More demand, more pressure on wild fish: Capture fisheries must supply a world that wants ever more seafood. Fleets have answered with methods that catch more, faster, and many stocks are now overexploited.
The points to remember
- About 38% of the world's assessed fish stocks were overfished in 2021, up from 10% in 1974.
- Technology makes fishing very efficient: sonar finds shoals, GPS finds the spot again, huge nets.
- Bycatch: animals caught by accident, such as turtles, dolphins and young fish, often thrown back dead.
- Illegal, unreported and unregulated (IUU) fishing ignores quotas.
- Subsidies for fuel and boats keep too many boats fishing.
- Results: stock collapse, broken food webs, lost jobs, less food for coastal people.
Example (SL): West Africa. Large foreign trawlers fish off Senegal and Guinea, some without licences. Local fishers in small canoes now travel further for smaller catches, and much of the catch is ground into fishmeal for export.
Reading a fish production graph: Percentage change = (new - old) ÷ old x 100; a fall gives a minus sign. For a reason for the change, link one cause to the rise or fall: more demand, better equipment, subsidies, a ban, overfishing.
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In bottom trawling, heavy doors and chains plough the sea bed as the net is pulled along.
The points to remember
- It flattens slow-growing corals, sponges and seagrass: the habitat many species need.
- It catches everything in its path: huge bycatch of young fish and other animals.
- It stirs up sediment, which clouds the water and smothers life nearby.
- Damaged reefs and sea beds take decades to centuries to recover.
Remember it as: Like clearing a forest to catch the deer.
Example (SL): Norway's cold-water coral reefs. These deep reefs shelter fish such as redfish. Trawl nets broke up an estimated 30-50% of them, so in 1999 Norway banned bottom trawling over its best-known reefs. The coral grows so slowly that recovery will take centuries.
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Ghost fishing happens when nets, traps and lines are lost in storms, snagged on rocks or thrown overboard.
The points to remember
- Nets made of plastic last for decades, so they go on catching with no one to empty them.
- Trapped animals die and attract more animals, which are caught too.
- Turtles, seals, dolphins, seabirds and fish drown or starve in them.
- Lost gear also smothers and breaks corals, and adds to plastic pollution.
Example (SL): northern Australia. Ocean currents carry lost nets from fishing fleets far away into the Gulf of Carpentaria. Rangers from Aboriginal communities have pulled thousands of these ghost nets from the shore, many with dead turtles tangled inside.
Ghost fishing is not bycatch: Bycatch is caught by a net that is still being fished. Ghost fishing is done by gear no one controls any more, so it kills for years and is never counted in any catch.
On coral reefs some fishers use poison or bombs. Both catch fish quickly and cheaply, and both destroy the reef that the fish depend on.
The points to remember
- Cyanide is squirted onto the reef to stun fish so they can be caught alive.
- Live reef fish sell for high prices to restaurants and aquariums.
- The poison kills coral and many small animals that are not wanted.
- Blast fishing: a bomb thrown into a shoal kills every fish nearby; only some float up and are collected.
- The blast turns the reef into rubble, which takes decades to recover, if ever.
Example (SL): Tanzania. Along the coast near Dar es Salaam, some fishers make bombs from fertiliser and fuel in bottles. A blast kills all the fish nearby and leaves a crater of broken coral. The government has run patrols and campaigns against it, but it goes on in places.
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Harvesting some aquatic species is controversial: people strongly disagree about whether it should happen at all. To explain why, give arguments on both sides for one named species.
Arguments against
- The species is endangered or overfished.
- Animals have a right to exist (biorights).
- The method is cruel or wasteful.
- It may break international agreements.
- Bycatch kills other species.
- Ecocentrics oppose large-scale harvests.
Arguments for
- People need it to survive (subsistence).
- Whole economies and jobs depend on it.
- It is a cultural tradition.
- Harvests within sustainable limits do no harm.
- Aquaculture can supply it instead.
- Anthropocentrics support managed harvests.
The points to remember
- Name one species and use real facts about it.
- Give arguments against as well as for: 'controversial' means people disagree.
- One point per paragraph: each [1], up to [7].
Example (SL): Atlantic bluefin tuna. A single fish sold for over US$3 million at a Tokyo auction in 2019. Overfishing and illegal catches pushed the eastern stock down by the 2000s. Strict quotas from 2007 let it recover, but people still argue about how much should be caught.
How this comes up: Paper 2 Section B asks why harvesting a named aquatic species may be controversial [7]; Paper 1 asks for a reason a fish catch changed [1].
Some aquatic species are harvested even though many people object.
Explain why the harvesting of a named aquatic species may be controversial.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.