1. Project Title: Current River Estuary Walleye Spawning Habitat
2. Contact
Doug Geiling
Great Lakes Laboratory for Fisheries and Aquatic Sciences, Department of Fisheries and Oceans, 1 Canal Drive, Sault Ste. Marie, Ontario P6A 6W4
Tel.: (705) 942-2848; FAX: (705) 941-3025; E-mail: Geiling@ssmare.ssm.dfo.ca
3. Agencies Involved
North Shore of Lake Superior Remedial Action Plans*, 1194 Dawson Road, Thunder Bay, Ontario P7B 5E3
(* Includes Environment Canada, Great Lakes Cleanup Fund, Ontario Ministries of Natural Resources and Environment and Energy)
Department of Fisheries and Oceans, Great Lakes Laboratory for Fisheries and Aquatic Sciences, 1 Canal Drive, Sault Ste. Marie, Ontario P6A 6W4
4. Restoration Goal
Compensate for walleye (Stizostedium vitreum) spawning habitat removed by dredging.
5. Project Type
Augmentation of remnant, and creation of new, walleye spawning habitat.
6. Background and Rationale
The Current River walleye stock is one of the few remaining self-sustaining walleye stocks in Lake Superior (Schram et al. 1991). Over the past 130 years spawning habitat has been lost or modified in the Current River by the effects of a silver stamp mill (1870's), saw mill (late 19th century), road and railway construction (late 19th to early 20th century), river impoundment for water management (Å1905), and construction of a boat launching and docking facility (1984).
We selected three sites of similar size for augmentation in the
Current River estuary (Figure 1). The total surface area of the
three sites approximated one half the area of habitat suitable
for walleye spawning removed by dredging for dock construction.
Two sites were downstream extensions of known remnant spawning
areas in lotic sections of the estuary. The third site was influenced
more by Lake Superior than the river but was also suspected to
have been used historically for spawning.
7. Regulatory Considerations
a) Completion of an Ontario Ministry of Natural Resources Class Environmental Assessment for Water Related Excavation, Dredging, and Fill Activities.
b) Completion of an Application for Approval for Work under the
Fill, Construction, and Alteration to Waterways Regulations administered
by the Lakehead Region
Conservation Authority.
c) File a Government of Canada Environmental Assessment Review
Process Screening
Decision Document.
d) Obtain an Ontario Ministry of Natural Resources Work Permit.
e) Ensure rock fill added to the estuary conforms with the Ontario Ministry of Environment and Energy Lake Filling Guidelines.
8. Criteria
Walleye are known to exhibit preference (Hartley and Kelso 1991) for spawning in:
Predominately gravel/cobble substrate;
Water depth < 2.5 m with preference for depths < 1.2 m;
Current velocities in streams ranging from 14 to 150 cm/s in the bottom one third of the water column
In lakes, spawning areas must be subject to wave-induced or wind-induced currents strong enough to prevent siltation.
9. Project Design
We attempted to duplicate the channel width, depth, flow diversity, and substrate characteristics of the two remnant spawning areas in constructing the two downstream lotic sites. No attempt was made to modify the existing flow pattern of the river as it separated into three channels at the mouth, and we did not affect the remnant successful spawning areas. The project was also designed to test benefits from spawning habitat augmentation in lotic and lacustrine sites in the same estuary.
10. Implementation
The project was completed in one week of December 1991, except for some minor site clean up which took less than one day in the summer of 1992. The substrate added was clean, silt free, igneous stone from a local quarry which was crushed and sized to our specifications. We used three diameters of stone: gravel (5-20 mm diam.), cobble (100-250 mm diam.), and boulders (500-750 mm diam.). All substrate used was free from contaminants and debris.
The total surface area of the three sites was approximately 1 700 m2. To this area we added 225 tonnes each of gravel and boulders and 125 tonnes of cobble. Placement of materials was by tracked backhoe, with care taken to not disturb the areas around the augmentation sites.
