which stimulate plant growth.
Such blooms might occur in many bodies of water in Illinois if suspended
sediment levels were reduced without also reducing levels of plant nutrients.

LAKE CHAUTAUQUA, ILLINOIS

V1ND VCLOCITV (n

Fic. © Tuibidities of Lake Chjutauqua occurring
at various wind velocities (average maximum oae
hour preceding collection time ) in the absence and
presence of vegeUtion. The graph shows that w-ind
has litde or no effect upon turbidity of Lake Chau-
tauqua when vegetation is present

Plant nutrients enter water from many sources, in addition to agricultural
sources. For example, phosphorous is used in detergents and contributes to
high phosphorous levels in effluents from sewage treatment plants.

In streams and rivers, primary production in the terrestrial environ-
ment is a major source of organic material, which is dropped, blown, or
washed into the aquatic environment.

In aquatic environments, higher plants have other functions in addition
to the function of producing food. Their roots can anchor the bottom against
wave action and against the rooting activities of bottom-feeding fish such
as carp. The stems and leaves of floating and emergent plants dampen waves.
Therefore plants can reduce turbidity by preventing resuspension of bottom
sediments by waves or fish. Figure 1, taken from Jackson and Starrett
(1959: 162) shows that wind had little effect on the turbidity of Lake
Chautauqua when vegetation was present, and a marked effect when vegetation
was absent.

Aquatic macrophytes provide habitat for fishes and for a group of inver-
tebrate animals called the "weed fauna." Yellow perch may have disappeared
from the bottomland lakes along the Illinois River due to the loss of plant
beds the perch use for spawning. Smith (1971: 8) indicates that populations
of the bigeye shiner, the bigeye chub, and the pugnose minnow have been
decimated in Illinois streams primarily because of the disappearance of
aquatic vegetation. The "weed fauna" consists of snails and insects which graze o
the macrophytes themselves or on the "scum" formed by bacteria and algae
on the larger plants. Predatory insects such as dragonfly and damselfly
nymphs hunt their prey among the leaves. The "weed fauna" is important because
it furnishes food for members of the sunfish family, such as largemouth bass

and bluegill. In bottomland lakes along the Illinois River, the biomass of
the weed fauna once averaged 2118 lbs. to the acre (2374 kg/h) and was eight
times greater than the biomass of bottom fauna (Richardson, 1921: 431-432).
Since the late 1950' s and early 1960's there has been no v;eed fauna in these
lakes because the weeds cannot gain roothold in the soft bottom which is con-
stantly disturbed by wind-generated waves and also because light penetration
has been reduced by turbidity. The turbidity and degraded bottom are caused
by sediiuent.

The source of the sediment in the Illinois River cannot be attributed
to municipal and industrial effluents originating in the Chicago-Joliet area,
because the upper Illinois River is less turbid than the lower Illinois.
In fact, beds of sago pondweed grow in the Des Plaines River below the entrance
of the Chicago Sanitary and Ship Canal. The Des Plaines and Kankakee Rivers
join to form the upper Illinois River. It is only further downstream where
tributaries which drain extensive agricultural areas begin to join the Illinois
that the turbidity increases and no submerged vegetation occurs.

Reduction of Visibility

Aquatic organisms use a variety of senses to locate food and mates and
to avoid danger. The game fishes rely heavily on sight in hunting their
food, and it is this attribute which contributes to their desirability as
game fish, for they will strike at artificial lures.

If the turbidity of water is increased due to suspended sedinent, the
ability of game fish to find food (or strike at lures) is reduced. The
distance at which a fish will sight and react to prey or bait is called the

reactive distance, and depends on both the size of the prey and the tur-
bidity of the water. Vinyard and O'Brien (1976: 28A6-2847) found that the
larger the prey size, the greati^r the effect of turbidity in reducing the
reactive distance of bluegills. A turbidity increase from 6.25 to 30 JTU
reduced the reactive distance from 8.5 to 2.5 cm for prey 1 mm in size and
from 37.5 to 6.0 cm for prey 2.5 mm in size. Thirty JTC appeared to be
an upper limit for a turbidity effect. Turbidities greater than 30 JTU did
not further reduce the reactive distance presumably because the fish stopped
relying on sight to locate their prey and were forced to rely on another
sensory system, such as the lateral line system, which is sensitive to water
pressure waves generated by movements of prey.

Reduction in reactive distance du(i to turbidity can have a major impact
on the feeding of game fish. Prey that move out of a fish's reactive
distance have in fact escaped, and the predator must begin a search for
food again. Reduction of reactive distance greatly lim.its the volume of
water a fish can search in a given time. For example, a 50 percent reduction
In reactive distance reduces the actual volume searched by a factor of 4,
if the fish is assumed to be searching a cylinder, and by a factor of 8, if
the fish is assumed to be searching a hemisphere or a sphere (Vinyard and
O'Brien, 1976: 2848).

The significance of the laboratory findings of Vinyard and O'Brien
(1976) is that turbidity can reduce the feeding of game fish even if there
is an abundance of food available in tlie water.

