Biology Project

1
Nature Resources in the World
Fisheries
2
Introduction

• Important natural / living resources
• Renewable natural resources
• Important components of the ecosystem

3
Distribution of fish
Freshwater fish
Marine fish
4
Distribution of fish
5
99 of the fish stock concentrated within 200
nautical miles off the coast which are plankton
rich
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Reason accounting for the distribution of fish

• The main reason
• Fish feed on plankton (including unicellular
  plants).
• ?They associate with the plankton.

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Reasons accounting for the distribution of
plankton

• Unicellular plants need
• Carbon dioxide
• Sunlight
• Nutrients

• Condition in these areas
• Shallow water - light can reach most part.
• Close to continent - receive loads which are rich
  in nutrient.

8
Another important factor - Temperature

• Most of the ocean is cold.
• Advantages of low temperature
• ? solubility of oxygen in water
• ? metabolic rates ? need less energy ? need less
  food.

9
Present situation of the world's fisheries

• People get an average of 20 of the animal
  protein in their food from fish and shellfish.
• Contribute 30 - 90 of animal protein in Asian
  coastal and Island countries.
• 87 comes from the ocean and 13 from fresh water.

10
Fisheries

• Concentration of particular aquatic species
  suitable for commercial harvesting in a given
  area of the ocean.

However, only a few groups harvested extensively
(40 out of 200000 known species half annual
harvest which is near to its maximum sustainable
yield) - cods, herrings, jacks, redfishes,
mackerels and tunas. Why?
Tradition and taste
11
Operating costs in what aspects?

• More than 90 of the fish obtained by small and
  large motorized fishing boats to hunt and
  gather over a large area.
• 30 - 40 of the operating costs spent on fuel.
  --gt higher price of many favourite types of fish
  and shellfish.

12
Is the fish resources renewable?

• The highest rate at which a potentially renewable
  resources can be used without reducing its
  available supply.
• 1950 - 1970, the weight of fish catch grew
  annually by 7 and increased more than threefold.
  The rate of growth has slowed down and the marine
  catch may soon reach the estimated sustainable
  yield.
• Although the total fish catch has grown, the
  world-wide per capita fish catch has declined.

13
The human impacts to fish

• Many human activities causes impact to fish
• Over-fishing
• Illegal fishing practices
• Water pollution

14
Over-fishing
Rate of removal of fish gt rate of production of
fish
15
Over-fishing

• Fishermen try to catch more fish by using net
  with smaller holes.
• Immature fish are also captured.
• Less fish can spawn.
• Foreign exchange for third world countries

16
Illegal fishing practices
Destructive fishing methods
17
Illegal fishing practices

• Not only kills the target fish, but also nearby
  small fish and even plankton.
• The related food chains marine ecosystem are
  destroyed.
• drift net fishing, dynamite / poisons - destroy
  habitat, pollution, destruction of mangroves,
  coral reefs and population growth.
• Disadvantages of drift net fishing on p. 4

18
Drift net fishing

• Indestructible nylon-mesh
• 15 meters deep and is up to 65 kilometres (40
  miles) long
• Intend to catch squid, tuna, swordfish, sea trout
  and salmon

19
Disadvantages of drift net fishing

• Not only depletes the target species but also
  kills dolphins, turtles, seals, sharks or even
  whales that entangled in the fine mesh of the nets

• Ghost net entangled and kill fish,
• marine mammals and birds year-round
• for centuries.

20
Water pollution

• Various types of water pollution
• Chemical pollution
• Thermal pollution
• Oil pollution
• Acid rain

21
Chemical pollution - organic and inorganic wastes
22
Chemical pollution - toxic chemicals
23
Thermal pollution

• Hot water discharged from power station
• ? solubility of oxygen in water
• ? metabolic rate ? ? the oxygen consumption
• Favours the growth of algae.

24
Oil pollution

• Oil spillage causes the death of fish by
• Oil is toxic.
• Oil cuts off the oxygen supply
• It prevents the oxygen from dissolving into the
  water.
• It prevents the entry of sunlight. Green plants
  cannot carry out photosynthesis.

25
Acid rain

• Exhaust gases from vehicles, factories,
  incinerators power stations contain acidic
  gases.
• They dissolve in rain water to form acid rain.
• ? acidity of water ? death of fish and other
  organisms.

26
Case studies on p. 3 Peruvian anchovy catch

• Reasons for decline of Peruvian anchovy to
  commercial extinct
• i. El Nino - Southern Oscillation kills
• phytoplankton which are the major
• food for Peruvian anchovy.
• ii. Government keep on financing fishing
• industry in order to pay off the loans
• and avoid people out of work.

In 1953, Peru livestock feed 20 of annual
commercial fish catch.
However, between 1971 and 1978, the Peruvian
anchovy became commercially extinct.
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Group discussion on any possible solutions and
the difficulties arised

• Report and give summary

28
Conservation
Government
Individual
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What government should do
FISH HALTING in South China Sea
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iv. Better management1982 United Nations
Convention on the Law of the Sea by 159
countries.This treaty gives all coastal
countries the legal right to control fishing by
their own fishing fleets and by foreign ships
within 364 kilometers (200 nautical miles) of
their coasts.
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If enforced, this treaty can reduce over-fishing.

• However, 22 countries refused to sign or ratify
  the
• treaty because
• (1) Conflicts between countries and islands. They
  disagreed the mineral and living resources in the
  open ocean belonging to the entire world so as to
  share their resources and profits with other
  countries especially the LDC.
• (2) Difficult to control.

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What government should do
33
What government should do
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What government should do
35
What individual should do
Control of fishing gear
Avoid the consumption of Humphead Wrasse and
Giant Grouper
Reduce the consumption of wild-caught live reef
food fish e.g. Leopard Coralgrouper
Avoid the consumption of sexually immature species
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i. Consume new species Processing the new
species to acceptable taste.

• ii. Aquaculture (e.g. Salmon in Norway)
• Change to substitute such as cultured LRFF
  and freshwater fish
• High technologies required, to avoid
  destruction of natural habitats and causes
  pollution.)

.
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THE END