ILLUSTRATIONS OF VARIOUS
KINDS OF FISHING
Fishing activities are exercised using a fishing vessel and
special equipment that can:
- be towed by the vessel either in contact with or at a
certain distance from the bottom of the sea
- be used to surround a shoal of fish or, finally,
- be positioned for a certain period of time in an area of the
sea and later collected together with the catch.
Main fishing methods are shown in the following table:
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A - TRAWLING |
A.1 – Net towed along the bottom of the sea |
A.1.1 - trawling |
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A.1.2 – rake trawl with depression |
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A.1.3 - dredge |
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A.2 - Net towed
in midwater |
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B – SEINE FISHING |
B.1 – Purse seine |
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B.2 – Danish seine |
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C – DRIFT NET FISHING |
C.1 – Trammel nets |
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C.2 – Gillnets |
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C.3 – Long lines |
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C.4 – Fish pots |
A.1 – TRAWLING
A.1.1 – trawling with a net towed along the bottom of the sea
Fishing with nets "towed"
along the bottom of the sea belongs to the vast chapter about “Trawling” in
which the equipment, normally a net, fishes while being towed by one or more
vessels. The expedition starts when the fishing vessel sails to the fishing
area at a speed that varies between 9 and 12 knots. Depending on the type of
vessel, the time needed for sailing to the fishing area may or may not
represent a more or less long period of the overall time required for the whole
expedition.
Fig.1 – Fishing vessel
with lowered nets (divergenti = trawl boards; galleggianti = floats; piombi =
lead; sacco = codend; cavi misti = mixed hawsers; cavi di acciaio = steel
hawsers)
Having reached the fishing area, the engineer reduces
power and later separates the propeller from the engine to stop the boat; this
takes place after the boat’s natural movement when engines are turned off also
stops.
From this moment onwards the lowering of the nets into
the water starts, an operation commonly known as "let down"; the
nets’ vertical opening (table 1) is guaranteed in different ways by the
presence of weights and floats, respectively placed on the lower (weight file)
and higher rims of the opening (float line). Horizontally instead the distance
between the nets’ seine is obtained thanks to the presence of two trawl boards.
As shown, the two trawl boards are linked to the fishing vessel by two steel
hawsers, with a diameter suited to the weight supported and the length of which
is established depending on the water depth in the fishing area. When all the
equipment is in the water, after checking its position, the engineer increases
the engine’s revs and then those of the propeller until the vessels reaches a
trawling speed of 4-5 knots.
The length of the expedition depends on the vessel’s
autonomy: it will therefore vary between two and fifteen days. At the end of
the trawl, operations for hauling in the net begin by coiling the two steel
hawsers around as many winch barrels; the trawl boards are then fixed to the
gallows to avoid them moving.
To coil the "mixed hawsers", that link the
trawl boards to the net’s seine, the extremities of the “messenger” hawsers are
uncoupled, coiled a few times around the warping ends and one transfers the
hauling on board of the net to the gallows of the two warping ends (Tables 2
and 3 ).
Table 2 – Transfer of
hauling in metal hawsers to the mixed hawsers
In some fishing vessels, instead of simply heaping the
mixed hawsers these are coiled around two barrels situated on the same axis as
those for the steel ones. In this case the winch has four barrels.
When the net’s two seines appear they are drawn close to
each other (Table 4) joined first by a chain that is then coupled using the
gilson (wire
tackle used for hauling onboard and emptying the codend) (Table 5).
Fig. 3 – Coiling various hawsers
Table 4 – Bring the seines close (mazzetta = head line;
ghia = gilson)
The last operation, emptying the codend, is carried out
with the help of the gilson placed
through a pulley at the end of the derrick and put into action using the gypsy.
Table 5 – Manoeuvres for drawing up the net
Sorting and packing the fish takes place on the
afterdeck, and the catch is then sent to the refrigerated holds.
The previous description indicates the need for
machinery, equipment and fixed positions capable of permitting work on board.
