A decade-long partnership between Bardi Jawi rangers and Australian marine scientists has confirmed the important connection between mangrove and reef ecosystems in Western Australia's Kimberley region.

Researchers from the Australian Institute of Marine Science worked alongside Bardi Jawi and Oorany Rangers, as well as Bardi Jawi Traditional Owners, to examine how fish move between the two habitats.

The study, published in Ocean & Coastal Management, found 10 culturally important fish species regularly used both reef and mangrove environments, including well beyond their juvenile nursery stage.

The findings supported knowledge that has been held by Bardi Jawi people for generations.

The Bardi Jawi are Saltwater People whose Country includes the 95,000-hectare Bardi Jawi Indigenous Protected Area and the 204,000-hectare Bardi Jawi Gaarra Marine Park.

The decade of research helped guide the planning for the protected areas and marine park.

Among the species studied was barrambarr, or bluebone, which was found moving between mangroves and reefs with the changing tides.

AIMS fish biologist and study lead author Katherine Cure told Mongabay the results differed when researchers focused specifically on species important to Bardi Jawi fishing practices.

"It was the first time that we looked at species that were of interest for fisheries for Traditional Owners in a specific locality," she said.

"And it was interesting that we found a pattern that was really different for those species than for the overall fish community."

The research also suggested mangroves could provide an important refuge for some fish when reef environments were under pressure.

That could become increasingly significant as climate change and marine heatwaves place greater stress on coral reefs.

Bardi Jawi men's ranger program coordinator Phillip McCarthy told Mongabay the results largely confirmed what Traditional Owners already understood and said maintaining the health of both habitats was critical.

"We knew most of it, but the science confirmed it," McCarthy said.

"Without the mangroves, certain species might not survive up here.

"Without the reefs the same - that was the big, important thing we learned.

"That, and how important it is that both ecosystems are healthy, and that the fish species survive for future generations."

Traditional knowledge shaped where and when the research was conducted, while rangers helped scientists understand local tides, fish behaviour and environmental changes.

Cure said the partnership demonstrated the scientific value of knowledge passed down over thousands of years.

"First Nations peoples are the first scientists of the world," she said.

"Science is about observation and asking questions."

McCarthy added that Bardi Jawi knowledge had been handed down across generations and provided scientists with an important starting point.

"We've been here for 30,000 years, and knowledge has passed down from generation to generation," he said.

Researchers and rangers are expected to continue monitoring fish populations and the health of reefs and mangroves, including through drones and underwater cameras.