The state Department of Land and Natural Resources yesterday released, for the first time, underwater photos of the "substantial" reef damage it says was caused by the 3 1/2-day grounding of the guided missile cruiser USS Port Royal in February.

The photos show upended chunks of coral as big as a car, coral walls cleaved off and crushed coral, forming what the state agency characterized as a "scar" on the ocean floor.

The DLNR said the damage to the "ancient" reef, "full of coral colonies some of which took hundreds of years to reach their present size," covers an estimated six to 10 acres.

Destruction was caused by the ship's hull, dropped anchor chain, tow cables and the possible grounding of tug boats used to pull it free, officials said.

Unlike shortly after the grounding, when the DLNR and the Navy issued information jointly, the DLNR now is demanding that the Navy immediately resume efforts to stabilize or remove damaged and crushed coral.

In a four-page letter sent Tuesday to the Navy, the DLNR said the state intends to make a full claim for damages that include: the cost of emergency mitigation; the value of the coral reef substrate damaged by the grounding of the Port Royal and attempts to free the 567-foot-long warship; and other damage to the reef ecosystem.

No cost figures were released.

"There is a critical need for the U.S. Navy to mitigate the damage which has occurred, which continues to occur, and which will get worse with the upcoming south summer swell," said Laura H. Thielen, chairwoman of the DLNR, in the letter.

"We urge the U.S. Navy to commit appropriate resources to rescue disturbed or destroyed coral, remove or stabilize rubble, and protect loose live coral that has resulted from this incident."

The DLNR released the information ahead of a meeting today with the Navy to discuss future plans for the spot, which is half a mile off the Honolulu International Airport's Reef Runway, in 14 to 22 feet of water.

The 9,600-ton Port Royal ran aground on the night of Feb. 5 and was freed on Feb. 9. The area where the ship grounded was a complex "spur and groove" fringing reef with outcrops of coral interspersed with sandy areas, the DLNR said.

Navy and state divers initially worked to repair large coral heads using quick-set cement and removed broken blocks that rolled in the surf and could have caused more damage.

"They (Navy divers) started for a while, and then they stopped," DLNR spokeswoman Deborah Ward said yesterday. "They need to pick it up again."

The DLNR said it was "compelled" to inform the Navy that "due to the state's current economic situation, it is unlikely that the state would be able to fully mitigate the situation to prevent further damage from occurring," and that it would seek full recovery costs for any lack of mitigation by the Navy.

The DLNR in the past has sought fines for coral damage; in January 2008, the department fined a Maui tour boat company $550,000 for damaging coral in the waters off Molokini Islet. A final settlement of $396,915 was reached, officials said.

The U.S. Pacific Fleet said yesterday in a statement that the Navy has been working on a proposal to remediate the damage caused by the Port Royal's grounding.

The command noted the meeting scheduled for today "to discuss our findings and proposed courses of action."

"As state officials are aware, the underwater portion of the Navy's detailed assessment of the affected area was only recently completed," the Navy said. "We briefed the (DLNR) and other interested parties about the preliminary findings of the assessment at the time."

Thielen warned that costs would increase substantially unless the Navy acts immediately. Among the mitigations being sought is stabilization of damaged coral rubble — in some cases now up to 6 feet deep — to prevent a scouring effect with large south summer swells.

The DLNR said evaluations by coral reef biologists identified the area as one of the finest remaining reef habitats on O'ahu before it was damaged.

The grounding "has resulted in the loss of of many valuable live coral specimens, as well as the loss of turtle habitat" for the endangered green sea turtle, Thielen said in her letter to the Navy.

The ocean off the Reef Runway has been heavily affected since World War II, however, when the Navy dredged out three seaplane runways, according to a 2001 Navy environmental report.

Much of the fringing coral that once formed the seaward boundary of Keehi Lagoon was destroyed during construction of the Reef Runway from 1973 to 1977, the Navy report states, with the loss of 1,240 acres of marine and estuarine habitat.

The Port Royal ran aground on the first day of sea trials following $18 million in repairs and refurbishment.

The ship is now in drydock at the Pearl Harbor shipyard. The Navy earlier this month said repairs were expected to cost $25 million to $40 million.