Fish Performance Indicators Adjacent to Oil Sands Activity: Response in Performance Indicators of Slimy Sculpin in the Steepbank River, Alberta, Adjacent to Oil Sands Mining Activity.

Since 2009, the Canadian and Alberta governments have been developing monitoring plans for surface water quality and quantity of the lower Athabasca River and its tributaries (2010-2013). The objectives of the present study to the fish monitoring program were to 1) assess the current status of fish in a tributary of the lower Athabasca River, 2) identify existing differences between upstream reference and within the oil sands deposit exposure sites, and 3) identify trends/changes in fish performance indicators relative to historical studies. The present study examines the fish performance indicators in slimy sculpin (Cottus cognatus) in the Steepbank River, Alberta, in terms of growth, gonad size, condition, and hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity as an indicator of exposure to oil-sands-related compounds.

Sensitivity of multiple life stages of 2 freshwater mussel species (Unionidae) to various pesticides detected in Ontario (Canada) surface waters.

Freshwater mussels contribute important ecological functions to aquatic systems. The water filtered by mussel assemblages can improve water quality, and the mixing of sediments by burrowing mussels can improve oxygen content and release nutrients. However, nearly 70% of North American freshwater mussel species are listed as either endangered, threatened, or in decline.

Investigation of clearance rate as an endpoint in toxicity testing with freshwater mussels (Unionidae).

The implementation of ecologically relevant sub-lethal endpoints in toxicity testing with freshwater mussels can provide valuable information during risk assessment, especially since these organisms are often exposed to low levels of contaminants. This study examined how to optimize quantifying the filtering capacity or clearance rate (CR) of mussels after exposure to a reference toxicant, sodium chloride (NaCl). CR was defined as the number of algal cells an individual mussel can remove from the overlying water by filtration over time and was determined using spectrophotometric absorbance and direct microscopic examination.

An Assessment of the Spatial and Temporal Variability of Biological Responses to Municipal Wastewater Effluent in Rainbow Darter (Etheostoma caeruleum) Collected along an Urban Gradient.

Municipal wastewater effluent (MWWE) and its constituents, such as chemicals of emerging concern, pose a potential threat to the sustainability of fish populations by disrupting key endocrine functions in aquatic organisms. While studies have demonstrated changes in biological markers of exposure of aquatic organisms to groups of chemicals of emerging concern, the variability of these markers over time has not been sufficiently described in wild fish species. The aim of this study was to assess the spatial and temporal variability of biological markers in response to MWWE exposure and to test the consistency of these responses between seasons and among years.

Severe intersex is predictive of poor fertilization success in populations of rainbow darter (Etheostoma caeruleum).

Municipal wastewater effluent (MWWE) contains emerging contaminants such as pharmaceuticals and personal care products (PPCPs) that have estrogenic properties. PPCPs are thought to be responsible for feminization of male fish in heavily urbanized areas around the globe. While many observations of feminized male fish have been made, the impact of feminization on reproductive success is not well understood.

Optimization of effects-assessment of greenside darter (Etheostoma blennioides) exposed to tertiary treated municipal wastewater based on seasonal changes of reproductive endpoints.

The present study describes the seasonal changes in reproductive endpoints of the greenside darter (Etheostoma blennioides) and its implications for environmental monitoring. Fish collections conducted at the appropriate time for the site-specific sentinel fish species can provide a wide variety of population-level information including recruitment, reproduction, and energy storage. The objectives of the present study were to: 1) characterize seasonal changes in reproductive endpoints of the greenside darter (both sexes) to determine the appropriate period for monitoring of this sentinel species; and 2) evaluate the effect of exposure of this sentinel species to tertiary treated municipal effluent at the selected monitoring period.

Occurrence and degree of intersex (testis-ova) in darters (Etheostoma SPP.) across an urban gradient in the Grand River, Ontario, Canada.

The variability and extent of the intersex condition (oocytes in testes, or testis-ova) was documented in fish along an urban gradient in the Grand River, Ontario, Canada, that included major wastewater treatment plant outfalls. A method for rapid enumeration of testis-ova was developed and applied that increased the capacity to quantify intersex prevalence and severity. Male rainbow darters (Etheostoma caeruleum) sampled downstream of the first major wastewater outfall (Waterloo) had a significant increase, relative to 4 upstream reference sites, in the mean proportion of fish with at least 1 testis-oocyte per lobe of testes (9-20% proportion with ≤ 1 testis-oocyte/lobe vs 32-53% and >1.

Intersex and reproductive impairment of wild fish exposed to multiple municipal wastewater discharges.

The Grand River watershed in Ontario, Canada, receives and assimilates the outflow of 29 Municipal Wastewater Effluent (MWWE) discharges which is a mixture of domestic and industrial wastes. The purpose of this study was to investigate the cumulative impact of multiple sewage discharges on populations of wild fish. In field studies, responses of fish populations and individual fish responses in terms of growth (condition factor), reproduction (in vitro sex steroid production, gonadosomatic indices, histology [cellular development and intersex]) were assessed upstream and downstream of two municipal discharges.