Sediment on the Great Barrier Reef is clogging up fish gills and can cause disease, a Queensland study of baby clownfish shows.
The clownfish, a species made famous by the film Finding Nemo, were found to have grown protective cells to shield their delicate gill tissue from damage caused by sediment particles.
The James Cook University study indicates it’s actually harder for sediment-exposed fish, particularly juveniles, to ‘just keep swimming’, as Dory famously said in the popular movie, because of the amount of mucus around their gills.
‘Larval fish have very high growth rates … they have a very high metabolic rate and high-energy costs and need their gills to be working as efficiently as possible,’ study co-author Dr Jodie Rummer said.
The sediment exposed fish had twice as much mucous around their vital organ as species in clean water.
Researchers also found suspended sediment promoted the growth of bacteria linked to fish disease.
Furthermore, Dr Rummer said the research may explain why some fish species had been found to have delayed development.
In the study, researchers replicated sediment conditions common to inshore reefs on the Great Barrier Reef but say the problem isn’t limited to Australian waters.
Dr Rummer said the findings were concerning given sediment in the ocean may have extra nutrients and contaminants.
‘It’s sad because our findings might be the best case scenario,’ she said.
The study highlighted the need for the continued protection of coastal oceans affected by suspended sediment.
As part of its commitment to protect the Great Barrier Reef, the Queensland government has appointed a water science task force which is working towards ambitious targets of reducing nitrogen run-off by up to 80 per cent and sediment run-off by up to 50 per cent.