Common-property fishing grounds are
◦ often overexploited because fishing grounds are rivalrous and excludable.
◦ often underexploited because non-excludability means there is little investment in the resource.
◦ always efficiently exploited because fishermen now understand the dangers of overfishing.
◦ often overexploited because fishermen are concerned with preserving fish stocks for future fishermen.
◦ often overexploited because individual fishermen have no incentive to leave fish for the "next" fisherman.