The Lost Pleistocene World of the Georges Bank

I’m taking an imaginary vacation this week away from southeastern North America to visit one of the few ice free spots in the northeast during the Last Glacial Maximum.

The Georges Bank used to be one of the richest fisheries in the world.  During the LGM it was an extension of the mainland inhabited by many species of megafauna.

East of the Gulf of Maine the sea floor rises 330 feet.  Both cold and warm currents sweep over this submerged island, and light can reach the shallow bottom which ranges between 10-50 feet deep.  The light and the mixture of currents create an ideal habitat for a rich zone of phytoplankton.  The phytoplankton  is the foundation of a food chain that feeds over 100 species of fish, and the gravel bottom, eroded from glacier-pushed rocks, provides excellent spawning structure.  One of the richest fisheries in the world used to be found here before fleets of international factory ships decimated the naturally abundant stocks in the 20th century.  Long before Basque fishermen discovered this amazing fishing ground in the 11th century, the Georges Bank existed as a special and beautiful part of the North American mainland.

20,000 years ago, a massive glacier, one mile thick, depressed the entire area of what’s now New England.  The weight of all that ice literally pushed the earth’s crust down.  Glaciers from previous Ice Ages had already gouged a trough off what today is Maine’s coast, explaining why the Gulf of Maine is so deep.  The most recent glacier, the Laurentide, advanced over the dried-out trough toward the receding Atlantic Ocean.  The ocean was receding because so much of the world’s water was becoming locked up as ice.  But on the narrow strip of higher land in the vicinity of the Atlantic Ocean, the climate was warmer, perhaps keeping the glacier at bay.

The Georges Bank was an extension of the mainland, 140 miles long and 75 miles wide.  It was bounded on one side by the enormous glacier, and on the other by the ocean.  The climate consisted of cool summers, thanks to the monstrous ice cube next door, and snowy but bearable winters because moderating oceanic winds prevented temperatures from plummeting as low as occurred farther inland.

Icebergs drift off shore here within site of the sand dunes where beach grass, beach pea, and bayberry grow.  Walruses swim to and fro from small ice floes to the beach.  Behind the beach dunes, brackish lagoons host ducks and geese and loons.  Forests of pine, spruce, fir, birch, and alder cover most of the island, interrupted here and there with cranberry bogs.  Grassy windswept steppes are located on the northern part of the island and on nearby Sable Island.

Tim Wichinbach dredged up this partial mastodon tusk while fishing for scallops over the Georges Bank.  Fishermen have accidentally caught Pleistocene fossils in their nets in more than 40 sites on the Georges Bank.  The list of accidental bycatch includes fossils of mastodon, mammoth, woodland musk-ox, stag-moose, long-nosed peccary, walrus, bearded seal, and wood from ancient forests.  Reportedly, tapir and ground sloth bones have also been dredged, but I can’t find documentation in the scientific literature.  A good comprehensive catalogue of Georges Bank fossils has not been published.  Information is limited to 3 old articles from very obscure scientific journals.

An early October snowstorm covers a north facing slope, yellow grass tufts stick above the white layer.  A herd of dwarf mammoths and lean musk-oxen graze on the grass, the mammoths clearing the snow with their tusks.  The horns on the musk-oxen cover their skulls like football helmets.  Closer to a forest edge in a low lying area on the other side of the slope, steam rises from a bog.  A huge solitary stag-moose stands ankle deep, a mouthful of green slime hangs from his mouth.  I think it’s a clump of duckweed.  In the open forest mastodons use their trunks to tear branches from young spruce and red pine saplings.  I can hear them grind the cellulose between their giant molars.  One of the hairy elephants has an itchy hindquarter.  He backs up against a jack pine and rubs, but it’s a dead rotten tree, and it snaps and falls over, startling a spruce grouse which flies away in panic.

5,000 years later, the climate warms, and the Laurentide glacier melts as rapidly as 300 meters a year.  Birch forests colonize the newly available land, and the animals follow, but soon, rising sea levels inundate not only the Gulf of Maine, but areas of the coast that are currently above sea level, including the future sites of Augusta and Bangor.  As the heavy weight of the glacier recedes, the land area of Maine rebounds because there is nothing pressing the earth’s crust down here any more.  This is known as isostatic rise.  Meanwhile, the Georges Bank has become a true island, surrounded by ocean water on all sides.  Eventually, sea levels rise more, dooming the animals that didn’t migrate west.  The Grand Banks to the north also falls below sea level.  Only a small spit of sand, the highest point of Sable Island, still remains above sea level in this region.

A Sad Timeline of the Rape of the Georges Bank Fishery

The Georges Bank was an astonishingly rich fishery.  When first discovered by Basque fishermen around 1000 AD, they kept it a secret for over 500 years.  Cod were so abundant fishermen could just stick a basket in the water and 50 pound cod would fill it immediately.  Early colonists living near Cape Cod complained about having to eat lobster every night.  The cod take continued to remain strong until the 20th century when industrial ships from all over the world caught thousands of tons of fish.  Finally, in 1977 the U.S. banned foreign trawlers but it was too late.  American fishermen continued to overfish and now there’s little left–a testament to man’s shortsighted greed.  It’s another sickening example of poor natural resource management.

1830–Right whales nearly exterminated

1850–Halibut disappear

1977–Herring fishery collapses

1994–Commercial cod fishing collapses.  Law passed to outlaw commercial cod fishing proves ineffective.  It’s still not policed.

In my opinion all commercial fishing on the Georges Bank should be banned for 20 years.  Maybe then, it would recover.

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One Response to “The Lost Pleistocene World of the Georges Bank”

  1. James Robert Smith Says:

    I visited Lubec Maine a couple of decades ago and one of the residents took me down one seaside street where there were once dozens of fish canneries. At that time, only one was open, running part-time. Humans have an an unstoppable urge to eat everything until it’s gone.

    Hate to point the conversation back to the south, but one of my cousins found some rather impressive fossils near a spring in Florida some years ago. Mammoth and sloth. The mammoth bones were especially important. I believe they’re in the University of Florida collection, now.

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