Understanding Discord NSFW Servers A Guide for Responsible Users.pdf
Technological evolution in fish catching
1.
2. FISHING
Fishing is the activity of catching fish.
It is an ancient practice dating back at
least 40,000 years. Since the 16th
century fishing vessels have been able
to cross oceans in pursuit of fish and
since the 19th century it has been
possible to use larger vessels and in
some cases process the fish on board.
Fish are normally caught in the wild.
Techniques for catching fish include
hand gathering, spearing, netting,
angling and trapping.
4. FAO STATISTICS
According to FAO statistics, the total
number of fishermen and fish farmers is
estimated to be 38 million. Fisheries and
aquaculture provide direct and indirect
employment to over 500 million people. In
2005, the worldwide per capita
consumption of fish captured from wild
fisheries was 14.4 kilograms, with an
additional 7.4 kilograms harvested from
fish farms.
5. TECHNOLOGICAL EVOLUTION OF
FISHING
The ancient river Nile was full of fish; fresh and
dried fish were a staple food for much of the
population. The Egyptians invented various
implements and methods for fishing and these are
clearly illustrated in tomb scenes, drawings, and
papyrus documents. Simple reed boats served for
fishing. Woven nets, weir baskets made from
willow branches, harpoons and hook and line (the
hooks having a length of between eight
millimetres and eighteen centimetres) were all
being used. By the 12th dynasty, metal hooks with
barbs were being used.
Nile perch, catfish and eels were among the most
important fish.
6. Fishing scenes are rarely
represented in ancient Greek
culture, a reflection of the low social
status of fishing. They were used
fish-cage for keeping live fish or as
a fish-trap. The Greek historian
Polybius (ca 203 BC–120 BC), in his
Histories, describes hunting for
swordfish by using a harpoon with
a barbed and detachable head.
7. Roman fishing comes from
mosaics which show fishing
from boats with rod and line
as well as nets. Various
species such as conger,
lobster, sea urchin, octopus
and cuttlefish are illustrated.
8. In India, the Pandyas, a classical
Dravidian Tamil kingdom, were
known for the pearl fishery as
early as the 1st century BC. Their
seaport Tuticorin was known for
deep sea pearl fishing. The
paravas, a Tamil caste centred in
Tuticorin, developed a rich
community because of their pearl
trade, navigation knowledge and
fisheries.
9. From ancient representations and
literature it is clear that fishing boats
were typically small, lacking a mast
or sail, and were only used close to
the shore.
In Norse mythology the sea
giantess Rán uses a fishing net to
trap lost sailors.
The Moche people of ancient
Peru depicted fisherman in their
ceramics.
11. EVIDENCE OF CHANGES REGARDING
GILL NET
Gillnetting was an early fishing technology in
Colonial America.
Immigrant fishermen from northern Europe and
the Mediterranean brought adaptation of the
technology during 1860s.
The fishermen used boat around 25‟(8mt.) long and
powered by oars.
Many of these boats also had small sails and were
called “row-sail” boat.
At the beginning of the 20th century steam powered
ships would haul these small boat to their fishing
ground and retrieve then at the end of each day.
Gas powered boat were beginning to make their
appearance and by 1930s the row-sail boat had
virtually disappeared.
12. In 1931 the first powered drum was created and this
allowed the nets to be drawn in much faster and
fishermen were able to fish in areas they had previously
been unable to go into.
During World War II, navigation and communication
devices, as well as many other forms of maritime
equipment (ex. depth-sounding and radar) were
improved and made more compact. These devices
became much more accessible to the average fisherman.
the fisherman were forced to invest more into their
boats and equipment in order to stay up to date with
the current technology.
The introduction of fine synthetic fibres such as nylon
in the construction of fishing gear during the 1960s
marked an expansion in the commercial use of gillnets.
13. This type of net was heavily used by many Japanese,
South Korean, and Taiwanese fishing fleets on the high
seas in the 1980s to target tunas. Although highly selective
with respect to size class of animals captured, gill nets are
associated with high numbers of incidental captures of
cetaceans, (whales and dolphins). In the Sri Lankan gill net
fishery, one dolphin is caught for every 1.7-4.0 tonnes of
tuna landed. This compares poorly with the rate of one
dolphin per 70 tonnes of tuna landed in the eastern Pacific
purse seine tuna fishery. Gillnets were banned by the
United Nations in 1993 in international waters, although
their use is still permitted within 200 nautical miles
(400 km) of a coast.
