A variety of management controls are imposed on commercial fishers. The purpose of these controls is to ensure that fishing is sustainable, both in terms of the fish that is taken as well as the effects of fishing on the aquatic environment.
The controls apply to species managed both under the QMS and outside the QMS. They are commonly referred to as “input controls” as they restrict the how and where fishing occurs. These controls can be contrasted with “output controls” which limit the total quantity of fish taken.
The management controls commonly imposed are:
- Closed areas
- Closed seasons
- Size limits
- Gear restrictions
- Prohibited species
Some areas are closed to all fishers to protect juvenile fish and species found on reefs. Others are closed to certain commercial bulk fishing methods. For example, areas along the west coast of the North Island are closed to commercial trawling to minimise the catch of juvenile snapper which inhabit shallow water. Other areas are closed to commercial fishing to avoid localised depletion of fisheries, and to reduce conflict with recreational fishers.
Areas can also be closed to reduce impacts of fishing on protected species. For example, an area on the west coast of the North Island is closed to set netting to protect Maui dolphins from being caught.
Some areas are closed for a specific time to protect the fish stocks by reducing the opportunities people have to fish them. These areas are often closed to protect the fisheries during breeding periods. In other cases, eg, scallops, the fisheries are opened during the breeding season to allow people to harvest them when they are in peak condition.
Seasonal closures can also be used to prevent fishing at certain times of the year when protected species are particularly at risk. For example, Hector’s dolphins move closer to shore in the summer, and to reduce the chances of them being caught, recreational set netting has been banned along part of the east coast of the South Island over the summer period.
Size limits are imposed on most species to protect fish stocks. For example, blue cod must be at least 30 cm long (33 cm in some areas), and trevally and snapper must be at least 25 cm long. This is so juvenile fish can be given the chance to breed at least once before being caught. If too many young fish are taken, the fish numbers will decline.
Gear restrictions are usually imposed to protect young fish. Limits are set on things like the size of the mesh nets and the size of the nets themselves. Restrictions are also placed on how people can use nets. For example, it is not legal to set a flounder or mullet net right across a waterway.
Gear requirements are also imposed to ensure that the effects of fishing on the aquatic environment are addressed. For example, trawlers are required to use tori lines to help reduce the number of seabird mortalities that occur as a result of seabirds hitting trawl gear.
In some instances, commercial fishers have imposed their own set of voluntary measures to help mitigate the effects of fishing. In the squid fishery trawl vessels use exclusion devices that are designed to reduce the number of sealions being caught in trawl nets.
Commercial fishers are prohibited under fisheries regulations from intentionally taking toheroa, marine turtles, and black corals. Other legislation prohibits the taking of protected species including marine mammals and seabirds. Although protected species may be unintentionally taken in the course of legitimate fishing activities, there is a requirement to report any mortality. A number of management controls, such as gear restrictions or closed areas, are commonly used to reduce fishing mortality of protected species.