Donadt, C.*, Cooke, C., Graydon, J. and M.S. Poesch. (2021) Biological factors moderate trace element accumulation in fish along an environmental concentration gradient. Environmental Toxicology and Chemistry 40(2): 422-434.

Citation: Donadt, C., Cooke, C., Graydon, J. and M.S. Poesch. (2021) Biological factors moderate trace element accumulation in fish along an environmental concentration gradient. Environmental Toxicology and Chemistry 40(2): 422-434.

Abstract

Trace elements can accumulate in aquatic foodwebs, becoming potentially hazardous wildlife and human health. While many studies have examined mercury dynamics in freshwater environments, evidence for the bioaccumulative potential of other trace elements (e.g., arsenic) is conflicting. Trace element concentrations found in surface water of the Red Deer River, Alberta, Canada, have raised concern for potential accumulation in aquatic biota. We investigated fish from this river to better understand the influence of biological and environmental factors in trace element bioaccumulation. We analyzed 20 trace elements and food web tracers, stable nitrogen (δ15N) and carbon (δ13C) isotopes, in muscle tissue. Zinc, selenium, arsenic, chromium, and nickel were detected in the majority of fish at low concentrations. However, mercury was detected in all fish and often exceeded criteria for the protection of consumers. Body size was often positively correlated with trace element concentrations. Additionally, food web tracers were correlated to mercury and arsenic concentrations, indicating that mercury biomagnifies whereas arsenic bio-diminishes. Spatial patterns of fish trace element concentrations did not reflect differences in surface water concentrations. These findings indicate that fish trace element concentrations are primarily moderated by biological factors, such as trophic position and body size, and are not locally restricted to areas of relatively high environmental concentrations in the Red Deer River.

*Lab members: Caitlyn Donadt and Mark Poesch. Check out opportunities in the lab!

Donadt, C.*, Cooke, C., Graydon, J. and M.S. Poesch. (2021) Mercury bioaccumulation in stream fish from an agriculturally-dominated watershed. Chemosphere 262: 128059.

Citation: Donadt, C., Cooke, C., Graydon, J. and M.S. Poesch. (2021) Mercury bioaccumulation in stream fish from an agriculturally-dominated watershed. Chemosphere 262: 128059.

Abstract

Bioaccumulation of mercury in freshwater fish is a complex process driven by environmental and biological factors. In this study, we assessed mercury in fish from four tributaries to the Red Deer River, Alberta, Canada, which are characterized by high surface water mercury concentrations. We used carbon (δ13C) and nitrogen (δ15N) stable isotopes to examine relationships between fish total mercury (THg) concentrations, food web dynamics and patterns in unfiltered THg and methylmercury (MeHg) concentrations. We found that THg concentrations exceeded the tissue residue quality guideline for the protection of wildlife consumers in 99.7% of fish sampled. However, while the surface water THg concentration was highest in Michichi Creek and the MeHg concentration was consistent across streams, patterns of fish THg concentrations varied depending on species. Furthermore, body size and trophic level were only correlated with THg concentrations in white sucker (Catostomus commersoni) and Prussian carp (Carrasius gibelio). The results of this study suggest that mercury poses a risk to the health of piscivorous wildlife in the Red Deer River watershed. Despite high THg concentrations in these streams, mercury bioaccumulation is not driven by environmental inorganic mercury concentrations. Additionally, commonly cited factors associated with mercury concentrations in fish, such as body size and trophic level, may not strongly influence bioaccumulation in these stream ecosystems.

*Lab members: Caitlyn Donadt and Mark Poesch. Check out opportunities in the lab!

Research by Kaegan Finn highlighted by Alberta Wildlife Society Chapter

Due to the covid-19 pandemic, undergraduate student Kaegan Finn was unable to present his research at the Alberta Chapter of The Wildlife Society (ACTWS) annual general meeting. Thankfully, ACTWS has been sharing some of the research from the conference on their website. In August, ACTWS highlighted Kaegan Finn’s excellent poster. Kaegan was an undergrad conducting research in the lab. I am delighted that Kaegan was able to share his hard work. Check it out for yourself here on the ACTWS webpage (link).

