1. Project Title: Toronto Islands Northern Pike Spawning Habitat
2. Contact
Jennifer Vincent
Metropolitan Toronto and Region Conservation Authority
5 Shoreham Drive, Downsview, Ontario M3N 1S4
Tel.: (416) 661-6600 ext. 349; FAX: (416) 661-6898
3. Agencies Involved
Metropolitan Toronto and Region Conservation Authority
Environment Canada's Great Lakes Cleanup Fund
Ontario Ministry of Environment and Energy
Ontario Ministry of Natural Resources
Municipality of Metropolitan Toronto
4. Restoration Goal
To improve northern pike habitat within the Toronto Islands by creating spawning habitat. To evaluate the feasibility of constructed northern pike spawning habitat.
5. Project Type
Creation of new habitat.
6. Background and Rationale
Historically, the Toronto Islands fish community has been seriously affected by urbanization and alteration to the natural island structure. As wetlands and seasonally flooded areas were filled, northern pike spawning, nursery and feeding areas were destroyed. Today the most diverse and populated fish community across the Toronto waterfront exists within the Toronto Islands vicinity.
In 1968, a section of the Toronto Islands lagoon known as Lighthouse Channel was partitioned off with an earth and rubble berm to create a "put and take" trout pond. The pond area contained extensive shallow, weedy areas. In order to maintain trout habitat, cold water was pumped in and regular weed removal was required. As years progressed, the cost of maintaining the pond outweighed its benefits. In an examination of other options, this area was recognized as having tremendous warmwater fish habitat potential, especially for northern pike. In 1992, as part of the Metropolitan Toronto Habitat Rehabilitation Pilot Projects program, the barrier-berm isolating the pond was breached at three points, providing the Toronto Islands fish community with access to valuable habitat.
Since breaching the berm, the additional habitat provided has increased spawning, nursery and feeding areas for an increased variety of fish species. By making the pond contiguous with the lagoon, the shoreline area is now subject to seasonal flooding. This has restored natural shoreline conditions and has the potential to provide valuable pike spawning habitat.
7. Regulatory Considerations
A number of approvals from Federal, Provincial, and Municipal agencies were obtained to meet legislative requirements before conducting this project. The following outlines each Federal, Provincial, and Municipal agency involved in the approval process.
Federal
Environment Canada
Summaries of Initial Assessment as per Federal Environmental Assessment Review Process
Department of Fisheries and Oceans
Fisheries Act
Provincial
Ontario Ministry of Environment and Energy
Provincial Environmental Assessment Act
Ontario Ministry of Natural Resources
Fisheries Act
Lakes and Rivers Improvement Act
Public Lands Act
Municipal
Metropolitan Toronto Parks and Property
Waterfront Agreement 1972
Metropolitan Toronto and Region Conservation Authority
Internal development project approvals
8. Criteria
According to Scott and Crossman (1973), ideal northern pike spawning habitat consists of seasonally flooded areas of soft grasses, bulrushes, and vegetative debris adjacent to a relatively warm weedy bay. Reid (1990) recommends the ratio of flooded area to weedy bay be 0.25. Other fish species benefitting from this type of habitat include largemouth bass and bluegill.
9. Project Design
To create shallow, seasonally flooded channels, projections (fingers) were made into the pond. These projections are designed at varying heights thereby being at varying depths when flooded. The idea behind this design is to create a variety of conditions that can provide habitat at a variety of water depths. The created channels vary in shape and sinuousity. This creates several quiet water areas as well as wave susceptible areas. Figure 1 is a conceptual diagram of the design.
10. Implementation
Silt curtains were used to mark off the work area and reduce the effects of sedimentation. Movement of the sediments after the project was complete was negligible.
The sand and compost materials required for the project were supplied by Metro Parks and Property, Toronto Islands Division from their stocked supply. Sand originated from dredging within the Toronto Islands.
To create shallow channels, five fingers were made into the pond.
Sand was delivered to the site with a dozer pushing it into the
water. This created a 6 m wide finger into the pond. Five evenly
spaced fingers were created in this manner.
Once the initial fingers were created, a backhoe carved out the centre of each. This created two projections approximately 2.5 m wide at the water interface with the carved area at a shallower depth than the surrounding area. By carving out the centre of the finger, quiet backwater areas were created. These areas will be protected when flooded and offer warmer water.
Sand was augmented with compost. The compost was mixed into the sand to a depth of approximately 40 cm. Two types of commercial grass mix were chosen to seed the area. Tables 1 and 2 list the contents of each mix. Augmenting the commercial mixes was hand collected sedge seed, tolerant of seasonally flooded areas. The newly created fingers were stabilized using coconut fibre matting (Coir 900). In the spring of 1994 this area was hydroseeded.
The base of the fingers and the adjacent shoreline were densely planted with red osier dogwood, gray dogwood, nannyberry, and silverberry. These plantings will provide detritus for the spawning areas, additional wildlife habitat and restrict public access.
Table 1. Commercial Groundcover Grass. Table 2. Commercial Wetland Grass.
Amount Species Amount Species
10% white clover 10% red clover
15% fiesta II perennial 10% white clover
25% rye 15% birdsfoot trefoil
10% mustang tall fescue 10% alsike clover
15% creeping red fescue 15% creeping red fescue
10% victory chewing 10% highland colonial
fescue 8% bentgrass
bronco Kentucky 10% nugget Kentucky
bluegrass 12% bluegrass
fiesta perennial rye
Poa trivialis
11. Degree of Environmental Intervention
The morphometry of the site was altered increasing topographical relief. Sediment created due to construction was restricted by fences.
Fall construction limited impacts to fish and wildlife and to public use of the park.
12. Cost
Construction: $24 600
Materials: $5 200
Planning/supervision: $10 350
Monitoring (5yrs) $5 000
Total $45 150
13. Biological Assessment
Electrofishing results after the berm was breached indicated a significant increase in species richness and biomass. A total biomass of 12.3 kg/ha is 869% higher than the prebreaching biomass.
In the spring of 1994 northern pike density within the pond was equal to that of the surrounding area. Vegetation on the newly created northern pike spawning "fingers" was incomplete. No active spawning was observed this year. Within the 1995 year vegetation establishment will be complete and it is expected that spawning pike will be observed and young-of-the-year pike found during fall electrofishing surveys.
14. Measures of Success
Initial results from breaching the berm to provide access to habitat has shown the need for shallow, weedy, bay habitat within the Toronto Islands. The addition of northern pike spawning areas within this new habitat has not been fully evaluated.
Success Rating: 1 - assessment incomplete
15. Key References
MTRCA, 1992. Toronto Waterfront Habitat Rehabilitation Pilot Projects. Technical Report: 1992. (Internal publication.)
Reid, K.B. 1990. Status of the pike (Esox lucius L.) in Lake Wilcox, Ontario and rehabilitation of its spawning habitat by marsh creation. M.Sc. Thesis, Trent University, Peterborough, Ontario.
Scott, W.B., and Crossman, E.J. 1973. Freshwater Fishes of Canada. Fish. Res. Board Can. Bull. 184: 996 p.
Vincent J, 1992. Toronto Waterfront Habitat Rehabilitation Pilot Projects. Technical Report: 1993. Metropolitan Toronto and Region Conservation Authority.
Wainio, A., Smitka, J., Veitch, I., Jones, M., and Kaszuba, A. 1973. A fish survey of the Toronto Islands. Ontario Ministry of Natural Resources.
Correct citation for this contribution:
Vincent, J. 1995. Toronto Islands nothern pike spawning habitat, p.139-144. 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.