The reduction in reactive distance of game fish due to turbidity also
has a marked impact on angling success, as sho\m belov; for Fork Lake, in
Macon County, Illinois during the Marcli through September, 1938 fishing
season (Bennett, Thompson, and Parr, 1940: 22):

Secchi Disk

Number

of Fish Cs

Visibility, Feet

Per Man-Hour

3.5 to 4,5

6.53

2.0 to 2.5

2.86

0.5 to 2.0

2.04

Reduction of Catch in
Relation to Catch \-Jhen

3.5 to 4.5

56%
69%

Many species of game fish exhibit complex reproductive and social
behavior which depends on visual cues. For example, male sunfishes build
nests in shallow water at the beginning of the breeding season. Since the
number of males may exceed the number of favorable nesting sites, and since
the fish seem to nest in colonies, each nale must aggressively defend his
nest against other males. At the same time, the male must be prepared to
accept ready females into his nest for spawning. The distinction between
a rival male and a ready female is based on visual cues. A female appraoches
the nest slowly in a submissive posture, with fins clamped, and her skin
assumes a characteristic washed-out color pattern. A rival male generally
moves rapidly, raises his fins, and exhibits a bold color pattern. A
reduction in visibility interferes with these visual cues. Heimstra et al.
(1969: 5-8) found that the activity levels of largemouth bass were reduced and
normal social behavior of green sunfish iias altered in moderately turbid water
(1^-16 JTU) . The fish also coughed and scraped themselves against the sides
of the tanks more frequently in the moderately turbid water (Heimstra et al.,
1969: 8).

Abrasion and Clogging

Most aquatic organisms can tolerate sediment in water for a period of

time. Wallen (1951: 18) found that the following turbidity levels (in JTU)

were required to kill fish:

Rock bass 38,250

Pumpkinseed 69,000

Channel catfish 85,000

Largemouth bass 101,000

Black crappie 145,000

Green sunfish 166,500

Fish exude a protective mucus on their skin and gills which traps and con-
tinually flushes away particles. Mussels have a protective mucus on their
gills and can close their shells. There is a group of caddisflies which
feed by spinning nets into which particles of food are washed by water
currents. These caddisflies then eat the net, food and all. If one
net becomes clogged with sediment, the caddisflies presumably can spin
another.

However, all of the above protective mechanisms are temperary measures.
Continual production of mucus by the fish requires metabolic energy and
constitutes a stress on the fish at the same time that its ability to find
food is reduced by turbidity. If the net of the caddisfly is continually
clogged with sediment of little or no nutritional value, the caddisfly will
eventually starve. Clams can resist temporary unfavorable conditions by
closing up, but then they cannot carry on normal activities such as feeding,
aerobic respiration, growth, and reproduction.

Therefore, while some adult organisms can withstand enormous amounts of
sediment in water for several day:; or weeks, the population may eventually
die out due to starvation, failure of rejiroduction, or cumulative stress.

For exam.ple, Ellis (1936) found that the defenses of mussels against
excessive sediment were eventually overwhelm.ed after a long period of exposure.

Silt interfered with the feeding of the mussels and caused mortality:

These experiments, extending over some fourteen months, showed
that most of the common fresh-water mussels were unable to m^ain-
tain themselves in either sand or gravel bottoms when a layer of
silt from one-fourth of an inch to one inch deep was allowed to
accumulate on the surface of these otherwise satisfactory bottom
habitats, although other individuals of these same species held in
the lattice-work crates a few inches or feet above the bottom
thrived in this same water. Daily analyses of the water at
various levels in these raceways shewed that the high mortality
of the mussels on the bottom was induced by the silt covering
and was not due to low oxygen, pH, carbonates or other water con-
ditions. The Yellow Sand-shell (Lampsilis anodontoides) , a sand
inhabiting species was the most readily killed by silt deposits,
and the Three-horned Warty-back, Obliquaria ref lexa, the Maple
Leaf, Quadrula guadrula, and the Monkey-face, Quadrula metanevra,
were among the m.ore resistant. However, the mortality rapidly
approached 90 percent or more for all species when the silt
layer began to permanently cover the sand or gravel. On the other
hand the mortality of the mussels in the crates was very low.

Laboratory experiments with fresh-water mussels in water
carrying heavy loads of erosion silt (this material being kept in
suspension by automatic glass stirring devices) showed that
erosion silt interfered with the feeding of fresh-water mussels.
The mussels in the muddy water remained closed a large percent
of the time, 75 to 95 percent, v;hile mussels in silt-free water
but subject to the same current influences as those in the erosion
silt tests V7ere closed less than 50 percent of the time. When
mussels opened in water carrying large amounts of erosion silt
an excessive secretion of mucus was produced and this served in
part to remove the silt which tended to settle into the mantle
cavity. Mussels dying In silt-laden water always contained
deposits of silt in the mantle cavity and frequently in the
gill chambers. (Ellis, 1936: 39-40. Material in parentheses
inserted by Sparks.)

