Eggs-traodinary Fieldwork

 We are very excited to welcome Michelle Lavery to the blog today. Michelle is currently finishing her MSc thesis at the Canadian Rivers Institute (University of New Brunswick), which examines Atlantic salmon embryo mortality and development in the Miramichi River system. For more about Michelle, see the end of this post. 

Winter is often ignored in ecological studies, for the simple reason that it sucks. It sucks to work in the winter because it’s expensive, difficult, and sometimes dangerous. You need a lot of extra gear like snowmobiles, snowshoes, shovels, augers, and mountains of Thinsulate – not to mention the cost of operating a field camp or finding backwoods accommodation in the snow. The work is often cold and slow, since ropes will freeze into knots, snowmobiles can get stuck, and river ice is often quite thick and temperamental. Frostbite is a genuine concern, as is hypothermia and the risk of falling through river or lake ice. However, when the equipment can be paid for, the workers are willing, and the dangers can be mitigated, winter is the most wonderful and fulfilling season for fieldwork. There aren’t any pesky biting insects, everything is covered in a sparkly white blanket, and you’re never sweaty. Plus, there’s often a lot more going on under the ice than you would expect.

In the spring of 2013, Dr. Rick Cunjak (one of the founders of the Canadian Rivers Institute and a professor at the University of New Brunswick) was on the hunt for a gullible student who would agree to examine how fluctuations in a suite of abiotic factors might be associated with Atlantic salmon embryo mortality and development in the Miramichi River system. Why would they need to be gullible? The project he had in mind required that the student complete two field seasons spanning the fall, winter, and spring – in Northern New Brunswick. Being from Southern Ontario, I had never experienced a Maritime winter. After a brief conversation and a flurry of emails, I began my Masters in September 2013. I had fallen into his well-laid trap and started planning my first field season.

[My kickass salmon-catching team – I couldn’t have done it without them and the giant beach seine] [Credit: Michelle Lavery]

Atlantic salmon are anadromous fish, meaning that they spend their juvenile years in freshwater streams and move to the ocean as smolts to feed and grow into adult fish. Once mature, the adults return to their natal freshwater streams over the course of the summer and bury their eggs in streambeds in the fall. These embryos incubate over winter and hatch in the spring, when their macroinvertebrate prey are emerging in high abundances. A river can experience a number of drastic changes over the winter; aside from the obvious drop in temperature, they might experience a considerable change in groundwater contribution and dissolved oxygen concentrations, as well as significant scouring and erosion from various ice formations and breakup processes. But before I delved into how these changes might be affecting salmon embryos, I needed to find some salmon embryos.

In 2013, the Miramichi River had the fewest returning adult Atlantic salmon in 43 years and, let me tell you, we noticed. We were desperately searching for “ripe” salmon – adult fish who haven’t yet spawned – so that we could manually spawn the fish and use their fertilized eggs to fill artificial nests that we had dug in our study rivers. After a full month of searching, seining, and snorkelling (in a wetsuit, in October), we finally found a few adults who suited our needs. Back at the hatchery and early in the morning, we spawned the adults and gently measured out the quantity of embryos we needed using exceedingly technical equipment.

[I firmly believe that a frying pan counts as scientific equipment, even though Kurt seems skeptical.] [Credit: Michelle Charest]

We meticulously filled each cell of over 140 Scotty incubator trays with single fertilized eggs and buried them in our salmon nests. This had to happen in the same day as fertilization, since the embryos are only resilient for a short period of time. Consequently, a lot of incubator burying happened at night, by the light of the moon (and a few headlamps). At one site, I felt something large and very strong slapping me in the kidney while I was burying one of the incubators. I peered into the water to see not one, but five fully grown male Atlantic salmon. I had kicked up lots of sediment while rummaging around for a comfortable spot to kneel and, since I had spawned fish that same morning, I had fluid from female salmon all over my waders. For all intents and purposes, I had become my study species – a ripe female salmon…

[I know, we look like long lost sisters…] [Credit: Nelson Cloud]

A few months later, I returned to my nests to see how the embryos were doing. To rephrase the previous sentence, I snowmobiled for over 50 km, snowshoed for another 8 km while dragging a chainsaw and a large iron ice chisel, dug several holes through metre-think river ice, and retrieved my incubators using a complicated triangulation method involving ropes, trees, and a long measuring tape. Then, I dragged the incubators back the field camp to count and sample them. The snowmobile got stuck more times than I can count, I was tethered to an oak tree and wore a lifejacket to venture onto some shady-looking river ice, and I came up with incredibly colourful compound curse words. To put salt on the frozen wounds, I returned to my redds just after the spring melt, when trucks inevitably get stuck in muddy back roads and field assistants are always grumpy and soggy.

[Ice-digging is an activity of extremes; it can be incredibly rewarding or soul-crushingly disheartening. That smile is 8 hours in the making.] [Credit: Michelle Lavery]

Looking back, I wouldn’t trade my field experience for anything. Unlike many of my ecological counterparts, I managed to maintain the majority of my blood volume during fieldwork by avoiding summer mosquitoes. I came away with some fond, frostbitten memories and some killer data. Plus, I have stories that I’ll be able to tell for a lifetime. That’s why we do this crazy stuff in the first place, right?

Michelle became enamoured with Atlantic salmon during a field season in New Brunswick for her Honours project at Queen’s University. Since then, Atlantic salmon embryos have taken over her life. Simultaneously, she’s discovered her passion for science communication. She’s attempting to launch some sort of freelance career while finishing up her Masters thesis. She writes, edits, and consults in exchange for money, favours, or snacks – not in any particular order. You can check out her work at jmichellelavery.com or follow her on twitter (@JMichelleLavery).