I made my own out of parts from Lowes and Ace Hardware. The funnel was bought at Advanced Auto Parts. All in all, I am about $50 bucks into the thing, it works great and can hold lobsters, hog fish and lionfish as well.
Just stick it with a 3-4 foot pole spear with a paralyzer tip, push the damn thing into the funnel, pull the spear out and repeat.
the tube is pre cut 6 inch sewer pipe. It comes in a 2 foot section, perfect size. they also sell the end caps. You simply dremel out one end cap to make the hole for the funnel.
The other end cap, you put a PVC T through it to allow the water to drain when you get out. You dont want just a hole as a spinne will certainly get through.
Thumbscrews and stainless nut screws with spines on them do a great job of holding both end caps in place.
You cut the funnel with a razor blade and use a soldering iron to "stop drill" the end to prevent the crack from spreading. The funnels need replace from time to time but are cheap. My current funnell has had more than 400 lion fish go through it and is still holding strong. As you can see from the pic, it is getting a little worn and I need to make a new one soon.
I have made a few of these for friends. If anyone is interested, I can make them one.
Just doin my part to "Try" and keep the population under control.