14. TRAWLING
In the Middle Ages, Brixham was
the largest fishing port in the South-
West, and at one time it was the
greatest in England. Brixham is also
famous for being the town where
the fishing trawler was invented in
the 19th century.
In the 1890s there were about 300
trawling vessels there, each owned
by one man who was often the
skipper of his own boat.
The largest fishing port in Europe
from the 1970s onwards has been
Peterhead in the North-East corner
of Scotland. In its prime in the 1980s
Peterhead had over 500 trawlers
staying at sea for a week each trip.
Peterhead has seen a significant
decline in the number of vessels and
the value of fish landed has been
reduced due to several decades of
overfishing .
15. THE CHINESE AMERICANS
The Chinese fishermen migrated to the California coast
during 1850s.
They explored a growing economy of the west coast of
the US from Canada to Mexico.
They used small boats to catch herring, soles and sharks.
And for larger fishes like barracudas they used Chinese
junks.
Later the US law passed mainly Scott Act in 1888,
established that the Chinese migrants, even when they
had entered and were living the US legally, could not re-
enter after having temporarily left US territory.
The Chinese fishermen could not leave their boats the 3
mile zone of the west coast.
It became unprofitable and they gave up fishing.
The fishermen remained unchallenged only the area of
shark fishing and salmon canaries.
16. TECHNOLOGICAL CHANGES IN CRAFTS
RAFT:-
A raft is any flat
structure for support or
transportation over
water.
It is the most basic of
boat design,
characterized by the
absence of a hull.
Rafts are usually kept
float by using any
combination of buoyant
materials such as wood,
sealed barrels or inflated
air chambers.
17. CATAMARANS
The catamarans are most
primitive fishing craft of
Kerala.
Keel-less craft made of
few logs of light wood.
Logs are tied together at
the two ends by coir
ropes.
7.5 to 8.5 m length and 8
m width.
It can accommodate
three to four persons.
Propelled manually with
bamboo oars and sails.
18. DUG OUT CANOE
Made by scooping out
material from large trunk
of tree(aini).
Dug out canoes are of
three types
Larger one is Odam(11-13
m long)
Medium one is Thonie(8-9
m long)
Smaller one
Bepputhonie(6-7 m long)
Oldest boats found by
archaeological excavation
are dug out canoes dating
back to the Neolithic
Period around 7,000-8,000
years ago.
19. PLANK BUILT CANOE
Constructed by
seaming together
planks.
Seaming by using coil
ropes copper nails.
Larger ones called as
Thanguvallom(11-13
m long)
Smaller ones called
Kochuvallom(6-7 m
long)
20. DOGGER
During 17th century the British developed the
dogger, an early type of sailing trawler or
long liner which commonly operated on the
North Sea
The dogger takes its name from the Dutch
word dogger, meaning a fishing vessels
which tows a trawl.
21. COMMERCIAL VESSELS
In recent times, fishing
boats are becoming
more specialized and
standardized
Commercial fishing is
a high risk industry,
and countries are
introducing
regulations governing
the constructing and
operation of fishing
vessels.
22. GLOBAL FISH PRODUCTION SCENARIO
The production increased from 100.36 million
tonnes in 1990 to 125.2 million tonnes in 1999.
The production of fish in 2010 was 159 million
tonnes.
Fish catches accounted for 74% and aquaculture for
26% of the total harvest.
China was the first to contribute overall
production. India got the 4th place to the overall
production.
23. GLOBAL CONSUMPTION OF FISH
In 1998 fish supply reached an exceptional low due to El
Nino and demand as well due to the financial crisis in
emerging markets.
The total food fish supply has been growing at a rate of
3.6% per annum since 1961.
The world population increased 1.8% per annum.
Per capita fish consumption increased from about 9 kg per
annum to 16 kg in the recent decade.
The consumption of fish in 2010 was 110 million tonnes.
