The Gulf of Maine: A world changing, not ending

The Chronicle Herald

Nov. 14, 2015

If the sun is in the sky as you read this, then take your mind's eye for a stroll to the hills that look down over Five Islands to the wide sweep of the Minas Basin.

You'll hear the boisterous clatter of Tony Lewis's chainsaw before you see him among the hardwoods that fall has already stripped nearly bare.

He's cutting yellow birch and maple for next spring's weir, as he has every fall for the past 23 years and as his Uncle Gerald did for the three decades before that, because the world isn't ending.

At least, his world isn't.

Lewis and his weir, a 1.6-kilometre horseshoe created by 1,200 hardwood poles he pounds with a maul into the mud each spring before draping them with nets, is part of the Gulf of Maine ecosystem.

Headlines around that great body of water, cradled inside of Cape Sable Island to the north and Cape Cod in the south, screamed alarm this fall about a pending ecosystem collapse brought on by climate change.

Most of those headlines linked back to a study by Andrew Pershing, chief scientific officer at the Gulf of Maine Research Institute, published in October in the journal Science.

In it, Pershing attributes the non-recovery of cod stocks to the Gulf of Maine having warmed faster between 2004 and 2014 than 99 per cent of all other saltwater bodies on Earth.

The warmest year ever recorded in the gulf was 2012 - about 1.8 C warmer than the 30-year average.

"That's a lot," Pershing said Friday.

But he isn't predicting the demise of gulf cod, nor are he or the other scientists spoken to by The Chronicle Herald predicting a total ecosystem collapse.

They're predicting change, as has always happened in the gulf, but at a faster rate over the coming decades.

Change, they say, that the species of the gulf - be they the type that have tails, claws or boats - will either adapt to or decline.

THE GULF

The Gulf of Maine defies the tersely prescribed word counts of editors.

From space, it appears to barely qualify for the geographic description of being a gulf.

That's because gates to this biologically productive kingdom are hidden below the surface.

Three upwellings on the sea floor, starting with Browns Bank just south of Yarmouth, then Georges Bank and the Nantucket Shoals, prevent any simple mixing of the waters in the gulf with those of the Atlantic.

For the most part, the ocean enters the gulf through the deep Northeast Channel between Georges and Browns, circulates through a series of currents and leaves through the Great South Channel between Georges and the Nantucket Shoals.

Offshore, the cold Labrador Current barrelling down from the north slams into the warm Gulf Stream that dominates the American Eastern Seaboard.

The eternal struggle of these currents, not localized air temperature, dictates how warm the water is that flows in through the Northeast Channel. The temperature of that influx dictates the rules on the ever-changing field of competition and dependence for life forms ranging from lowly plankton to great mawed grey whales.

"Animals like to stay within certain temperature and depth ranges," Nancy Shackell, a research scientist at the Bedford Institute of Oceanography, said Thursday.

"So what we looked at is if there's a temperature shift, how much habitat would an animal lose or gain?"

Though trying hard, Shackell could only simplify her research so much for a story in which she knew she was destined to get little more than a paragraph.

Because species prefer different temperatures and live at different depths during the varied stages of their life cycles.

Shackell's research shows some species gaining more habitat with suitable temperatures and others losing territory.

Species, like cod, that are at the southern end of their range lose a bit over the next 60 years.

Meanwhile, lobster gain territory, at least in Canada's northern section of the gulf.

Her research doesn't point to the imminent extirpation of any species, but it does raise red flags for managers.

"These changes that we see are most pronounced in heavily fished species," said Shackell.

"If we put too much pressure on them, they don't have a buffer and react more heavily to climate change."

WHAT's NEXT?

"When I started, if one boat managed to land 1,000 pounds on their first day, it was talked about," Kirk Symonds said Thursday.

While many of Clark's Harbour's men were in the woods Thursday trying to get their deer before lobster season opens at the end of this month, Symonds was working on the Ocean Princess 1 and thinking about dumping days four decades ago and fishing with his father aboard the Lady Gaye.

"Now, boats go out and average three to four thousand pounds on their first day," said Symonds, 58.

Lobster stocks have exploded in the Gulf of Maine.

In fishing area 34 alone, which takes in the communities of southwest Nova that stand at the northern entrance to the gulf, landings of over 23,000 tonnes were reached in 2013-14.

Lobster grow faster in the warming waters and the cod's collapse during the early 1990s has reduced predation upon them as juveniles.

But abundant bottom-feeding crustaceans don't mean a healthy ecosystem, warns Pershing.

Shrimp and snow crab stocks surged off the coast of Newfoundland and Labrador too after the collapse of cod on the Grand Banks.

Health looks like variety and abundance in an ecosystem.

In the Gulf of Maine, that means microscopic plankton thrive on the nutrients funnelled in through the Northeast Channel and pouring in from river estuaries.

Zooplankton and bait fish like herring carry the biological matter higher up the food chain to be consumed by high-level predators like cod and whales and seabirds.

Then whatever falls down to the silent depths can get munched upon by lobster and crab and filter-feeding scallops.

We still have all those species, but they remain out of whack, pushed by overfishing in the last century and climate change in the first decade of this one.

But it's not all doom and gloom.

The gulf is expected to get warmer, but Pershing predicts the next few years will see its temperatures either stabilize or cool down. Forty years out, the average temperature may start to hover around the record highs of 2012.

Depending on how you read his October report that sparked so many scary headlines, you could see it as an optimistic document.

Though the temperature changes will decrease the habitat available to cod so that they won't return to historic levels, he thinks they will come back over the next 15 years to levels that could support a modest fishery.

The very modest fishery that occurs now won't prevent that return, he believes.

That dovetails with what Symonds and his son, Patrick, have seen. This summer, Patrick had enough quota to allow for one trip to Georges Bank.

"Back in the late '80s, there was lots of cod and haddock," said Symonds. "The draggers cleaned that up and I was part of that too."

But on this latest trip, they saw more fish. And both agreed that quotas need to be kept low to shepherd any tentative gains groundfish might be making.

Long term, out past 60 years, remains a mug's game.

The changes in the Gulf of Maine are ultimately fuelled by the global climatic trends that strengthen and direct the Labrador Current and Gulf Stream.

There are limits to even the adaptability of the species in the Gulf of Maine.