Sportfishers introduced the Zander, a type of perch, to Britain' s rivers and canals in the 1970s  Because zander eat large numbers of smaller fish, they have had a devastating effect on native fish populations  To protect the native fish, a government program removed a significant proportion of the zander from Britain' s waterways last year
Surprisingly, this year the loss of native fish to zander has been greater than before
Every year a large number of zander are caught by sportfisher in Britain's waterway.