Proceedings - Teaching and Learning Centre - Simon Fraser ...

Fraser River Action Plan 3rd Research Workshop
Response of Peamouth chub (Mylocheilus caurinus) to
BKME exposure in the upper Fraser River, B.C.
W.N. Gibbons 1 , K.R. Munkittrick 2 and W.D. Taylor 1
1 Department of Biology, University of Waterloo
2 Great Lakes Laboratory for Fisheries and Aquatic Sciences
As part of the Environmental Quality component of the Fraser River Action Plan (FRAP), effort was initiated to
study the effects of pulp and paper effluents on the upper Fraser River. One of the elements of study included
monitoring the effects of pulp mill effluent on resident fish populations of the upper Fraser River. The emphasis
of this project was to evaluate the suitability of small fish species as “sentinels” for monitoring effluent-related
effects in river environments.
The upper Fraser River was selected as the study area because pulp mills contribute a substantial proportion of
the industrial effluent discharged into this section of the river: three Kraft mills (two discharges - referred to as
mill A and B) near Prince George, plus a TMP/CTMP mill (mill C) and a Kraft mill (mill D) near Quesnel. For
the purposes of the field research, the study area was confined to the receiving waters of pulp mills at Prince
George to focus the initial monitoring program on effluent from Kraft mill processes. A sentinel species was
selected based on limited mobility, abundance and capture efficiency. Fish responses were defined according to
measurements describing body and organ metrics, reproductive parameters, age estimates, mixed function
oxygenase activity (MFO; EROD activity) and sex steroid levels. The project consisted of three components: 1)
field surveys conducted during fall 1993 and spring 1994; 2) laboratory exposure to mill effluent; and 3) an onsite
field exposure test conducted in the fall of 1994.
The fall 1993 pilot survey was conducted to allow sentinel species selection and initiate monitoring of a resident
sentinel fish species exposed to mill effluent. Capture success of most of the potential sentinel fish species (e.g.,
cyprinids, cottids) were low. Of the potential species, peamouth chub (Mylochelius caurinus) was the most
abundant and widely distributed species captured. Moderate success was achieved in catching live peamouth
chub by beach seining, although overnight sets of 40 mm mesh gillnets also proved successful and less labour
intensive.
Instream concentrations of conductivity were used to track the approximate delineation of the downstream mill
effluent to ensure that sampling sites were located in areas influenced by effluent. The exact location of sampling
sites within the reference and exposure zones were dictated by capture success of peamouth chub at a particular
spot. Despite moderate success in the reference zone, capture success of mature peamouth chub in both nearfield
zones was poor. Limited sample sizes made it difficult to compare responses between reference and
exposed fish; however, preliminary results did not suggest dramatic changes in whole organism parameters.
Hepatic MFO activity in exposed immature chub was induced relative to reference fish and remained induced for
a considerable distance downstream (30 km). In the absence of previous knowledge, it was sometimes difficult to
confidently identify mature and immature individuals. Subsequent analyses indicated that many of the chub
collected were of borderline size and age of maturity, and that the fully mature peamouth were not sampled
effectively. This was especially true for the near-field zones where sites of suitable habitat for sampling were
limited relative to the reference zone.
Increased concentrations of conductivity, chloride, sodium and sulphate downstream of both mill A and B
diffusers indicated that the sites of intensive fish collections were exposed to effluent. As well, EROD induction
in immature chub from the near-field and far-field sites also indicated effluent exposure. Instream concentrations
of AOX and chlorinated phenolics were not above detection limits.
A second field survey was conducted the following spring (1994) in an effort to capture greater numbers of
sexually mature male and female chub. Beach seining, gillnetting, electrofishing, setlining and trap netting
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