In theory, it's hard to set up property rights systems over many goods. A classic example is fish in the sea. Usually property rights involve stuff that stays put or whose movement you can control. But dividing up the ocean would be unimaginably difficult and hardly desirable even if we could do it. And fish will swim around.
So it would seem that it's pretty hard to have property rights over fish—who's to say that this fish is mine or yours? When a fish swims into my plot of sea does it become mine, or is it still yours because it came from your plot of sea?
Of course, laws have got around these simplistic problems, and given fishermen "individual transferrable quotas"—each of them are only permitted to bring back a certain number of fish (details explained well here). It encourages efficiency, because if someone else can haul in your take cheaper than you, you can sell your right to them. But unlike a total quota, there's no race to bring in as many as possible in as short as possible a time.
This system has done pretty well at preventing stock collapses and has been emulated in Alaska, New Zealand and elsewhere. But it may have another benefit, according to a new paper by Lisa Pfeiffer and Trevor Gratz: reducing fisherman risk-taking:
Commercial fishing is a dangerous occupation despite decades of regulatory initiatives aimed at making it safer. We posit that the individual allocation of fishing quota can improve safety by solving many of the problems associated with the competitive race to fish, which manifest themselves in risky behavior such as fishing in poor weather. We present a previously unidentified approach to evaluation: estimating the change in the propensity to start a fishing trip in poor weather conditions as a result of the management change. We chronicle a revolution in risk-taking behavior by fishermen (a 79% decrease in the annual average rate of fishing on high wind days) that is due to the change in economic incentives provided by rights-based management.