SREL Reprint #0465
Body Condition and Stomach Contents of Fish Inhabiting
Thermally Altered Areas
R.
E. Lattimore and J. W. Gibbons
Abstract
Body condition and stomach contents in three species
of sunfish (Centrarchidae) were compared in natural and thermally
influenced streams in South Carolina. The thermal stream was divided for sampling purposes into
four zones variously affected by the heated water.
Individuals of each species collected from the normal temperature
adjacent to the heated water had higher condition factors than those from any
other area. Also, the largest
individuals collected in the thermal stream were from the area of high
temperatures. Large body size may
allow tolerance to sudden changes in water temperature. Although higher percentages of the fish from the natural
stream had food in their stomachs, their diet was more herbivorous than that of
thermal stream.
With the increased usage of power reactors in the
United States, studies of thermal loading and its effect on aquatic organisms
have become very important. Although
many studies have been conducted in lake or river environments (Gibbons and
Sharitz, 1974a,b), few, if any, studies have examined the biological changes
associated with stream ecosystems which intersect with reactor effluents having
temperatures lethal for most aquatic organisms. These systems provide a unique opportunity to examine plant
or animal populations which are confronted with a spectrum of thermal conditions
ranging from natural to abnormally hot.
Respiration rate in aquatic animals increases as water temperatures are
elevated, so that a high metabolic rate could result in poor body condition if
food is limiting. Bennett and
Gibbons (1972) found that bass near the “hot dam” of Par Pond, a reservoir
receiving thermal effluent, contained less food in their stomachs then those at
the “cold dam”. They conducted
that this may reflect an increase in the rate of digestion at high temperatures.
Graham (1974) reported that the fish from the cool end of Lake Julian,
N.C., showed considerable difference in external physical conditions from
emaciated sunfish taken from a cove receiving thermal effluent.
Zhiteneva (1971) found that young bream inhabiting the warm water zone of
Konskova power station in Russia where characterized by a lower relative body
depth than those from other areas of the same reservoir.
These and other studies suggest that water temperature may serve as a
controlling factor by affecting metabolic rates and consequently influencing the
body condition of fish.
The objective of this study was to compare
differences in body condition and stomach contents of fish in stream areas which
are variously affected by heated effluent. Three species of sunfish (Centrarchidae) were used in
this study: spotted sunfish (Lepomis
punctatus), redbreast sunfish (L. auritus) and blue-spotted
sunfish (Enneacanthus gloriosus).
SREL Reprint #0465
Lattimore, R.E. and J.W. Gibbons. 1976. Body condition
and stomach contents of fish inhabiting thermally altered areas.
The American Midland Naturalist 95:215-219.
