Squid washing ashore by the hundreds 'live fast and die young'
Experts say such mass die-offs are unusual, but the reason why might just be biological in nature
Lloyd Westhaver has lived in the Mahone Bay, N.S., area for over 60 years and said he's never seen something like what he saw on the morning of June 7. He was walking down the shore when he saw hundreds of dead squid.
"They were all in good shape," said Westhaver. "I said, something has gone wrong here. Because I've lived around here for 60-odd years, and I've never seen this happen yet."
The last few years he has been catching them to eat, and said he would find the odd one washed up, but never to this extent.
This comes just a couple of weeks after a sighting near Lunenburg, where a YouTube user saw multiple dead squid along the coast.
An alarming number of squid are washing ashore along parts of Nova Scotia's coast. Experts say although it's unusual to see such mass die-offs, the deaths are part of the creatures' "live fast and die young" reproductive cycle.
Kent Smedbol is a scientist with the Department of Fisheries and Oceans and works with monitoring fish and invertebrate populations. He said northern shortfin squid are common in the waters off Nova Scotia. They range from the mid-United States right up to around Iceland.
"They're a highly mobile species, highly migratory and they only live for about a year," said Smedbol. "So, they live fast and die young."
What is less common, however, is seeing mass amounts of dead squid washing up on the shore.
Ian McLaren, a marine biologist from Dalhousie University, said not only do squid live fast and die young, they actually die for their young.
Because the chances of mortality are so high between reproductive cycles, they put everything they have into that one cycle and die shortly afterwards.
The 'big bang'
"There are many species for which future investment is not particularly useful. So, if you can pardon the expression, it's the 'big bang,'" said McLaren.
"Getting [reproduction] out of the way and then die — that's sometimes the most efficient way of doing it, particularly for species that suffer a mortality anyway."
This type of squid species is semelparous, meaning they have a single reproductive cycle before death, so the fact that this many died at once is part of their normal life cycle, said McLaren.
Normally when squid die, they end up somewhere on the bottom of the ocean or drift along with the bottom current.
Smedbol said DFO isn't ruling out environmental factors as a reason for why so many squid have been washing ashore.
"What could happen if you see a small mortality event like this in a cove, the water is quite shallow, which means that a few environmental effects could come into play," he said.
The squid might find themselves in the cove at high tide, and when the tide goes out, they then get stuck in shallow water.
This exposes them to weather events in the local environment, whereas in the deep ocean, the temperatures change very little.
Smedbol said the deaths could have been caused by temperature changes.
"It was very cold that weekend as well, so it's possible that the local water column went through a rapid temperature change and that marine animals, other than those that live on the intertidal [zone], aren't adapted to deal with those rapid changes and that could have stressed them out and killed them," said Smedbol.
DFO believes this is a localized event, and has no evidence to believe this was caused by pollution or any type of human activity.
Fisheries officers will keep an eye on the situation, and suggest that if anyone sees this type of thing happening again to contact DFO so they can investigate further.