By Jacob Seguin

 Lake sturgeon used to be so plentiful in the Great Lakes that steamboats crossing the waters would burn their dried carcasses in their boilers to supplement their coal supplies. Then, because of caviar’s sudden popularity, lake sturgeon were fished out of much of the Great Lakes watersheds in a matter of decades –  less than the lifespan of an individual fish. When the fish you are catching only spawns once every four to six years, and even then only maybe 1% of their eggs survive, and those 1% take 20-25 years to reach breeding age themselves, the population is bound to plummet when harvesting pressures grow. While we now better understand these long survival odds, we still have a lot to learn about this ancient fish.

Fast forward to today. Now we have the benefit of not just hindsight, but new technology to help us better understand the behaviour and threats to sturgeon survival.  Today, we’re deploying advanced fish tracking technology in the watersheds of Hudson’s Bay, which represent sturgeon’s last stronghold of intact habitat in Ontario.  Fortunately for the fish, Ontario’s far north is one of the few places left in North America where their passage upriver is rarely blocked by dams or other human-made obstructions, with five major intact watersheds supporting lake sturgeon in the region. Here sturgeon travel hundreds of kilometers upstream to spawn, meaning it is not easy to follow their movements.

Since 2016, WCS Canada has been participating in a joint lake sturgeon research project with Moose Cree First Nation: tracking sturgeon health, habitat use, and behaviour in the Moose River basin. This includes the Lower Mattagami River, with its four hydroelectric dams, and the North French River, which flows unimpeded as it has for centuries. We catch sturgeon in nets and make a small incisions to insert smooth transmitters the size of an AA battery into the fish’s body cavity. We then suture the cuts closed and release the fish (Figure 1). These implants transmit data remotely to receivers rather than storing it, which means there’s no need to re-capture the sturgeon to gather the information we need. The transmitter can remain in the sturgeon without harming them, so we don’t need to bother them again!

Figure 1: A lake sturgeon being given an acoustic transmitter, a type of biologger that will teach us how this fish uses its habitat over time, and in relation to disturbances like hydroelectric facilities. Photo credit: Alex Litvinov

This June, I was lucky enough to join the WSC Canada and Moose Cree First Nation team in time to tag nine lake sturgeon in a section of river between two hydroelectric generating stations on the Lower Mattagami River. We deployed receivers, anchored to the river bottom with heavy pieces of granite. These receivers will listen for the messages that each implanted fish is sending. Whenever a sturgeon swims by, the recorder captures the sturgeon’s identity and the time and date, so we know what fish was where and when. Twice a year we visit all our receivers to change their batteries, check their seals and download the stored data.

With this work done, we now have fish teaching us about how they use different types of river habitat: segments of river in between dams, above dams, below dams, and in intact (dam-free) rivers. This means we can make a full set of comparisons of how fish are moving and behaving in these different river segments and understand how dams may alter sturgeon behaviour (Figure 2).

Figure 2:  This sturgeon is going off to teach us about its species and their needs without even knowing it.  Photo credit: Jennifer Simard.

This kind of remote monitoring technology allows us to measure characteristics that we simply had no way of measuring before – everything from fish swimming in a river to songbirds flying across North America. These small devices that animals carry, including our sturgeon transmitters, are known as biologgers, and they allow us to learn more from wildlife with smaller devices that are less intrusive or bulky for wildlife to carry. But it takes skill and care to make sure we employ these pieces of technology without harming the animals that we are learning from.

Prior to my work with WCS, I had a chance to deploy similar technology in the southeast Yukon. This project focused on lynx, and was developed by Ally Menzies at McGill University and partially funded by WCS Canada through its W. Garfield Weston Foundation Fellowship program. Ally was investigating how lynx use their body’s energy and how they may cope with changing conditions such as those driven by climate change. For example, changing snow conditions could alter how much energy it takes for lynx to move and hunt, ultimately influencing how profitable (in terms of energy gained) hunting is for them.

We placed implanted biologgers in lynx to record their heart rate and body temperature and better understand their metabolism and energy expenditure as they move through the landscape. However, in this case, we had to recapture the lynx four weeks after deploying the biologgers to get the information back (Figure 3). This could sometimes prove difficult, as was the case with Tony the Tiger, a male lynx who was particularly difficult to recapture (Figure 4). We were finally able to catch Tony, along with his data, but only after we concocted a special lure that my family used for trapping.

Figure 3: Tony the Tiger receiving a heart rate and body temperature logger to teach us how northern mammals regulate their energy use as the conditions around them change. Lots of brown disinfectant, a tiny incision, and a little white capsule. Such a similar procedure as with our sturgeon, but such different data to answer a unique conservation question. Photo credit: Ally Menzies

Figure 4: Tony the Tiger (the lynx) goes free after being caught a second time to remove his implanted body temperature monitor. He doesn't even know it, but he's taught us more about his species and his ecosystem than we could have ever come up with on our own. Photo credit: Ally Menzies

Another high-tech research method is becoming increasingly popular in fieldwork: remotely operated vehicles, or ROVs.  The most well known of these are aerial drones that are now being used for everything from aerial mapping to counting animals. But ROVs can be used in underwater research as well. We were fortunate this fall to be a part of DeepTrekker’s Ambassador Program, through which the company let us borrow one of their ROVs. Not only was it an incredible experience to learn to pilot this type of novel technology, but it gave us a small glimpse into the future of scientific research, where, for example, robot-esque technologies help us find and maintain the lake sturgeon receivers at the bottom of a hydroelectric dam reservoir (Figure 5).

Figure 5: Moose Cree First Nation youth and WCS Canada piloting a submersible ROV in the reservoir of the largest of four hydroelectric dams on the Mattagami River.

We were also fortunate to be able to share this technology with Moose Cree youth during our fieldwork, and with a science class at Dennis Franklin Cromarty High School, as a part of our lake sturgeon research project’s youth program.

As researchers, we can now use everything from underwater sound recorders left under the ice in the Arctic for an entire year, to light sensing backpacks on birds to better understand wildlife behaviour, population trends and health.  Whether it is crawling into bat caves to deploy temperature and humidity loggers, netting tiny songbirds deep in thick boreal forest to solve a migration riddle or wading into cold, fast flowing northern rivers to retrieve receivers loaded with data on the underwater movements of sturgeon, it’s a brave new world of high-tech solutions, but it still requires plenty of legwork.

As a field technician with WCS Canada I get to use my outdoor skills to navigate around some very remote places and deploy cutting-edge technology. The real reward, however, is seeing a sharper picture of what wildlife need to survive emerge thanks to our hard work in the field.

Check out our project website at learningfromlakesturgeon and the WCS freshwater story-map at The Water We Share to see what we are learning.