World GeographyUnit 4: Primary Resources

Food From the Oceans

Technology and Fishing ActivityThe commercial fishery in most countries

consists of two sectors.InshoreOffshore

Both sectors use a wide range technology that allows them exploit the fishery.

Inshore FisheryInshore Fishery:

Boats under 25 m Owner operatedSuitable for shallow water within 20 miles of

shoreNo refrigeration on boardSmall CrewsReturn to port everyday Cannot operate in poor weather

Offshore FisheryOffshore Fishery:

Capital intensive: Requires large investments of capital resources (boats, gear, crew)

Less labour intensiveLarge trawlers 35-45mBoats owned by large companiesLarge range, can fish anywhereThey have refrigeration on board so they can

stay at sea for long periods

Categories of Fish CaughtThere are three main categories of fish that

are caught in the commercial fisheryDemersal: fish that live near the ocean floor;

also known as groundfish. Ex: Cod, halibut, and shellfish.

Pelagic: Fish that live in schools near the ocean surface. Ex: Mackerel, Herring and Salmon.

Shellfish: Aquatic animals that have a shell. Ex: Lobster, crab, mussels.

Fishing GearThere are four types of gear that we will be

discussing:1. Otter trawl2. Gill net3. Purse seine net4. Trolling

1. Otter TrawlOtter Trawl: A funnel shaped net attached to

the stern (back) of a trawler by towing cables.Used for demersal species (cod)The net is towed along the sea floorTwo boards hold the mouth open Fish are scooped upOnly suitable in water no less than 200m deep.

http://www.youtube.com/watch?v=c_Vd4L37X4k

2. Gill Nets Gill Net: A nearly invisible mesh net

Held up by floatsDragged down by weightsHangs like a wall in the oceanMesh is large enough to allow fish to swim into

the net but not through itIn trying to get out the fish get tangled

3. Purse Seine NetPurse Seine Nets: best looked at as a procedure.

Used for pelagic fish.1. Fish are spotted2. Net is put out3. High powered small boat takes the end of the net

and circles around the fish, trapping them in.4. A cable that runs along the bottom of the net is

drawn in causing the net to come to the surface.5. As the net surfaces it is taken into the boat full of

fish... Hopefully.

http://www.youtube.com/watch?v=ACcO2_E5RfY

4. TrollingTrolling:

Fishing poles with many hooks are extended over each side of the vessel

The lines have numerous lures on each lineThe fish take the lures and are caught.Pelagic fishing.

Trends in global fish catchesThe location of major fishing grounds:

1. About 80% of fish harvested come from oceans

Why is this obvious? Most of the world’s water is ocean therefore it

would be expected that fresh water would only contain a small portion of the world’s fish.

2. There are 4 major fishing regions • North east Atlantic (England/Norway) • North west Pacific (Japan) • West central pacific (China/Indonesia) • South east pacific. (Western South America)

These images are found in your textbook on pages 199 and 202.

Trends continuedThe continental shelfMost fishing grounds are found on

continental shelves for 2 reasons:1. The shallow waters of the shelf make

harvesting more cost effective. 2. The shallow waters of the shelf promote

plankton production which serve as the base of the marine food web including fish

Shallow water ensures: enough light for phytoplankton. Effective circulation of nutrients

Trends in NL fish catches…Diagrams 12.16 & 12.17 on pages 212 and 213 are

graphs that show the long term trends in fish catches in Newfoundland.

Figure 12.16 shows the steady decline in the fishery from 1962 to 1992. In the late 1970s-early 1980s there was a small rise in fish stocks which gave scientists hope for the cod stocks. Unfortunately, by the early 1990s it was clear that if drastic measures were not taken the fishery might never come back. This lead to the complete shutdown of the commercial cod fishery in NL, known as a moratorium, in 1992.

Trends…As the ground fish stocks were proving

unreliable fishermen began to explore other types of fish through the 1980s. A growing trend in shellfish has come on stream and pelagic fish such as mackerel and capelin have become popular as well. Aquaculture is also fast become a vital part of the Newfoundland fishing economy.

Why?Why did the cod stocks collapse? There were

several things that lead to the ultimate collapse of one of the world’s most lucrative groundfish fisheries.

Technology – the introduction of factory freezer trawlers, otter trawls, and radar and sonar all allowed fishermen to catch more fish in one voyage than ever before.

