First overfishing, then hydro dams. Lake sturgeon, Ontario’s largest and longest-lived fish, now belongs to one of the most beleaguered groups of animals on the planet.
By Peter Christie
Tim Haxton shifts his chair to allow his visitor a better view of the photograph on the computer screen. The dark image of a fossilized fish makes a subtle “S” in the lighter brown mud-stone that surrounds the shape. It is as if the creature suddenly turned to stone during a lazy swim through murky water. The petrified details – even the fine rays of fins – are crystal clear, and the identity of the fish is unmistakeable. “Sturgeon,” confirms Haxton, a fisheries specialist with the Ontario Ministry of Natural Resources (MNR). “This one is probably about 200 million years old, from the Jurassic period. They really haven’t changed much in form or function since.”
The soft-spoken biologist has collected hundreds of photos during his 15 years of studying lake sturgeon, Ontario’s largest and longest-lived fish. His picture of the fossil, however, adds an almost mind-boggling historical view to our discussion of sturgeon conservation: close ancestors of this formerly indomitable animal were swimming the world’s waters before the Atlantic Ocean was born, before birds flew and about 200,000 millennia before humans first appeared. They swam right through the great extinction of the dinosaurs and, despite volcanic eruptions, ice ages and other climatic calamities, have overcome every threat they encountered – until now.
Sturgeon today confront a higher risk of extinction than any other non-insect animal in the world, says Haxton, citing the conclusions of a 2010 workshop of the International Union for Conservation of Nature (IUCN). Decimated by periods of overfishing and prized for their eggs, which are sold as expensive caviar, many sturgeon populations around the globe have been in free fall for decades. All 27 sturgeon species – including lake sturgeon – are on the IUCN’s Red List of Threatened Species. Two-thirds of these are considered “critically endangered” because their plummeting numbers or shrinking, fragmented ranges mean that the odds of this fish disappearing for good are “extremely high.” Four sturgeon species may already be gone forever.
Which is why, Haxton says, conservation of Ontario’s lake sturgeon is so crucial. These fish are better off than many sturgeon species but have troubles of their own. In 2009, two of the three populations of lake sturgeon – the only type of sturgeon found in Ontario – were listed as threatened on the province’s Species at Risk roster. The other, most northerly population is considered of special concern. In the Great Lakes in particular, stocks of this now rarely seen fish never recuperated after an overzealous fishery a century ago reduced their numbers to a fraction of their former population. Meanwhile, human interference seems to be hampering their recovery. The worst culprits are hydro dams, whose number is expected to surge as the province pushes for more renewable energy (see “Waterpower,” facing page).
All this only makes Haxton’s main point more significant: the lake sturgeon that live in at least 128 lakes and reservoirs and 101 rivers across Ontario (as well as sturgeon in parts of Quebec and Manitoba) represent “the last, good remaining stock of pristine sturgeon anywhere in the world.” They are, in other words, possibly the final hope for one of the oldest and most beleaguered groups of animals on the planet.
“That’s what I’m trying to get across,” he says. “We have one of the few bastions left.”
If lake sturgeon are a living link to our primeval past, they certainly look the part. Lead grey or deep, primordial brown, adult sturgeon appear to belong to another time. Their skin is without scales and leathery, and their fins set back toward their sickle-like tail. Mature sturgeon are huge, frequently a metre or more long. Some are giants, reaching a length of four and a half metres and weighing up to 185 kilograms (the weight of a small piano). Despite their size, lake sturgeon inhabit the relative shallows (between five and 10 metres deep) where they patiently scour the bottom, using four sensory barbels hanging near their noses to locate insect larvae, snails, crayfish, clams and sometimes small fish. Like sharks and other ancient fish, sturgeon have a skeleton of cartilage instead of bone and move with an almost fluid gracefulness. Also like sharks, these prehistoric fish have a long snout, and their eyes are eerily black.
