A fishing ban sparked by mass deaths of sea creatures in Chile has left tourists stranded and markets empty on an island cut off by protest blockades.

In the south of the world’s second-biggest salmon-producing country, fishermen have blocked roads with burning tires.

They have cut off access to the island of Chiloe in the picturesque Los Lagos region.

They are furious at what they say is paltry compensation offered to them by the authorities for the so-called “red tide that is ruining their livelihoods.

Heaps of dead salmon, sardines and clams have washed up on the nearby Pacific shores over recent months, choked to death by a surge in red algae.

Some scientists say the algae are thought to have proliferated due to the El Nino phenomenon, which warms the Pacific to wreak havoc with the weather in Latin America every few years. Fishermen accuse the salmon farming industry of worsening the effect of the algae by tipping contaminated salmon into the sea – a claim the companies deny.

The government initially offered fishermen’s families vouchers worth $150 each to tide them over, but they angrily rejected that. The government has since upped its offer to total about $1000.

Economy Minister Luis Felipe Cespedes asked the fishermen’s groups to “be reasonable. But with their livelihoods threatened by an environmental crisis that could last months, they are demanding more in ongoing negotiations with Cespedes.

Schools stayed closed on Monday in various districts of the island, home to 170,000 people. Chiloe’s petrol stations have run dry and are closed.

Chile is the second-biggest producer of farmed salmon in the world after Norway, according to the industry organization Salmon Chile.

The southern Chile labor unions’ federation estimates the red tide has killed 30 million salmon. It says sales of fish and seafood from the region have dropped 90 per cent.

“We are facing the worst social and economic conflict of our time … which affects the direct livelihood of thousands of families, it said in a statement.

News Corp 2016