It is noteworthy that the yellow-sand-shell was most readily killed

by silt deposits in Ellis's experiments, and that it has apparently

disappeared from the Illinois River, probably due to increased silt loads

(Starrett, 1971: 334). The silt-resistant maple-leaf and three-horned

warty-back were still found in the Illinois River in 1966 (Starrett, 1971)

Habitat Alteration and Destruction

Sediment deposits can cover gravel and sand bottoms which many organisms

10

require for carrying on normal activities such as feeding and reproduction.
In extreme cases, sediment can completely fill, and thereby destroy, an
aquatic habitat.

Smith (1971: 8) states that "the gravel chub, Ozark minnow, weed shiner,
western sand darter, banded darter, and slenderhead darter have reduced
ranges because they have lost extensive gravel- and sand-substrate habitats
to silt,"

The formerly productive bottomland lakes along the Illinois River
are almost completely filled with sediment. In February, 1976, the
Illinois Natural History Survey made a survey of the water depths of Lake
Chautauqua, a bottomland lake along the Illinois River at Havana in Mason
County. The maximum depth of the southern 2/3 of this large lake (2000-3000
acres, depending on water levels) was 18 inches. The findings were analyzed
by the Illinois State Water Survey, and compared to their earlier studies
of sedimentation in Lake Chautauqua (Stall and Melsted, 1951). In the
period from 1926-1976, Lake Chautauqua has lost 34.7% of its original capacity.

The loss in terms of fish habitat is much worse than the capacity loss
indicates, because the deeper areas of the lake have filled much faster than
the shallow areas, and the lake is now uriformly shallow. It once contained
areas which were 7 feet deep during low water stages. A diversity in the
topography of the bottom is important in maintaining a diversity of plant and
animal life. The deeper the water, the less the light penetration, and
different species of aquatic plants are adapted to different light intensi-
ties. In very deep areas, there are holes in the mat of vegetation because
plants are absent or their growth is reduced. As many fishermen know, large
gamefish often inhabit the edge of these holes. The deep areas also

11

offer a refuge for fish both in winter, when shalloxij water freezes solid, and

in sunuraer, when the water temperature in shallow areas can approach lethal levels,

In the summer of 1975, the Illinois State Water Survey measured sedi-
ment deposition in Lake DePue , a 500-acre bottomland lake along the Illinois
River in Bureau County. Their findings were as follows (Lee and Stall, 1976:11):

(1) From 1903 to 1975 the capacity of Lake DePue has been
reduced from 2837 ac-ft to 778 ac-ft, a 72.6% capacity loss.
In terms of annual deposition rate, the lake lost 28.6 ac-ft
or 1.01% per year.

(2) The change of lake volume is c'ue to the rising of the lake
bed. It was estimated that the annual rate is 0.57 inches per
year. The expected time to r<?ach the current normal lake level
is about 33 years.

The latter finding indicates that there will be no lake at all in 33 years.

As to the source of the sediment in the lake, Lee and Stall (1976: 29)

conclude that it comes from the suspended sedim.ent load carried by the

Illinois River. According to local residi^nts, the former depth of Lake

DePue was about 18 or 20 feet (Lee and Stall, 1976: 2) and annual speedboat

races and regattas were held there. The Last annua] speedboat race was in

1973, and the 1974 race was cancelled because the water was too shallow

(Sparks, 1975: 62).

Lake Meredosia, a lAOO-acre lake along the Illinois River in Morgan
and Cass Counties, has lost 46% of its capacity since 1903 (Lee, et al.,
1976: 7).

In the summer of 1976, a Natural History Survey crew attempted to
sample 7 additional bottomland lakes along the Illinois River. It was
impossible to float a canoe in more than about 1/3 of the surface area of
each of these lakes, due to extens;ive sediment deposits.

There is evidence that the rate of sedimentation in these lakes is
greater in recent times than it has been in the past. Figure 2 shows that

12

Figure 2

THE RATE OF SEDIMENTATION !N LAKE CHAUTAUQUA IN TWO PERIODS,
1926 ■ 1950 AND 1850 ■ 1976

+.10-,

2 3 4

DEPTH OF WATER IN FEET

15

In August 1974, dissolvecl cxygc" levels in Meredcsia Lake were 3 mg/1.
while oxygen levels in the river on the same date were 6 mg/l. The read-
ings were taken in the middle of the afternoon on an overcast day, and
waves produced by a strong v;ind were resuspending botton sediments in the
lake. In the lake, a die-off of gizzard shad was occurring, and almost all
the fingernail clams maintained in plastic cages on the bottom of the lake
had died since they had last been checked in mid-July.

Metals are known to accumulate in sediment. For example, Mathis and
Cummings (1973: 1580-1581) found that most metals in the Illinois River
occurred in sedim.ent at levels several orders of magnitude greater than
levels in water. Organisms which livec In the sediment, such as oligochaets
worms and clams, contained higher levels of the metals than organisms such
as fish. Since the chemical environment in the gut of a worm or at the
gill surface of a clam is different than it is in the sediment or water,
it is possible that m.etals and other toxicants can be mobilized from the
sediment and taken up by organisms which ingest sediment or live in contact
with sediment.

