WHERE DO FISH AND SHELLFISH COME FROM?

 
These notes help children to find out how we catch or farm the fish and shellfish we want to eat. With the Seas and Oceans covering two thirds of the planet fishing is an important Industry throughout the world. To become confident and informed consumers of fish and shellfish children can investigate some of the ways fish and shellfish may be caught or farmed. They can think about the impact of the differing fishing and farming methods on the environment and consider sustainability.





 
Fish to Food.. a short introduction to fishing lasting 6-7 minutes the video focuses on - a beach fishery at
Hastings where the fishing fleet is made up largely of small day boats.  The fish are caught using a
variety of nets such as trammel nets, iced and transported for sale.  There are some pictures too of
Billingsgate and traditional fishmongers. 

 

 




  







There are over 10 different methods for catching wild fish and shellfish. 
Consider some of the main catching methods and which catching method maybe used for
which species.  The Catching Fish & Shellfish worksheet illustrates some of the methods. 

 

 

Catching Fish and Shellfish - Notes
 
 
Pots and Creels - traps, baited with fish, lay on the sea bed to be collected later.
Species - shellfish such as crab, lobster, whelk, langoustines and octopus.


Line Caught - Longlines - a line approximately 50 – 100km long is set and from this come branch lines carrying baited hooks.  Fishing can be large or small scale with in shore boats using less than a thousand hooks while offshore vessels would set tens of kilometres of lines with thousands of hooks.
Pole and Line is particularly suited to schools of fish such as Tuna. Poles are simple hand held rods with bait attached or for larger scale fisheries mechanically operated rods.
Species - Pelagic fish such as Tuna and Mackerel; Demersal species of fish such as Sea Bass, Cod, Pollack, Haddock, and Halibut.


Nets - gill, Tangle and Trammel - these vary in design but they are used in areas where it is difficult to tow a net because the habitat is rocky or there are wrecks.  Different nets are designed for different species and the mesh sizes can vary.  Depending on the type of net the nets float vertically in the water, are fixed to buoys or staked to the sea bed.
Species - tuna, squid, monkfish, Dover sole, mullet, gurnard, wild salmon and trout


Fishing on or near the sea bed - Demersal Trawling -  There are several different methods – otter and beam trawling, seine netting; but essentially the nets are towed by a boat – a trawler.  One or two boats may tow a funnel shaped net behind the boat or from either side of the boat. With Seine netting , the net is towed vertically in the water.  Some methods “tickle” the sea bed to disturb the fish and encourage them into the nets.
Species - Demersal (bottom living) species – flat fish as well as prawns and round white fish – cod Pollack, Coley


Mid Water Fishing - Pelagic Trawling – a funnel shaped net is used and one or two boats, the net is towed through the water and intercepts the shoal of fish. Some boats pump the fish on board form the net. A similar method is called Purse Seining – where a whole school of fish is encircled with a large wall of net up to a mile long. The net is then drawn together like a purse.
Species - Herring and Mackerel, Anchovies; possibly young Tuna for stocking Fish farms


Dredging - Metal framed nets are dragged through the sea bed, rakes are attached to release the shellfish from the sea bed.
Species - Scallops, oysters and clams, mussels


 

 












Aquaculture (or fish farming) accounts for about 50% of the global seafood supply. 
There are several methods – the whole process from breeding eggs to harvesting the fish when grown,
for example sea bass, sea bream; catching young fish or shellfish in the wild and then harvesting when
grown, for example mussels; eggs are hatched and the released into the wild as young fish to
be caught as wild species when grown, for example lobsters.

The Farming Fish and Shellfish worksheet (below) illustrates some of the main farming methods.



 
 
 
Farming Fish and Shellfish (Aquaculture) - Notes
 

Advantages & Disadvantages

Cage, Pens – Stock numbers need to be well managed and disease monitored.  Escapes need to be monitored to prevent impact on the wild species. Natural controls have been put in place for diseases.  Some fish are herbivores so there is not the need to rely on wild stock for food.  A certified farming scheme has been introduced to monitor the operations.  
Species - salmon, sea bass and sea bream, trout, pagasius (basa or river cobbler)

Tanks or Ponds – Does not rely on local water supply so less likely to compromise the local habitat.  Location needs to take into account environmental issues. If stocks use wild caught young species, this needs to be from a well managed fishery.
Species – Trout, tilapia, eels, warm water prawns

Mollusc Farming Rope grown mussels filter the water to feed and are sometimes considered to benefit the areas in which they grow by improving the water quality
Species – mussels, oysters, scallops, clams,









 


 


Use the simple concept map (below) to establish and discuss what the children understand about sustainability and the environmental impact of fishing and aquaculture on our oceans, rivers and seas.











Buying, Cooking and Eating Fish and Shellfish