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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

  • 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

  • Good way to supply habitat for fish
  • Main uses of a farm pond are:
  • Livestock watering
  • Irrigation
  • Fish production
  • Wildlife
  • Recreation
  • Fire protection
  • USDA says that the ideal size for a family farm pond is less than two acres.

Management of the Farm Pond

  • 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

  • Embankment Ponds
  • Water is held of impounded by an embankment or dam across a watercourse
  • Excavated Ponds
  • Made by digging a pit below surrounding ground level
  • Built primarily in nearly level areas

Factors in Pond Selection and Maintenance

  • Watershed
  • Should be surrounded by a permanent vegetation buffer strip
  • 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
  • Pond Basin
  • The area to be flooded
  • Cover crops should be planted before it is flooded
  • Pond Banks
  • Should be protected from washing rain

Pond Development

  • Many ponds are developed for wildlife, recreation, and fish production
  • Trees and shrubs should be planted around the pond to act
  • Safety equipment should be present for the recreational activities of fishing, boating, and swimming
  • Stock pond with the right kind and numbers of fish

Pond for Production

  • Ponds can be used as a production site if properly managed
  • It is very important to

Fisheries Management

  • Management is necessary to ensure survival of the pond or reservoir for long periods of time.

Management Procedures

  • 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
  • Controlling Aquatic Plant Population
  • Watershed improvement
  • 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
  • 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.
  • 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
  • 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
  • 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

  • Good quality water is
  • Fish grow best if the temperature is
  • Oxygen must be in the water for fish to survive
  • The pH of water is best for fish
  • Must keep muddy water under control as well
  • Fish are stunted if they grow in water with a bad siltation problem

23.02 – Differentiate among freshwater fish common to NC.

  • Common Freshwater Fish
  • Black Crappie
  • Also called
  • Most common fish for fishing in NC
  • Irregularly space on their silver-green to yellowish sides
  • Can grow to 15 inches and 3 pounds
  • Young are called fry
  • 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
  • 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
  • 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.
  • 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
  • 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
  • Classified by many methods
  • Most common is by depth and light penetration
  • 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
  • Concentration of salts in the ocean water
  • 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 the sign – 0/oo
  • Range is from 330/oo to 380/00 which is equal to 3.3%to 3.8%
  • Physical Characteristics – Temperature Density
  • Temperatures change depending on the different latitudes and depths of the ocean
  • The density of the ocean increases as the pressure and depth increase.
  • Water Movements
  • 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
  • Tides
  • Specialized waves caused by the gravitational attraction of the sun and moon on the earth.
  • 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
  • Estuarine Ecosystem
  • 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
  • Life in the Estuary
  • Economically important to marine fisheries
  • by American fishers either comes from or passes through the estuarine ecosystem
  • 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.

  • 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
  • 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.