Traditional pōhā (bull kelp bags) are still used today by South Island Māori to preserve many types of food, and to transport preserved food from one area to another.
Pōhā is an ancient Polynesian word that is still used throughout the Pacific. In Tonga, the word puha means a container, carton or box, or something used for storage. In Te Wai Pounamu (the South Island), this word gradually became pōhā.
Pōhā are made from blades of rimurapa (bull kelp). Ngāi Tahu, a South Island iwi (tribe), gathers the long broad blades of rimurapa that grow around the coast of Te Wai Pounamu. The outer skin of the blades is airtight and traps air in the honeycomb-like structure inside each blade. Food preserved inside a pōhā can be kept safely for up to two to three years.
According to Ngāi Tahu tradition, January or February is the time to start making pōhā. First, the rimurapa blades are cut to the right length and hollowed out. Then, in March, the pōhā hau (the hollowed out blades) are inflated and placed outside to soften in the night dew. Finally, the pōhā are rolled up and taken to the Tītī Islands for the start of the mutton bird season in April.
Weka (wood-hens) and tītī (mutton birds) are prepared by wrapping the birds in pouaka (fescue grass), leaving them in a trench for a few days, and then soaking them in an ipu (wooden bowl) in water heated by hot stones. The birds are kept there until their fat has seeped out and is lying at the bottom of the ipu. Once this process is complete, the birds are placed into pōhā and covered with their own fat. The top of the pōhā is plugged with a wooden plug and the outside is protected with kiri tōtara (tōtara bark), before the whole pōhā is placed in a flax kete (bag) and bound. The finished pōhā has a distinctive shape designed to be easy to throw and catch because there are no beaches on which to land supplies on the Tītī Islands. Pōhā are often made to hold up to 110 birds, although the average size would hold 40 to 50.
Pōhā or, in particular, pōhā mata (fresh kelp bags that have not been dried), were also traditionally used to preserve kiore (Māori rat: Mus exulans). In addition, food such as kākihi (limpets), kaimoana (seafood), fish, duck, and seagull eggs were put in pōhā mata and then cooked in umu (earth ovens).
Pōhā were also used to carry fresh water, and for a process called whakawhiti kaimoana (the moving of seafood from one area to another). They were especially useful when seeding a new coastal area with shellfish, starfish, and pāua (New Zealand abalone). The kaimoana would be put in pōhā, taken to the new area and placed in the sea. Special slits in the sides of the pōhā would then open up letting the shellfish escape. The kaimoana released in the new area would attract others of its species.
Pōhā were not only used for food or food preservation. There are stories of the Ngāi Tahu tribe using pōhā for surfing long before the arrival of surfboards! They would take two pōhā, blow them up tight and tie them together, then put the string over their necks and a pōhā under each arm. They could then paddle out to sea and come back in over the breakers like a bird. This sport was called kauai or kaukau. Pōhā were also used to protect the body when gathering seafood on the open coast. They were worn over the torso or other limbs like wetsuits, or made into sandals to be worn on the rocks while fishing or gathering seafood.