Passive Capture Techniques

Fish Harvest and Movement

Passive Capture Techniques

• Fish caught by– Entanglement– Entrapment– Angling gears

• Gear is not moved through the water

Entangling devices

• Fish are snared or tangled in fabric or mesh

• Examples– Gill nets– Trammel nets

Entrapment devices

• Capture fish that go through small openings in gear

• May be more than one opening• Fish can't find their way out• Examples

– Hoop nets– Trap Nets– Lobster Pots

Angling devices

• Use baited hooks on lines• May be unattended• Examples

– Trot lines– Long lines– Jugs and yo-yos

Problems with passive gear• Gear selectivity - bias for or against

certain species, sizes or sexes of fish.

• Example - trap nets catch crappie, but usually not largemouth bass

orr

X

Gill Nets - Fish caught by...

• Wedged• Gilled• Tangled

Gill Nets - Construction

• Wall of Netting• Floats, Weights• Anchors, Bouys

• Hanging Ratio• Mesh size (Bar or

stretch)

• They can be a little cumbersome!!

• Common in commercial fisheries

Trammel Nets - Sets

• Same as gill nets

• Standard sets• Floating sets

Angling Gear

• Long lines– Floats, lines drop hooks– Mostly oceanic fisheries

(miles/longline)

On the Farm:• Working fish on the farm is a daily activity.

• REM: No fish sales = no business!

• Fish must be moved during harvesting, counting, weighing, bagging, transport, etc.

• How do we move them without harm?

• Let’s look, shall we.

Trapping

• Normally, for small orders, fish can be trapped overnight.

• Traps are baited and set the night before, or very early in the AM.

Seines• Seines (nets) help work a large area quickly (assuming

no vegetation).

• Fish are surrounded, crowded and removed to be placed into storage tanks, or counted out, bagged and transported for sale.

Holding

• Once collected fish may be held in vats.

• Again, minimize stress. Watch your fish!

• Tank, vats, or aquaria are used.

Grading

• Grading, or sorting by size is essential to aquaculture sales.

• Because it is a production science, everything must be similar (identical).

• Placing fish in common groups by size, species, or gender assures uniform products at time of sale.

Grading by bar• Grader bars are useful when you have 1000’s of

fish to sort quickly.

Hand Sorting

• Time consuming!

• Close up of fish.

Bagging and Tagging

• Once you’ve got the size and number,• Bag, tag, sell!

Double-bagging

• Fish must be bagged twice, if you suspect they will puncture the bag (catfish).

Fish Bagging Checklist• 1. Label bag.• 2. Bag ¼ filled with water.• 3. Fish in bag!• 4. Compress bag to remove air?• 5. Crimp top and fill bag with pure oxygen.• 6. Remove oxygen line.• 7. Twist top closed. • 8. Wrap top with rubber band/clamp.• 9. Check for leaks, place in shipper!