NWT RESEARCH DATABASE

Tags: contaminants, water quality, environmental monitoring, fish habitat, fish, benthic invertebrates

Objective(s): To continue the periodic monitoring of fish and benthos at Jackfish Bay, Horseshoe Island Bay and Kam Bay, to determine if treated Con Mine effluent is affecting fish and fish habitat.

Project Description: The objective of the study is to carry out the third year of periodic monitoring of fish and benthos at the determined study locations; Jackfish Bay (exposure area), Horseshoe Island Bay (reference area for fish survey) and Kam Bay (reference area for the benthos survey), to determine if treated Con Mine effluent is affecting fish and fish habitat. The study has been designed to replicate the study design for the Phase 5 EEM (second year of periodic monitoring) study as much as possible. A small-bodied fish survey of ninespine Stickleback (NNST) will be conducted in late August/early September 2018 within one exposure area (Jackfish Bay) and one reference area (Horseshoe Island Bay). This survey will include lethal and non-lethal components. Ninespine Stickleback will be captured using seine nets. For the non-lethal survey, 100 young of year fish will be captured and all fish will be released live back into the waterbody where they were captured. The following parameters will be assessed prior to release: fork length, weight and external conditions (e.g., wounds, tumours, parasites, fin fraying, gill parasites, lesions) and catch-per-unit-effort (CPUE). The lethal adult field survey of ninespine Stickleback has target sample sizes of 40 adult male, 40 adult female and 20 juvenile fish from each area. These sample sizes are required to detect statistical differences between fish collected at the exposure and reference areas. Lethally sampled adult fish will be measured for the following parameters: fork length, weight, age (otolith removal), external condition (e.g., wounds, tumors, parasites, fin fraying, gill parasites, lesions), internal condition (presence/absence of parasites, abnormalities such as tumours), maturity, sex, gonad weight, gonad histopathology (all samples), liver weight and CPUE. A subset of the liver samples will be analyzed for lipids (glycogen and triglycerides). Any remaining liver samples will be archived for possible future analyses. The collection of ninespine Stickleback samples is anticipated to have a negligible impact on the environment and fisheries resources in Jackfish Bay and Horseshoe Island Bay. Benthic invertebrate samples will be collected at five stations in each of the study areas. Samples will be collected using an Ekman grab sampler during a field survey in late August/early September 2018. Samples will be analyzed for taxonomic identification and enumeration of the benthic invertebrate community. The following parameters will be analyzed: total density, richness, Simpson’s Evenness Index and Bray Curtis Index. The collection of benthic invertebrate samples is anticipated to have a negligible impact on the benthic invertebrate community, environment and fisheries resources in both Jackfish Bay and Kam Bay. In addition, sediment quality and water quality samples will be collected. Water quality samples will be collected in each area during the field program, and additional samples will be collected for quality assurance/quality control (QA/QC) purposes. In situ field parameters (temperature, dissolved oxygen, pH, conductivity) will be measured at the time of water quality sample collection. One composite sediment quality sample will be collected from each station (5 stations/area) with additional samples for QA/QC purposes. Sediment will also be collected from each station to provide sufficient volume for laboratory-based sediment toxicity tests. Water temperature will be monitored throughout the open-season using temperature loggers deployed at each area. Plume delineation surveys will be conducted in Jackfish Bay in late August/early September. Conductivity will be used as a conservative tracer of the treated effluent within Jackfish Bay. Technical reports will be submitted to Environment Canada and will be available by request from Con Mine, and reports and/or community presentation if requested. The fieldwork for this study will be conducted from July 1, 2018 to October 31, 2018.