* For a graphic on the British fishing industry and Brexit, click here: http://tmsnrt.rs/2DKUKZD
LONDON, Jan 31 (Reuters) - British fishermen hopeful of a post-Brexit boom may find life outside the European Union choppier than expected, a Reuters Graphic shows.
Changing sea temperatures, caused by climate change, have forced many of the fish most popular with British consumers, such as cod and haddock, to migrate north into cooler waters controlled by Norway and Iceland.
The graphic, drawn from the activities of tens of thousands of British and European fishing vessels, also highlights the importance of access to the European market to the industry - with Britain exporting around 75 percent of its catch to EU markets.
Britain and its European Union neighbors currently enjoy equal access to EU waters, and can buy and sell fish freely inside the worlds largest trading bloc. That will change with Brexit, but how is still to be negotiated.
Britain's waters have helped sustain fishing industries in neighboring countries such as Denmark, France, Ireland and Spain while the European Union controlled access under its Common Fisheries Policy.
But the British fishing industry is demanding a large share of the catch when control of the waters shifts from Brussels to London.
However, any restriction on EU market access would be likely to take the form of tariffs which can be as high as 24 percent on seafood.
(Writing by Nigel Hunt and Mark Hanrahan; Editing by Robin Pomeroy)