Sunday, September 16, 2012

Umu (also known as ‘Imu’)

In 1846, Article V of the “Statute Laws of His Majesty Kamehameha III” was published. The law defined the responsibilities and rights the konohiki and people had to the wide range of fishing grounds and resources.  It codified the prior traditional and customary fishing practices.

The law also addressed the practice of designating kapu or restrictions on the taking of fish, tribute of fish paid to the King and identified specific types of fisheries from the freshwater and pond fisheries to those on the high seas under the jurisdiction of the Kingdom.

Section II of the law stated, "The fishing grounds from the reefs, and where there happen to be no reefs from the distance of one geographical mile seaward to the beach at low water mark, shall in law be considered the private property of the landlords whose lands, by ancient regulation, belong to the same".

Therefore, a typical ahupuaʻa (what we generally refer to as watersheds, today) was a long strip of land, narrow at its mountain summit top and becoming wider as it ran down a valley into the sea to the outer edge of the reef.  If there was no reef then the sea boundary would extend into the deep water.

While Hawaiʻi has some fantastic reefs, there are areas where there are no reefs (i.e. sandy bottom or muliwai (estuaries and river mouths where flowing freshwater prevented coral growth.))

So, how can a konohiki and the tenants of an ahupuaʻa that does not have a reef fronting the land fish for reef fish?

Like today, in many cases, the ancient Hawaiians built artificial reefs.  They were called umu (or imu.)

In Hawaiʻi, as well as other areas of Polynesia, rock shelters were constructed that provided protections and sources of food for reef fish.

Large and small stones were piled into walls with an underwater chamber.  Algal growth on the rocks provided them a source of food.  Small fish attracted larger fish.  Openings in the rock piles allowed small fish to hide.

These rock piles acted like naturally-occurring rock outcrops and coral reef habitats.   They provided protection from predators and a food supply for reef fish.

"Such shelters were quite common in the islands.  On Oʻahu, evidence of their existence has been found in Kāneʻohe Bay and around Kahaluʻu and Waiʻāhole."  (Kanahele)

"Besides providing stability and some protection from predators, these shelters also helped to regulate fish growth and potentially increase fish stocks by serving as artificial homes for fish to congregate and reproduce."  (Kikiloi)

Some of the prominent fish species that inhabited these shelters were squirrelfish (u‘u), unicornfish (kala), surgeonfish (manini), goatfish (moano), greater amberjack (kahala), parrotfish (uhu) and eels (puhi).  (Kikiloi)

"These were the predecessors of present-day attempts to attract fish to Waikīkī and other places with artificial reefs."  (Kanahele)

The Territory of Hawai`i began looking into the possibility of installing artificial shelters in areas of sparse natural habitat.  Back in 1957, the proposed purpose of these shelters was to increase and enhance opportunities for fishermen.

In 1961, the State's first artificial reef was created at Maunalua Bay, off Kahala, Oʻahu (74 acres). Then, in 1963, two more artificial reefs were created off Keawakapu, Maui (54 acres) and Waianae, Oʻahu (141 acres).

A fourth artificial reef was created in 1972 off Kualoa, O`ahu (1,727 acres). The Ewa Deepwater artificial reef (31 acres) was built in 1986.

Unlike the other four reefs, which were deployed at depths of 50-100 feet, the Ewa reef was sunk in 50-70 fathoms (300-420 feet) of water for "new" bottomfish habitat.

Initially, car bodies were the primary material used to construct artificial reefs.  Then, from 1964-1985, concrete pipes were mainly used to build these reefs.  In addition, several barges and minesweeper vessels were sunk.

From 1985-1991 the program used concrete and tire modules as the main artificial reef components. Other items used included derelict concrete material, barges, and even large truck tires.

From 1991 to the present, materials deployed have mainly been concrete "Z-modules" (4-feet by 8-feet, with 1-foot high "legs" on end of opposing sides.) Other components include barges, derelict concrete material and several small vessels.

The image shows a layout and depiction of the Hawaiian Imu - Umu (from Kekuewa Kikiloi.)  In addition, I have added other images of artificial reefs in Hawaiʻi in a folder of like name in the Photos section on my Facebook page.

© 2012 Hoʻokuleana LLC

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