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NRBS - HomeTable of Contents |
Northern River Basins Study Final Report
3.0 Major Findings
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Introduction Previous Fisheries Work Fish Species and Distribution Fish Movement Fish Habitat Food Chain Relationships Gross Pathology of Fish Relevant Documents |
| Related NRBS Question: | |
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| 1. a) | How has the aquatic ecosystem including fish and / or other aquatic organisms been affected by exposure to organochlorines or other compounds? |
| 6. | What is the distribution and movement of fish species in the watersheds of the Peace, Athabasca and Slave Rivers? Where and when are they most likely to be exposed to changes in water quality and where are their important habitats? |
| 8. | Recognizing that people drink water and eat fish from these river systems, what is the current concentration of contaminants in water and edible fish and how are these levels changing through time and by location? |
The Northern River Basins Study placed emphasis on fish in its efforts to evaluate the effects of development on the basins. Fish provide food, livelihoods and recreational benefits to visitors and residents of the northern river basins. In addition, because of their wide distribution and movements in the basins and their key positions in food webs, they can give indications of the health of the aquatic ecosystem.
It was decided early in the Study that the Food Chain Component would not conduct studies to determine the population dynamics of fish. These were agreed to be too complex, time-consuming and costly to be effectively addressed within the scope of the Study. Instead, fish-related studies were incorporated into a comprehensive approach that linked closely to other research components investigating the physical, biological, chemical, resource use and traditional knowledge aspects of the aquatic ecosystems in the basins. Most of the NRBS fisheries related work in the Northwest Territories took place during 1994. Further information regarding these issues can be found in the aquatic uses (Section 3.3), traditional knowledge (Section 3.4), flow regulation (Section 3.5), nutrients (Section 3.7), dissolved oxygen (Section 3.8), contaminants (Section 3.9) and cumulative effects (Section 3.14) sections of this report.
Fish-related information needs were addressed in several ways. Food Chain Component scientists conducted a series of field and laboratory investigations aimed mainly at responding to question number six, relating to distribution, movement and important habitats of fish. Work related to the dissolved oxygen requirements has been incorporated into Section 3.8 of this report. Nearly all field studies of fishes conducted during the course of the study also provided samples of fish for contaminant analyses. Food chain studies were conducted to determine diets of fish, food web relationships among fishes and other elements of the food chain in the river basins and to help assess the likelihood and duration of exposure of fish to contaminant sources.
Research within the Food Chain Component has contributed information related to the distribution, movements, spawning, early rearing and overwintering habitat use of several species. It has also provided insights into the biology of several species, including bull trout, mountain whitefish, burbot, inconnu, spoonhead sculpin and lake chub. Finally, NRBS researchers discovered new food chain relationships. This will contribute to assessment of the flow of nutrients and contaminants in the food webs of the northern river basins.
Work within the Food Chain Component builds upon previous studies within the northern river basins. Much of the previous work concentrated on fish in lakes draining into the mainstem rivers and tributaries of the Athabasca, Peace and Slave Rivers. There has also been some extensive work in the lower Athabasca River. Frequently, the work focussed on species with commercial or recreational value. Seldom were studies conducted that focused on the population of fish, their communities or their place in the aquatic ecosystem. Recent work has often been in response to the need to evaluate the status of fish in the rivers and to assess the impacts of industrial development. Four major reports cited at the end of this Section serve to summarize the work of previous studies and provide general fisheries information:
In addition, an extensive bibliographic database of the known literature about fish from the basins, including the many reports on tributary rivers and lakes, can be found in the NRBS technical report, entitled "Fish and Fish Habitat Bibliographic Database for the Peace, Athabasca and Slave River Basins."
NRBS investigations discovered no new species but made extensive additions to our knowledge of the distribution of the known species and confirmed the presence of several questionable ones. Precise information regarding where these species are found is documented in the synthesis report cited at the end of this chapter.
The physical and chemical features of the river channel and water are forever changing. Consequently, the fish species that live in these aquatic environments are confronted with extreme seasonal and environmental fluctuations that is reflected in their life histories. A key strategy for many species is extensive movement.
Knowledge of these movements, in turn, is important for understanding the exposure of fish to contaminant sources. The proportion of time that the fish spend in the vicinity, or immediately downstream of contaminant sources is a factor in the uptake and accumulation of contaminants.
Researchers within the NRBS Food Chain Component reviewed more than 30 important studies of fish movement in the NRBS area and conducted additional field investigations in efforts to describe the patterns of movement of fish. Studying fish movement in large river systems is challenged by technical difficulties arising from strong current, turbidity and the open-ended nature of the physical boundaries in which the fish are contained.