Sediment can serve as either a source or a sink for nutrients such as
phosphorus, depending upon conditions such as pH, temperature, oxidaticn-
reduction potential, and the amount present in water.

Ecosystem Effects

The plants and animals living together in a certain habitat form a
characteristic assemblage of species called an ecosystem^ and one dramatic
effect of excessive sediment can be to cause a shift froui one type of eco-
system to another. For example, sediment very likely contributed to the

13

at depths greater than 2 feet below an arbitrary reference point of A35 feet
above mean sea level (>fSL) , the rate of sedimentation in Lake Chautauqua has
been greater in the period 1950-1976, than in the p?.riod 1926-1950. For
example, at a depth of 5 feet, the 1926-1950 rate was . OA inches per year,
while the 1950-1976 rate was approximately .06 inches per year. It is
necessary to compare rates for the two periods at the same depth, because as
was mentioned earlier, the rate of sedimentation increases with depth.
The reason that there is a negative rate of sedimentation in v/ater depths
less than two feet is that shoreline and islands in these lakes have eroded
as a result of wave action. The wave action has probably been more severe
since the aquatic vegetation in these lakes disappeared in the 1950' s
(see Figure 1) .

Six other bottomland lakes along the Illinois River showed much the same
pattern as Lake Chautauqua: the rate of sedimentation has increased in recent
periods compared to older periods going as far back as 1903. While the navi-
gation dams installed on the Illinois River in the 1930' s have slowed the
current and increased sedimentation and while boats using the navigation
channel resuspend bottom sediments, the input of sediment to the river m.ay also
have increased in recent times, because sedimentation rates have increased
in lakes such as Chautauqua which are upstream from the influence of the
dams and which are connected with the river only during high water.

Backwater areas along the Minsissipi i River bordering Illinois are also
filling in noticeably, although the process seems to bs taking longer than it
has in the Illinois River, perhaps becau;;e the Mississippi is a much larger
river than the Illinois.

The loss of bottomland lakes along the Illinois and Mississippi Rivers
represents loss of the majority of natur.il lake habitats available in Illinois.

14

Tiie only natural lakes in Illinois are Lake I'iciiigan, the lakes in the glaci-
ated lands of northeasterr- Illinoj-?, and the bottonLLand lakes along the
Illinois and Mississippi Rivers.

Sedimentation rates for res irs in various parts of the state are
given in the suBmaj-y report of t1; . Soil Erocicn and Sedirnentation Subcommittee.
The rates range from 0.28 to 7.7 tons of reservoir sediment per year per acre
of watershed. The useful life span of these reservoirs, in terms of producing
fish and aquatic life, is shortened in proportion to the rate of sedimentation,
just as the useful life span for water supply is shortened.

Interactions Between Sediment and Other F.'.ctors

Ellis (1936) found that organic matter mixed with erosion silt created
an oxygen deuianu in water and that the oxygen demand \-;as maintained 10 tn 15
times as long as the oxygen demand created by the same amiount of organic ma-
terial mixed with sand. The ox>'gen demand can increase many-fold when sedi-
isent containing organic material and bacteria is re.suspended by waves or
currents (Butts, 197A; Baumgartner and Palotas, 1570). For example. Butts

(197A) found that under quiescent conditions the sediment ox^'gen dei^iand in

2
the Illinois River at miJe 198.8 in Peoriu Pool was 2.8 g/m /day, while the

2
demand was 20.7 g/m /day when the sediment v;as disturbed. At three sampling

stations in Meredosia Lake (mile 72-78) the sediment oxygen demand under

2
quiescent conditions ranged from 2.58 to A. 32 g/m'/dayj and frcmr 12^92 to

2
83.0 g/ffi /day under disturbed conditions (Personal Communication, 2 September

1975, Mr. Thomas A. Butts, Assoriare Professional Scientist. Illinois State

yatpr Survey. Peoria. Illinois). Trie oxygen demand exerted by sediment in

some teach.es of the river and '-r- poTr-c bot^omiand iakRS is grest -rrif'sjgh tn seriouslv

dimirijsh the oxygen supply' in the water.

In August 197^, dissolved oxygen levels in Meredosia Lake were 3 mg/1.
while oxygen levels in the river on the same date were 6 mg/l. The read-
ings were taken in the middle of the afternoon on an overcast day, and
waves pre ed by a strong wind were resuspending bcttcn sediments in the
lake. In .he lake, a die-off of gizzard shad was occurring, and almost all
the fingernail clams maintained in plastic cages on the bottom of the lake
had died since they had last been checked in mid- July.

