Riverine In-Situ Bioassays, Oil Sands Region

Fish Status and Ecosystem Health - Caged Invertebrates In situ exposures of Hyalella azteca in Athabasca River tributaries - Summary of activities (2010, 2012, 2013, 2014) In situ exposures with Hyalella azteca were conducted within the oil sands region to assess differences in survival and growth of invertebrates caged at natural sites (i.e., exposed to naturally occurring sources of bitumen) compared to sites influenced by oil sands mining activity (i.e., exposed to both naturally occurring and anthropogenic sources of bitumen).Hyalella were collected from a wetland within the Athabasca River watershed but outside the area of oil sands development and activity. They were then placed in cages submerged at 3 sites on the Ells River, 3 sites on the Firebag River, and 4 sites on the Steepbank River. Five cages were deployed per site, each cage containing 20 Hyalella. Cages were removed two weeks after deployment, and Hyalella were counted and weighed as a group to determine growth. The data show no differences in survival or growth of Hyalella caged in situ at any of the 10 sites, when comparing natural sites to sites influenced by oil sands mining activity within each river (i.e., upstream to downstream sites) or between rivers. Caged Mussels Mature mussels (Pyganodon grandis) were collected from a site outside the oil development area (Clearwater River and Long Lake, Alberta) and placed into cages at various sites in the Athabasca River and tributaries for 4 to 6 weeks during the months of August, September and October 2012, 2013 and 2014. The data revealed that mussel growth and survival rates were not affected. Mussels exposed to river water for 4 to 6 weeks were less likely to survive when kept outside of the water for long periods of time (days). Further investigations are warranted to confirm these observations.