This coin features a European spider crab (Maja squinado), known locally in Guernsey as the 'Chancre Crab' (pronounced SHANKer). This crab supports an important commercial fishery and is served as fine cuisine. So it seems strange they would call it a 'shanker' which has a very unappetizing meaning.
This bronze coin was issued from 1985 to 1990, then a copper-clad steel version (KM40a) was issued from 1992 to 1997. In 1998, a version with the same crab reverse, but an updated portrait started (KM89).
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