RNR 1001 Chapter : Fisheries And Marine Habitat
Document Summary
Lentic systems (still water systems) provide several distinct habitats that can be important for fisheries production. These habitats often have different structural complexity, water quality, and biota. Thermocline - where there is a significant drop in temperature in a body of water depth-wise. Thermocline formation is related to the annual mixing cycle - critical to lentic fisheries. The annual cycle depends on water temperature (and density) and wind velocity. Lake temp during winter is 4-6 degrees c with a layer of ice at top. Spring overturn comes, ice melts, and the wind mixes around water (that is all same density). Summer stratification happens, wind stops blowing as much and the sun warms up the top layer of water leaving colder water at bottom creating a thermocline (stratified). Develop hypoxia (low oxygen; less than 2 mg/l). Fall overturn, wind blows mixing water then water becomes colder and colder until it"s winter again.
