The Fish and Fisheries of the Athabasca River Basin
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THE FISH AND FISHERIES OF THE ATHABASCA RIVER BASIN Their Status and Environmental Requirements Ron R. Wallace, Ph.D. Dominion Ecological Consulting, Ltd. and Peter J. McCart, Ph.D. Aquatic Environments Ltd. for Planning Division Alberta Environment March 31, 1984 PREFACE Thi s report was prepared by consul tants supervi sed by Bryan Kemper for Planning Division of Alberta Environment, and Dave Rimmer for Fish and Wildlife Division of Alberta Energy and Natural Resources. The Fisheries Overview series of reports have been commissioned to summarize known data to assist river basin planning studies and assist in the planning of new studies with the appropriate management agencies. The opinions expressed in this report are based upon written and verbal i nformati on provi ded to the consultant and therefore do not necessarily represent those of Alberta Environment. EXECUTIVE SUMMARY The information presented here reviews what is currently known of fish ecology and production of the Athabasca Basin, and includes discussions of fish production, sport and commercial use of fish popul ati ons, and alternative opportuniti es for recreational fi shi ng in the rivers of the Athabasca Basin. Fisheries management objectives for the basin rivers and data gaps in existing knowledge of fish and fisheries are also discussed. In addition, water quality criteria for the protection of fish and aquatic life have been referenced, and, where possible, stream flows which affect fish populations have been included. The Athabasca Basin accounts for 23% of the land area of Alberta. For the purposes of this report, the basin has been divided into 10 sub-basins: four mainstem sub-basins, and six tributary sub-basins. These sub-basins are grouped under the following headings: The Upper Sub-Basins The Central Sub-Basins Jasper National Park Pembina Berland Lesser Slave McLeod The Athabasca Sub-Basins The Lower Sub-Basins Athabasca' I Lac La Biche Athabasca II Clearwater Athabsca II I i The mai nstems of the principal rivers of the 10 sub-basins PTovide approximately 4,390 km of.fish habitat which can be roughly divided as providing 1,500 km (34%) coldwater habitat (supporting mainly trout and whitefish), 2,250 km (51%) warmwater habitat (supporting mainly pike, walleye, and goldeye), and 640 km (15%) transition zone intermediate between the two. Both commercial and recreational fisheries occur within the Athabasca Basin. The commercial fish catch represents a substantial proportion of the overall harvest and total market value of the Alberta commercial fishery. The recreational fishery occurs mainly in rivers and streams, though some lakes and reservoirs provide alternate opportunities. In 1980/81, approximately 9% (26,346) of Alberta's licensed anglers resided and fished within the Athabasca Basin. The opportunities provided to sport fishermen by the basin rivers have local, regional and in some cases, national significance. The Athabasca River rises high in the Rocky Mountains, and terminates at the delta created by the Peace and Athabasca rivers at the western extreme of Lake Athabasca. Over its length, the Athabasca River grows from a torrential high-mountain stream to a silt-laden major river at its delta, and its basin encompasses virtually every temperate stream type. In its upstream reaches, the Athabasca River flows generally northeast, steadily increasing in volume as it receives flows from the Berland, McLeod, Pembina, Lesser Slave, Lac La Biche, and Calling rivers. i i Further downstream, in the vicinity of a series of rapids, the r i ver receives flows from the Pel ican and Horse rivers. Near Fort McMurray, the Athabasca forms a confluence with the Clearwater River, and turns to flow north through the Athabasca Oi 1 Sands region. Within the oil sands, the Athabasca River receives flows from many rivers and streams, including the Steepbank, Muskeg, Mackay, Ells, Firebag, and Richardson rivers. Reaching the Peace-Athabasca Delta near Embarras Portage, the Athabasca River subsequently forms part of the Mackenzie drainage, which empties into the Beaufort Sea. Flowing through diverse and widely differing terrain, including remote alpine areas, populated urban settings, and the 1 argest open-pit 0; 1 sands mining sites in the world, the Athabasca Basin is made up of a corresponding variety of waterbodies. Within the basin, each sub-basin has characteristic fish-producing capabilities, which are largely determined by the conditions which contribute to its environment. The primary features of each sub-basin and the characteristics of its lakes and rivers are summarized below: The Upper Sub-Basins The extreme headwaters of the Athabasca River lie within the Jasper Park Sub-Basin, which accounts for 7.4% (10,878 km 2) of the area of the Athabasca Basin. In this sub-basin, the productivity of the salmonid sport fishery is limited by the cold, short growing season. Low rates of discharge in the winter, 1 imited nutrients, and the nature