NWT RESEARCH DATABASE

Tags: biology, fish, fish health

Objective(s): To examine fish health of two small-bodied species in the exposure and reference areas – likely slimy sculpin and ninespine stickleback.

Project Description: The objective of the study is to examine fish health of two small-bodied species in the exposure and reference areas – likely slimy sculpin and ninespine stickleback. A small-bodied fish survey will occur within the exposure area (mouth of Baker Creek) and a reference area (Yellowknife River/Yellowknife Bay). Small-bodied fish will be captured and measured for weight and fork length, using beach seines, minnow traps, backpack electrofishing, and hoop nets. If sufficient numbers of slimy sculpin are captured during the survey of the exposure area (i.e., 30 adult males, 30 adult females and 30 young-of-the-year), these fish will be lethally sampled. These sample sizes have been developed for this site and are based on initial recommendations (n = 20) from the Technical Guidance Document (TGD) (Environment Canada) for an EEM study to ensure a minimum number of fish to adequately detect statistical differences between exposure and reference areas. A non-lethal assessment of 100 (minimum) to 400 (maximum) ninespine stickleback will be made. The captured fish will be measured for weight and fork length, and then live released and an age structure will be collected if possible. The same assessments (i.e., lethal and non-lethal survey) will be conducted at the reference area on the same species. The following parameters will be measured on adult fish of one species if they are lethally sampled: fork length; total body weight; age; life stage and maturity; external condition; gonad weight; gonad histopathology; liver weight; liver pathology; carcass weight; visceral tissue arsenic; sex; and internal condition. Possible species that may be captured include walleye, burbot, sucker sp., northern pike, round whitefish, lake whitefish, lake cisco, inconnu, arctic grayling, lake trout, lake chub, slimy sculpin, ninespine stickleback, emerald shiner, shiner sp., yellow perch, and trout perch. All non-target fish species will be documented and released alive. In addition, a benthic survey will be performed using Hester-Dendy artificial substrate samplers to collect invertebrates. A total of 15 stations will be sampled for the program with a total of 6 samplers deployed at each station. The researcher will prepare reports and conduct community presentation, if desired. The fieldwork for this study will be conducted from July 31, 2010 to October 31, 2010.