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Science & Technology in the Environment
Obj 23.00 Freshwater Fishery Management
Obj23.01 – Discuss the lake habitat to include basic fishery management techniques
The Lake Habitat
o Lakes are divided into three zones based on the depth of the lake.

zone
 Shallow zone that has rooted vegetation, such as pond lilies and cattails
 Starts at shorelines and extends to where rooted vegetation ends
 Photosynthesis takes place on the lake floor because light penetrates the
water.
 Limnetic Zone
 No rooted vegetation

, giving off
oxygen in the area

Zone
 Bottom zone of the lake
 No photosynthesis takes place
 Warmest in winter, coolest in the summer
Farm Ponds
o Good way to supply habitat for fish
o Main uses of a farm pond are:
 Livestock watering
 Irrigation
 Fish production
 Wildlife
 Recreation
 Fire protection
o USDA says that the ideal size for a family farm pond is less than two acres.
Management of the Farm Pond
o Management techniques depend on whether a new pond is being built or an old one is
being renovated
 Built or new
 concerned with care and development
 Existing or old
 concerned with correcting existing problems
Types of Artificial Ponds
o Embankment Ponds
 Water is held of impounded by an embankment or dam across a watercourse

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o Excavated Ponds
 Made by digging a pit below surrounding ground level
 Built primarily in nearly level areas
Factors in Pond Selection and Maintenance
o Watershed

 Should be surrounded by a permanent vegetation buffer strip
o Dam and Spillway
 Should be covered with a fast growing grass
 No trees or shrubs should be planted on dams because roots can weaken it.
 Spillway should be three feet or more below the top of the dam and have
vegetation growing on it
o Pond Basin
 The area to be flooded
 Cover crops should be planted before it is flooded
o Pond Banks
 Should be protected from washing rain
Pond Development
o Many ponds are developed for wildlife, recreation, and fish production
o Trees and shrubs should be planted around the pond to act
o Safety equipment should be present for the recreational activities of fishing, boating,
and swimming
o Stock pond with the right kind and numbers of fish
Pond for Production
o Ponds can be used as a production site if properly managed
o It is very important to
Fisheries Management
o Management is necessary to ensure survival of the pond or reservoir for long periods of
time.
Management Procedures
o Vegetation Control
 Important to any pond, lake or reservoir
 Provides food, shelter, oxygen, and spawning and nesting habitat
 Cools surface water and stabilizes bottom sediments
 Excessive vegetation can harm fish and inhibit recreation
o Controlling Aquatic Plant Population
 Watershed improvement
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 Keep soil and nutrients on the land and out of the water
Water level management
 Involves changing the level of the water to expose plants to adverse
conditions
 Biological control
 Using some other living organism, either plant or animal, to control
aquatic plants
 Chemical Controls
 Using herbicides on weed-infested waters
o Fish Sampling
 Need to keep track of what species are in the water and how well they are
growing
 Methods include nets, spot poisoning, boat shocker, and angling.
o Population Removal and Adjustment
 Ponds can become overpopulated with undesirable species, such as suckers,
shad, and crappies
 One method of population removal is to
(not
recommended for reservoirs) and trap all the fish in nets, keep the desired fish
to restock and destroy the undesirable fish
 Another method is
o Fertilization Techniques
 Fertilizing ponds to increase fish production is more common in Southern States
 Annual fertilization program consists of applying eight to ten treatments of a
commercial fertilizer
 Causes an increased production of plankton which is a food for fish
 Can cause problems, like the

o Fishing Regulations
 Regulations exist controlling the fish taken from public waters
 Normally based on the size of the fish taken
 Can also be based on the number of fish taken
 The idea is to provide the ideal environment for the fish
Water Quality
o Good quality water is
o Fish grow best if the temperature is
o Oxygen must be in the water for fish to survive
o The pH of water is best for fish
o Must keep muddy water under control as well
o Fish are stunted if they grow in water with a bad siltation problem
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23.02 – Differentiate among freshwater fish common to NC.
 Common Freshwater Fish
o Black Crappie
 Also called
 Most common fish for fishing in NC
 Irregularly space
sides
 Can grow to 15 inches and 3 pounds
 Young are called fry
on their silver-green to yellowish
o Bluegill
 Native to NC
 Have a hand or
 Lower jaw and gill cover are powder blue