of gl aci al stream flows also characterize this typical cold, clearwater fish habitat zone. The low rate of biological productivity relative to angling demand is offset by fish stocking programs throughout many 1 akes in Jasper Park. Moderate to heavy iii angl ing pressure exists in favoured tributaries and along accessible portions of the Athabasca mainstem. Fish populations in the area are relatively unproductive and slow-growing. As a result, these popul ations may be particularly vulnerable to over-fishing, especially given the predicted, long term use of the park by recreationalists. The Berl and Sub-Basin makes up 3.9% (5,750 km2) of the Athabasca Basin. While sparsely populated, this sub-basin has experienced significant forestry clear-cut operations, and oil and gas e x p lor at ion and d eve lop men t. The Be r 1 and Sub - Bas i n h as a h i g h recreational demand and presents excellent well-known sport fishing habitat. The relatively clear, cold waters of the tributary rivers provide habi tat for coldwater species, chiefly rainbow trout and eastern brook trout, although Dolly Varden, mountain whitefish and Arctic grayling are known to occur. Large populations of mountain whitefish are known to utilize the lower Berland River. The lakes of the sub-basin are well fished, especially Gregg and Jarvis, where northern pike and lake whitefish are taken. Most of the anglers using the region originate in Edmonton, and evidence of over-exploitation of remote popul ations of such species as Dolly Varden in wilderness areas, due to substantial angling pressure, is beginning to emerge. The McLeod Sub-Basin constitutes 6.7% (9,850 km 2) of the Athabasca Basin, and embraces a wide spectrum of fish habitat, iv habitat, including coldwater highland tributary streams which typically support coldwater species. The upper reaches of the Gregg River, for instance, support a sizeable rainbow trout population (Hawryluk 1973), as do the adjacent MacKenzie Creek (Hawryluk 1974), and the more distant Spinx Creek (Alberta Fish and Wildlife Division, internal report). In the more easterly Edson River, rainbow trout make up the primary part of the sport fishery (Hawryluk 1976). Habitat damage in portions of the McLeod Sub-Basin resulting from forestry and mining operations is, at times, pronounced. Although the lowland tributaries of the McLeod Sub-Basin have limited potential for fish habitat development, the upland tributaries could be maintained as significant sport fishery areas. Indeed, the area could be used for enhanced recreational experiments. The Tri-Creeks Watershed Study area provides an almost ideal base of long term data upon which such enhanced research and operational programs could be predicated. The Central Sub-Basins The Pembina Sub-Basin constitutes 9.7% (14,300 km 2) of the Athabasca Sub-Basin, and is characterized by a wide variety of fish habitat. High summer temperatures occur along most of the watershed, especi ally in the slow, exposed, lower reaches; however, these temperatures do not appear to exceed warmwater species tolerance. The quality of fish habitat, of potential value to resource managers, is limited by low seasonal flows in the headwaters, seasonal flooding in the lower reaches, and the impact of the most intensive industrial, urban, and agricultural development within the Athabasca v Basin. Documentation for specific tributaries indicates that the sportsfish potential of the Pembina Sub-Basin has declined in the past 40 years; however, stocking programs in lakes have tended to offset this decline. The mainstem reaches, particularly at the primary confluences (Paddle, Bigoray, and Lobstick rivers) are heavily angled, as i s the con f 1 uence with the Athabasca Ri ver. Access throughout the sub-basin is excellent, and fishery programs, where implemented, have received significant attention from sport fishermen. In the upper reaches of the Pembina Sub-Basin, rainbow and brook trout are the most abundant sportsfish. In terms of angling effort, walleye represent the principal gamefish in the mainstem of the Pembina River, and most of the effort is di rected to areas where concentrations are, or have been, known to occur. Walleye are most abundant in the lower reaches (Sangudo to Flatbush) of the Pembina. The Lesser Sl ave Sub-Basin makes up 20,600 km 2 (14%) of the Athabasca Basin. The range from coldwater to warmwater fish habi tat which occurs throughout the Lesser Slave Sub-Basin results in a di verse fish population which includes coldwater species inhabiting the upland tributaries, and warmwater species inhabiting the tributaries of the Lesser Slave Lake flatlands. Agricultural practices and incidents of severe flooding have probably degraded fisheries habitat throughout the Lesser Slave Sub-Basin, but no clearly documented research has summarized these effects. The river represents a transition zone--fish common to both warmwater and coldwater aquatic habitat are found here. Of the coldwater species, mountain whitefish are probably the most numerous, although brown trout are also present.