Metals are known to accumulate in sediment. For example, "Mathis and
Cuinmlngs (1973: 1580-1581) found that most metals in the Illinois River
occurred in sediment at levels several orders of magnitude greater than
levels in v/ater. Organisms which livec' in the sediment, r :ch as ollgochaets
worms and clams, contained higher levels of the iretais than organistis such
as fish. Since the chemical environment in the gut of a worm or at the
gill surface of a clam is different than it is in the sediinent or water,
it is possible that metals and other toxicants can be mobilized from the
sediment and taken up by organi-sms which ingest sediment or live in contact
with sediment.

Sediinent can serve as either a source or a sink for nutrients such as
phosphorus, depending upon conditions such as pH, temperature, oxidation-
reductioa potential, and the amount present in water.

Ecosystem Effects

The plants and aninals living together in a certain habitat form a
characteristic assGiriblage of species called an ecosystem, and one dramatic
effect of excessive sediment can be to cause a shift from one type of eco-
sj^steiu to another. For example . sediment very likely contributed to the

16

shift in the numerous bottomland laker, along the Illinois River from clear,
vegetated waters with abundant gane fish populations to turbid, vegetation-
less waters dominated by species such as carp and buffalo (Sparks, 1975: 54-56)

The presence ot sediment brings about these changes in both direct and
indirect ways, some of which have been mentioned above, Th.e relationship
between sediment and an obser\'ed change in an ecosystem is often complex,
and some examples of these complex cause-and-ef f ect patterns will be discussed

As mentioned above, the reactive distance of predatory fish is reduced
by turbidity. In addition, populations of prey used by gamefish generally
decline in turbid water. For exaniple. Buck (1956a: 49) found that the ratio
of forage fishes (gizzard shad, minnows, and small sunfishes) to the predaceous
bass and crappie was approximately 1 to 1 in a muddy reservoii and 13 to i in
a clear reservoir. As a consequence, the growth of bass, crappies, and other
carnivorous species in the turbid reservoir -.as severely limited. The popu-
lations of plankton-feeding forage fish, such as gizzard shad, were limited
due to the low level of plankton production in the turbid reservoir (Buck.
1956a: 51).

Sediment can change the species com.position of a body of water by changing
the habitats the food supply, and bringint about differential rates of repro-
duction in different species. Foi example, the sunfishes, a family which in-
cludes largemouth bass, bluegill. and crappieS; lay their eggs in nests which
are constructed in shallow water. They prefer to construct nests en firm,
rather than soft substrates^ Buck (1 956a r 23) found that large-mouth bass and
sunfish produced young in new farm ponds with firm, unsllted bottoms^ but not
in older ponds with soft, silt-lacen bottoms. The sunfishes must be able to
see their TEatec re go through the reprodictivc act, which is mediated by visual

i?

cues. The males fan Lheir eggs to keep away sediment and supply oxygenated
water. The eggs can be sr-othered by excessive sedirient-. The guardian maJe
must also be able to see In order to keep av7ay suckers and rdnnows which eat
eggs.

Juvenile gamefish take refuge in plant beds and feed on the insects and
other "weed fauna" they find there. Older gamefish feed on forage fisli,
which in turn are dependent on the plankton, which is less abundant in
turbid waters than in clear water.

The end result of the complex interactions described above v?ere observed
by Buck \i956b) , who studied fish product Lon in fann ponds ^ hatchery ponds-,
and reservoirs in Oklahoma which had a wide range of turbidities. The farm
ponds were rotenoned, then restocked with largemouth bass and bluegllls or
largernouth bass and redear sunfish, A total of 12 farm ponds v;as divided into
3 turbidity classes. After two growing seascns, the cverage total weights of
fish were:

clear ponds (less than 25 JTU) i&i.5 jb/acre

intermediate ponds (25-100 JTU) 9A.0 lb/acre

touddy ponds (100 JTU) 29.3 lb/acre

"Tl. 1 J 1.1 -• T 1 fJ_U ».,«».^J..„.,^' ™«>-^ oK.-r^^ or.^^ 1. ctr,A rrr^l.! factor-
ill clear vater. Survival of bass was greater in internedlate poTid? than in

clear ponds, perhaps due to competition vlth abundant smifish populations in

the clear ponds. However, the surviving bass grew faster in clear ponds:

average average

weight length

clear ponds i'i.Ox 6.9 in.

intermediate ponds 7.1 x 5.1 in.

auddj pcads 2.5x 2,^ Ir.,

IS

The results from hatchery ponds, where turbidities were artificially con-
trolled, and from the reservoirs, generally paralleled the results from the
farm ponds.

In the turbid reservoir. Buck (1956b: 257) found an unusual preponderanc(

of old bass and a scarcity of young bass — this was very unusual for a new

reservoir:

For example, of 56 bass collected in 1954^ 64 percent were in their

sentative of all samplings. Ail evidence points to a small popu-
lation dominated by slow-growing-, older bass and with limited
recruitment through, natural reproduction. It seems doubtful that
the bass population will be able to sustain itself in the face of
increasing turbidities.