 Have a black earflap
 Very sought-after game fish
 3-5 inches average length
 2-4 ounces average weight
o Brook Trout
 Only trout native to NC
 Small, ranging in size up to 8 inches
 Back and upper sides of body are olive green with mottled dark green wavy
marking
 Most common in
o Large-Mouth Bass
 Most sought after freshwater fish in the US

 Abundant throughout NC
 Can reach 7-15 pounds
 Exciting to catch due to their fighting nature
 Native to NC
 Lays 2000 plus eggs when spawning, the same as many fish species.
o Rainbow Trout
 Known for their fighting abilities
 Broad ink or bright red lateral band extending along the sides from gill cover to
tail

 Smaller than 10 inches
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o Small mouth Bass
 Sporting fish due to their fighting and leaping abilities
 Founds in streams in mountain and foot hills
 Usually 10 to 20 inches long and weight 1-4lbs
24.01 – Describe the characteristics of the ocean and estuarine ecosystems.
 Physical Characteristics - Zonation
o Classified by many methods
o Most common is by depth and light penetration
o Five Zones
 Supratidal – above water level, above high tide and below vegetation line
 Intertidal – area between low tide and high tide
 Neritic –starts at waterline, depth and width can vary, stops at the end of the
continental shelf
 Bathyal – Contains continental slope
 Abyssal – very deep parts, considered the ocean deep zone
 Physical Characteristics – Salinity
o Concentration of salts in the ocean water
o
o Defined as the number of grams of dissolved salt in 1,000 grams of sea water
Symbol for salinity resembles a percent sign with an additional loop on the bottom of
o
the sign – 0/oo
o Range is from 330/oo to 380/00 which is equal to 3.3%to 3.8%

Physical Characteristics – Temperature Density
o Temperatures change depending on the different latitudes and depths of the ocean
o The density of the ocean increases as the pressure and depth increase.

Water Movements
o Waves
 Wind generated – are either sea, swell, or surf; most common ocean wave
 Internal – underwater wave created by temperature changes
 Catastrophic – tidal wave is an example
 Stationary – bays and calmer waters; the surface is moving up and down
o Tides
 Specialized waves caused by the gravitational attraction of the sun and moon on
the earth.
o Current
 Surface currents are caused by wind
 Turbidity currents – caused by earthquakes or hurricanes
 Bottom currents – in deep water, responsible for moving sediments on the
ocean floor
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
Estuarine Ecosystem
o Characteristics
 Estuary –
 Shallow and turbulent, which results in high amounts of dissolved oxygen in the
water
 Tides cause the area to be nutrient rich

because of the high amount
of oxygen, which causes rapid decomposition of organic wastes
o Life in the Estuary
 Economically important to marine fisheries

by
American fishers either comes from or passes through the estuarine ecosystem
o Three areas
 Species that travel only a limited distance in the estuary
 Species found in both the estuary and in other parts of the ocean
 Species whose entire life cycles are in the estuary.
Obj 24.02 – Discuss ocean cultivation as related to regulation and laws.
o Ocean Laws and Regulations
 Great deal of debate and dispute
 Many groups formed to regulate the resources of the ocean
 United Nations “Law of the Sea”
 Formed in November of 1994
 US is a party to it, but as of May 2000, had not ratified it
 Provisions of the law are:
 Coastal states have sovereign rights in
with respect to
natural resources.
 Coastal states have sovereign rights over the continental shelf, which can
extend at least
from the
shore or more
 Controlled by the United Nations
o World Fisheries Production
 Between 1988 and 1998, the world marine fisheries catch has varied somewhat,
but 1998 was less than 1988
 Aquaculture production has more than
in the decade from
1988 to 1998
 Over the last 20 years, world fishery products have remained relatively the
same.