Hey OO,
On a marine biology trip we caught a few bobtail squid of a small warf - basicially we used a small light trap powered by a car battery to catch them.
The light trap is made of clear acrylic and has funneled entrances so they cant get back out. This trap was actually for catching plankton and other animals but we caught 3 bobtail squid after only 2 hours.
They died pretty quickly, although one did last over night. They were in a 2 cm deep viewing tray - which is probably the reason for their quick demise.
Unfortunately I didnt know what I know about them now, it would have been great to try and see how long I could keep them alive. Their chromatophores were cool - when you move close to them they went dark red. The squids were about 4 cm's long, and I'm pretty sure they were bobtails.