Chapter 7

Fish and Wildlife Habitat and Shoreline Treatments along the Toronto Waterfront (Gord MacPherson, Toronto and Region Conservation Authority)

Introduction

The Toronto and Region Conservation Authority (TRCA) is the agency that is responsible for shoreline management initiatives within the Toronto Waterfront. Over the years, this has led to the development of a series of regional parks, public marinas, erosion protection for shoreline residents, acquisition of vulnerable properties, and development of significant shoreline parklands. Within the Conservation Authority, the Coastal Ecology Unit is a small group of individuals that are charged with the responsibility of monitoring the shoreline ecosystem, providing community outreach, and designing, developing, and implementing significant shoreline restoration projects.

Over the years, the collective efforts toward monitoring the shoreline have led to the development of habitat classifications and a general philosophy for the design of shoreline structures. Simply, within the north shore of Lake Ontario there are three major types of shoreline habitat:

• open coasts (highly energetic exposed shorelines that are typically beaches and do not support diverse, or strong, resident populations of fish; however, on a seasonal basis these shorelines are critical spawning areas for pelagic forage species as well as a connective corridor and staging area for a broad suite of species);
• sheltered warm water embayments (Lake Ontario is a cold, deep, oligothrophic lake and therefore, the isolated warm water shoreline habitats attract/hold a variety of species by providing significant critical habitat; sheltered embayments along the Toronto waterfront are either natural geologic features like the Toronto Harbour/Toronto Island Complex or man-made structures, including the many waterfront parks and marinas); and
• coastal marshes (many of the rivers that drain into the Toronto waterfront reach Lake Ontario through a coastal marsh complex; the size, morphology, and thermal characteristics of these habitat structures make them the most important habitat features within the waterfront).

Monitoring of these habitats has provided meaningful insight into the design of habitat restoration projects and principally, the best lesson learned to date, is the concept of critical habitat. We design critical fish and wildlife habitat components at the shoreline to facilitate the creation of:

• reproductive habitats;
• nursery habitat;
• foraging and resting areas; and
• over-wintering habitats.

The conscious development of critical habitat features at a restoration project guarantees that the appropriate terrestrial and aquatic species are attracted to your site and are capable of colonizing the site successfully. Two newly created projects that exemplify the concept of integrating fish and wildlife habitat creation into the shoreline are the Humber Bay Shores and the Spadina Quay Wetland projects.

Humber Bay Shores

Situated close to the mouth of the Humber River and adjacent to the Humber Bay Waterfront Park, the former Motel Strip was the cause of many problems within the local lakeshore community (Figure 23). To provide a catalyst for redevelopment, and clean up the problematic uses within the area, the Toronto and Region Conservation Authority (TRCA) led a partnership of agencies in the development of a public amenity scheme for this waterfront area. The TRCA proposed limited lake-filling to facilitate a desirable building envelope, attract development, and avoid encroaching on private property in an effort to create this important public waterfront area. Our understanding of this shoreline ecosystem assisted in the development of a park plan that truly integrated the needs of the community, allowed redevelopment, and created significant habitat features. Our local knowledge provided valuable insight that was utilized during the design of shoreline structures, as well as the development of habitat components, which were required for regulatory approval of the project.

The design of the shoreline was dictated by the wave climate of the site. In response, we developed habitat components that were suitable for the local wave conditions and included cobble beaches, offshore islands, sheltered shorelines, and a wetland complex (Figure 24). The beach shoreline consists of a series of "T" shaped headlands that secure three cobble beach cells. The cobble beach was considered the best treatment because it provided a shallow beach profile that is so important for spawning forage fish. In addition, it was determined to be the best shoreline treatment technique to attenuate the waves while still providing a significant habitat function. Additional features such as shoals, reefs, and randomly placed stones were attached to the headlands in an effort to attract and hold pelagic fish.

The islands were designed to provide, to a degree, sheltered back water areas and to reduce the wave conditions so that the site was suitable for habitat features (Figure 24). The islands are vegetated with shrubs and have large clusters of anchored woody material attached to the back-shore. Also, a diversity of substrate types have been placed between the islands and shoreline. The overall configuration of the shoreline was undulated to enhance the characteristics of the back-shore area of the islands. Back-shore conditions, such as shoreline slope, crest height, and habitat features, were altered to take into account the shadow effect of the islands. In selected locations we provided areas of finer substrates by constructing a shelf within the shoreline structure in the hope of establishing emergent vegetation.

