Hawai'i surfers combined to win seven championships at the Surfing America USA Championships this week at Oceanside, Calif.

The contest is considered the national championships of amateur surfing, and more than 500 surfers from around the country participated in the week-long event.

Kaua'i surfers won five championships, including the prestigious open men and open women divisions.

Nathan Rex of Kilauea won the open men's title in his first appearance at the national championships, and Mia Melamed of Hanalei won the open women's division in her final appearance at the nationals.

Rex, who is a senior at Kapa'a High, defeated Maui's Kevin Sullivan in the final. Rex started surfing more than 10 years ago, but he did not start entering contests until last year.

Hawai'i surfers dominated the boys divisions, winning four of the five championships.

In addition to Rex, Chas Chidester of O'ahu's North Shore won the boys under-18 division, Tyler Newton of Kaua'i won the boys under-16 division, and Kaikea Elias of Kaua'i won the boys under 14 division.

Chidester posted a near-perfect score of 9.25 (out of 10) to edge Maui's Kai Barger in the final of the under-18 division.

Melamed said the contest was blessed with consistent conditions.

"This is my first win at nationals, so it's a good closing," said Melamed, who is 18 and planning to attend a college in Australia next year. "I was just happy that there were some pretty good size waves this year. I think that helped me."

She said the waves were "at least shoulder-high" throughout the week, and increased to "head-high to a little overhead" for the finals on Tuesday.

Other champions from Hawai'i were Kaua'i's Coral Gonzales (girls longboarding) and Honolulu's Candice Appleby (women longboarding).

How Hawai'i surfers fared:

MALE

Under 12: 1, Kaikea Elias. 3, Christian Graham. Under 16: 1, Tyler Newton. 2, Johann Hedemann. Under 18: 1, Chas Chidester. 2, Kai Barger. Open: 1, Nathan Rex. 2, Kevin Sullivan. Bodyboarding: 4, Pohaku Kekaualua. Junior longboarding: 4, Nelson Ahina. Men longboarding: 2, Cedric Caires. Senior longboarding: 4, Brian Suratt. Legends: 2, Brian Suratt.

FEMALE

Open: 1, Mia Melamed. 3, Coral Gonzales. Girls longboarding: 1, Coral Gonzales. Women longboarding: 1, Candice Appleby.

Reach Dayton Morinaga at dmorinaga@honoluluadvertiser.com.