Bloody mess: the exotic species cocktail the Great Lakes have become

When the Captain of the Griffin sailed his ship towards Frontenac (now Kingston, Ontario) in 1679, what did he see? Should someone ever work out how to time travel, I want to see the Great Lakes when the ‘coureur des bois’, the romantically-named ‘runners of the wood,’ paddled their canoes up and down the Great Lakes piled high with beaver pelts. What would the Captain
make of the state of them now?

“Just as overfishing impoverishes the life of the sea, the forgetting impoverishes our own lives” George Mombiot recently wrote in a recent blog on the declining state of fisheries.

I agree. But, I wonder how many people now have any memories of the seas or lakes they live near in the first place? Unless they fish, paddle or swim in their waters, that connection – and the memories that spring from it – is never formed.

I grew up in Toronto on the shore of Lake Ontario, but have no childhood memories of it. It was a large lake I could see off in the distance from time to time, or walked beside. My memories are of the lakes up in Algonquin Park, which I swam and paddled in during my childhood and my teens.

But my dad is an avid fly fisherman who fished tributaries feeding into Lake Ontario near Toronto for many years. I remember him returning from a fishing trip cold and a bit shocked and recounting how he nearly drowned in one such river in late fall – it’s a story neither of us are likely to forget. He’s seen the astounding changes the lake has undergone over the years.

To people who haven’t physically seen them, the great expanse of the Great Lakes is hard to imagine. When standing beside them they look like oceans – there is no land in sight on the other side. Together they contain one-fifth of all the world’s surface fresh water; their combined surface area is approximately the same size as the United Kingdom. Four of the five freshwater lakes straddle the border between Canada and the States (with the fifth, Lake Michigan located in the USA), which has further complicated their ecological management over the years.

On stormy nights, the Lakes can prove deadly. The French explorer, René Robert Cavelier, Sieur de La Salle, who financed the building of the Griffin, the largest vessel the Great Lakes had ever seen at that time, learned this the hard way. The ship vanished in 1679 with his pilot and crew on board on its way back from exploring Green Bay, Wisconsin on the edge of Lake Michigan loaded with furs. Was it attacked? Did it sink? 330 years on a new project is trying to solve the mystery. A [British] Royal Navy warship, which sank during the American Revolution in 1780, was just another of the 4,700 shipwrecks that have taken place in the Great Lakes.

It’s likely that if a member of the Griffin fished the Lakes now, they wouldn’t recognise any of the fish swimming in them. They’d be advised not to eat the large fish anyway, as the larger sizes of fish have high levels of toxic Polychlorinated Biphenyls, which were once used in coolant fluids in power stations and transformers around the Great Lakes.

But industrial pollution is no longer the main threat to the lakes – the more than 180 invasive species in the Great Lakes are (this is a 2007 figure, so now the numbers are likely higher). The story of the Great Lakes is one of wave upon wave of invasive species creating a messy cocktail of organisms that has thrown the original lakes’ ecosystems completely off-balance.

In the 1900s, the creation of locks and canals, are what allowed invasive species in the Great Lakes to flourish. The sea lamprey (Petromyzon marinus) is a case in point. While many think it entered the Lakes through the St Lawrence Seaway some suggest  the sea lamprey is indigenous to Lake Ontario. Once there, it migrated to the other Great lakes through the Welland Canal, which connects Lake Ontario to Lake Erie and allows ships to bypass the treacherous Niagra Falls.

Looking like (but not the same as) an eel with a round mouth and sharp teeth, the lamprey latches onto fish and feeds on the blood of their fish host, often leading the prey to die. With no natural enemies, by the 1950s lampreys were decimating fish stocks such as Lake trout; catches in Lake Huron fell from 3.4 million pounds in 1937 to “virtual failure in 1947”. The sea lampreys are so predatory that the swimmer Marilyn Bell had to be covered in grease to try and stop them from latching onto her as she swam across Lake Ontario in 1954.

Millions of dollars are now spent each year trying to keep lamprey numbers down by effectively poisoning the juveniles. This has helped the Lake trout recover in Lake Superior – but they never came back in the other Great Lakes for reasons that are unclear.

The St Lawrence Seaway, opened in 1959, dropped the speed of the water current through the creation of locks, to allow ships to travel from the Atlantic upstream into the Great Lakes. Whereas previously a lot of fish in the Atlantic hadn’t been able to swim strongly against the current, they now could. This is how the alewife (Alosa pseudoharengus) or ocean herring invaded the Great Lakes.

The larger fish, like the Lake Trout, who might have fed on the newly-arrived alewife were getting destroyed by the lampreys. With no natural predators, the alewife population exploded and then died off. My dad remembers seeing millions of them lying dead and rotting along the side of the lake.

Zebra mussels and Quagga mussels likely entered the Lakes in the ballasts of ships making their way along the Seaway, and have led to the decline of the white fish population (Coregonus clupeaformis), which is the most economically valuable freshwater species of the Great Lakes. That’s because the mussels filter water and the plankton within them, the food which once sustained the white fish and other fish species. As the mussels are such efficient filter feeders, the fish are vastly outnumbered and left with slim pickings.

Called Assihendo, some explorers described how First Nations groups, like the Chippewa made the Great Lakes white fish a key part of their diet. They also sold them onto other First Nations Groups, and to the French. It “…must be the best fish in the world, since all those who have eaten it say that they never grow tired of it and prefer it to all other meats that one could find,” wrote French explorer Antoine Denis Raudot in 1710.

Gary Fahnenstiel, an ecologist with the National Oceanic and Atmospheric Administration, has said this invasive species has changed the “food web” in the last five years, “more than any other time in the last thousand years.” So does First Nations fisherman Albert Lablance.

This has led to the near-complete collapse of the once commercially viable Great Lakes fishing industry, and the generations of fishermen who rely on them. Fishermen like Dan Anderson, the last of the Milwaukee fisherman, who has had to leave Lake Michigan for Alaska in search of fish, poignantly described by Dan Egan of the Milwaukee Journal Sentinel. Egan is a Pulitzer Prize finalist and winner of the Grantham Prize for his in-depth (and thus unusual) feature stories on threats facing the Great Lakes.

The latest threat? Asian carp, introduced in Arkansas in the early 1960s to eat weeds in filthy sewage-infested rivers and which are now at the “gates of the Great Lakes,” the Chicago river. As plankton feeders, they could out-compete native fish in the already-out-of-kilter Great Lakes food chain, which is why the Canadian government is spending (CDN) $17.5 million to keep them out.

Apart from the ecological havoc created, it seems combating invasive species costs big money, with Canada and the USA spending a combined (CDN) $500 billion each year.

To make matters worse, Lake Erie experienced its worst algae bloom in decades in 2011 – possibly due to the invasive mussels and a wet spring, with rains carrying phosphorous off farms into the lake. When the algae dies, bacteria break it down consuming oxygen in the water, creating ‘dead zones’ where no fish can survive.

Nature changes, everything is in flux. The protected chalk downs I blogged about [link] are a product of human management – developed through centuries of cutting, grazing and burning.

But how many people realise how much the Great lakes have changed, or can remember them as they once were in the 1920s or 30s, when my dad was born, or when his dad was trapping animals for pocket money, and catching fish the crew of the Griffin might have recognised?

If people knew what we know now, and the consequences of their actions, would they have judged using the PCBs and building the seaways and locks to be worth it? What would the crew on board the Griffin make of it all?