Fishermen in the Western Isles say they are concerned about the spread of disease in fish farms across the area.
A parasite which causes fish to choke to death is devastating stocks of farmed salmon.
Warmer and saltier waters are being blamed for the outbreak.
It is estimated some are losing 20% of their stock.
On the Western Isles local fishermen, who have to exist side by side with the giant tanks, are worried about the possible effects.
Creel fisherman Angus Campbell said: “The reports on Sepa indicate that there are hundreds of tonnes of fish dying in these sites.
“Last week we saw a load of 26 tonnes heading down to Uist to get buried. It’s just incredible the amount of dead fish coming out of these sites.”
The protozoan parasite Neoparamoeba perurans only appeared in Scotland last year, but has colonised in farms from Shetland to Argyll.
Producers are blaming unusually warmer seas this summer.
Critics say the over expansion of farms and the overcrowding of salmon has encouraged the disease to flourish.
Industry body, the Scottish Salmon Producers Organisation claims "the treatment being used to kill the parasite, is entirely safe for both fish and the marine environment”.