Unsustainable Fishing Practices (DP IB Environmental Systems & Societies (ESS))

Unsustainable Fishing Practices

• Developments in fishing equipment and changes to fishing methods have led to dwindling fish stocks and damage to habitats

• Fish stocks (the populations of fish that we catch for food) in the oceans are declining

• This is mainly due to overfishing

• This could potentially result in:

  • Some species of fish completely disappearing in certain areas or even going extinct (e.g. we are at risk of losing cod completely in the north-west Atlantic)

  • Ocean food chains being disrupted, affecting many other aquatic species

  • Fewer fish for human consumption – this would be especially problematic for populations that rely on fish as a main source of food

• For these reasons, it is important to maintain fish stocks at a level where breeding continues

• Sustainable fisheries are required to achieve this – these are fisheries in which the overall population size of fish species does not decrease as the number of fish caught in a given time period (e.g. a year) does not exceed the number of new fish that are born

• Sustainable fishing means:

  • Leaving enough fish in the ocean

  • Protecting habitats and marine food webs that fish rely on

  • Human communities that catch and process fish can maintain their livelihoods

Measures to make commercial fishing more sustainable

Mitigating Unsustainable Exploitation

• Unsustainable exploitation of aquatic systems can be mitigated at a variety of levels (international, national, local and individual) through policy, legislation and changes in consumer behaviour

• For example, control of net size and the introduction of fishing quotas play important roles in the conservation of fish stocks at a sustainable level

• Increasing the size of gaps in fishing nets can help in two main ways:

  • Fewer unwanted species (that are often simply discarded) will be caught and killed, as they can escape through larger net gaps (as long as they are smaller than the species being caught – the accidental capture and killing of larger species is still a problem that is reducing the populations of these species)

  • Juvenile fish of the fish species being caught can escape through larger net gaps, meaning they can reach breeding age and have offspring before they are caught and killed. This ensures the population of the fish species being caught can be replenished

• In addition to tighter controls on net size, fishing quotas that limit the number and size of particular fish species that can be caught in a given area have been introduced by many countries to stop species becoming overfished

• Governmental regulation can be enforced by:

  • Establishing fishing quotas

  • Agreeing areas of the ocean where fishing is banned (e.g. spawning grounds) and permitted (e.g. within a country's territorial waters)

  • Regulating mesh size of nets (to allow undersized/juvenile fish to escape)

  • Limiting the size of the fishing fleet by issuing licenses

  • Inspecting the catch as a fishing boat returns to port

  • Banning certain practices e.g. gillnets (static nets that catch anything that swims by, and the fish struggle and die in distress)

  • Promoting sustainable practices such as trolling (different to trawling) that reduces bycatch

  

  Trolling uses hook-and-line and reduces bycatch and damage to the seabed

• Nevertheless, a lot of commercial fishing is still carried out illegally

  • There is an extremely large area of ocean for authorities to patrol

  • High demand and profit potential have made fish poachers more daring and willing to break the law