Fishing

AimsKnow the life cycle of a salmon.Know the pros and cons of salmon farming.Look at some of the advances in commercial

fishing.Identify the reasons that the atlantic cod

fisheries almost collapsed.Identify methods that can be used to help

avoid overfishing.Know what the common fisheries policy is

Salmon farming

Eggs

Fry – tiny fish

Parr

Smolt – young salmon on its way to the sea

Adult salmon

Life cycle of the Atlantic Salmon

How are they farmed?Fish farm companies keep ‘brood fish’ from which they carefully collect eggs and sperm to produce

fertilised eggs.

The fertilised eggs are kept in trays with well-oxygenated water flowing over them. When they hatch they are transferred into tanks where they

grow from fry into parr and then change into smolts. It usually takes about two years for the

salmon to reach the smolt stage

Once the young salmon have become smolts and are ready for life in the sea the fish farm

companies move them (in tanks on lorries or, in some cases, by helicopter) from their fresh water

tanks to the large sea cages where they spend another one or two years growing to a suitable

size for sale .

Fish farming provides

consumers with a source of food

Fish farms can be seen as an eyesore in

unspoilt wild landscapes.

Parasites and diseases from the farmed fish may spread to wild fish

Waste food, faeces and ammonia excreted by the fish can cause eutrophication and organic matter pollution.

fed on food made from other fish which have to be caught

Fish farming helps the economy and provides jobs, often in areas where there are few job opportunities.

Farming fish under controlled conditions may help to reduce pressure on wild stocks of fish.

Making fishing more efficient

larger, more powerful boats with engines, rather than small sailing vessels;

sonar and echo-sounding equipment – ‘underwater radar’

(but using sound rather than radio

waves) which allows fishing boats to

locate shoals of fish much more easily;

nylon nets and lines which are lighter and

stronger (and can therefore be much larger) than earlier

ones which were made from natural

fibres;

use of factory ships which allow fish to be

processed at sea, allowing fishing

boats to spend much longer periods of

time on the fishing grounds.

Why are natural fish stocks running low?This is a four mark question. To get all four

marks you must give two reasons and explain them.

The Newfoundland cod fishery – a classic example of overfishing Between 1850 and 1950 the catch of Newfoundland cod amounted to around

250,000 tonnes every year. The fishing was done using traditional boats and nets. In the 1950s modern factory ships, mainly from Europe, began fishing off

Newfoundland. There were large trawlers with massive nets. The peak catch from Newfoundland waters was 800,000 tonnes in 1968, but by

1975 it was clear that overfishing was happening and the catch that year was down to 300,000 tonnes.

In 1976 the Canadian government extended its exclusive fishing zone from 12 miles to 200 miles from the coast, preventing foreign boats from fishing within that limit.

By the mid-1980s Canadian fishermen were taking over 250,000 tonnes of fish each year. They used large trawlers with massive nets which scraped along the bottom, harming sea-bed habitats and catching many spawning fish.

In 1988 fisheries scientists recommended that the total catch allowed should be cut by half, but nothing was done and so by 1990 the scientists were warning that the Newfoundland cod fishery was in danger of being wiped out by overfishing.

In 1990 the total biomass of spawning cod off Newfoundland was estimated at 400,000 tonnes. By 1994 this had fallen to 1,700 tonnes.

In 1992 the Canadian government banned fishing for cod off most of the Newfoundland coast and there were further cuts on fishing in 1994.

Over 40,000 people lost their jobs as a result of the Newfoundland cod collapse and although the economy of the area has begun to grow again there are very few signs that the cod population is recovering. some ecologists believe that once overfishing removes the cod other species move in and prevent the cod from returning.

Limiting overfishingFisheries scientists study fish populations to find out whether they are being managed sustainably, but it is up to governments to take measures to prevent overfishing. Possible methods include:

Closing fisheries to allow stocks to recover by breeding;

Limits on times when fishing occurs so that spawning fish are not caught;

Fleet reductions – fishing boat owners are given compensation in return for taking boats out of use so that there are fewer boats catching the fish;

Mesh size regulations – regulations which state a minimum size for the holes in nets so that small fish can escape and hopefully grow large enough to breed.

Quotas – limits on the amount of fish which can be caught and landed.

Common fisheries policy Commercial sea fishing in the

waters around the countries of the European Union is regulated under the Common Fisheries Policy. The Fisheries Commission meets each year to set quotas and impose other regulations for EU fisheries. It is very difficult to find a balance between the need to make sure that fisheries are managed sustainably and the wishes of fishermen from all the different EU countries who want to be able to stay in business by catching as much as they can. The main scientific organisation which monitors EU fish stocks is ICES (the International Council for the Exploration of the Sea)

In most years there are complaints from fishermen that they are being driven out of business, but at the same time many scientists and environmentalists say that the EU gives in too easily to the fishing industry and is allowing overfishing to happen. As an example in 2007 ICES recommended that there should be no fishing for cod in the North sea in 2008: instead of following this advice the EU ministers decided to increase the amount which could be caught by 11% from the year before. Some people are worried that the North Sea cod fishery could go the same way as the Newfoundland fishery.