Nesting hawksbill turtle numbers have been lower this season on WA's Rosemary Island, off the coast of Dampier.

Department of Parks and Wildlife staff and volunteers have just spent two weeks on the island monitoring the turtles as they visit the island to lay their eggs.

Marine conservation officer Joanne King said she had seen fewer turtles this year, but was not overly concerned.

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"This year has been quiet, compared to the last couple of years," Ms King said. A critically endangered hawksbill turtle. ( Supplied: Nature Conservancy )

"It's not that unusual, it's just that if we see that happening over time, then it starts to get concerning — something's going on.

"As a one off, it happens in a nesting population, they'll have quiet years."

The turtle monitoring is done during the night after the turtles have walked up the beach and decided whether to lay eggs.

"We'll have a look and see if they're already tagged. If they aren't, we'll put new tags in, record all that data and we can look at the trends," she said.

Ms King said the main risk to the hawksbill turtles was the light from the nearby port at Dampier where ships were loaded with iron ore, LNG, and salt.

"On this beach it's not so bad; some of the beaches closer into town and closer to the plants and the port it's a bit more of an issue for hatchlings.

"They'll tend to walk towards the light, rather than to the ocean. Seagulls are also a problem, you get seagulls around humans, and you get higher predation rates."

This year, a turtle that was tagged on the island in 1990 re-visited.

"It was tagged by Anna, one of our volunteers here with us again this year," Ms King said.

"It's one of the fun things — you get to track their history and the history of everyone who's been out here and been part of this program." Turtle nesting area on Rosemary Island, off WA's north-west coast. ( ABC Rural: Eliza Wood )

While Rosemary Island might be a beautiful spot, turtle tagging is considered hard yakka, with kilometres of beach to cover during the night and hot sleeping conditions during the day.

"There's a bit of sleep deprivation at night, but you get to soak up the sun and enjoy the beach life," Ms King said.

"I think [the volunteers] get a little bit addicted to coming back and looking at the turtles and seeing how they're going."