Lecture 4 - Fishing Methods Flashcards
Traditional/ atrisanal/ pre-industrial fishing methods
1) spears, arrows, harpoons
2) fish ponds
3) fish weir (aka fence)
4) pound net
5) pots and traps
6) hooks and lines
Modern/ industrial fishing methods
1) traps and pots
2) hook and line, trolling
3) longline
4) gill netting (anchored or drift)
5) trawl nets
6) purse seines
7) fish aggregating devices (FADs)
Annual catch amount by industrial method:
1) Purse seine ~50%
2) Otter trawl ~17%
3) Lines ~9%
4) Pound/trap nets ~8%
5) Gill nets ~6%
What are the general technological advances that have enabled increased industrial fishing capabilities?
1) echo sounds
2) synthetic fibers (for nets and lines)
3) power (power winch, power block, etc.)
4) boat range (and size)
5) navigation aids (GPS)
6) preservation of catch (drying/salt and factory ships that completely process at sea)
What are negatives associated with bottom trawling?
1) very high bycatch, in some cases
2) damage seafloor environments
Trawl doors/otter doors (definition)
Hold trawl nets apart when fished
Cod end (definition)
The bag at the back of tawl net where the fish go
What are the two type of trawl nets?
1) Mid-water
2) Benthic or otter trawl
Bycatch (definition)
The unwanted fish and other marine creatures caught during commercial fishing for a different species
Ghost fishing (definition)
Discarded gear that continues to fish
Why and when were gill nets banned on the high seas?
Banned in 1992 due to high bycatch and ghost fishing
What is the length of a pelagic longline used for swordfish, tuna, and billfishes?
15-60km
What is the length of a benthic longline used for halibut and black cod?
1-10km
Why are synthetic fibers and wire mesh beneficial for industrial fisheries?
They resist damage in the ocean
