Brassica on a Bullock, that net is garish. You're not going to lose that, are you? I bet that your eyes lock onto it every time you open your inventory. First thing you see. Boom - MYSTIC NET.
It has the same effect on marine life, of course. They're merrily swimming about, doing whatever lobsters and shrimp do, and then boom - MYSTIC NET. Not much they can do, is there? They're transfixed, drawn in by the brightest of blue colours, like moths to a mirrorball.
Which explains why the mystic net is rather formidable as a net. Not the most fashionable, mind.