In Table 6, which shows a typical layout of a deck on a
trawler, please note in particular the presence of:
- A two barrel winch,
- Two pulleys, with the base welded to the vessel and need for correctly
defining the passage followed by the hawsers on deck.
- Two gallows situated one on each side of the vessel aft of the working
deck, provided with rollers and/or pulleys in which the two hawsers can
move freely to and from the sea.
- An aft roller, mounted transversally compared to the vessels symmetric
plan and freely rotating.
The crew is formed by the skipper, the engineer and
three sailors; the crew works continuously from Monday until Thursday and
carries out four fishing trips, each starting at three in the morning when the
vessels leaves the harbour; after one or two hours’ sailing to the fishing area
where operations involving lowering the nets begins, lasting about half an
hour; the trawling stage follows which lasts about two hours, finally the
drawing on board that requires another half an hours.
Only the first and last trip follow different hours: the
first is shorter to assess the area chosen and the other is the longest because
it takes place before returning to the harbour.
At the end of every fishing trip, during which the nets
are let down eight times, the vessel returns to harbour, unloads the catch and
sails once again for a new fishing area.
After leaving the harbour the sailors go to their bunks
to rest while the skipper remains at the controls and following communications,
advice and suggestions exchanged over the radio with over fishing vessels, sets
course for new fishing areas where the net will be first dropped.
Having reached the area, the sailors are woken up using
a special sound signal situated near each bunk, and after putting on their
personal protective clothing, go aft to drop the net; during all dropping and
drawing up operations one sailor stays at the winch while the other two work on
the equipment
Each time the net is drawn up the codend is opened and
the whole catch is emptied into one of the two holds at the end of the stern,
the net is immediately dropped once again while on board the sorting begins,
which consists in selecting the fish and placing it in the other hold.
The selected fish is put in crates and placed in the
refrigerated hold, the working area is then cleaned and, with the exception of
the skipper who is replaced by the engineer, the whole crew returns to the
bunks.
During fishing trips there are only watches for ship
manoeuvring and handling while everyone helps in lowering and drawing up the
net as well as sorting and packing the catch and storing it in the refrigerated
hold.
Excluding two intervals for meals, during which the crew
are all together, the sailors alternate working and resting watches that last
throughout the trawling stages.
The crew is therefore continuously exposed to noise both
when on deck and when resting. 
Table 6 – Design of a trawler
A.1.2 Beam trawler equipment
This equipment is used for catching soles and consists
in a net mounted on a rigid framework that guarantees that it is both
vertically and horizontally open. These are currently shaped as the rapido with curved and forward leaning tines on the lower side.
On the higher part of the framework, a forward leaning depressor is mounted,
which while fishing pushes all the net and in particular the tines, due to a
hydrodynamic effect, downwards, ensuring good penetration at all speeds: by
increasing the trawling speed, the depressor’s force increases and it is
therefore possible to trawl this equipment at high speeds, hence the name
‘rapido’.
Fig.7 – Shape of rapido
The net, directly attached to the framework, is made
using sufficiently strong netting to resist the friction of the seabed and is
usually protected (the lower part) by a lining and by a rubber lining too.
The width of the framework does not exceed 4 metres. One
fishing boat can drag between 2 and 5, depending on its power. Each rapido is
linked to a hawser by a bale sling.
The rapido is generally used at night rather than a bottom trawl; very often
the two kinds of nets are taken on board at the same time. Fishing does not
last long because the tines need to be cleaned frequently to maintain their
efficiency unvaried.
A fishing vessel using rapidos works from continuously Monday to Thursday making four
fishing trips. The crew consists in the skipper, the engineer and four sailors.
Each fishing trip begins at three o’clock in the morning
when the boat leaves the harbour, after one or two hours sailing fishing
operations start consisting in the trawling phases and drawing up phases.
Usually, initial trawling phases last
about fifty minutes while the last two can even last two hours; drawing up and
lowering the four parts of equipment lasts between fifteen and twenty minutes.
The nets are usually lowered eighteen times after which
the vessel returns to the harbour, and after unloading the catch leaves once
again for a new fishing area. During each fishing trip there are only watches
for manoeuvring the boat while everyone helps in lowering and drawing up the
nets as well as sorting, packing and placing the catch in the refrigerated
hold.
