Sustainability

• Sustainable fishing preserves future fish stocks

  There is concern over how fishing methods are damaging the environment so there needs to be methods to conserve fish stocks and make fishing more sustainable.
• Bottom trawling is destructive, e.g. the nets that drag across the seabed can destroy corals, which are a habitat for lots of marine life.

  Trawlers can also catch unwanted animals, like dolphins or turtles, in their nets. (Bycatch)

  Overfishing is when more fish are caught than can be replaced by natural reproduction. E.g. the demand for bluefin tuna to make sushi has led to overfishing. Bluefin tuna are now endangered (at risk of going extinct).
• A sustainable method is one that doesn't damage the environment or use up finite resources.
• Alternative fishing methods


  E.g. Longline fishing uses a fishing line with baited hooks secured between two buoys. Fewer fish are caught and there is less chance of catching unwanted fish.
• Fishing quotas


  Quotas set by governments help endangered species of fish. They limit the amount and sizes of fish that can be caught.
• Regulating net size


  Holes in fishing nets have to be a certain size, so that smaller, unwanted fish can escape.
• For thousands of years, humans have caught wild fish from the sea and rivers to provide them with protein. Today, fish and seafood (shellfish such as mussels, scallops; crustaceans such as prawns and crabs, etc.) provide over three billion people with their main source of protein. Fisheries (places where caught fish are brought on boats) are very important for local communities as they provide employment and bring in money, but there are pressures on fishing to become more sustainable.
• Modern fishing boats are large trawlers (sometimes called factory ships). They drag (trawl) large fishing nets through the water and sometimes across the sea bed to catch fish. The fish are pulled onto the ship and then processed: sorted into type, gutted (cut open to remove their digestive systems and other organs) and chilled to keep them safe to eat for when they are brought ashore and sold in a market
• 1. Trawling a net at sea to catch fish
  2. A catch of fish brought in by a trawler
  3. Processing fish on a trawler
  4. A busy fish market in Greece
• Environmental concerns about fishing

  Over the years, large-scale, commercial sea fishing has become big business, which has caused problems for fish stocks (the numbers of fish available to catch) and the marine environment (the sea, seabed and all the other plants and animals that live in the sea). Fishing has become unsustainable because of:

  • Damage to habitats and ecology
  • By-catch
  • Overfishing
• Damage to habitats and ecology


  When trawlers drag their nets across the seabed, they remove everything (plants, animals and fish of all sizes) and can damage habitats (where animals and plants live and breed) and the natural ecology, which can take years to recover. This severely reduces the food available for any remaining fish.
• By-catch


  Fish that are caught but too young and too small to be eaten, so they are discarded (thrown back dead into the sea)
• Discarding young and small fish

  Breaks the natural life-cycle of the fish and reduces the number that will go on to become adults to lay eggs for the next generation of fish
• By-catch

  Not all the species of fish that are caught are wanted because they cannot be sold, so they are discarded
• By-catch

  Sometimes other marine life (e.g. dolphins, sharks, sea turtles, corals, starfish, etc.) get caught up in the nets and cannot escape
• Catching other marine life

  Upsets the natural life-cycles of these species, causes pollution as they decompose and reduces the biodiversity (the varieties of marine life) in the sea
• Overfishing

  This means that more of particular species of fish (e.g. cos) are caught than is sustainable, because they cannot be replaced quickly due to the length of the life-cycle of the fish. In 2009, it was estimated that more than half of the world's fish stocks were overfished (Food and Agricultural Organization).
• Overfishing also affects the food chain because it removes species of fish that are eaten by other species of marine life.
• Making fishing more sustainable

  The numbers of fish (fish stocks) in the sea need to be conserved (protected by law from overfishing) so that their natural life-cycle can go on and increase their numbers, which will take a long time for some species of fish.
• Making fishing more sustainable

  To reduce overfishing, fish quotas (the number of fish of certain species and size that are allowed to be caught by law) have been set for EU countries and fishing boats. If fewer fish are caught, there is more chance that remaining ones will breed and help the fish stocks recover.
• Making fishing more sustainable

  The size of the holes in fishing nets have been increased by law, so that only larger, mature fish can be caught, and smaller, immature fish have a greater chance of escaping the net.
• Making fishing more sustainable

  Fish need to be caught using methods that do not cause damage to natural ecosystems and habitats, and limit the amount of by-catch (e.g. line caught)
• MSC logo means 'Marine Stewardship Council' - an organisation that promotes sustainable fishing practices.
• It is possible to buy fish products that have come from sustainable sources. They often have a logo on the packaging to indicate this.
• Sustainability

  Sustainability describes human activity that is not harmful to the environment and does not deplete natural resources, thereby supporting long term ecological balance.
• Sustainable source:


  When a food or ingredient originates from a continuing or renewable source.

  E.g. Fishing from farms or other sources that are able to sustain reproduction without a negative impact on the species or environment.
• Give 4 reasons why fish stocks are declining in our seas and describe how it can be avoided.

  Overfishing, by-catch, climate change and pollution.

  These can be avoided by sustainable fishing - using bigger nets to avoid by-catch, amount of fish caught not exceeding a quota...
• What is by-catch? How can it be avoided?

  By-catch is when fishing boats accidentally catch fish and animals that they don't really want or shouldn't take.

  It can be avoided by using nets with larger holes or line catch flags.
• What is MSY and explain what this means?

  Maximum sustainable yield. The amount of fish they can catch without overfishing.
• Name 4 sustainable species of British fish.

  Hake, oysters, mussels and mackerel.
• Which species of fish are particularly decreasing in British and overseas waters?

  Sturgeons, salmons, and giant catfishes.
• Why does seasonality of fish have a bearing on when in the year we should fish particular species?

  Because we need to leave them there for a period in a year for them to reproduce and grow so that the lifecycle is not broken.