Krill paint Te Rauone Beach in Otago Harbour red

A carpet of red krill washed up on Te Rauone Beach near Harington Point in Otago Harbour. Photo / ODT

A big stranding of tiny lobsters at Te Rauone Beach in Otago Harbour could be a sign of a return to the more regular summer strandings of red krill which were more common 10 years ago.

Marine biologist and former director of the University of Otago's Portobello marine laboratory Dr John Jillet said this week's summer stranding, affecting part of the beach near Harington Point, was a much more expected event than a much bigger stranding which took place in the area last May.

Observers said the squat lobsters, Munida gregaria, were yesterday concentrated in a 50sq m area at the southwest end of the beach, and also in a 2m-wide band extending northeast along another part of the beach.

The krill seen yesterday were "an extremely important part of the food web" for many fish and birds, and penguins.

The krill that washed up this week had been living outside the harbour mouth on the nearby continental shelf but may have been sucked into the harbour about two weeks ago, before being washed up on the beach, he said.

Auckland brothers Caleb (13) and Miles Wichman (11) run over a carpet of krill washed up on Te Rauone Beach. Photo / ODT

This had been part of a normal pattern 10 years and more ago, but in recent years such strandings had become less common, he said.

The latest krill were much younger than the krill washed up in much bigger strandings last May, Jillet said.

On May 14 last year, bigger strandings of the same krill species on the coast near Portobello had been highly unusual, and had not been seen there in late autumn for at least 20 years, he said.

The reddish remains of washed-up krill were visible in several places, including Broad Bay, Edwards Bay, and on the coast just north of Portobello.

This stranding of the free-swimming form of the species may have been among the biggest since they were studied near Portobello in 1976.

A carpet of red krill washed up on Te Rauone Beach near Harington Point in Otago Harbour. Photo / ODT