Finfish Harvesting Methods
TRAWLING or DRAGGING
The most common method of fishing, trawling is simply
described as towing a net through the water. A trawl net is funnel-shaped,
and can harvest bottom-dwelling fish when dragged along the ocean
floor. Pelagic fish can be caught by mid-water trawling,
in which the net is towed through the water column between the
surface and the bottom. Other variations include stern trawling
and side trawling, which refer to the position of the
net relative to the boat during setting and hauling, and pair
trawling, in which two boats are used to spread wide the
mouth of the net.
GILLNETTING
Gillnetting can also be used to harvest bottom or pelagic
fish, but is a passive fishing method. A gillnet is a wall of
netting set in a straight line, equipped with weights at the
bottom and floats at the top, and is usually anchored at each
end. Fish swim through the virtually invisible netting, and are
entangled when their gills are caught in the webbing, hence the
name gillnetting. If allowed to drift freely, the method is referred
to as driftnetting.
LONGLINING
Rather than a net, longlining uses baited hooks on offshoots
(gangions or leaders) of a single main line to catch fish at
any level. The line can be anchored at the bottom in areas too
rough for trawling, or set adrift, suspended by floats. Currently
used to catch swordfish, longlines have received renewed interest
over the past decade or so due to the development of automated
longline systems.
PURSE SEINES
Purse seines are walls of netting, used to encircle entire
schools of fish at or near the surface. Spotter planes are often
used to locate the schools, which are subsequently surrounded
by the netting and trapped by the use of a pursing or drawstring
cable threaded through the bottom of the net. When the cable
has pulled the netting tight, enclosing the fish in a pouch,
the catch is hauled on board with a crane-operated dip net in
a process called brailing. This method is used in the Northeast
to catch sea herring and other schooling species, including tuna.
WEIRS
A weir is a passive fishing method consisting of brush
or twine fences permanently attached to the bottom. Two prolonged
fences, called leaders, direct fish to swim voluntarily into
successive enclosures known as the heart, pound, and pocket.
A seine (see above) is often used to remove the fish from
the pocket. In Maine, this method is used to catch juvenile sea
herring, also known as sardines.
POUND NETS or FISH TRAPS
Similar to weirs, these traps are instead constructed
with netting or wire, and are often designed to float where bottom
terrain prohibits stakes or pilings. Floating traps are held
in place with anchors, the bottom of the trap covered with netting.
Scup, sea herring, menhaden, squid, bluefish and mackerel are
some of the species caught in such traps in the Northeast.
Shellfish Harvesting Methods
DREDGING
Commonly used for the commercial harvesting of scallops, clams,
oysters and mussels, a dredge consists of a metal rectangular
frame to which a bag-shaped net of metal rings is attached. The
frame's lower end is called the raking bar, and is often equipped
with metal teeth used to dig up the bottom. The frame is connected
to a towing cable and dragged along the sandy floor, much like
a trawl net. Variations include hydraulic or jet dredges,
which use pressurized water to stir up deep-burrowing clams,
and suction dredges, which use pump-driven suction to
suck the shellfish up a pipe to the boat.
RAKING
Various types of rakes are used to harvest clams and seaweed.
Simple rakes called scratch rakes or clam rakes
are like heavy garden rakes with longer, sharper teeth that are
often curved upward toward the inside of the rake. Basket
rakes are equipped with wire mesh baskets to hold the catch,
and bull rakes have very long, often telescoping handles
for operation from a skiff. Recreational shellfish collectors
use simple tools like rakes, hoes, shovels, forks, or even their
bare hands.
TONGS
Used to harvest oysters and quahogs, tongs are best described
as a huge set of salad tongs. They are simply a pair of basket
rakes attached like scissors, with the fulcrum near the lower
end. Patent tongs are a modification using power assistance.
POTS or TRAPS
Pots or traps are rigid devices, often designed
specifically for one type of fish, used to entrap finfish or
shellfish. Generally baited and equipped with one or more funnel
openings, they are left unattended for some time before retrieval.
Pots are weighted to rest on the bottom, with marked buoys at
the surface, and are sometimes attached with other pots to one
long line called a trawl line. In the Northeast, pots are used
to capture lobster, crab, whelk (conch), eel, scup, and other
fish.
More Harvesting Methods
JIGGING
Jigging is the setting of a line, with baited hooks or
lures, that is continually jerked. The motion, achieved by hand
or with a jigging machine, induces fish to take the hook. This
method is sometimes used to catch squid and cod in the Northeast.
HARPOONING
Used extensively in the whaling days, harpoons are still
used today to catch swordfish, shark and tuna. Thrown by hand
or shot by mounted guns, harpoons are each tipped with a barb
which is attached to a long line with a buoy at the end. The
line is free of the boat, and fish are followed with the assistance
of the buoy until they tire and can be hauled aboard.
SPEARING
Spears are used by scuba divers to catch fish, and are
used to a small extent to catch eels through the ice.
HOOK-AND-LINE
This method, whether involving a hand line or rod-and-reel,
is no longer a commonly used commercial fishing method. However,
the market supply of striped bass, bluefish and some other species
is very dependent on sport fishermen selling their catch.
TROLLING
Trolling is simply towing single fishing lines behind
a moving boat. In the Northeast, it is primarily a sport fishing
method, but on the Pacific Coast trolling is used commercially
to harvest salmon.
TROTLINES
A trotline is like a bottom longline (see above)
without hooks. Bait is tied to the line, either directly or on
short offshoot lines called gangions. This method is used in
the Mid-Atlantic region to capture crabs.
HAUL SEINES
A haul seine is like a smaller, simpler purse seine
(see above) that is set from a small boat or by wading. This
method is used primarily to gather bait or for scientific sampling
purposes.
STOP SEINES or STOP NETS
These are long walls of netting (see purse seines above),
set across the mouth of restricted bodies of water such as embayments
or coves. When the tide ebbs, trapped fish are easily accessible.
This method is used in Maine to capture small sea herring.
LIFT NETS
A lift net has a metal frame which supports a shallow
bag of netting. It is lowered to the bottom, left for a while,
and then lifted rapidly to the surface. This method is used primarily
to gather bait or for scientific sampling purposes.
CAST NETS
Circular nets with weighted edges, cast nets (not to be
confused with the musical instruments) are thrown by hand and
sink to the bottom. Fish covered by the net are gathered by drawing
together ropes attached to a recovery line, and are then hauled
in. This is not a commercial method in the Northeast.
DIP NETS or SCOOP NETS
These are mesh bags suspended from a frame, and are commonly
used to collect bait or in sport fishing. Large, power-operated
dip nets (also known as brail nets) are used to remove
fish from purse seines (see above).
FYKE NETS and HOOP NETS
Cylindrical nets constructed by covering a hoop-like frame with
netting or wire mesh, hoop nets are conceptually similar
to weirs and fish traps (see above), but are three-dimensional
and much smaller. Anchored to the bottom, fyke nets and
hoop nets are sometimes used in the Northeast for the
capture of eels.
Ref Source: Fishfacts.com
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