Vagaries of the UK Tax system – “sharefishermen”

Having been self employed for the last tax year, I have to contribute National Insurance contributions only at the paltry rate of £2.00 a week. Not bad. But what really made me laugh was the appearance of a separate category for conributions entitled “Sharefisherman” who have to pay £2.65, a whole £33.80 extra a year. I mean, what the %$*! is a “sharefisherman”?? Google to the rescue – Under an Irish tax document, you find this definition –

“In the fishing industry, one of the traditional methods of payment to crewmen/women working on board fishing vessels is by ‘share’ of the value of the catch. If you work in the fishing industry and are paid solely by ‘share’ of the catch you are a Share fisherman /woman.”

No particular explanation as to why they are charged more, but I’ll let you know if I find out.