Dynamic Environment & Ecosystem Health Research

Nova Scotia invasive & non native aquatic species impacting vulnerable species.
Snail sampling crew Loon Lake 2017



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Historical gold mine tailings
    Invasive & vulnerable species
   Chinese mystery snails
    Chain pickerel


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A wide-spread issue for the province.

Note: If you are interested in potential applications of our research, joining our research group or would like to contribute to our data analyses, please email Dr. Linda Campbell.

Nova Scotia lakes and rivers have been impacted by introduced and invasive aquatic species.  To date, most focus on freshwater non-native species have been on sport fish species. In particular, chain pickerel and smallmouth bass are of high interest. Both species were first illegally introduced to Nova Scotia lakes around the 1940's and have now spread throughout the province. Chain pickerel has been associated with declines in amphibians and native fish species.  We are also interested in Chinese mystery snails, an aquarium & food species native to east Asia, which may be spreading through the Shubenacadie waterway system and the rest of Nova Scotia. 

We are collaborating with Department of Fisheries & Oceans, Nova Scotia Fisheries & Aquaculture, Cape Breton University, Eastern Charlotte Waterways, New Brunswick Museum, and other groups & colleagues to identify the impacts and presence of invasive species. The DEEHR team is carrying out several investigations looking at chain pickerel, smallmouth bass, Chinese mystery snails and other species, including those projects:
  • Assessing impact of chain pickerel on freshwater food webs which also include known Species At Risk (SAR) in Nova Scotia and New Brunswick.
  • How mercury contaminants biomagnify in food webs with chain pickerel and smallmouth bass.
  • Ecology and presence of Chinese mystery snails in lakes across the Halifax Regional Muncipality.
  • Culturing and maintaining wild-collected Chinese mystery snails in the laboratory.

Chain Pickerel (Link to research page)

Chain pickerel (Esox niger) is a widely introduced fish species in Nova Scotia lakes. It is an aggressive ambush predator which will consume a wide variety of food ranging from dragonfly larvae to fish to frogs. Small mammals, birds and turtles have even been found in chain pickerel stomachs!  Chain pickerel is associated with significant declines in diverse fish and amphibian populations and will impact native sport fisheries. Our work looks how chain pickerel may be affecting contaminant transfer and vulnerable species in many lakes across Nova Scotia and New Brunswick. Currently, we analyzing data for numerous lakes from Sydney in Cape Breton to Yarmouth in southern Nova Scotia. In addition, we are studying the impacts of chain pickerel on Species-at-risk organisms including yellow lampmussel in Cape Breton lakes and small-bodied rainbow smelt in Lake Utopia.

A graph from Mitchell et al (2010) showing the number of lakes with chain pickerel since 1940s, increasing to over 100 lakes in 2010.

Chinese mystery snails (Link to research page).

Chinese mystery snails, Cipangopaludina chinesis (synonyms: Bellamya chinensis, Paludina chinensis), are more recently discovered in Nova Scotia, and are thought to be probable aquarium species released inappropriately into lakes. Those snails have been reported widely across the USA but are not as well studied in Canada.  This snail species orginates from the far east of Asia & Russia regions. Chinese mystery snails are a very hardy species which can tolerate a wide range of temperatures in freshwater ecosystems. Those snails have a "trapdoor" (operculum) covering their shell opening providing significant protection. Chinese mystery snails have gills for underwater respiration and can survive extended periods in air. In addition, those snails are live-bearing (does not lay eggs), with female snails having the capacity to contain over 100 fertilized embryos for eventual development and release as juvenile snails. We are investigating the presence, abundance and impacts of Chinese mystery snails across the province. We are also investigating reports of Chinese mystery snails in freshwater ecosystems across Canada.  There is concern that the Chinese mystery snails may be distrupting native mussel and snail populations, impacting fish feeding patterns and even shifting nutrient cycling in lakes which could encourage algal blooms.

A hand holding a number of large Chinese mystery snails recently collected from a lake. In the backgroud is a white cooler full of water and snails with a yellow collecting bucket.

Smallmouth bass

Smallmouth bass are widespread across Nova Scotia and were introduced around the same time as Chain pickerel.  Those are native to other parts of Canada, but not in Nova Scotia. Smallmouth bass are visual predators and prefer warmer clearwater lakes, and can significantly reduce frog, turtle and nearshore fish populations in lakes.  Impacts are widespread and impact the entire food web.  In lakes with both chain pickerel and smallmouth bass, biodiversity and native species both can be greatly reduced.  We are studying the impacts of both non-native fish species across Nova Scotia to better understand trophodynamics and contaminant transfer.

A medium-sized smallmouth bass on a measuring board

  • Nova Scotia Invasive Species Council. Link.
  • Alien species in Nova Scotia. NS Government public communication document. Link.
  • NS Fisheries & Aquaculture AIS page with links to fishing regulations and tips for preventing spread. Link.
  • NS Lake bythometry maps & water chemistry data. Link.
  • Report: "Impact of introduced chain pickerel (Esox niger) on lake fish communities in Nova Scotia, Canada" SC Mitchell, JE LeBlanc & AJ Heggelin. 2010. PDF document.
  • Report: "Geographic distribution of smallmouth bass, Micropterus dolomieu, in Nova Scotia: history of early introductions and factors affecting current range." JE LeBlanc. 2010. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/028. PDF document.
  • Publication: "Occurrence of the Chinese mystery snail, Cipangopaludina chinesis (Gray, 1834) (Mollusca: Viviparidae) in the Saint John River system, New Brunswick with review of status in Atlantic Canada.  DF McAlpine et al. 2016. BioInvasions Records 5(3):149-154. PDF Document.
  • Sarah Kingsbury's Chinese mystery snail MSc research website. Link.
  • USGS Map of Chinese mystery snails across the USA. Link.
  • Summary of the Yellow lampmussel (Lampsilis cariosa) status. DFO Species at Risk. PDF Document.
  • COSEWIC 2013 Status Appraisal Summary on the Yellow Lampmussel Lampsilis cariosa in Canada. PDF Document.
  • COSEWIC 2008 Assessment and Update Status Report on the Rainbow smelt (Osmerus mordax) - Lake Utopia large-bodied and small-bodied populations in Canada. PDF Document.

View of Shortts Lake with water lilies in foreground, the fishing boat on shoreline in distance/


- Non-native species in Nova Scotia.
- Collaborations and projects.
- Chain pickerel.
- Chinese mystery snail.
- Smallmouth bass.
- Readings & resources.

Animated GIF of a juvenile Chinese mystery snail moving across white sand
All images and content copyright (c) Linda Campbell and other members of Dynamic Environment & Ecosystem Health Research Group.