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Fishing
methods
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Types
of fishing methods
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Modern
technology
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Types
of fishing methods
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Although
there are many methods of catching fish, they fall into
three main groups:
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1
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Catching
fish singly or in schools by use of nets or spears
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2
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Trapping
fish in stationary gear, such as fish traps or set nets
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Attracting
fish to get caught on hooks by use of bait, artificial
lures other means such as light |
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Before
you go fishing you must decide what is the best method
to use. There are many factors to consider - especially
if you are a commercial fisher. Factors include:
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where
you are fishing
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what
species you are fishing for
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the
weather and sea conditions
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the
cost of the boat, gear and fuel
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the
market requirements
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(Fishing
method drawings in this section are courtesy of the NZ Fishing
Industry Board - now Seafood Industry Council)
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Netting
While there are many types of nets, all rely on
the fish getting snared or caught in the net's mesh.
Nets are typically long, narrow and flat, weighted at
the bottom edge and supported at the top edge by floats.
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The most common form of netting for recreational fishers
is "set" netting. It is also used by commercial
fishers to catch fish like flounder and butterfish.
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Lining methods
The most commonly used lining methods are hand-lines
and long-lines. Hand-lines are mainly used by recreational
fishers, though they are sometimes used for commercial
species, such as southern bluefin tuna.
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Long-lines consist of a main line running parallel to
the bottom, with baited short lines (snoods) attached
at intervals. The line is anchored at each end and held
at the surface by floats. Long-lines are used to catch
high-quality, high-value fish such as snapper.
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Trolling
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trolling, baited hooks or lures are towed behind a boat
and fish are pulled aboard when caught. This method is
designed to target fast moving surface swimming fish such
as tuna, marlin and kingfish. |
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Trawling
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Trawling
is the most important commercial fishing method in New
Zealand, especially for deepsea species. Trawling is
used to catch a range of species, for example, orange
roughy, hoki, ling, hake and squid. Recreational fishers
are not permitted to use trawl nets.
Trawling
involves one or two fishing vessels towing a large net.
Most New Zealand trawlers are single, rather than pair
trawlers. Nets are usually towed for two or three hours
at a speed of three or four knots.
Nets
of both bottom and mid-water trawling are held open
by two "doors", which act as paravanes, or
underwater kites.
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top
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Danish
seining
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seining is used to encircle, herd and finally trap the
fish. A net bag, similar in shape to a trawl bag is operated
by a long, weighted rope fixed to each end. The two ropes
are used to encircle the fish and also to haul the net
in. They are usually operated on the bottom and are used
to catch snapper and John dory. |
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Purse seining
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seining is used to catch surface dwelling species such
as tuna, mackerels, kahawai and trevally. Aerial spotter
planes are usually used to locate the intended catch.
The purse seine net is laid in a circle around the school
. The net is then "pursed", drawing the bottom
closed and entrapping the fish. Purse seining cannot be
used by recreational fishers. |
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Beach seining/drag netting
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seining or drag netting is normally carried out using
a length of net and an additional length of warp (rope).
The net and warp are laid out from, and back to, the shore
and retrieved by hauling on to the shore. The net used
is similar to that used for set-netting. Mullet, flatfish,
snapper, trevally and crabs are caught this way. |
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Dredging
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is used to gather scallops and oysters. To gather scallops,
the fishing vessel tows a rigid steel-framed dredge along
the sea floor. With oysters, a heavier ring mesh is usually
used. |
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| Jigging |
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Jigging
is a method of catching squid by continuously lowering
and retrieving lines from the fishing vessel. Fishing
is generally done at night when squid are attracted
by powerful lights on the vessel. Jigging is used in
preference to trawling when high quality squid is required.
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Pots
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lobsters and blue cod are caught in pots, usually made
of a steel frame, covered with wire mesh. The pot is baited
with fish and dropped from the boat on the end of a rope
long enough to reach the bottom. The position of the pot
is marked with floats so the pot can be easily recovered. |
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Diving |
| Some
commercial and recreational fishers dive for paua, scallops
and rock lobsters. Paua may only be taken by divers using
snorkels, not scuba gear. |
Modern
technology
Today
there is more than just luck involved in finding a good fishing
spot, especially in commercial fishing. Electronic navigation
equipment and sophisticated fish-finding equipment can place
the fisher within a few metres of the best fishing areas.
On
the bridge of a modern deepwater trawler there is millions of
dollars worth of electronic equipment, including a colour echo
sounder, a colour net recorder, a radar set and a satellite
navigation system.
Colour
echo sounder
The colour echo sounder/fish finder is used to find fish and
display the depth and contours of the ocean floor. The information
is shown on a colour screen.
It works
through a pulse sent out by a transducer in the hull of the
vessel. It strikes the seabed and is reflected back upwards
where it is received by the same transducer. Fish also reflect
the pulse - it is the air in their swim bladders which makes
them visible to the echo sounder. Orange roughy, however,
have oil in their swim bladders, and so don't show up very
well.
This
trace from an echo sounder shows possible schools of fish
(darker areas)
Colour
net recorder
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Click for larger version
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This works along side the colour echo sounder. The screen gives
specialised information on the net and the fish moving into
it, using data from a small echo sounder attached to the net
itself. Modern colour net recorders can also measure the width
of the net, its fullness and even the temperature at the net
mouth. Experienced skippers can tell not only how much fish,
but also what kind of fish, they are catching.
High
tech electronic gear such as this helps commercial fishers
operate more efficiently
 Radar
(radio detection and ranging)
Radar is used to detect objects on the surface up to 30 to
40 km away. Radar works in a similar way to sonar (used in
the echo sounder ), except it works in air rather than water.
Objects the radar identifies show up as "blips"
on the screen.
Satellite
navigation system
Skippers also use a satellite navigation system to determine
the position of the vessel. A small screen displays the vessel's
position - latitude and longitude - to within a few metres.
Accurate measurements can only be made when satellites are
above the observer's horizon. At other times the system uses
"dead reckoning", based on the ship's course and
speed.
Satellites
are also increasingly being used at sea to obtain information
about weather, sea surface temperature, wave height, wind
patterns and the location of fish and other vessels.
For
more information click on any link below.
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