24. HINDU DIETARY CUSTOMS
General Rules
Tamas, Rajas and Sattva; - these Ayurvedic "vibrations" are
characteristics of various foods and affect both the physical
and astral bodies. This is the root theory behind various
Hindu food customs.
Tamasic (heavy) foods such as meat and fermented foods
(including alcohol) promote dullness and inertia.
Rajasic (expanding) foods including onions, garlic, hot spices,
stimulants,FISHES, eggs and salt. are thought excite intellect and
passion which interfere with meditation.
Sattvic (ascending) foods including fruits, vegetables and grains
are thought to promote transcendence, sublimity and orderliness.
Higher caste people adhere to sattvic foods, middle
casts indulge rajasic and lower castes are tamasic foods.
25. According to religious aspect fish is an
unique food item to meet the nutritional
demand for human population.
From the economical view point the
global demand of fish is increased rapidly.
So, to meet the global demand aquaculture
is necessary.
26. HISTORY OF FARMING
The Neolithic culture and technology spread
worldwide between 4,000 and 8,000 years ago.
In China the „Sung Dynasty‟ started aquaculture.
They were collected and store the fish only. It
was around 500 BC.
After this the „Ming Dynasty‟ started culture
practice. They collected the fishes and also
reared the fishes.
Later „China Dynasty‟ came and they introduced
the technologies of collection of fishes, rearing
and fry production method.
27. TECHNOLOGICAL CHANGES ON
AQUACULTURE
EXTENSIVE AQUQCULTURE:-
The growth rate of fish is limited.
The available food is supplied from the nature.
Additional fertilizer use to increase the
photosynthetic production.
Here aquaculturist choose a fiter algae feeder
such as tilapia, a benthic feeder such as carp or
catfish, zooplankton feeder various carps and
submerged weed feeder grass carp.
28. INTENSIVE AQUACULTURE
The amount of fish per unit surface area can
be increased by providing sufficient oxygen,
optimum water quality and best feeding
schedule.
The cost of inputs per unit of fish weight is
higher than in extensive farming, especially
because of the high cost of fish feed.
Some producers have adapted their intensive
systems in an effort to provide consumers
with fish that do not carry dormant forms of
viruses and diseases
29.
30. CAGE CULTURE
Fish cages are placed in
lakes, ponds, rivers and
oceans to contain and
protect fish until they can
be harvested.
The methods are called
„off-shore cultivation‟
when the cages are placed
in the sea.
The possibility of poaching
and disease is less in cage
culture and require
minimum maintenance.
In recent year the cage
industry has made
numerous technological
advances in cage
construction.
31. IRRIGATION DITCH OR POND
SYSTEM
These use irrigation
ditches or farm ponds to
raise fish.
In small systems the fish
are often fed commercial
fish food, and their waste
products can help fertilize
the fields.
In larger ponds, the pond
grows water plants and
algae as fish food.
Control of water quality is
crucial.
Yields can be low if the
fish grow ill from
electrolyte stress.
32. COMPOSITE FISH CULTURE
The composite fish culture
method is introduced in
India in 1970 by the ICAR.
A combination of five or
six fish species is used in a
single fish pond.
Food available in all parts
of pond is used.
Fish used in this system
include catla and silver
carp which are surface
feeders, rohu a column
feeder and mrigal and
common carp which are
bottom feeders.
In optimal conditions will
produce 3000–6000 kg of
fish per hectare per year.
33. INTEGRATED RECYCLING SYSTEM
The largest-scale pure fish farms use a
system derived from the New Alchemy
Institute in the 1970s.
Basically, large plastic fish tanks are placed
in a greenhouse. A hydroponic bed is placed
near, above or between them.
Tilapia is used as they eat the algae when the
tank is properly fertilized.
To maintain fishes in this method is very
complicated so this method is not so
common.
34. CLASSIC FRY FARMING
This method is also
known as „Flow through
system‟.
Trout and other sport
fish are often raised
from eggs to fry or
fingerlings and then
trucked to streams and
released.
Normally, the fry are
raised in long, shallow
concrete tanks, fed with
fresh stream water.
The fry receive
commercial fish food in
pellets.