In contrast, young-of-the-year bass ware abundant in the clear
reservoir both years of the study. To illustrate, the population
of flngerling bass in a 10-acre cove roteuoned in 1955 was estimatec;
conservatively at 21,780.

Buck observed the same pattern in the other gamefish. In contrast,

catfish and rough fish were favored in the turbid waters (Buck, 1955b: 257):

Both channel catfish and flathead catfish are abundant in the
turbid reser\'cir. In the clear reservoir, only two adult channel
catfish and one adult flathead were taken. In the first year of
clear reservoirs, the bass, crappies, and other scaled species
apparently out-produce the catfish ^nd then limit them by predation
on their young. Turbid waters, on the other hand, offer young
catfish protection from these predators. Furthermore, catfish
can find food in turbid waters more easily than can species which
do not have so highly a developed sense of smell. As a result,
the bass and crappies lose ground. Even growth of the channel
catfish, however, was slower in the turbid reservoir than In less
turbid waters. Flathead catfish exhibited the most favorable
growth of any species studied in the turbid reservoir, reaching
an average length of 28.3 inches in their fourth year.

The combined weight of rough fish (carp, river carpsuckers^ and bullheads)
represented 42.4 percent of the population by weight in the turbid reservoir,
com.pared with 7.0 percent in the clear rt.'servoir.

Buck's (1956b: 260) final conclusion was: "The clear reservoir at-
tracted more anglers, yielded greater returns per unit of fishing effort:, es

19

well ns more desirable species, and was iirineasurably more appealing In the
aesthetic sense."

The same causal relationships and end i-er.ults Buck observed in the Okla-
homa ponds and reservoirs have occurred in Illinois. The bottomland lakes
along the Illinois River have changed from clear, vegetated waters which
supported an abundance of gamefish, commercial fish, and waterfowl, to turbid,
vegetation-less waters dominated by carp and buffalo. In socie cases the
lakes are so filleu with sediment the carp, buffalo, and gizzard shad do not
survive. The sediment not only fills the lakes, but also exerts an oxygen
demand v;hich depletes the dissolved oxygen required by fish and other aquatic
organisms.

At one time, special trains brought sport fishermen to to\«is, such as
Havana, along the Illinois River, and freight trains hauled £v;ay commercial
fish to Chicago and New "iork (Milis, et al. , 1966-. 14). Now, Dixon's fee
fishing area in Peoria imports carp from Wisconsin, the restaurants along
the Illinois River buy channel catfish from Arkansas, and the residents of
beach communities, such as Quiver Beach and Baldwin Beach, in Mason County , are
no longer able to swim. In the bottomland lakes or even to launch their boats
from their cottages in mid-summer.

Tabic 1
Reported Levels of Effect of Sediment and Turbidity on Aquatic Life

14-16

JTU

20 JTU

Biological Effect

Largemouth bass activity reduced and
social behavior of green sunfish altered.
Coughing and scraping increase.

Reactive distance of bluegill reduced by
50%, in comparison to reactive distance
in clear water.

Reference

Heimstra et al. ,
1969; 5-8.

Vinyard and O'Brien,

1 Q 7 £ . 0 0/7

30 JTU Reactive distance of bluegill reduced by
80%. Upper limit for effect on bluegill
react-ive distance.

Vinyard and O'Brien,
1976: 2S47

25-!

JTU

Su% reduction in net plankton^ comparec
clankton production in clear farm pond;
( 25 JTU).

'laffcv, 1955: 43

51-350
JTU

f;-i JTU

90% reduction in net Dlankton. compared

to plankton prod-,
ponds C 25 JTU)

in clear farm

Highest turbidity in which largemouth
bass were able to spawn.

Claffey, 1955: 43

Buck, iS56a:
19, 23-24

100 JTU Spawning success of redcar and bluegill Buck; 1956a;
severely restricted or completely 23-24

restricted above this level.

25-100 42% reduction in total weight of largemouth i
JTG bass, redear sunfish, and bluegills produced

in farm, ponds, relative to total production
in clear farm ponds. 49% reduction in aver-
age weight gain and 26% reduetion in average
length increase of young bass after two growing
seasons, in comparison co gains by bass in

I56b;

100 JTU 82% reduction in total weight of largemouth Buck, 1956b: 249
bass, redear sunfish, and bluegills produced
in farm ponds, relative to total production
in clear farm ponds, 82% reduction in average
weight gain and 65% reduction in average length
increase of young baf.s after two growing seasons,
xii COuipaixsOu to gains by \>czg ir. c3 53.r ponds.