“The first European settlers hated them,” says John Casselman, an adjunct professor at Queen’s University and a former senior scientist at MNR’s Glenora Fisheries Station near Picton. Before the mid-19th century, vast numbers of sturgeon swam in the clear water of the Great Lakes and its undammed tributaries, and were despised for fouling nets and gear set for trout and other, more useful species. (The settlers’ view of sturgeon was in sharp contrast to the centuries-old beliefs of many Ontario First Nations people, who revered it as a source of food, oil and leather, and celebrated it in rituals and legends.) Fishermen stacked “nuisance” sturgeon onshore by the thousands and left them to dry, later to be used as furnace fuel for steamships.
In the 1860s, that negative attitude changed. Canneries appeared in the United States that could process sturgeon meat for markets elsewhere, and caviar became a sought-after delicacy. A huge commercial sturgeon fishery boomed throughout the Great Lakes, as well as in other large Ontario waters such as lakes Nipissing, Nipigon and Simcoe, Lake of the Woods and the Ottawa River. More than seven million kilograms of sturgeon were harvested in Ontario at the peak of the fishery between 1885 and 1889. Then, with spectacular suddenness, stocks collapsed. In the period from 1905 to 1909, the catch fell to less than one-tenth of what it had been 20 years earlier.
Lake sturgeon in Ontario and elsewhere in the southern reaches of its range have never really recovered, either in number or, says Casselman, in our imaginations. “I think we lost our association with the fish. People just didn’t think about them anymore. The commercial fishery continued, but it was small, until the seventies and eighties, when it virtually disappeared altogether.”
Almost 40 years have passed since Ontario ended commercial harvests of sturgeon in three of the four Great Lakes. (A limited fishery in Lake Huron and Lake St. Clair was closed in 2009.) In 2008, even recreational fishermen were forbidden to take sturgeon – if they could find them. Indeed, sturgeon became an uncommon sight in the province; in some former sturgeon rivers, none have been seen in years. For decades, even scientists seemed uninterested in the species.
Then, last September – more than 100 years after the great decline – MNR completed an official recovery strategy for the Ontario lake sturgeon. The government has until summer 2012 to respond to the report. But nothing is easy about sturgeon conservation in the province – especially since the government continues to actively encourage the development of new hydroelectric dams, perhaps the greatest threat to the sturgeon’s survival.
“Sturgeon are a big fish, and they’re highly mobile,” says University of Guelph biologist Rob McLaughlin. “If you put in a dam … you’re going to fragment the population.” Dams are widely acknowledged – including in the MNR recovery strategy – as one of the top reasons why lake sturgeon populations are in trouble in Ontario. Many sturgeon migrate long distances (more than 100 kilometres) upstream from their adult habitat to breed in shallow river rapids or at the bottom of falls. Typically, these are historical spawning sites, revisited year after year. Dams can block the migrants’ routes or spoil the fast-flowing, pebbly breeding beds on which the sturgeon depend. Some facilities even chop up adult fish or trap the downstream-drifting fry. Almost 200 waterpower projects already interrupt many Ontario rivers.
This is a serious worry in light of what a long-term and tentative business sturgeon breeding is. The fish live up to 150 years, and females can take 33 years to become sexually mature. Even then, they spawn only every four to nine years. (Males mature somewhat earlier and spawn about twice as frequently.) As well, the potential mothers remain in spawning condition for only a short time, and they reabsorb their eggs if no suitable sites on which to deposit them are available.
While dams have been clearly linked in the past to reductions in sturgeon populations, including the collapse of sturgeon stocks in Lake St. Francis (which has dams at both ends) and declines on parts of the heavily developed Ottawa River, they’re not the only pressures on lake sturgeon. Climate change may warm some waters above the cool temperatures spawn need to hatch, and water pollution threatens to poison the eggs. Invasive sea lamprey prey on adult sturgeon, but efforts to control the lamprey are proving to be hazardous to sturgeon as well: the chemical used to kill young lamprey in streams can also affect the struggling fry of sturgeon. While invading mussels and gobies are a source of food for sturgeon, gobies also eat sturgeon eggs and mussels cover and spoil the pebbly spawn beds.
