Climate change and a starfish outbreak have shrunk coral reefs in Fiji, forcing locals to change their lifestyle.
A new study, published in Global Change Biology, has found that from 2000 to 2006 the size of coral reefs around Fiji's Lau Islands contracted by about 50 per cent.
Dr Nick Graham from Australia's James Cook University, who took part in the study, says fishing and habitat disturbance are having a big impact.
He says the area was disturbed by a crown of thorns starfish outbreak in about 2000 and then, the subsequent year, there was also a coral bleaching event associated with climate change.
Dr Graham says they were pretty shocked at just how severe the impact was.
He said so-called bottom up pressure from habitat changes was reducing the number of small fish, while top down pressure, from fishing, reduced the availability of larger fish.
Dr Graham says it has forced the local population to change its diet, reducing its fish consumption.