Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 17 Resources from the Sea
Jan 14, 2015
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 17
Resources from the
Sea
Food from the Sea
“Give a man a fish, you feed him for a day…Teach him how to fish, and you feed him for life!”
Seaweeds, Jellyfish, Sea Cucumbers, Sea Turtles, Worms, Crabs, Oysters…
Finfish = fish harvested = 84% world catch
What percentage of the world’s
food comes from the ocean?
Even at 1% world total
It is one of the world’s most important protein sources!
Finfish =16% of protein eaten around the world!
Figure 17.02
World Human Population Growth!
Domestication of Animals and PlantsBetter Sanitation
Advances in Medicine
Projection:8.9 Billion by 2050
Major Marine Fishing Areas of the World
Boundaries are established by the FAO (Food and Agriculture Organization of the United Nations).
Numbers in millions of tons!
What are the world’s major fishing areas?
Bering Sea, Newfoundland, Coast of Peru,
SW and NW Africa
What makes a good fishing spot?
Rich WIDE continental shelf.
Easy to harvest demersal (bottom) species.
Primary production is higher over the shelf supporting abundant life!
Good upwelling of nutrients in these major fishing areas too!
Protein deficiency is a major cause of disease
and death in poor developing countries
6 Major Fishing Nations
Decline in world total
China may overstate for promotion
Peru’s catch is up and down due to anchovy up and down populations
Increased demand for seafood in affluent countries and growing population increases
pressure on food resources from the sea.
More effective gear
Use of satellites to find fish
Increased efficiency
Long range vessels
Examples of Fishing Methods
Examples of Fishing Methods
Which country / culture eats more fish on average per person?
Japan
or
United States
Japanaverage of 159 lb. of fish
per person every year
United Statesaverage of 46 lb. of fish
per person per year
Clupeoid FishesSmall plankton-feeding fish
in huge schools
Herrings, Sardines, Anchovies
Herrings
Sardines
Anchovies
Fish Protein Concentrateor Fish Flour
odorless powder for protein supplement
Fish MealFeed for poultry, livestock or farmed fish
Fish Oilmargarine, cosmetics, paints, fertilizers, pet food
Wow! 1/3 of fish catch
Demersal Cold Water Species come in 2nd!
Cods, Pollock, Alaskan Walleye,
Haddock, Flatfish are all caught
with trawls dragged on bottom!
Many of these “cheap fish” are being over-fished!
Cod Fish
What a Halibut!
King Fish = Salmon
Valuable Catch in the North Pacific!
One of the most important open-ocean fish that cross the tropical oceans.
High Priced Fish for affluent countries - Canned or Raw
Caught with high-tech equipment on boats, long lines and gill nets.
Mollusks are next most valuable group of marine food after fish.The Octopus is valued as a delicacy
Other Eaten Fish!Seaweeds (in Far East)
Sea Urchins for their gonads or roe (in Japan)
Roe can be called UNI (eaten raw)
Sea Turtles for eggs
Seals and Whales
Theoretical Population Growth Chart
Figure 17.09b
Rate of Growth is related to Population Size and is highest at Intermediate Abundances
Replace Themselves
Even though they are RENEWABLE…
THEY ARE NOT INEXHAUSTIBLE!
Sustainable YieldCatch is large enough to prevent the population from growing but not so
large as to reduce it!
Catch-Effort Curve
Fishing Rights for a country used to extend only 3 miles offshore,
but now extend 200 miles offshore!
90% of the Ocean’s fisheries are within a country’s control.
But – The open ocean is common property!
Mariculture is a specialized branch of
aquaculture involving the cultivation of marine organisms for food and other products in the open
ocean, an enclosed section of the ocean, or in tanks, ponds or raceways which are filled with seawater.
An Oyster Farm in New Zealand
Milkfish being harvested from a brackish-water pond in the Philippines.
A Japanese Flounder (Halibut) grown at a mariculture facility in Hawaii
Aquaculture is the
farming of aquatic organisms such as fish, shellfish and even plants
Greenpeace
Artificially red salmon flesh on sale doesn’t reveal the rampant destruction that this industry causes in regions where the fish are produced.
Expanding at a rapid rate, fish farming now accounts for over
30 percent of all fish protein consumed annually in the world.
But it is single-handedly responsible for the destruction of countless ecosystems and the fishing communities that rely upon them, in some of the most vulnerable marine environments on the planet.
Drawback of mariculture
Pollution!Thousands of fish in ponds or pens with huge
amounts of feces, urine, uneaten food and poor water quality and harmful algal blooms with toxic chemicals. Antibiotics, pesticides, and synthetic
pigments and colors.
Destruction of natural resources to make these farms too!
Saltwater and freshwater crocodiles grown together in New Guinea for their valuable skin. Its also a way to dispose of chicken offal.
Biotechnology alters DNA to produce faster-growing more disease-resistant or
better-tasting fish.
Some of these escape and breed with wild populations!
Sponge from Fiji being grown for chemicals that kill worms and human parasites.
Ocean Mining
Seabed is source of many minerals
New technologies help to make it
feasible as land ores become exhaused
Recreation
Sport Fishing
Oil and Gas
Aquarium Trade
Desalination Plants
Minerals (Table salt)
Energy
OTEC Ocean Thermal Energy Conversion
circulates ammonia or liquids that when evaporate power turbine generators.
Potential sources of electricity from the sea include tides, waves,
currents, and the temperature difference
between surface and deep layer (OTEC)