Tema Reef, also called Tima Reef, is a submerged coral reef

Coral reef

Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...

 in the northern Cook Islands

Cook Islands

The Cook Islands is a self-governing parliamentary democracy in the South Pacific Ocean in free association with New Zealand...

, 23 km southeast of Pukapuka

Pukapuka

Pukapuka is a coral atoll in the Cook Islands in the Pacific Ocean, with three small islets threaded on a reef that encloses a beautifully clear lagoon. It is the most remote island of the Cook Islands, situated about 1140 kilometres northwest of Rarotonga. It is a triangular atoll with three...

.

No coral or rock shows above water, but the sea breaks heavily over the reef.
The reef measures about 550 by 360 meters, covering a shallow but submerged area of 0.16 km².

History

Legend has it that Tima, an Aitutakian warrior sailed to Nassau

Nassau (Cook Islands)

Nassau is an island in the Cook Islands.Located 90 km south of Pukapuka, the small island of Nassau is just 9 metres above sea level, with an oval sandy cay on a coral reef foundation and is surrounded by a narrow reef flat. It is covered with palms, and is the only island of the Northern...

, but was chased away by Ngalewu, a chief from Pukapuka. On his return to Aitutaki

Aitutaki

Aitutaki, also traditionally known as Araura, Ararau and Utataki, is one of the Cook Islands, north of Rarotonga. It has a population of approximately 2,000. Aitutaki is the second most visited island of the Cook Islands. The capital is Arutanga on the west side.-Geography:Aitutaki is an "almost...

 he passed the reef nearby and named it Te Toka-O-Tima, the Stone of Tima

The reef was sighted by Commodore John Byron

John Byron

Vice Admiral The Hon. John Byron, RN was a Royal Navy officer. He was known as Foul-weather Jack because of his frequent bad luck with weather.-Early career:...

 on June 21, 1765. Captain William Williams

William Williams

-Authors and artists:*William Williams , artist, author of first American novel, Penrose*William Joseph Williams , his son, artist; painted George Washington, John Adams and Thomas Jefferson...

of the missionary ship “John Williams” sighted the reef on May 15, 1864. It was again examined by H.M.S. “Alert” in 1880.