Table ] (continued)
Reported Levels of Effect of Sediment and Turbidity on Aquatic Life

Level Biological Effect Reference

An increase 26% increase in raacroin/ertebrate drift. Gaumion, 1970 :

in suspended 68,96

sediment

(iimestone

duet) from 9.7

to 28. 3 uig/1

An increase 90% increase in macroinvertebraLe drift. Gammon, 1970:

in suspended 68, 96

sediment

(limestone

dust) froir. 20.3

to 125.0 mg/1

38,250 JTU Lethal to rock bass. Wallen, 1951: 18

85,000 JTU Lethal to channel catfi;;h. Vsllen, 1951; 18

101,000 JTU Lethal to largemouth bass. Vallen, 1951: 18

Literature uited

Baumgartner , D.J., and G. Palotas. 1970. The oxygen uptake demand of

resuspended bottoui sediments. U.S. Environrriental Protection Agency,
Water Pollution Control Research Series 16070 DCD 09/70. U.S.
Governr.ent Printing Office. Washington, D.C.

Bennett, G.W. , D.H. Thoir.pson, and S.A. Parr. 19A0. A second year of
fisheries investigations at Fork Lake, 1939. Illinois Natural
History Survey Biological Notes No. U. Urbana, Illinois. 24 p.

Buck, D.H. 1956a. Effects of turbidity on fish and fishing. Oklahoma

Fisheries Research Laboratory Report No. 56. Norman, Oklahoma. 62 p.

. i956b. Effects of turbidity on fish and fishing. Transactions

of the T\-7enty-First North Ajnerican Wildlife Conference. Wildlife
Managenient Institute. Washington, D,C, pp. 2A9-26i.

Butts, T.A. 1974. Measurements of sediment oxygen demand characteristics
of the Upper Illinois Water^-.'ay. Report of Investigation 76. Illinois
State Water Survey. Urbana, Illinois. 32 p.

Ciaffey, F.J. 1955. The productivity of Oklahoria waters with special
reference to relationships betv?eeri turbidities from soil, light
penetration, and the populations of plankton. Thesis. Oklahoma
A and M College. 102 p.

Ellis, M.M. 1936. Erosion silt as a factor in aquatic environments.
Ecology 17: 29-42.

Gammon, J.R. 1970. The effect of inorganic sediment on stream biotti.

U.S. Environmental Protection Agency, Water Pollution Control Research
Series 18050 DWG 12/70. U.S. Government Printing Office. Washington.
D.C. 141 p.

Heimstra, N.W. , D.K. Damkot, and N.G. Benson. 1969. Some effects of silt
turbidity on behavior of juvenile largemouth bass and green sunfish.
Technical Papers of the Bureau of Sport Fisheries and Wildlife No. 20.
U.S. Department of the Interior, Fish and Wildlife Service. Washington,
D.C. 9 p.

Jackson, H.O,, and W.C. Starrett, 1939, Turbidity and sedimentation at

Lake Chautauqua. Illinois. Journal of Wildlife !Ianagement 23: 157-168.

Lee, M.T. 1975. Sediment deposition of Lake Chautauqua^ Havana, Illinois.
Illinois State Water Survey. Urbana, Illinois. 9 p.

, and J.B. Stall. 1976. Sediment deposition in Lake DePue, DePue,

Illinois and its implications tor future lake management. Illiuuj
State Water Survey. Urbana, Illinois. 31 p.

, 2nd T=A- Butts. 1976. Tha 1975 sediraent survey of

Lake Mereaosia, .'eredosia, liiinois. liiincit; State V/Hter :iur'.'ey.
Urbana, Illinoi- . 23 p.

Mathis, B.M. , and T.F. Cuinmings. 1973. Selected metals in sediments,
vater, aad biot.- in the lilincis River. journal Water Pollution
Control Federation 45(7): 1573-1583.

Mills, H.B., W.C. Starrett, and F.C, Eellrose. 1966, Man's effect on
the fish and vjilalife of tlie Illinois River. Illinois Natural
History Survey ^riological Notes No. 57. Urbajia, Illinois. 2A p.

Richardson, R.E. 1921. The small bottom and shore fauna of r.he middle
and lov;er Illinois River and its connecting lakes, Chlllicothe to
Grafton: it? v.-Aluation; its sources of food supply; and its
relation to the fishery. Illinois State Natural History Survey
Bulletin 13(15) • 363-522.

Smith, P.W. 1971. Illinois streams: a classification based on their
fishes and an analysis of factors responsible for disappearance of
native species. Illinois Natural History Survey Biological Notes
No. 76. Urbana^ Illinois. 14 p.

Gparkij. R.E. 1S75. Environrnental inventory and assesf^iaent of navigation
pools 2^, 25, and 26, upper Mississippi and lower Illinois Rivers:
An electrof ishing -survey of the Illinois River. U.S. Army Engineer
Waterways rxperi^.ent Snaticn, Fnviron:nentaj Effects Laboratory.
Vicksburg, Mississippi. 121 p.

Stall, J.B.s and S=W, MeJsted, 1951. The silting of Lake Chautauqua,

Havana. Illinois. Report of Investigation 8, Illinois State Water
Survey, in cooperation with Illinois Agricultural Experiment
Station. Urbana, Illinois 15 p.

Starrett, V.C. 1971. k survey of the m.ussels (Uninnacea) of the Illinois
River: a polluted stream. Illinois Natural History Survey Bulletin
30: 267-^03.