In the lotic sites cobble was spread as evenly as possible followed by an evenly spread gravel layer. This substrate assemblage was tapped down with the backhoe shovel to shake the gravel down and to set the cobble into the channel bed. Randomly placed individual boulders were then added to disrupt flow patterns and to act as instream cover.
In the lacustrine site, cobble was spread as evenly as possible followed by a random distribution of boulders. This assemblage was tapped down into the substrate with the backhoe shovel. A layer of gravel was added on top of the cobble/boulder assemblage. It was assumed that wave action would imbed the gravel among the coarser substrate.
11. Degree of Environmental Intervention
Morphometry, microhabitat water velocities, and substrate characteristics were primarily affected. Original materials of the stream bed or estuary were not removed. Rather, the new material was superimposed. No mortality to fish or macroinvertebrates and no evidence of increased downstream sedimentation were observed. Placement of material was in December when flow was low and spawning by species whose reproductive habits are known was non-existent. Winter (Jan. to mid Mar.) and late summer (mid July to end Aug.) construction of spawning habitat would be acceptable alternatives.
12. Cost
Labour and Materials $30 000
Engineering Support $5 000
On-Site Supervision $2 500
Subtotal, Construction $37 500 ($22.06/m2)
Assessment costs (estimated):
Field crew (10 person weeks/year, 5 years) $36 000
Biologist (1 week/year, 5 years) $5 000
Gas, Oil, Net Repair, Supplies $1 000
Subtotal, Assessment $42 000
Total Estimated Project Cost: $79 500
NOTE: To achieve efficiencies of scale, construction of this project was tendered in conjunction with another local project. Therefore the construction cost quoted is a best estimate.
13. Biological Assessment
Mark and recapture population estimates of walleye vulnerable to a 1.8 m trap net (50 mm stretched mesh) were derived during the spawning runs in 1991, 1992, and 1993. The methodology will be replicated at least twice in the years 1996 to 1999 to evaluate any change in recruitment to the population. Qualitative diving surveys of egg deposition in the estuary were conducted in 1991 and 1993. Seining surveys for young-of-the-year walleye were conducted in 1991-1993 and may be continued in conjunction with future population estimations. The estuary was also visually surveyed with powerful spotlights at night to detect the presence of spawning adults during the 1993 spawning run.
14. Measures of Success
If the enhancement or increase in spawning area for walleye is successful, increases of either or both total egg deposition and fry production in the estuary would be expected. Ultimately, these increases will lead to increased abundance and/or harvest of adult walleye using the estuary for spawning.
The 1993 diving survey found viable walleye eggs in the historic and newly created lotic spawning habitat. Eggs were not found in the lacustrine site. Complete assessment is not possible until the 1992 and subsequent year-classes become recruited to the spawning population.
Success Rating: 4
but it is unknown whether abundance of spawning walleye will increase.
15. Key References
Hartley, K.A., and Kelso, J.R.M. 1991. Habitat information and rehabilitation alternatives for restoring spawning habitat of walleye and salmonids in streams. Can. Tech. Rep. Fish. Aquat. Sci. 1813: iv + 60 p.
Schram, S.T., Atkinson, J.R., and Pereira, D.L. 1991. Lake Superior walleye stocks: status and management, p. 1-22. In P.J. Colby, C.A. Lewis, and R.L. Eshenroder [editors]. Status of walleye in the Great Lakes: case studies prepared for the 1989 workshop. Great Lakes Fish. Comm. Spec. Publ. 91-1.
Correct citation for this contribution:
Geiling, D. 1995. Current River estuary walleye spawning habitat, p. 27-31. In J.R.M. Kelso and J.H. Hartig [editors]. Methods of modifying habitat to benefit the Great Lakes ecosystem. CISTI (Can. Inst. Sci. Tech. Inf.) Occas. Pap. No. 1.