Dozens have perished in Brazil's sixth-largest city after a record-breaking deluge.

Roughly 60 dead starfish were scattered on a stretch of beach about 1/4-mile long, showing potential signs of sea star wasting disease.

January has so far been colder than average and the trend is expected to continue, breaking the 22-month trend of consecutively warmer-than-normal monthly temperatures.

Luck was against these young cockles, which were likely washed up on to the beach during a storm and did not survive the cold air temperatures during low tide.

Ecologist fears the Macleay River may take decades to recover, with heavy rains likely to affect other waterways