Here's the court findings in that case.

http://www.ustaxcourt.gov/InOpHistor...ll.SUM.WPD.pdf

If you are not confident of convincing an IRS auditor, that you are engaging in tournament fishing to establish an income, it will be risky to declare it as a business. You could win your case, but could still be out money and time to prove your claims. And your entire tax records would be scruitinized as well, so it they uncover anything else, you would even be out more.