In addition to the obvious potential for quota busting or poaching, unreported highgrading and bycatch discards may either increase or decrease with the introduction of an IFQ regime. Gilroy et al. (1996) demonstrated that highgrading did not appear to change in either the Alaskan halibut or sablefish fisheries. It was estimated that bycatch mortality should decrease because fishermen can own quota shares for both species, so that regulatory discards are reduced.
Whether these problems are intensified or diminished by the implementation of an IFQ program depends (in part) on the economic incentives confronting fishermen. The incentives for highgrading, for example, depend on the magnitude of price differentials for various types and sizes of targeted species. As the price premium for fish of a particular size and type increases, the incentive to use quota for especially valuable fish increases along with the incentive to discard less valuable fish.
Incentives for bycatch can vary considerably as well. The more leisurely pace of fishing afforded by IFQs allows fishermen to avoid geographic areas or times when bycatch is more likely. At the same time, the more leisurely pace reduces the opportunity cost of hold space and, consequently, may also provide fishermen with new opportunities to retain a greater proportion of the bycatch as joint products. For example, although the halibut fishery encounters significant bycatches of rockfish (Sebastes spp. and Sebastalobus spp.) and although most rockfish and thornyheads command high exvessel prices, most of this bycatch was discarded during the derby fishery because halibut were even more valuable. A greater portion of this bycatch is now being retained. On the other hand, implementing an IFQ regime may favor some technologies over others. If the favored technologies typically involve more bycatch, bycatch rates can rise in the absence of enforcement.
Ultimately, therefore, whether highgrading, bycatch, and bycatch discard increase or decrease under an IFQ regime depends both on local circumstances, whether highgrading and bycatch discards are legal (or even required5), and on the enforcement response. One way to assess the likelihood of one outcome in relation to another involves comparing fisheries before and after they have implemented some form of IFQs. According to a survey conducted by the OECD (1997):