Where conditions are suitable, crayfish occur right round the New Zealand coast and the commercial catch is predominantly the one species Jasus lalandii. A less common species, J. verreauxi, is taken commercially mainly in the vicinity of Mercury Bay, but isolated specimens do occur in most North Island waters. Although occasionally some catches of crayfish are made in trawls, the method universally adopted is fishing with baskets or pots. This fishery has expanded very considerably since 1947, when an export market for the tails developed with the U.S.A., and it has become the most valuable single species landed. The southern and south-western parts of the South Island produce over 60 per cent of the total catch. Fishing is done by boats from Bluff and Stewart Island, and also from Dunedin, Westport, and Greymouth. The total catch of crayfish increased rapidly from 1947 to a peak in 1956 when 130,815 cwt were landed. It has since declined quite appreciably but in areas where the fishery has been long established production is relatively steady.