Resources from the SeaResources from the Sea

Shipley Marine BiologyShipley Marine Biology

Summit High SchoolSummit High School

Food Products Materials Recreation

Marine Resources are Utilized For:

What types of organisms are harvested?

Finfish (about 90% of worldwide harvest) Shellfish Other species such as jellyfish, sea cucumbers,

polychaetes and seaweed While seafood represents only about 1% of the

food consumed each year, it represents about 30% of total animal protein consumed

Food From the Sea

1950’s to present- there was a five-fold

increase in fishing effort 1980’s to present- worldwide catches

relatively constant despite the increased fishing effort

Many of world’s most important catches are overexploited or exhausted (especially in the Atlantic, Pacific and Mediterranean)

The Fisheries Industry

Worldwide Commercial Catches

Worldwide Marine Catch and Mariculture

Most located near coast over continental shelf Easier to catch demersal species High primary production in these areas means

more species are present Ex: Grand Banks of Newfoundland, North Sea

and Bering Sea

Major Fishing Areas

Examples of Commercially

Important Fishes Around the World

Clupeoid fishes

Sardines, menhaden, shad and herrings How they are used:

Eaten directly Fish flour (powder used as a dietary supplement Fish meal (ground fish used as protein

supplement for poultry, livestock and aquaculture

Fish oil (used in manufacture of margarine, cosmetics, paints, omega-3 fatty acids

Major Food Species

Cods, haddock, hakes, pollock, whiting Demersal, cold water species Has been harvested for centuries Sold fresh and frozen Vital source of inexpensive protein in many

parts of the world

Major Food Species

Fishery peaked in the 1960’s then began to

decline Moratorium declared in 1992 to attempt to

save the fishery Closure caused high unemployment in

American and Canadian fishermen The fishery may never recover The cod is listed as endangered in that area

even today

Cod Fishery of the Grand Banks

Jacks, Mullets, Rockfishes and Mackerels

Important in worldwide tonnage Cheap protein in some parts of the world

In the United States, flounders and other flatfish are important

Salmon also remain important catch

Major Food Species

Tuna

Caught in open water These fish command high prices They are caught on long lines or in gillnets Fishing boats are equipped with freezers so they

can stay at sea longer

Major Food Species

280 lb Bigeye tuna

120 lb. Swordfish

Wahoo

This is a Cobia

Golden Tile Fish

Molluscs

Second most valuable catch after finfish Squids, cuttlefish, and octopus are particularly

important in the Far East Clams, oysters, mussels, scallops and abalones

are important worldwide

Major Food Species

Crustaceans

Prized worldwide Command high prices Shrimp, lobster, crab

Major Food Species

These species contribute little to the

worldwide catch Sea weeds, jellyfish and sea urchins

harvested in Far East, especially Japan Gooseneck barnacles are harvested in Spain Polychaete worms are harvested in South

Pacific Sea turtles and their eggs are harvested and

eaten even where they are protected by law Seals and whales are still eaten in some

cultures despite laws to protect them

Other Harvested Marine Life

Sea-life species are renewable resources However, for a fishery to last long-term, it

must be fished in a sustainable way The sustainable yield is the amount that can

be caught and just maintain a constant population size

Maximum sustainable yield is the highest catch that can be maintained year after year without affecting the stock

Optimal Yield and Overfishing

If catches fall despite increased fishing effort,

overfishing has occurred Market forces often cause this to happen If other fishermen are making money, other

fishermen will be attracted to the fishery and cause overfishing to occur

Exceeding Maximum Sustainable Yield

It is estimated that about 70% of marine

fishes are overfished This is especially true for large species like

tuna, swordfish and sharks In many of these species, the fish that are

harvested today are about half the size of those harvested 20 years ago

Ex: Bigeye tuna were two times as heavy and eight times more abundant in 1950’s than they are today

Exceeding Maximum Sustainable Yield

Swordfish Catches of these fish fell 70% between the

1960’s and the late 1990’s A campaign to reduce consumption of these

fish was successful Numbers of the fish are recovering

Exceeding Maximum Sustainable Yield

Habitat destruction

Critical breeding grounds like seagrass beds, estuaries and mangroves are destroyed each year

This is especially detrimental since 75% of commercially important species use estuarine areas as nursery areas

Trawls used in fisheries also damage the ocean floor which is detrimental to demersal species

Other Dangers to Fisheries

A fishery is regarded as collapsed if numbers

fall to 10% of historic highs It is estimated that one-third of fisheries are

already collapsed A 2006 study indicates that all major fisheries

will collapse by 2050 if protective measure are not taken to better manage and protect these resources

Collapse of a Fishery

Management can be difficult for many

reasons: Maximum sustainable yield is difficult to

calculate Harvested species may compete with other

species and fishing pressure may affect competitive balance

Real fisheries are more complex than models High seas are “common property”

Managing the Resources

Limiting total catch and closing the fishery when

the catch is reached Limiting length of fishing season Limiting areas open for fishing (to include marine

reserves) Limiting number of boats permitted to fish Limiting gear size or gear type Limiting size of fish caught Limiting catches per boat Limiting fishing methods

Ways to Manage a Fishery

Passed in 1996 Requires federal fisheries managers to

develop plans to avoid overfishing, restore depleted stocks and reduce by-catch (species caught incidentally while fishing for a target species)

US fishermen must abide by rules as well as foreign fishermen with valid permits

In 2003, the Pews Ocean Commission calls for management of ecosystems as well

United States- Sustainable Fisheries

Act

New fisheries may be available by

increasing the use of by-catch However, consumer tastes are fickle and

these species may not be appealing to consumers

Some species may be able to be used in the manufacture of imitation crab (as pollocks are currently)

Other untapped potential fisheries – squid, flying fish and lanternfish

New Fisheries

Aquaculture is the application of farming

techniques to the growth and harvesting of aquatic organisms

The term mariculture applies specifically to marine organisms

The column of marine organisms produced through mariculture has risen three-fold since 1990

As an example, farmed fish account for 25% of shrimp consumed each year

Other “farmed” species include milkfish, molluscs, seaweed, salmon and Pacific threadfish

Mariculture and Aquaculture

Commercial Mariculture Species

Disease and parasites can be high due to many organisms

in close proximity Different food requirements may be present at different

life stages Species that require open water cannot be raised this way Maintaining water quality may be difficult If farmed species escape, they may breed with wild stocks

and dilute genome of wild population Pollution from farm ponds can leak into nearby waters In some areas of the world, mangroves and other

estuarine communities are destroyed to create farm ponds

Problems Associated with

Aquaculture/Mariculture

Other items harvested for reasons other than

direct consumption: Mangroves – for timber and charcoal Pearls, shells, coral and sea turtle shells for

jewelry Some species harvested for their chemical

compounds that are used as “marine natural products”

Marine Life as Items of Commerce and

Recreation

Amateur anglers – in general, marine

resources caught by recreational anglers is only about 30% of the amount caught by commercial fishermen

However, for some species, the number of individuals caught each year may be solely from recreational anglers

Other species are harvested each year for the aquarium trade

Marine Life as Items of Commerce and

Recreation

Oil and Gas

Sand and gravel for the construction industry

Freshwater via desalination process

Non-Living Resources Harvested from the Marine Environment

NaCl

Non-Living Resources Harvested from the Marine Environment

Non-Living Resources Harvested from the Marine Environment Tidal energy

Non-Living Resources Harvested from the Marine Environment Polymetallic nodules – contain manganese,

nickel, copper and cobalt