Crayfish, or kōura, have always been an important food for Māori. Traditionally they were caught by hand or taken in baited pots that were lowered around coastal reefs. Round or beehive-shaped pots, known as pouraka, were constructed from the stems of a native vine, pirita or supplejack, which were lashed together with harakeke (flax) fibre. Pots were set during the day and left overnight.
Commercial crayfishing was slow to develop. A small canning industry operated from 1906 until the 1930s, but the demand for crayfish was not high until 1948. In that year some crayfish tails were sent to the United States and an export market quickly developed.
Boom and bust
Large volumes of crayfish were caught from the Fiordland coast and around the Chatham Islands in the 1950s and 1960s. With high prices being paid overseas for crayfish tails, many fishermen decided to go crayfishing. They used steel-frame and wire-mesh cages in preference to the traditional supplejack pots.
By the late 1960s, more than 230 crayfishing boats were operating around the Chatham Islands. There was enormous waste of crayfish meat at this time as only the tails were frozen and exported; the bodies were usually dumped at sea or buried on land.
The boom years ended in the 1970s as crayfish landings in the Chatham Islands dropped from a peak of 5,945 tonnes in 1968, to around 510 tonnes in 1974. With a long period until maturity, the crayfish population was unable to recover quickly from such an intensive harvest.
Managing the fishery
In 1980 and 1981 the government attempted to control the number of boats harvesting crayfish by declaring certain areas to be controlled fisheries. In 1990 the Quota Management System (New Zealand’s system for monitoring commercial fish stocks) was applied to the crayfish industry.
In 2004, crayfish were New Zealand’s third-largest seafood export earner. Since 1991 there has been a steady export trade of live crayfish to Taiwan, Hong Kong, Japan and the United States, worth about NZ$110 million each year.
Around 400–500 tonnes of crayfish are legally caught by recreational and customary fishermen each year. Regulations govern the size of animals that may be taken, and there is a limit of six crayfish per person per day. Females carrying eggs have to be returned to the sea.
Crayfish play an important role in determining the type of habitat that prevails in an area. Animals and plants that play this pivotal role are known as keystone species. In areas where crayfish are fished to low levels, grazing kina (sea urchins) numbers often increase dramatically. With few predators controlling their numbers, the kina eat their way through kelp ‘forests’ so effectively that they destroy the kelp beds. When marine reserves are created, the density of crayfish and other predators increases, kina numbers fall and kelp forests are re-established.