Apart from two
intervals for meals, which take place at eleven and then at 8 P.M., the men
alternate working and resting phases that last as long as trawling does.
Each time they are awoken by the special sound signal,
the crew puts on the necessary personal protective clothing and goes aft to the
working area.
While the skipper does all that is necessary to stop the
vessel and start the hydraulic pump, two men control the winch and two others
move to the near the blocks waiting for the order to lower the equipment.
This is the only kind of fishing that requires two men
at the winch because working it requires a great deal of attention, speed and
movement synchronism.
The first of the four barrels in started by a section
clutch with a single lever control, and by starting a pedal operated pneumatic
command, which starts the hydraulic engine (one for all the barrels) while the
distributor valve is held at light line speed.
When the signal is given, having drawn up the length of
the steel hawser, recovery speed is reduced until the first “iron” appears near
the stern gantry. At this point, with the help of a rope coiled around the
winch head, operations for drawing the catch on board begin hoisting the
dredger on board and opening the knot at the end of the net.
The equipment is immediately re-coupled to the hawser to
be lowered again with the barrel in neutral but at the same time a second
barrel is engaged to carry out the same operations.
Generally speaking, each rapido is hoisted on board,
unloaded and lowered again working only one barrel which through being put into
neutral allows the activation of another barrel to carry out the same
operations and this is repeated four consecutive times lasting for a total of
twenty minutes.
The catch is now sorted at the back of the stern in
positions that are not very ergonomic and always out in the open.
The catch is sorted according to type and size, placed in
crates that are each placed in the refrigerated hold to then be collected
during the next fishing trip.
Stowage and collecting operations are carried out
passing the crates from man to man and the whole crew joins in.
When this is done the sailors was and tidy up the aft
deck and then go back to rest while watches at the helm last longer, changing
every six hours except for the first watch when the skipper sails out of the
harbour to sail to the fishing area chosen for that day and verifies that it is
good area remaining at the helm until eleven o’clock.
Fig.8 – Schematization
of a fishing vessel for fishing with a rapido
A.1.3 Dredgers
Vessels used for fishing clams on sandy or sandy-muddy
seabeds at a depth of about 312 metres, belong to this category. The equipment
consists in a metallic framework, closed on all sides except one (the front),
and by a grilled formed by round metallic bars or a perforated sheet.
Fig.9 – Clam fishing
(trawling direction – hose – trawling hawser)
On the sides there are two sleds that allow the
dredger’s base to only penetrate for 46 centimetres. The dredger is linked
to the fishing vessel by two hawsers measuring about double the depth of the
sea. After fishing the dredger is hauled on board using another hawser.
To encourage the clams to leave the muddy seabed it is
the custom to place a collector at the opening of the net with a number of
nozzles expelling pressurized sea water (about 2.5 kg/cm 2) through an hydraulic pump, usually
worked by the fishing vessel’s main engine, and sent to the collector through a
hose. Experimental pumps placed directly on the dredger have recently also been
used.
Fishing operations begin when the anchor is dropped at
the centre of the area where it is thought that there are many clams. Then the
fishing vessel moves about 250 - 300metres away, allowing the hawser
linked to the anchor to unwind from the winch. At this point the dredger is
lowered and the backwards trawling phase begins during which the hawser is
retrieved. During these stages, water is injected into the dredger to remove
foreign elements, mainly sand.
When the hawser has been coiled around the winch the
dredger is retrieved. It is then emptied through the back and the catch is
examined to eliminate and immediately throw back into the sea those clams that
are too small as well as other small organism. If the catch is a good one and
there is no need to change the area, the anchor is not raised but the vessel
following a slightly different course moves away from it to explore the entire
area in a circle. The size of the dredger’s grill and
that of the sieve, the maximum width of the dredger, the smallest fishable size
of the clams and the maximum size of the daily catch are all regulated by the
law.
