Individual fishing quotas (IFQs) also known as "individual transferable quotas" (ITQs) are one kind of catch share, a means by which many governments regulate fishing. The regulator sets a species-specific total allowable catch (TAC), typically by weight and for a given time period. A dedicated portion of the TAC, called quota shares, is then allocated to individuals. Quotas can typically be bought, sold and leased, a feature called transferability. As of 2008, 148 major fisheries (generally, a single species in a single fishing ground) around the world had adopted some variant of this approach, along with approximately 100 smaller fisheries in individual countries. Approximately 10% of the marine harvest was managed by ITQs as of 2008. The first countries to adopt individual fishing quotas were the Netherlands, Iceland and Canada in the late 1970s, and the most recent is the United States Scallop General Category IFQ Program in 2010. The first country to adopt individual transferable quotas as a national policy was New Zealand in 1986.
Historically, inshore and deep water fisheries were in common ownership where no one had a property right to the fish (i.e., owned them) until after they had been caught. Each boat faced the zero-sum game imperative of catching as many fish as possible, knowing that any fish they did not catch would likely be taken by another boat.
Commercial fishing evolved from subsistence fishing with no restrictions that would limit or direct the catch. The implicit assumption was that the ocean's bounty was so vast that restrictions were unnecessary. In the 20th century, fisheries such as Atlantic cod and California sardines collapsed, and nations began to limit access to their fishing grounds by boats from other countries, while in parallel, international organisations began to certify that specific species were "threatened", "endangered", etc.
One early management technique was to define a "season" during which fishing was allowed. The length of the season attempted to reflect the current abundance of the fishery, with bigger populations supporting longer seasons. This turned fishing into a race, driving the industry to bigger, faster boats, which in turned caused regulators to repetitively shorten seasons, sometimes to only a few days per year. Landing all boats over an ever-shorter interval also led to glut/shortage market cycles with prices crashing when the boats came in. A secondary consequence was that boats sometimes embarked when the fishery was "open" regardless of weather or other safety concerns.