Fisheries exam 2

Fishing Gear

  • Passive gear

    • Entaglement

      • Gill nets: Nets that are established at the bottom or midwater and trap fish by tangling them or gilling them

        • Drift nets

          • Target:fast moving fish

          • Deployment: fished subsurface to midwater in open ocean

        • Target fish: schooling fish

        • Size of nets: are based on what type of fish they want so the girth of the fish

    • Entrapment:

      • Pot and trap: Many pots are deployed at the bottom of the sea and have small opening for fish

        • Target: bottom dwelling fish

        • Are collapsible and small and use bait

      • Hoop net: Are a series of funnels that lure fish into

        • Target fish: Fish that move around especially to the gear

        • Deployment: In shallow water like streans

    • Longlining: The hanging of a bunch of lines and hooks

      • Target: species seeking food

    • Advantage: 

      • Are simple in design and construction

      • Can be used w/o big machinery

    • Disadvantage:

      • Fish can only be caught if they get caught in it themselves

  • Active Gear: When gear is actively used to catch fish

    • Trawling: When they use a net that is dragged along the bottom or through a water column to catch fish by straining them through the water

      • Bottom trawl: bottom dwelling fish

      • Midwater trawl: Midwater fish

    • Trolling: when boats hang lines and lures from the boats to try and cath them

      • Oceans or lakes, but mostly in deeper water

      • Targer: fast moving fish

    • Purse Senie: When 2 boats encircle a school of fish and wraps around them and as they raise the net the bottom closes trapping the fish

      • Target fish: schooling fish

    • Hook and line 

      • Fly fishing

      • Reeling

    • Spearing:

      • Spearing a fish

      • Close range and marine

      • Target: large fish

Temperature

  • Cold blooded

    • Internal temp is .001-.3 C warmer to the water

  • Many fish use temp to guide them during their movements in large water bodies

  • Eurythermal: Ability to withstand broad temp 

  • Stenothermal: Ability to withstand a narrow range of temps

  • Thermocline: A layer that marks a sharp change in temperature