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A)
afterdeck |
D)
wheelhouse |
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B)
operation area near the winch |
E)
fore deck |
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C)
galley |
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Fig.10 – Vessel for
fishing clams
This kind of fishing is done using a boat that, by law,
cannot have a gross tonnage over 10 or an engine over 150 HP.
Work involves two people and lasts between 5 and 6 hours
per day: one hour is used for sailing (to or from the fishing area) while the
rest of the time is used for repeating, about every ½ hour, the stages required
by this kind of work.
The harbour is left at 5.00 A.M. and the vessel sails at
a speed between 8 and 9 knots (maximum speed is 9.5 knots).
During this time, while the skipper is on the bridge,
the other sailor prepares the equipment at the bows. Having reached the fishing
area the operations can be summarised as follows:
1 ) Dropping the anchor and uncoiling about 600 metres
of hawser;
2 ) Lowering the equipment [iron] and activation of water pump;
3 ) Starting to coil anchor chain;
4 ) Finish retrieval and hoisting of iron;
5 ) Emptying of iron and sorting;
6 ) Packing the catch and storing in hold.
The hawser is lowered in five minutes while the real
fishing phase lasts about twenty five minutes.
If conditions are good and the area chosen profitable,
these phases are repeated 9 or 10 times. While the skipper is busy working the
winch and the hydraulic pump, during lowering and recovery phases, the sailor
is busy working the sieve and packaging the catch at the bows; the only
operation undertaken simultaneously by both men is hoisting on board the “iron” and emptying it.
Having sorted the catch the bags are prepared and later
piled up along the starboard corridor from where they are removed when the
vessel returns to harbour.
A.2 – Fishing with a Larsen trawl
Table 11 – Schematization of a trawler using a mid-water
floating trawl
Trawling using a mid-water floating trawl takes place from
Mondays to Thursdays with four fishing expeditions alternated with
disembarkation lasting about 8 hours. The crew is formed by a skipper, an
engineer and four sailors.
Each fishing expedition starts at four in the morning when the
vessel leaves the harbour; after five hours sailing fishing operations begin
alternating trawling and retrieval phases.
Trawling usually last one hour while hoisting the net on board
and lowering it again lasts between 15 and 20 minutes.
The net is usually lowered four times after which the vessel
returns to the harbour and the catch is unloaded while the crew returns home to
re-embark the following morning.
During fishing there are only watches for sailing the vessel
while everyone helps in lowering and lifting the net as well as organising the
catch.
Apart from intervals for meals, during which the whole crew
eat together, the men are always busy sorting and packaging the fish from the
previous catch.
Exposure to noise is particularly severe while working on
deck.
After leaving the harbour all the sailors go to their bunks to
rest a little longer while the skipper sails the vessel and after
communications, advice and suggestions exchanged over the radio with other
fishing vessels, he sails towards the fishing area where the nets will be
lowered.
The skipper reduces speed near the chosen area and starts to
look carefully at the images provided by the sounder to identify the size of
the schools of fish and thereby decides to lower the net.
The sailors are then woken up by a sound signal and having put
on their personal protective clothing they go the afterdeck to lower the net
(this for the vessel that is the first to lower its net); during all lowering
and drawing up operations one sailor is at the winch while the other two are
involved in working other elements of the equipment.
Every time the net is hoisted on board, operation alternated
between the two fishing vessels, the net’s bag is opened and the catch emptied
in an area at the back of the deck; the net is immediately prepared for the
next lowering and sorting begins.
The selected catch is placed in large basins containing a
water and ice solution where it is left for a while; the catch is then sorted
according to size and packaged in crates and covered with a layer of ice. Once
packaged the crates are piled in the corridor ready to be unloaded in the late
afternoon. Preparation takes such a long time that when it is completes it is
already time to once again lower the net.
Return to harbour can vary but normally takes place at about 7
P.M.
B.1 – FISHING WITH PURSE SEINE
Purse seine nets are used with the objective of totally
enclosing in a circular shape a certain area of the sea where there are large
quantities of fish.