Ecology – Large by-catches of non-commercial species such as capelin disrupted the food chain, rising ocean temperatures due to climate change affected the survival of the species and inadequate data regarding the ocean ecosystem lead to mismanagement.

Impacts on Marine EcosystemsTypes of gear: Some types of fishing gear such

as otter trawls greatly disturb the ocean floor and destroy spawning grounds.

Air pollution: Damage to the ozone layer has been linked to a decrease in plant production. Phytoplankton is a major food source for fish and it needs sunlight to grow; just like plants on land.

Water pollution: Chemicals and waste products that are dumped in oceans affect the entire marine food chain. Plankton, fish, sea birds and sea mammals are all impacted through poisoning, sickness loss of habitat or loss of a food source.

Impacts continued…Over fishing: Severe over fishing of a

particular species has led to the collapse of fish stocks and the disruption of the food chain in some areas.

Climate change: Climate change has lead to a global change in ocean temperature. While it’s only a few degrees, that is enough to kill off entire species which are accustomed to a particular temperature. Lack of pack ice leads to a decrease in the number of seals as they have no where to give birth.

Major Sources of Ocean PollutionShips at sea dumping bilge and waste materials such

as plastics and other garbage.Runoff from industrial facilities on land.Oil spills from tanker ships transporting oil, or leaks

from offshore oil rigs.Air pollution – not only does damage to the ozone

layer affect marine life but physical particles of pollution in the air settle on the ocean and hurt marine life.

“Down the Drain” mentality – the dumping of oil and chemicals from household use. Used oil from vehicles, chemical cleaners, paint, and road runoff are a huge contributor to ocean pollution.

Natural disasters and storms often end up spreading large amounts of debris and pollution into the ocean.

The value of aquacultureAquaculture is the cultivation of aquatic animals

and plants, especially fish, shellfish, and seaweed, in natural or controlled marine or freshwater environments.

Economic effects?Provides jobs: fisherpeople, plant workers, truck

driversHelps other industries: nets, ropes, shipbuilding,

fibreglass workers, creates work in these areasFacilitates partnerships world wide: governments

trade fish quotas with other countries in return for other goods, services, tax breaks, etc.

Can create problems when the economy is based too much on one thing. In NL, when the fish stocks collapsed, the economy collapsed too.

Environmental effects?Ocean ecosystems are disturbed by some types of

gearIf too much of one species is taken the food chain

could be disruptedSometimes some food chains are kept in balance

when species are hunted. Ex: Seal hunt kept the seal population in check. Seals are over abundant now and put a lot of stress on cod stocks.

Ships that do not follow proper procedures at times dump oil and chemicals in the ocean rather than face the expense of proper disposal.

Large by-catches of some species can create problems in the ecosystem. Ex: Dolphins are often caught in Tuna nets. Turtles are often caught on trolling lines.

Issues in a sustainable fisheryTo maintain a sustainable fishery means

learning how to control how much of the resource we use and how to keep the quality of the resource at a high level.

It is equally important that once these methods have been discovered, we must practice them.

The world’s average consumption of fish is only about 16%. However, in regions with large populations (such as Africa and Asia) fish is much more heavily relied upon as a source of protein. Researchers estimate that as the world’s population rises there will be a greater and greater demand for fish.

The current pressure on fish stocks have already cause some to collapse.

Issues continued…Some nations maintain huge fleets of factory-freezer

trawlers, factory ships and smaller trawlers and support vessels. These large fleets put enormous pressure on fish stocks and tend to put the small boat fisherman out of work. This causes them to leave their homes and entire communities have disappeared as a result.

Many countries with coastline (maritime countries) have extended their legal jurisdiction to 320km offshore to help combat these trends. However, governments often sell licenses to foreign countries to fish within these limits. As well, many foreign countries still send factory-freezer trawlers and fish without permission in (or just outside of) these zones. Some countries have vast maritime regions and do not have the resources to police their 320km limit zones.

These trends have angered inshore fishermen who try to fish in more traditional ways. The foreign fleets put a lot of stress on the offshore stocks, and eventually the inshore stocks.

Pages 209-211 in the text outline some examples of “fish wars” in India and Canada where fish stocks and migrating patterns have caused problems with the neighbours.

In 1995 the Canadian government, lead by Newfoundland politicians took on the government of Spain in what became the “turbot war”. The government of NL accused the Spanish government of illegally overfishing within the Canadian zone and also using nets that were too small. There were a lot of disputes with actions almost escalating to violence. In the end there were new treaties and groups put in place to manage such international disputes.