New Zealand's Quota Management System is considered to be the acme of fishing policies. It basically works like emissions trading for fish - the government sets a (supposedly sustainable) total allowable catch for each species, deducts off a fudge factor for recreational fishing, then the rest is sold as transferable quota which can be bought and sold. So theoretically the people who can profit the most from fishing buy the quota, while the total catch is kept within sustainable limits.
However, fishermen don't always catch the fish they're supposed to. All sorts of stuff comes up in their nets, and is usually discarded (this is known as bycatch). The QMS handles this by requiring fishermen to keep track of their bycatch, and pay a "deemed price" for it - essentially a fine for catching the wrong fish.
But now a study from the Ministry of Fisheries shows that - surprise, surprise - fishermen lie about their amount of bycatch in order to minimise their costs. The variation between reported bycatch between boats with inspectors on them and boats without is so large that the chances of it happening by chance are "miniscule". Their conclusion? Bycatch reports by fishermen contain "large elements of fiction".
This is a serious problem. The QMS depends on accurate catch reports to assess the environmental impact of fishing. If those reports are inaccurate, then more fish are being killed than expected, with a consequent effect of sustainability. The upshot is that they will need to lower the total allowable catch to compensate - effectively adding a fudge factor to account for lying fishermen.