These nets are rather like a large sheet: the upper
frame is armed with a headline provided with numerous floats for
maintaining the net on the surface while the bottom frame equipped with a headline
with leads keeps the net stretched vertically. On this last headline at regular intervals there are
straps with iron rings at their extremities.
A steel hawser goes through these rings and is used for
closing the net. After fishing this hawser is hoisted first to transform the
net into a bag from which the fish cannot escape.
Fig.12
– The encircling net 
In Italy purse seine nets have for a long time been used
together with lights as an expedient for encouraging a concentration of the
fish. This form of fishing known as a lampara, obviously
only takes place at night and when there is no full moon so that the artificial
light has a greater effect on the fish that during these hours rises to the
surface.
Most of the vessels used for this kind of fishing are
average size to large (with engines between 400 & 500
HP).
Each vessel usually tows or carries on board 3 small
boats, each provided with large lamps with a very strong light for attracting
the fish. In the past, these lamps worked on gas or oil but the modern ones are
electric are run on generators kept directly on the boats.
Fishing starts at dusk searching the
sounder for an area in which there is a considerable amount of fish. At this point the boats are placed at a certain distance one
from the other to individually attract as many fish as possible to then move
closer pushing all the fish into one school. The remaining two smaller boats
turn off their lights and leave. One of these, called stazza, moves over
to the fishing vessel to take one end of the net.
The fishing vessel can now lower the net forming a circle the
centre of which is determined by the position of the last small boat with its
light still on to keep the school of fish together.
The radius of the circle is instead determined by the length
of the lowered net. The manoeuvre must be as precise as possible to determine
the lowering in the exact point in which that last boat has been left with the
other end of the net.
At this point the hawser running through the rings of the
lower headline is retrieved: the net, closed at the bottom, emptied of its
contents using large brailers, or in some cases a fish pump is finally lowered,
passing through a large pulley called a hydraulically run power block placed on
top of a swinging derrick or a crane.
Nets used for this kind of fishing measure between a few
hundred metres and one kilometre; they can even reach a height of 300 metres,
limited however by the depth in which fishing takes place to avoid it heaping
at the bottom or be damaged. The width and height are also proportional; a very
long and not very high net would become cylinder shaped as soon as dropped and
not closed at the bottom as is normally necessary.
A purse seine fishing vessel works from Mondays to
Saturdays. Activities are characterised by night time fishing expeditions
alternated with 8 hours shore leave during the day. The crew consists in the
skipper, the engineers and thirteen sailors.
Each fishing expedition starts at 19.00 hours when the
vessel leaves the harbour; after a few hours sailing, the skipper starts
checking the sounder to identify the size of the school of fish present in the
area.
This is the most delicate stage because choosing the
right moment for lowering the equipment conditions the night’s catch since the
net is drawn on board only once for each expedition.
A fishing expedition usually lasts two hours while the
remaining time is used for sailing to and from the area, and at times for an
unsuccessful first attempt at lowering the net.
Fishing requires favourable weather conditions and in
particular not too much light from the moon. After one lowering of the net the
fishing vessel returns to the harbour where the crew, after unloading the
catch, returns home to then embark once again in the late afternoon.
During one fishing expedition there are no watches
because the skipper is always at the helm,
busy choosing the right location for lowering the net,
while all the others work at lowering and hosting the net as well as preparing
and storing the crates filled with the catch.
No meals are eaten on board but during the return trip,
after the catch has been stowed in the refrigerated hold and all the equipment
has been tied up, the crew meet in the galley to rest for a while.
The crew is exposed to noise both on deck and in other
areas of the vessel; in particular one must bear in mind that one should
consider the auxiliary boats on which high revving generators are placed as
also belonging to the workplace.
After leaving the harbour the whole crew watches
television and drinks coffee in the main cabin; at about eleven o’clock they
retire to their bunks to rest while the skipper remains at the helm, sailing
towards the fishing area and starts to watch the sounder.
When reaching the chosen area the skipper reduces speed
and pays even greater attention to the images on the sounder to decide exactly
when to lower the net.
