POWELL RIVER, B.C. – The Department of Fisheries and Oceans is investigating the cause of a mass death of krill near Powell River.

The die-off was first discovered along the shoreline just southeast of the Beach Gardens Resort and Marina, on Wednesday evening.

A post by Powell River resident Darlene Williams stated that she saw what appeared to be “1000 dead baby prawns.”

Photos show many small animals washed up on the beach.

In an email, the DFO said it is working on getting samples to determine the cause, because it’s not possible to determine the cause without samples.

The DFO noted that it is unsure how long this will take or if it’s even possible, because they krill might have since washed away.

According to zooplankton taxonomist Moira Galbraith, who works at the Institute of Ocean Sciences in Patricia Bay, the animals appeared to be female krill in the process of mating, or having recently mated.

She believed the mass death of the animals could be linked to an earlier bloom of phytoplankton near Powell River back in March. DFO scientists had been passing through the area and got samples for temperature, salinity, and oxygen level.

“There was a huge plankton bloom at the surface, so we were thinking that it’s possible that that bloom has now passed, gone on, and as it dies and falls out of the water column, it drops to the bottom,” said Galbraith.

“Decomposition of that much biomass would use up a lot of action, and possibly turn the bottom 50 metres or 100 metres anoxic, or very low oxygen, potentially, which could kill the krill when they’re down at that depth.”

She also believed the krill could have been at the surface at the time of their death.

“These animals are usually long lived, one to two years, sometimes three years,” said Galbraith.