In 1891 Ann, 70 is at Beach Ho, living on own means, Rushen with son Arthur 30, fisherman. Next door were Thomas and mary Cregeen. In 1901 Arthur, mariner 40, is a lodger with Thomas and Mary Cregeen on Shore Road, Rushen.
I cannot find Ann in 1901. There is a burial on Brian's site January 15, 1896, age 74, which looks like her, if she was born in February of 1821. There is an 1896 will on film number 0106523. There are two othe ann Wattersons who wer buried in Rushen in 1896, but it could be your Ann.
Arthur was buried in Rushen in 1938 aged 77.