The sailors are awoken by a sound signal situated near
their bunks, and after putting on their personal protective clothing they go to
the afterdeck to lower the first large net and then the three smaller boats
equipped with lights. While the small boats start to move inside the area
delimited by the float line used for attracting the fish, the skipper moves the
boat around slightly to get closer to them and receive information about the
size and quality of the fish present.
Manual retrieval of the line that runs through the rings
on the net begins immediately allowing the lower part to be closed.
After the closing and a partial retrieval of the net
using the power block, the catch is moved on board with a brail net the lower
opening of which allows the crates, placed on deck near the hatch of the
refrigerated hold, to be filled.
The full crates are stored in the refrigerated hold to
leave the decks free for the next catch.
Having finished stowage the afterdeck and equipment is
tidied while the skipper sails back to the harbour.
The fishing vessel normally returns to harbour at about
10.30 P.M. but this can vary depending on how far away the fishing area is.
(TABLE 14 – Schematization of a purse seine fishing vessel)
C – FIXED NETS
Fixed nets consist in passive equipment; in fact they do
not move, it is instead the fish that, when swimming, come into contact with
them and are entwined or
tingled.
These nets are currently made of nylon which because it
is very strong allows the use of very thin threads. In some cases the use of
simple yarn is becoming popular, presenting among others the advantage of being
almost totally invisible in the water.
This equipment is used by all fishing communities, even
the smallest. In fact small rowing boats or boats with small outboard engines
are used, evening leaving from beaches. The equipment is often used
successfully in depths where trawling is impossible.
Usually these nets are lowered and drawn on board by
hand, however in some cases, to reduce physical effort or use longer nets, a
so-called salpatramagli (trammel net
lowering equipment) is used.
Fixed nets are made using rectangular pieces of net
armed using two headlines:
on the top one there are the floats while on the lower one there are the leads
so they assumes a vertical position in the water.
Depending on whether they are anchored to the seabed or
not and also on their position in the water they are divided into fixed, drift
nets and purse seines.
Fixed nets include all nets, whether on the
seabed or in mid-water, are anchored to the seabed using an anchor or weights.
The weights or anchors are signalled on the surface of the sea by buoys with
yellow flags during the day and lights at night so it is possible to identify
and retrieve them. Once lowered, these nets are left in position for a certain
period of time, usually one night, so as to make them even more invisible for
the fish, and then retrieved. Normally the vessels return to the harbour for
the period between lowering the nets and drawing them on board.
Drift nets are not anchored to the seabed but
left free to move with the currents. The net’s extremity is linked to a buoy
while the other is linked to the boat itself. Due to the fact that this form of
fishing takes place near the surface excellent markings are necessary as well
as accurate supervision to avoid accidents with other vessels.
Purse seine nets are lowered so that the headlines are
placed in a circle to catch the fish within the formed cylinder shaped net; the
fish are then frightened to direct them towards the walls of the net where they
are entwined.
C.1 – Trammel nets
A trammel net consists in a large net wall placed just
above the seabed for fishing demersal types of fish or however when mid-water
fishing at a given depth.
The net is formed by three pieces of netting,
superimposed and linked along the longest side, with the two external nets have
a larger mesh.
The height of the three nets is also different: the
external ones are identical while the central one is considerably higher and
free to move between the other two, measuring between 1.5 and 2 metres.
from which ever direction it may come the fish can
easily pass the first net, but having come into contact with the second finds
itself it a sort of sack, and attempting to escape becomes increasingly
entangled.
Trammel nets are usually anchored to the seabed and used
for very commercial fish (sea breams, crustaceans, flatfish, etc.). The higher
part of the net is linked to a headline of floats while the bottom one is
linked to a line of weights. The combined effect of the floats and the weights
maintains the net vertically stretched. The floats are usually oval, measuring
10 centimetres with a diameter of 5 centimetres. The weights, normally placed
at the same height as the floats, are hollow cylindrical shapes measuring about
10 centimetres and weighing about 170grams.
With anchored trammel nets sufficient weight is used to
keep the weight headline on the bottom of the seabed while floatability
provided by the floats is only sufficient to maintain vertical tension.
