If you have a strap at the back of your neck, or a D-ring you can conect a quick release magnet there. They have a long coil cord that has more reach than you'll need. I carry my hikeing staff on my back conected to one. All you would do is reach back and grab your net and pull on it and the two magnets would release. When you are done with it, just hang the magnet in the area that it is conected to and the two magnets will join together.
I bought mine at an Orvis shop, I paid a little over 30 dollars after tax for it. You might be able to find one for less.