Subsistence and Commercial Activities. The principal protein sources for islanders are turtles, dugongs, fish, and shellfish. Most of the Torres Strait Islands are not particularly suited to cultivation to any great extent, because of their small tillable areas and low soil fertility. The larger northern and eastern islands support swidden horticulture, but elsewhere in the strait most vegetable matter is gathered in the wild. Vegetable staples include yams, edible mangrove fruits, beans, and a variety of fruits and nuts. On those islands capable of supporting cultivation, the primary crop is yams, but other crops include bananas, taro, sugarcane, sweet potatoes, tobacco, and coconuts. Harvesting the products of the sea was always a major portion of the islanders' subsistence Economy, but this took on a more commercial aspect with the European introduction of the trepang and pearling industries. In the 1950s, the development of plastics disrupted the islander economy by undercutting the market for pearl shells, and this in turn precipitated a major labor migration to the Australian mainland and prompted islander youths to seek cash-based employment.
Industrial Arts. Until recent times, many items of daily use, such as spears, stone clubs, canoe hulls, bows, and arrows, were acquired through trade, for the islands do not provide suitable timber or hard stone for their manufacture. But Torres Straits Islanders made their own shell hoes and digging sticks, as well as adzes and axes that were constructed from the shells of the giant clams. Other tools and implements were fashioned from turtleshells. Mats, used in the construction of temporary shelters, as canoe sails, and for sitting or sleeping on, were woven from pandanus or coconut leaves. While canoe hulls were imported from Papua New Guinea, the construction of a finished Torres Strait canoe involved a great deal of additional work: to the dug-out hull would be attached outrigger poles and floats; masts and paddles; a platform; and storage "lockers" for food and trade items. Other manufactured goods included: masks; items of personal adornment made of shell, tooth, bone, and imported feathers; and net bags.
Trade. Traditionally, the most important trade was with the peoples of Papua New Guinea: the islanders traded items made of pearl shells, turtleshells, and conus shells—as well as trading human heads—in return for canoes, drums, cassowary and bird-of-paradise feathers, and weapons. A lesser—but nonetheless important—trade network existed between the islanders and the Aboriginal peoples of Australia, who provided spears, spear throwers, and red and white ocher. Trade also occurred among the Torres Strait Islands themselves, primarily involving foodstuffs and tobacco but also permitting the circulation of finished ear ornaments, pendants, hair combs, necklets, armbands, and the like.
Division of Labor. Men hunt sea turtles with harpoons or, more commonly, simply by slipping a rope around the front flippers and towing them back to land. Dugongs are harpooned. Fish are caught with multipronged, thrusting spears, with hooks and lines of turtleshell, or with the use of spear throwers. On some islands bamboo scoops or stone fish traps are used. Men also collect crustaceans and shellfish from the reefs and atolls. Women collect wild vegetables, fruit, and nuts in net bags that they weave from pandanus leaves, grass, rattan, and rushes. Women also provide most of the labor for weeding and harvesting on those islands supporting hortiCulture, while men on such islands do the heavy work of clearing gardens and burning off the ground cover in preparing the gardens. Garden magic is men's work, while cooking and food processing is routinely done by women. Both men and women participated in the early days of the trepanging and pearling, but once the shallower coastal beds were worked out it became a predominantly male enterprise.