Fig.15
– Drawing on board a trammel net
As far as mid-water trammels are concerned, a sufficient
number of floats are used to counter-balance the weight of the lead headline used
to ensure the net’s verticality.
The hawsers linked to the two headlines at the
extremities of the net are linked to those that connect the anchors on the
seabed to the floats on the surface indicating the position and extension of
the net and then used to retrieve the net.
The nets are lowered often during the summer. When the
vessel reaches the fishing area an anchor and a buoy are prepared. The anchor
is dropped and while the buoy is positioned the fishing vessel moves forward at
a speed of about 3-5 knots.
Once the whole net is in position, with a length varying
between 300 and 10.000metres, another anchor is dropped as well as another
buoy.
Vessels of a length between 12 and 14 metres are used to
fish using this system, and normally have:
- a wheel house
- a motorized hydraulic block, situated to starboard
just beyond the midsection .
- a barrel placed on the afterdeck
- a roller at the extremities measuring between 70 and
100 cm.
While the net is lowered the fishing vessel remains
stationary moving very slowly instead while the net is hoisted on board.
C.2 – Gill nets
These nets are made in one single piece. Fish is caught
by holding them
in the meshes meaning
that once the fish has entered the net’s meshes it can no longer move in any
direction.
These are drift nets, left to follow the effect of the
currents and the wind.
The size of the mesh varies in these nets depending on
the species and the size of the fish one intends to catch. If the mesh is too
wide in fact the fish can go beyond it without suffering any injuries while if
they are too small the fish is not entangled and manages to escape. Small mesh
nets are mainly used for Mediterranean fishing. Average mesh nets (50130
mm circa) catch quite large commercial species.
Medium to large meshes (160200
mm) are required for specific tunas and white tuna. Finally large mesh nets (330400
mm and over) are used specifically for catching swordfish. Tuna are caught
mainly because the fish are trapped in the net.
This kind of net, which at times measures even various
kilometres, can be used as a fixed net and also as a drift net.
Table16
– Gill net
Simple techniques are used for fishing with gill nets; 1
or 2 crewmembers and a small boat are all that is needed.
In the past swordfish were caught using special boats
called passerelle (Translator’s
note: no English equivalent) because they were equipped with a narrow deck across the boat in front of the
cabin,
from which the harpoon was launched, and also a very tall mast for seeing the
fish from afar. The nets currently used for catching swordfish are about 30
metres tall although they appear considerably inferior when fishing; however,
since they are lowered and kept on the surface using floats, they effectively
create a barricade in the middle of the sea with inevitable consequences for
pelagic species or other vessels in the same lanes.
The nets are lowered to form bell shaped forms: seen from above these nets form a
sinusoid and therefore are necessarily very long.
C.3 – Long lines
A long line equipped with hooks is the most common
equipment used by professional fishermen: essentially it consists in a series
of branches ending in hooks and another linked to a long line measuring various
kilometres. The branches are attached to the long line at regular intervals,
equal to twice their length.
Long line fishing is normally carried out at night; the
nets are lowered at sunset and are drawn up at dawn. During the day the baskets
are prepared and the hooks baited.
Success in this kind of fishing is in particular linked
to the number of hooks each vessel manages to lower: the use of this equipment,
requiring little energy, is fundamentally linked to the automation of all phases.
Currently, in nearly all Italian fishing communities these operations, with the
exception of drawing in the hawser, are done manually in spite of the fact that
for a number of years now totally atomised machinery for all these activities
has been available on international markets.
Long lines can be fixed or drifting depending on whether
they are anchored to the seabed or left to drift with the currents. Fixed long
lines are mainly used of the seabed of mid-water while drifting long lines are
used on the surface.
These are different not only for the method used but
also in the length of the branches and the size of the hooks.
This activity is strictly seasonal (May-June) because it
depends on the tuna passing through the Sicilian Channel. This involves quite
long fishing expeditions varying in length.
