Pink waves of lobster krill washed into Picton last week, with some fishermen claiming they hadn't seen so much at one time for at least 30 years.
The baby crustaceans, officially known as juvenile squat lobster or Munida gregaria, arrived in large swarms around the coast of Marlborough, including Picton Marina, last week, probably due to strong winds and oceanic tides.
Long-time Picton commercial fisherman Graeme Fishburn said bright red swarms were spotted around Cloudy Bay and Clifford Bay on Marlborough's east coast at the start of February. They then spread up to the northern entrance to Tory Channel and across to the outer Kenepuru and Pelorus Sounds.
The last time he remembered seeing so many was at least 30 years ago. "They're so thick in places that you could just about walk on them."
German tourist Stephan Funke was photographing the red waves in Picton Marina, which he recognised from an educational movie on whale feeding he saw at Whale Watch tours in Kaikoura.
"It's crazy, we saw the whales sucking them in on video but never out on the tour.
"Now, here in Picton, there's millions of them."
EcoWorld Aquarium manager Regan Russell said he had never seen so many krill in the harbour in the 10 years he had lived in Picton. The tiny crustaceans feed on zoo plankton and phytoplankton and are in turn eaten by whales, penguins, fish, seals and birds.
Canterbury University professor of marine science David Schiel said strong winds and oceanic tidal currents could push krill inshore, especially in the warmer summer months. They tended to live along coastlines where oceanic and coastal waters met and supplied their food.
Picton's close proximity to the "complex conditions" in Cook Strait probably led to them congregating in the inner Queen Charlotte Sound.
They could lure bigger predators further into the Sounds, which could make for some "exciting fishing", he said.
Prof Schiel dismissed the idea that the krill's sudden appearance was linked to the ocean warming by about one degree Celsius over the past year because "one point on a graph doesn't make a trend".
Te Papa marine invertebrates curator Rick Webber said the creatures were commonly known as lobster krill because they looked like baby lobsters and swam near the surface in swarms like krill.
Adults lived on the bottom of the ocean in the outer Marlborough Sounds and from Cook Strait south to Campbell Island, where they had been seen as deep as 1000 metres.
"In years when reproduction is very successful, they often swarm in great numbers at and near the surface and that is what you are seeing," Mr Webber said.
More photos at Richard-Seaman.com
- The Marlborough Express