NRBS studies found that burbot undertake brief seasonal movements during their spawning period in mid-winter. In contrast, mountain whitefish undergo long and complex seasonal movements within the Athabasca River. The relatively sedentary nature of burbot, combined with their distribution throughout the basins contributed to its selection as a likely indicator for monitoring changes in fish contaminant burdens. Another reason to choose burbot was that contaminant analysis had been performed on this species in previous years through the Slave River Environmental Quality Program.
In addition, intensive investigations in the Slave River Delta have added to knowledge of fish movements and habitat requirements in this area. In particular, the movement patterns of inconnu (an important harvest fish) in the delta can now be described in detail. Significantly, the fish community of the Slave River Delta appeared to be unchanged since the 1980s.
Fish require specific habitats to complete the various stages of their lifecycles. To further knowledge of fish habitat in the basins, researchers from the Food Chain Component recorded the physical structures of the river banks, beds and channel features of the mainstem rivers that are known to be important fish habitat features.
Many fish species' life stages include extensive movement between these physical habitat structures. In this way, their habitat needs for spawning and incubation, early rearing of young, feeding and growth, resting, escape from predation and overwintering are met in different locations in the rivers. Extraordinary variation in these life strategies exists between species. There can be complex patterns even within a species, perhaps reflecting different sub-populations.
NRBS studies were the first to definitively characterize the Athabasca River for its entire length (albeit in reaches) and represents the most extensive investigations ever performed in the Jasper National Park portion of the river. NRBS studies described the growth, feeding and early rearing life strategy of mountain whitefish in the upper Athabasca River. Studies also revealed that Athabasca River tributaries in Jasper National Park are important spawning, incubating and early rearing habitats for Athabasca River bull trout and mountain whitefish.
Knowledge of the food chain in the northern river basins is important for understanding how contaminants move through the aquatic ecosystems. As organisms eat contaminated food, and are in turn eaten, the contaminants are passed up the food chain. These contaminants tend to become more concentrated in the animal tissues as they are passed up the food chain.
For fish in the basins, the food chain was found to be a primary route of exposure to pulp mill contaminants. However, the level of exposure is largely related to individual feeding habits. Fish that feed primarily in tributaries tend to contain lower levels of pulp mill contaminants than those feeding in the mainstems. More information related to contaminant levels in fish can be found in Section 3.9.
The NRBS provided a number of opportunities to collect detailed information regarding fish health (see sections 3.4, 3.8, 3.9 and 3.14). Research within the Food Chain Component was designed to include specific measures of gross external and internal pathology. Over 30 000 fish were captured and measured during the four years of field studies, most of which were released alive after being measured and marked with tags.
Measures of gross pathology included external abnormalities like tumours, lesions, scars or injuries, skin discolouration, deformities and parasites. Some internal measures were taken when fish were sacrificed for chemical or physiological analyses. These measures included tumours, parasites, fat deposits and colouration of internal organs.
The record of external abnormalities provides a simple, mainly qualitative and observational database that can be analyzed quantitatively. Nearly 23 000 fish were examined and analyzed for gross pathological abnormalities. Many of the species found in the basins have some detailed record of these measures. Mountain whitefish, lake whitefish, northern pike, burbot, longnose suckers and white suckers were the main species for which gross pathological measures were recorded. This is mostly due to their prevalence in the sample collections. It is not necessarily due to their susceptibility to environmental stresses, although this point requires further study.
Significantly, pathological abnormalities for most species occurred in less than one per cent of the fish in large-scale collections. Occasionally, high frequencies of pathological abnormalities were reported (e.g., 23 of 30 lake whitefish) that may be related to physiological and behavioural responses to spawning. Similarly, suckers (especially longnose suckers) appear to have occasional high frequencies of pathological abnormalities. It is also important to note that fishermen interviewed within the Traditional Knowledge Component reported an increasing number of physical deformities in their catch (Section 3.4).
High frequencies of pathological abnormalities also appear in fish sampled near pulp mill effluent discharges. Detailed pathological studies of fishes near pulp mill effluent sources are needed. Two field studies discovered more pathological abnormalities shortly downstream of mill effluent sources than in the remainder of the Athabasca River.
Mill, T.A., Sparrow-Clark, P. and R.S. Brown. 1996. Fish Distribution, Movement, Habitat and Gross Pathology Information for the Northern River Basins in Alberta. Northern River Basins Study Report.
Tallman, R.F. 1996. Synthesis of Fish Distribution, Movement and Critical Habitat, Slave River North of 60 . Northern River Basins Study Synthesis Report No. 13.
Balagus, P., de Vries, A. and J. Green. 1993. Collections of Fish from the Traditional Winter Fishery on the Peace-Athabasca Delta, February 1993. Northern River Basins Study Technical Report No. 20.
Barton, B.A., Bjornson, C.P. and K.L. Egan. 1993. Special Fish Collections, Upper Athabasca River, May 1992. Northern River Basins Study Technical Report No. 8.