Research on Prussian Carp eradication highlighted in media (Magazine: Ontario Nature)

Research from a team in the Poesch lab was highlighted in Ontario Nature magazine. The story about eradication of carp, also discusses new results of a study just accepted and coming out soon in the Journal of Wildlife Management. Former post-doctoral researcher, Dr. Jonathan Ruppert, is highlighted in the piece. Other people who contributed to the study include former lab members Jamie Card and Caitlyn Donadt, and colleague Dr. Caleb Hasler from the University of Winnipeg.

Fisheries and Aquatic Conservation Lab lead a workshop on offsetting strategies in the oil sands region

Sebastian Theis, Jonathan Ruppert, Karling Roberts, Michael Terry and Mark Poesch led a workshop with around 60 participants from industry, consulting, provincial and federal governments and academia. The workshop brought stakeholders together to discuss research in the lab on offsetting in freshwaters, including how to create ecologically robust compensation lakes. Thanks to everyone who participated. Feel free to follow-up with us with any questions. 

Research in the lab was highlighted in “This self cloning crayfish is scuttling into rivers and streams throughout Alberta (News: CBC)”

It’s not unusual to spot a trout species in a Calgary river but you might not expect to find a lobster-like crustacean. In the last 10 to 20 years however, the marbled crayfish — a crustacean not native to the Bow River — has begun spreading to rivers and lakes throughout Alberta. It’s a problem that Nicole Kimmel, aquatic invasive species specialist for Alberta Environment and Parks, is trying to tackle. Historically, the crustaceans are normally found in between Wainwright and Ryley in the Beaver River watershed south of Edmonton, Kimmel told The Calgary Eyeopener. But now they’ve been showing up in water bodies anywhere from the Edmonton area, down to Calgary and Medicine Hat, as well as in the Milk River region. It’s not likely that the critters are crawling between rivers and lakes, though they can move on land for short periods, Kimmel said. Instead, the province suspects the movements of the crayfish might be aided by humans either for bait use or they are potentially being brought back home and discarded in local waters.

‘Freak accident’ leads to quick reproduction

“Once they’re introduced to a breeding pair, they can breed pretty fast,” Kimmel said — the creatures can produce 200 to 400 eggs in a reproduction cycle.  Kimmel calls the marbled crayfish a kind of “freak accident” of two crayfish species that may have been imported from Florida into Germany in the ’90s and  were able to mate. Through that mating, the crayfish kept an additional set of chromosomes that allowed them to reproduce asexually, meaning all the females could lay unfertilized eggs which develop into genetically identical offspring. In essence, a self-cloning crayfish was born. To attempt to control their spread, Alberta has banned the crayfish province-wide unless it’s kept as a pet. Most pet stores have stopped carrying the specimens, but it’s still possible to find them sold online by individuals. Ducks have been munching on them, along with some humans, but Kimmel says its important to make sure the ones used for consumption are coming from clean water sources. Kimmel says the province has partnered with Mark Poesch, Associate Professor in Agricultural Life and Environmental Sciences at the University of Alberta, to understand what the effects are on the habitats the creatures are invading. “We highly suspect that they’re probably impacting food webs where they’re being moved around,” she said.

Other crayfish creeping into Canadian waters

The marbled crayfish aren’t the only species of their kind causing concerns — there’s an extensive list of crayfish-type creatures being found in Canadian waters, Kimmel explained. For example, B.C. is worried about red swamp crayfish and in Manitoba there are concerns about crusty crayfish. Meanwhile Saskatchewan, along with Alberta, has ramped up its legislation around marbled crayfish. If you spot a crayfish, Kimmel says to report it to the province along with the location it was found. “We’re very much interested in knowing the location that you’re finding them as well as if you can snap a picture of what they look like,” Kimmel said. “We don’t want any of those other invasive ones that other jurisdictions are worried about.” The province isn’t actively getting rid of the crayfish right now until there’s a better understanding of where the crayfish are located and what can be done for eradication.

Link to CBC article.