Vinyard, G.L. , and W.J. O'Brien. 1976. Effects of light and turbidity

on the reactive distance of bluegill (Lepomis macro c h irus) . Journal
of the Fisheries Research Board of Canada 33: 2845-28/^9.'

Wallen, E.I. 1951. The direct effect of turbidity on fishes. Bulletin
Oklahoma Agricultural and Mechanical College. Series 2, Ko. •^8.
26 p.

'MUs

GLOSSARY

Effects of SedimenC on Aquatic Life

Prepared by

Richard E. Sparks

January A, 1977

The plants and animals living on the bottom of a stream or lake,

FTU. Formazine turbidity units. Turbidity as determined in a nephelometer

which has been calibrated with a suspension of formazine as a turbidity
standard. Formazine is formed by reacting hydrazine sulfate and hexa-
methylcnc tetramine under carefully controlled conditions (Chevalier,
1959: 132-133).

Jackson candle turbidimeter. A turbidimeter which measures "the depth of a
column of water sample that is just sufficient to extinguish the image
of a burning standard candle observed vertically through the sample."
Results are expressed as Jackson turbidity units (JTU) (American Society
for Testing and Materials, 1973: 232).

JTU. Jackson turbidity units.

Nephelometer. A turbidimeter which measures "the light-scattering charac-
teristics (Tyndall effect) of the particulate matter in the sample.
. . . The measurement of nephelometric turbidity is accomplished by
measuring the intensity of scattered light at 90 deg to the incident
beam of light. Numerical values are obtained by comparison with the
light-scattering characteristics of a known or an arbitrarily chosen
material in an equivalent optical system. Comparison may also be made
between transmitted light effect and scattered light effect." The
results from a nephelometer are sometimes expressed as nephelometric
turbidity units (NTU) (American Society for Testing and Materials, 1973:
232).

NTU. Nephelometric turbidity units.

Particulate matter. Same as suspended matter and total suspended solids.

The amount of material in suspension, determined by measuring the weight
gain of a filter after a known volume or weight of the water sample
has passed through it.

Photosynthetic zone. Same as euphotic zone. The depth of water in which

there is enough light for photosynthesis to exceed respiration (Odum,
1971: 14). In general, this zone extends down to the depth where
the light intensity is 1 percent of full sunlight intensity (Odum,
1971: 301).

Sparks Glossary paf

^ Phytoplankton. Microscopic, drifting aquatic plants, mostly algae.

Resuspended sediment. Sediment which is stirred up from the bottom by

water currents, wave action, boat traffic, or by the rooting activities
of fish such as carp.

Secchi disk. A circular metal plate, 20 cm in diameter, the upper surface
of which is divided into four equal quadrants and so pointed that the
two quadrants directly opposite each other are black and the inter-
vening ones white. The disk is used to measure the limit of visibility
in water by lowering it into the water on a graduated line, and noting
the depth at which it disappears (Welch, 1948: 159). Secchi disk
transparency represents the zone of light penetration down to about
5 percent of the solar radiation reaching the surface and marks the
lower limit of the major photosynthetic zone (Odum, 1971: 297).

Sediment. Solid, particulate material which is deposited by water.

Submergent vegetation. Large free-floating or rooted aquatic plants which
are entirely submerged in the water, such as coontail, or which have
leaves at the surface of the water, such as lotus. In contrast,
emergent vegetation refers to plants such as cattail, which can grow
in shallow water, but which have leaves above the water.

Suspended sediment. Sediment which is carried in the water column.

Turbidimeter. A device for measuring turbidity.

Turbidity. "Turbidity in water is caused by the presence of suspended matter,
such as clay, silt, finely divided organic and inorganic matter, plank-
ton, and other microscopic organisms. Turbidity is an expression of
the optical property that causes light to be scattered and absorbed
rather than transmitted in straight lines through /a/ sample /of watery.
Attempts to correlate turbidity with the weight concentration of sus-
pended matter are impractical because the size, shape, and refractive
index of the particulate materials are important optically but bear
little direct relationship to the concentration and specific gravity
of the suspended matter." (Rand, 1976: 131.)

Zooplankton. Microscopic, drifting aquatic animals.

Sparks Glossary page 3

Literature Cited

American Society for Testing and Materials. 1973. 1973 Annual book of
ASTM standards, part 23, water, atmospheric analysis. American
Society for Testing and Materials, Philadelphia, Pennsylvania. 1108 p.

Chevalier, P. 1959. Formazine standard for turbidity. Brasserie 152: 132-133.

Odum, Eugene P. 1971. Fundamentals of ecology. Third edition. W.B. Saunders
Co., Philadelphia, Pennsylvania. 57A p.

Rand, M.C., Arnold E. Greenberg, and Michael J. Taras, editors. 1976.
Standard methods for the examination of water and wastewater.
Fourteenth edition, /jnerican Public Health Association, Washington,
D.C. 1193 p.

Welch, Paul S. 1948. Limnological methods. McGraw-Hill Book Co., New York.
381 p.