Barton, B.A. and R.F. Courtney. 1993. Fish and Fish Habitat Bibliographic Database for the Peace, Athabasca and Slave River Basins. Northern River Basins Study Technical Report No. 17.
Boag, T.D. 1993. A General Fish and Riverine Habitat Inventory, Peace and Slave Rivers, April to June 1992. Northern River Basins Study Technical Report No. 9.
Brown, S.B., Evans, R.E. and L. Vandenbyllaardt. 1996. Analysis for Circulating Gonadal Sex Steroids and Gonad Morphology in Fish, Peace, Athabasca and Slave River Basins, September to December 1994. Northern River Basins Study Technical Report No. 89.
Brown, S.B., Evans, E., Vandenbyllaardt, L. and A. Bordeleau. 1993. Analysis and Interpretation of Steroid Hormones and Gonad Morphology in Fish: Upper Athabasca River, 1992. Northern River Basins Study Technical Report No. 13.
Clayton, T. and C. McLeod. 1994. Seasonal Movement of Radio Tagged Fish, Upper Athabasca River, August 1992 to March 1993. Northern River Basins Study Technical Report No. 33.
Gibbons, W., Munkittrick, K. and W. Taylor. 1996. Suitability of Small Fish Species for Monitoring the Effects of Pulp Mill Effluent on Fish Populations, Athabasca River, 1994 and 1995. Northern River Basins Study Technical Report No. 100.
Golder Associates Ltd. 1994. Fish Tagging Along the Athabasca River Near Whitecourt, October 1993. Northern River Basins Study Technical Report No. 41.
Hesslein, R.H. and P.S. Ramlal. 1993. Stable Isotopes of Sulphur, Carbon and Nitrogen in Biota, Upper Athabasca River, 1992. Northern River Basins Study Technical Report No. 22.
Hesslein, R.H. and P.S. Ramlal. 1996. Assessment of Trophic Position and Food Sources Using Stable Isotopes of Sulphur, Carbon and Nitrogen, Peace and Athabasca Rivers. Northern River Basins Study Technical Report No. 97.
Hvenegaard, R.J. and T.D. Boag. 1993. Burbot Collections, Smoky, Wapiti and Peace Rivers, October and November 1992. Northern River Basins Study Technical Report No. 12.
Jacobson, T.L. and T.D. Boag. 1995. Fish Collections, Peace, Athabasca and Slave River Basins - September to December, 1994. Northern River Basins Study Technical Report No. 61.
McLeod, C. and T. Clayton. 1993. Fish Radio Telemetry Demonstration Project, Upper Athabasca River, May to August 1992. Northern River Basins Study Technical Report No. 11.
Patalas, J. 1993. Lake Whitefish Spawning Study Below Vermilion Chutes on the Peace River, October 1992. Northern River Basins Study Technical Report No. 23.
Pattenden, R. 1993. Biophysical Inventory of Critical Overwintering Areas, Peace River, October 1992. Northern River Basins Study Technical Report No. 24.
R. L. & L. Environmental Services Ltd. 1994. A General Fish and Riverine Habitat Inventory, Athabasca River, April to May 1992. Northern River Basins Study Technical Report No. 32.
R. L. & L. Environmental Services Ltd. 1994. A General Fish and Riverine Habitat Inventory, Athabasca River, October 1993. Northern River Basins Study Technical Report No. 40.
R. L. & L. Environmental Services Ltd. 1995. A General Fish and Riverine Habitat Inventory, Athabasca River, May 1994. Northern River Basins Study Technical Report No. 53.
Smithson, G. 1993. Radionuclide Levels in Fish from Lake Athabasca, February 1993. Northern River Basins Study Technical Report No. 26.
Tallman, R.F. 1996. Migrations of Harvested Fish - Inconnu and Burbot. Northern River Basins Study Technical Report No. 117.
Tallman, R.F. 1996. Life History Variation of Inconnu from the Lower Slave River. Northern River Basins Study Technical Report No. 118.
Tallman, R.F. 1996. Diet, Food Web Structure of the Slave River Fish Community. Northern River Basins Study Technical Report No. 119.
Nelson, J.S. and M.J. Paetz. 1992. Fishes of Alberta. The University of Alberta Press and the University of Calgary Press, Alberta.
Paetz, M.J. 1984. The Fish and Fisheries of the Peace River Basin: Their Status and Environmental Requirements. Alberta Environment, Planning Division and Fish and Wildlife Division. 169 pp.
R.L. & L. Environmental Services Ltd. 1982. Slave River Hydro Feasibility Study: Task Area. Environmental Studies Regions C and D. Volume 4, Part B. Fisheries. Alberta Environment. 135 pp.
Wallace, R.R. and P.J. McCart. 1984. The Fish and Fisheries of the Athabasca River Basin: Their Status and Environmental Requirements. Prepared for Alberta Environment Planning Division. 269 pp.
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