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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)