A typical drifting gill net for catching swordfish,
tuna, etc consists in a line similar to the one used for the seabed. The
branches instead are much longer, measuring between 5 and 10 metres, and formed
by two parts: one linked to the line, also in nylon or polyester although a
little smaller, whiles the second part, the one with the hook, is nearly always
made of steel.
The two parts are linked by a swivel that prevents it
from twisting when the fish squirm.
If the fish involved is instead tuna, the equipment
consists in hooks, suitably baited, and a vessel (see Table 18) with a crew
formed by a skipper and nine sailors. A typical fixed gill net for seabed
fishing usually consists in a nylon or polyester line, either twisted or
plaited; the branches, nearly always made in monofil nylon, measure between 50
and 150 centimetres.
Table 2 shows a fishing vessel used for fishing tuna
with gill nets. Tuna fishing is characterised
by the high level of uncertainty as far as the catch in concerned and
therefore, so as to elevate the yield of the equipment, it is necessary to
lower the lines many times therefore increasing the time spent checking them.
Due to the high value of the catch, it often happens
that a number of fishing vessels working in the same area alternate their
returns to harbour leaving their equipment in the water; the fishing vessel
that stays behind continues to fish, also checking from a distance the
equipment left by the others while the boat returning to the harbour also takes
back the catches of others.
Fig.17
– Positioning of long lines
A typical fishing expedition lasts for four days and
starts on Sundays at midnight ending at dawn on Thursdays; one loads ones own
fish and that of the vessel remaining in the area to check the lines; food is
embarked and in the evening the fishing vessel sails once again.
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Table18
– A gill net fishing vessel
The fishing area lies to the north of Pantelleria and is
reached after six hours of sailing at a speed of 10 knots with the engine at
the highest possible number of revs (1600 revs/1’); having positioned the
vessel so as not to interfere with the others (the gill net extends for dozens
of kilometres), and the nets are lowered with the engine at 1200 revs/1’.
Having lowered the last marker, the longest phase
begins, that of checking, also known as the
“walk“.
Navigating parallel to the “line” and with the engine at
1400 revs/1’, one returns towards the first buoy lowered and every time one
seas a sunken float the engine is reduced to the minimum and the hook with the
tuna is retrieved; the large fish is hoisted on board, and after being cleaned
and treated as required by the markets, it is placed in the refrigerated hold.
The fishing vessel, which during these operations
remains stationary, once again sets its course until another sunken float is
seen; the previously described operations are repeated and once again the
skipper sets his course.
This continues until one reaches the first buoy lowered
and by now it is usually sundown, a favourable moment for hoisting the
equipment back on board. Checks are only interrupted for meals, during which
the fishing vessel is stopped with the engine at minimum.
At 21.00 hours the recovery of the lines begins followed
by once again lowering the lines which keeps the crew busy until five o’clock
the next morning.
During the expedition the skipper, except for an
interval during the afternoon, is always at the helm, helped by a sailor who
looks out for the immersed floats and gives the order for drawing up the catch.
The crew rest after the lines have been lowered until
late in the morning while during the “walk” they alternate fishing activities
with repair and maintenance work. There are normally two meals each day during
which the whole crew meets in the galley and the vessel’s command is entrusted
to an automatic pilot; there is a brief rest period after wheels. Fishing
phases are repeated for three days after which, depending on the quantity of
fish caught, the vessel return to harbour to unload the catch or it is
entrusted to another boat, which takes it to the harbour and fishing continues for
a few more days.
Exposure to noise happens both at work (on deck and in
the area reserved to sorting and preserving the catch) as well as in the cabins
and the galley.
C.4 – Pots
Pots consist in passive equipment where the fish are
caught with no chance of escaping. The fish are usually drawn to the pots by
bait placed inside the pots. The pots are used for catching an enormous variety
of fish from fish to crustaceans and shellfish.
They are practically cages in which potential victims
are encouraged to enter with bait and from which they are incapable of
escaping.
The pots are usually anchored to the seabed with weights
and indicated on the surface with buoys so they are easy to identify and later
retrieve. They are not very large and at time a number of pots linked by a
hawser are lowered together.
Table 19 – Pot
fishing vessel