Nevertheless, dams are of most concern, if only because of the very real potential that the problem is about to get much worse. Two years ago – just months before lake sturgeon were added to the Species at Risk list – the Ontario government passed its Green Energy Act, partly in an effort to encourage more renewable power in the province. As of September, 102 new hydro projects had applied to take advantage of a guaranteed pricing program (the feed-in-tariff, or FIT, program). More are likely to follow: according to an inventory by the Ontario Waterpower Association (OWA), an industry group representing hydroelectric companies, 2,000 other sites across the province have at least the water-flow potential to support hydro dams in the future.
The conundrum is that laudable efforts to generate more clean power threaten to have other environmental consequences, especially for river-dependent fish such as sturgeon. “I worry about it big time,” says Casselman of Queen’s University. “What we have is two renewable resources competing for our attention, and we’re not paying enough attention to the fish component of this … We need to take a deep breath and step back to look at our impact in terms of river fragmentation.”
Colin Hoag, a policy advisor with OWA, argues that saying that all dams hurt sturgeon is overly simplistic. “Each case is different,” he says. In 2009, OWA – with input from MNR, Fisheries and Oceans Canada and others – published a “best-management practices” guide to minimizing the impact of hydroelectricity generation on lake sturgeon in Ontario rivers. Although sturgeon have difficulty climbing dam “fish ladders,” such as those used in the United States and Quebec to help eels, other possible mitigation methods include managing downstream, sturgeon-friendly water levels, flows and habitat; physically trapping and transporting the fish past the barriers; or simply choosing to locate projects on other rivers, where their effects will be less disruptive to sturgeon.
Many of these tactics are reviewed in the OWA report, but it is only a guide. (“There’s no requirement for our members per se,” says Hoag.) What is urgently needed, advises the University of Guelph’s McLaughlin, is more research and, with it, a more thorough, informed public discussion. “What I’d like to see is a clearer explanation to society of what the trade-offs are when we are going to build a dam,” he says. “What are the options? There may be options that allow us to generate the electricity society needs in ways that we believe will minimize the impact on the fish.”
Tim Haxton supports McLaughlin’s central idea. At his brightly lit desk in the science section of the Peterborough MNR office, Haxton explains his current, multi-year sturgeon research program as a way to move discussions forward, by getting to the bottom of the complex relationship between sturgeon and river dams.
While doing his PhD a few years ago, Haxton was among the first to link the population health of sturgeon in stretches of the Ottawa River with the type and intensity of dam development there. Now, with a crew of other MNR biologists, he is hoping for similar findings in 30 other representative waterways across Ontario. “You can have dams and you can have sturgeon, in my opinion,” he says, but “there seems to be a right way and a wrong way.”
Meanwhile, there are some reasons for optimism about the prospects for Ontario sturgeon. In Lake of the Woods and Rainy River, studies by the Minnesota Department of Natural Resources (which shares these watery jurisdictions with Ontario) show that lake sturgeon longer than a metre more than tripled in number between 1990 and 2004, from approximately 16,000 to almost 55,000. Sturgeon stocks in the Detroit River have also increased, according to MNR. Casselman believes that sturgeon in the 1000 Islands area of the St. Lawrence River near Cornwall appear to be rebounding as well. “Fishermen here would tell you that they believed these fish spawned in the Long Sault rapids and, of course, the construction of the Moses-Saunders [hydroelectric dam project] cut them off,” explains Casselman, who has started a new study of sturgeon in the St. Lawrence. “It’s taken about three generations, but it now looks as though they’ve started to reproduce in the fractionated river.”
Sturgeon are resilient, says Haxton. Indeed, their ability to adapt should hardly be surprising in a fish with a history that goes back to the time of ichthyosaurs. Despite river dams, overfishing and a host of other troubles facing them today, the sturgeon’s long evolutionary past may be the best clue to the promise of their future. “Here you have this living dinosaur,” says Haxton. “It’s incredible to think about what they have survived.”
Peter Christie is a Kingston-based science writer who remembers being introduced to his first leviathan lake sturgeon years ago by his late father and former Ontario coordinator of Great Lakes fisheries research, Jack Christie.