Discarding can be highly variable in time and space as a consequence of changing economic, sociological, environmental and biological factors.
[3] Discarding affects the environment in two ways; firstly, through increased mortality to target and non-target species,[4] particularly at juvenile life-history stages, and secondly, through alteration of food webs by supplying increased levels of food to scavenging organisms on the sea floor, and to seabirds.
For example, species such as the Pacific halibut caught in longline fisheries in the Bering Sea,[7] or lesser-spotted dogfish[8] in beam trawls in the English Channel have survival rates of between 88 and 98 per cent.
Survival rates of roundfish discards are significantly lower, and this mortality is included in most International Council for the Exploration of the Sea stock assessments.
[11] The initiative in Norway has been coupled with a comprehensive programme of monitoring and surveillance and a system whereby areas can be opened and closed when bycatch rates become excessive.
[15] There was a measurable increase in discarding immediately following the introduction of the ITQ system,[16] despite the fact that fishers were offered 10 per cent of the market price for fish landed outside quota.
In an attempt to address this change, the New Zealand Government increased the percentage of market price paid to 50 per cent.
Years after difficult negotiations between stakeholders and member states, the EU updated the Common Fisheries Policy and included in Article 15 the Landing Obligation (Discard ban).