Food Security - Sustainable Fisheries (GCSE Biology)

Sustainable Fisheries

Fisheries

Sustainability

Fish have been a part of the human diet for years upon years. Societies have survived upon fishing. Our impact on the world has now led to huge reductions in the fish stocks in the sea as biodiversity decreases. We have overfished during periods, which has led to a dramatic reduction in the population of many fish such as cod.

We must make sure that fish stocks stay at a high enough level to that they can continue to breed or we may eventually lose species. The EU and other governments in the world have worked to reduce this by introducing fishing quotas.

• The EU have set TACs. TACs are Total Allowable Catches. These are quotas set by the EU regarding the fish stocks that can fished. They are changed every two years dependent on the stocks of fish. This helps to maintain fish stocks at a sustainable level.
• Fish nets sizes have increased. Fish nets have been made larger, in order to catch only large adult fish. This means that young fish can grow and reproduce, in order to maintain biodiversity.

Fish Farming in Tanks

Fish can be farmed in tanks so that the conditions and water quality can be controlled. Temperature, oxygen levels and pH levels can be monitored. The water can also be filtered to remove waste including leftover food and excretion. All of these together prevent the water becoming polluted. An added benefit is that it is really easy to control food supply to the fish.

Fish Farming in Cages

Cages in the sea can be used to farm fish too and the conditions in the cage can be controlled and monitored for effective fish farming:

• Prevents energy loss – the cages prevent fish from losing energy when swimming around.
• Can control their diet – the fish can be fed so they have a controlled diet so they get better quality food and can grow more.
• Protection from intraspecific competition – the fish won’t be eaten by predators.
• Protection from interspecific competition – younger fish are kept separate from the older ones so that they aren’t eaten by them.
• Selective breeding can occur – those fish that grow fast and are not as aggressive can be bred.

However, cages are prone to parasites and disease e.g. sea lice. Pesticides or biological pest control can be used to tackle this e.g. by introducing other small fish that feed on this lice.