NWT RESEARCH DATABASE

Tags: contaminants, biology, mining impacts, fish health

Objective(s): The EEM will investigate the cause of differences in fish health that were observed in fish from an area exposed to mine effluent (Jackfish Bay) when compared to fish not exposed to mine effluent (Horseshoe Island Bay). Data will be examined to see what environmental factors are causing the observed effects.

Project Description: The EEM will investigate the cause of differences in fish health that were observed in fish from an area exposed to mine effluent (Jackfish Bay) when compared to fish not exposed to mine effluent (Horseshoe Island Bay). Data will be examined to see what environmental factors are causing the observed effects. Fish Program: A small-bodied fish survey will be conducted within one exposure area (Jackfish Bay, Great Slave Lake) and one reference area (Horseshoe Island Bay). For consistency between phases, ninespine stickleback will be targeted as one of the small bodied species to be sampled. The non-lethal young-of-the-year field survey will consist of five consecutive days of fishing effort, at 12 hours per day in mid to late August, in both the exposure area and reference area with the goal of reaching the following end points from each area: capturing 100 young-of-the-year (and possible juvenile) of one small-bodied species (nine spine stickleback (NNST). The following parameters will be measured on non-lethally sampled young-of-the-year fish prior to live release: length, weight, external condition, and abundance/catch per unit effort (CPUE). The lethal adult field survey will consist of five consecutive days of fishing effort, at 12 hours per day in late August to early September, in both the exposure area and reference area with the goal of reaching the following endpoints from each area: capturing 90 adult fish of one small bodied species (NNST). Lethally sampled adult fish will be measured for the following parameters: length, weight, age (otolith removal), external condition, abundance/CPUE, maturity, sex, internal condition, gonad weight, liver weight, liver histology (subset of samples), and liver assays (glycogen, lipid, and total arsenic concentration). Plankton Program: This program will collect information on the plankton and phytoplankton (chlorophyll a) communities in Jackfish Bay and Horseshoe Island Bay. The plankton program will be completed during late August to early September in 2009. Supporting environmental data will include profiles of water temperature, pH, dissolved oxygen and specific conductivity at each sampling site. Benthos Program: Benthic invertebrate samples will be collected at 10 stations in Jackfish Bay and at five stations in Horseshoe Island Bay. Five replicate samples will be collected at each station in each bay. Samples will be collected during the open water season during late August and early September. Samples will be used for taxonomic identification and enumeration of the benthic invertebrate community. 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 Horseshoe Island Bay. A final Report will be submitted to Environment Canada in June 2010. The fieldwork for this study will be conducted from August 12 to October 31, 2009, on Yellowknife Bay / Jackfish Bay (62°22'45.9" N 114°24'34.5" W) and Horseshoe Island Bay (62° 23' 31" N 114° 16' 30" W).