The most challenging aspect of this project was the development of a 3 ha wetland complex (Figure 24). Our desired wetland shoreline consists of a shrub buffer, sedge strand, and emergent, submergent, and floating leaf vegetation. To create this shoreline condition, we filled in the perimeter and closed off an existing embayment with a rock-rubble berm that was covered by a 1 m veneer of clean fill. To ensure that we had the proper elevations for wetlands plants, we initially surveyed our coastal marshes to determine the elevations of naturally occurring coastal wetlands. Using this information, we created a pilot project at one of our earlier habitat creation projects to determine the critical elevations for plant material. We created a gradual shoreline slope that was planted with emergents and monitored, over the course of five years, to determine the exact elevations at which wetland plants would establish. These elevation data have since been used at all of our wetland project sites. Our general philosophy, in creating coastal plant communities is to create the conditions suitable for the desired community and inoculate the site, rather than plant a plantation. To inoculate this wetland, we planted our emergent material in nodes to facilitate colonization and connected these areas with perimeter plantings.

One unique aspect of this project was the material we received from the Toronto and Region Conservation Authority initiative, the "Aquatic Plants Program." This program was started a number of years ago and now involves more than seven hundred classrooms in the Toronto area growing a variety of aquatic and terrestrial plants for our rehabilitation projects. The TRCA provides materials, equipment, and technical support to the classroom instructors and in return we receive quality plant material at a fraction of the cost, with the added benefit of an effective community outreach program.

Additional habitat features were also detailed within the wetland complex. In an effort to diversify the deep water areas of the wetland, five log crib structures were sunk in the open water. The cribs were constructed of logs eight foot long, five feet high, and filled with a rock ballast. They attract a variety of fish in the area. We also deployed a number of brush bundles that were anchored to cinder blocks and sunk in the same vicinity of the log cribs. A variety of log stumps, whole trees, and logs were placed along the shoreline to mimic woody debris along the shore. To facilitate pike spawning, we created a braided network of shallow channels that were planted with slender emergent wetland plants. During construction, we noticed that the island created, when we closed off the embayment, was attracting a large number of Caspian Terns. We altered our original plans and left this island feature barren of vegetation and put a veneer of sand and gravel down to mimic the back-shore beach feature utilized by nesting Caspian Terns.

Spadina Quay Wetland

Over the past ten years the Toronto and Region Conservation Authority has monitored the fish communities along the Toronto Waterfront. About four years ago, we started to receive reports from anglers fishing at the foot of Spadina Avenue in the Inner Harbour. They called in stating that they were catching tagged northern pike during the spawning season. This was significant because we never tagged any fish along the north shore of the Inner Harbour of Toronto and we couldn't believe that northern pike would be trying to utilize the marginal habitats of the Inner Harbour. We later verified, that indeed, many pike moving from the Toronto Islands were congregating in the Inner Harbour during the early spring spawning season.

Two years ago, a colleague in the Toronto Parks Department asked if we had any ideas for the parking lot at the eastern portion of the existing Spadina Parklands in light of some major redevelopment within the area. Our immediate response was to suggest the creation of a spawning and wetland area for the pike we were seeing at that location. The challenge faced by us was to fit a viable wetland in such a small physical space in such a high profile area.

To get water onto the site, we cut the seawall in two locations and removed the top wall section down to the waterline (Figure 25). A new wooden boardwalk bridged the gap and a set of gates were installed to separate any floating harbor debris from the wetland and control and exclude carp during their spawning season. The openings were designed to take advantage of the Lake Ontario water level regime and strategically time the extent and duration of inundating water.

Essentially, we were hoping to allow for shallow water in the spring, maximum water depth throughout the summer, gradual recession of the water in the fall, and a dry condition in the winter months. The criteria for setting the elevation were focused on providing conditions suitable for pike spawning in the spring, allowing for a permanent water feature during the tourist season, and allowing for complete draw-down to ensure the viability of slender emergents and ensure some dynamic stability to the system.

We focused on creating three plant communities within the Spadina Quay Wetland: Eastern cottonwoods; staghorn sumach; and a variety of shoreline grasses were planted in the upland riparian zone. The lowland riparian zone was planted with a variety of sedges, grasses, and herbaceous plants. The wetland zone was planted with a variety of slender emergents, including hard and soft-stem bulrush, giant burreed, and arrowhead. The site was prepared before planting with a mixture of compost and sand that was mixed with the parent material to 30 cm. To control the colonization of undesirable weeds and plants, and to control our site maintenance, we also extensively seeded the site with annual oats. This provided a quick and extensive ground cover that helped control weeds, retain soil moisture, contribute to the soil conditioning on site, and turn a barren construction site green in a matter of weeks.

The Spadina Quay Wetland was the source of some pointed criticisms. Concerns were raised that it was too small to provide any functional habitat and that the Inner Harbour is not an appropriate location for habitat creation. The jury is still out on whether or not the site will be utilized by the pike or become problematic in the future. But we are very optimistic about the potential of this site and anxiously await next spring when we fully expect the first spawning northern pike. As for the value of this project, we are convinced that wetlands in urban areas are priceless when it comes to raising public awareness surrounding habitat restoration in the Great Lakes.

Contact Person

Gord MacPherson
Coordinator Coastal Ecology Unit
Toronto and Region Conservation Authority
gmacpherson@trca.on.ca