Harvesting Gear Trawl

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Harvesting Gear - Trawl

• Trawl Probably from Latin tragula - to Drag
• Modern To Fish by Pulling a Net Through Water
• Alaska Otter Trawl, Beam Trawl, Factory Trawl
• Pelagic Otter Trawl - does not Contact Bottom
• Bottom Otter Trawl - in Contact with Bottom

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Otter Trawl Anatomy I

• 1. Trawl is Hauled on Board by 2 Winches
• Ship Left - Port, Ship Right - Starboard
• 2. Winches Pay-Out and Retrieve Stout Wire Rope
• Winches Bolted to Deck Forward
• Winch Size Scales with Boat Size
• Wire Rope (Warps) Scales with Net Size
• 3. Warps Attach to Trawl Doors Near Center

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Otter Trawl Anatomy II

• Door Shape Size Change with Nets Species
• Door Function
• Keep Mouth of Net Open - Doors Lateral Pull
• Allowing Fine Control Over Net Position
• Impose Considerable Drag on Forward Motion
• Not Fishing - Doors Held on Board
• Net Mouth
• Top - Hard Plastic Floats Hold It Open
• Bottom - Foot Rope, Bobbins Tickler Chain

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Otter Trawl Door
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Otter Bottom Trawl - The Net
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Otter Trawl Net

• 1. Think of Mouth as Rectangle
• L Corners to Top Bottom Left Door
• R Corners to T B Right Door
• 2. Floats to Hold Top of Net Body Up
• 3. Heavier Rope Sewn Circularly
• Helps Support Full Net
• 4. Back End of Net - Cod End or Bag
• Opened Closed with Cinch
• 5. Bottom of Net Often Protected - Chafing Gear

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Otter Trawl Chafing Gear
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Otter Trawl Bottom Fishing
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Otter Trawl Fishing

• 1. Net Flies through Water Due to Doors
• 2. Used for Pelagic Fish like Pollock
• Pelagic Nets, Doors, Light Weight Bobbins
• 3. Used for Benthic Trawls like Flatfish
• Benthic Nets Doors, Rock Hopper Gear
• 4. Used in Benthic Pelagic Shrimp Trawls
• Shrimp Nets - Often Double Haul, 2 Nets

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Beam Trawl Nets

• 1. Warps Attached to Solid Beam
• Beam Weight Brings Net Down
• Beam keeps Net Mouth Open
• 2. Beam Has Shoes to Ride on Bottom
• 3. Generally Much Smaller than Otter Trawl
• 4. Often Used for Shrimp Trawling -
• SE Alaska Shrimp Harvesting

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Beam Trawl
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Beam Trawl II
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Trawl - Scallop Dredging

• 1. Scallop Dredge Trawled Behind Scallop Boat
• 2. Dredge Hard on Bottom - Digs Into Substratum
• 3. Large Mesh Allows Escape Except Big Scallops
• Rocks Sometimes Captured Can Damage Scallops
• 4. Hydraulic Dredge used for Infaunal Species
• No Hydraulic Dredging in Alaska
• Cause Serious Deep Disruption of Bottom

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Scallop Dredge
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Longline

• 1. Halibut and Blackcod Fisheries
• 2. Stuck Gear vs. Snap-on Gear
• a. Groundline (GL) - ? - ½ inch Sinking Line
• b. Stuck Gear - Gagnions Spliced into GL
• c. Snap-on Gear - Gagnions Clipped to GL
• 3. Stuck Gear Groundline in 300 fthm Skates
• 4. Snap-on Groundline on Winch

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Longline II

• 1. Gagnions Act Like Leaders in Sports Fishing
• a. One End Attached to Groundline
• b. Other End Attached to Circle Hook
• 2. Gagnions Stiff Heavy Nylon Cord
• a. Depending on Species 6 Long
• b. Depending on Species, 12 Apart on GL
• 3. Anchors, Buoys, Flag w/ Radar Reflector

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Longline Set (Halibut)

• 1. Anchor, Buoy, Flag Over. GPS Location Mark
• 2. GL Tied to Anchor, Runs Through Baiter
• Circle Hooks Self Bait as Running Out
• 3. Next Skate Tied to First - 3 Skates Per Set
• 4. At End Anchor, Buoy, Flag, GPS Marked

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Longlining
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Longline Fishing

• 1. Put Out Numerous Sets - Wait 12 Hrs Pick
• 2. Picking Set
• a. Find Flag Buoy
• b. Retrieve Line - Anchor - GL on Winch
• 3. Fish Self Hooked on Circle Hooks Gaffed
• 4. Fish Brought Aboard, Gills Viscera Removed
• 5. Ice Cavity and Fish

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Longline Fishing

• 1. Longline Much Smaller CPUE than Trawl
• 2. Longline Much Higher Quality Fish
• 4. Longline Used for the Most Valuable Fish
• 5. Start-up Costs Longline Lower than Trawl
• 6. Good Set Target on Greater than 10 Hooks
• 7. Bait Could Be Used to Reduce Bycatch
• 8. Killer Whales Have Learned to Pick Fish Off

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Longliner Heading Home
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Next Lecture

• 1. Crab Gear
• 2. Jigging
• 3. Introduction to Salmon Gear

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