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The study of fish habitat preference is an important
element to understanding their distribution and populations within
a body of water. Population structure of fish species in Candler
Lake a small shallow lake was studied to detect a correlation between
each species and type of habitat. Abundance of fish was measured
at different points in order to find a correlation between number
of fish and one of the five parameters (dissolved oxygen conductivity
pH photic zone and depth). We expected that a correlation would
exist between one of the parameters and density of fish. Several
species of fish were caught along the banks of Candler Lake categorized
by sex and size and released at the location of capture. Global
Positioning System (GPS) readings were recorded at the location
of each capture. The five parameters were measured in several transects
across the lake and at the location of each measurement a GPS reading
was recorded. Eleven different species were found in the lake and
bluegill sunfish (Lepomis macrochirus) was the most abundant species.
The highest densities of L. macrochirus were concentrated
around areas of moderate depth. The population of L. macrochirus
in Candler Lake is composed mainly of juvenile fish most in the
4-6cm size range. The size ratio of adult female to male L. macrochirus
was not significantly different. The majority of adult fish both
male and female ranged between 8-10cm. The habitat that the lake
provides is ideal for most species of sunfish (Centrarchidae). Most
Centrarchidae prefer standing to slow moving water and also prefer
to spawn in shallow waters. Because the sunfish were spawning during
the study most were found near the bank in moderate depth near surface
structure such as trees that provide shade and keep the water temperature
at a tolerable level. Sunfish spawn several times from spring through
fall thus creating the large juvenile population we found.
Habitat is an important element to the success of
fish populations within a body of water. Different types of habitat
are necessary for the completion of life cycles of many fish species.
They provide a place to hunt for prey hide from predators spawn
and retreat from extreme temperatures. The amount of habitat that
a body of water provides can dictate the size of a fish population
as well as their distributions. Furthermore by finding the habitat
preference of a fish species it may be possible to predict a where
some species are present and how they may be distributed. This information
can be very helpful in the management of aquatic life (Argent et
al.2003). Bluegill sunfish (Lepomis macrochirus) are among the most
successful fish species in the U.S. These fish spawn several times
from spring to fall thus creating a large population. During spawning
time bluegill sunfish are concentrated into a few spawning sites
in a small area. Here the fish build nests on the ground were eggs
and sperm are deposited. Several females may deposit eggs in one
nest that is safeguarded by one male. Females may lay up to 80 000
eggs per season (Brunson and Morris 2000). Due to the success and
nature of bluegill sunfish spawning habits where present this species
can easily thrive.
The lake was sampled along the banks for all types of fish species.
Rod & reel cast net minnow traps and fish traps were used for
capturing fish. Fish were measured and marked Global Positioning
System (GPS) reading was recorded for each location of capture.
pH conductivity dissolved oxygen depth and photic zone were measured
in several transects across the lake. Data were used to create a
series of maps using Global Information System (GIS). Maps were
analyzed to find a correlation between the distribution of fish
and one of the five parameters.
Eleven different species were caught. Certain areas of the lake
showed greater species diversity than other areas. Bluegill sunfish
(Lepomis macrochirus) was the most abundant species. Higher
densities of bluegill existed in areas of moderate depth. Areas
of high density were mostly spawning sites Population structure
of bluegill sunfish was mainly composed of juveniles. Average size
of juveniles was between 4-6cm. Average size of adult bluegill sunfish
was between 8-10cm.
There is a high diversity of fish species due to large number of
habitat types in the lake. Most bluegill sunfish were found at moderate
depths because they prefer the more shallow waters for spawning.
High numbers of juvenile bluegill sunfish may be a result of multiple
spawning during a season. Data from the study will be added to the
Lullwater Management Plan and be used to manage aquatic systems
of Lullwater.
We thank Dr. Steve Baker for assistance in identifying fish, Dr.
Cathy Quinones for providing the opportunity to perform this project,
the Chaces for providing the canoe that was used during the project,
and Colleen M. Gault and Dan K. Schwarz for assistance in setting
and checking traps.
My research is on fish habitat and population. I wanted
to find out where in this small lake called Candler Lake did certain
fish species prefer to live. I also wanted to find out what type
of species exist in the lake and how large is their population.
My original project was to catch and mark fish in order to track
their movements through out the summer however that project was
not successful. What I did to catch the fish was use rod and reel
cast net minnow traps turtle traps and fish traps. At the location
of each capture I would measure the fish and record a Global Positioning
System reading. Then I would release the fish at the location of
capture. Later in the summer we measured the lake for pH conductivity
photic zone and depth. We found that the most abundant species in
the lake was the bluegill sunfish it's scientific name is Lepomis
Maculatus. Ten other species were caught and identified but
were not caught in the same abundance as the bluegill. A series
of maps were created using a Global Information System. The data
for bluegill was color coded to show higher densities at different
points on the lake. Then it was matched up with one of the abiotic
parameters. After analizing the maps we found a correlation between
bluegill density and depth. We found that higher densities of bluegill
were found at relatively shallow depths. This was explained due
to the fact that they were spawning and they prefer to spawn at
more shallow depths.
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