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The nearshore areas of the Great Lakes are diverse physical habitats,
exhibiting a range of morphometric features, current velocities,
substrates, and aquatic vegetation. These features, combined with
seasonal fluctuations in temperature, provide conditions optimum
to most species of fish in the Great Lakes for at least a portion
of their life cycle. Of 139 Great Lakes fish species reviewed
by Lane et al. (1996a), all but five species-the deepwater ciscoes
(Coregonus hoyi, C. johannae, C. nigripinnis,
C. reighardi, C. zenithicus) and deepwater sculpin
(Myxocephalus thompsoni)-typically use waters less than
10 m deep as nursery habitat; and even the latter has been captured
from shallows in the St. Clair River delta (Leslie and Timmins
1991a). Adults of many species occur over a range of depths, but
80 percent of fish species in the Great Lakes use nearshore areas
for at least part of the year (Lane et al. 1996b). It is therefore
not surprising that species diversity and biomass of fish are
higher in the nearshore than in the offshore and profundal areas
of the Great Lakes. Steedman and Regier (1987) noted that areas
that provide the essential conditions for specific activities,
such as reproduction, are far more ecologically significant than
their small size would suggest. In addition, a disproportionately
large number of these critical areas, which they term "centres
of organization," occur in shallow nearshore areas.
Nearshore areas are also locations of greatest human interaction
with the Lakes. This concentrated activity has resulted in the
degradation of water quality and also in a significant loss of
nearshore habitat around the Great Lakes. Loss of fish and wildlife
habitat has been identified as a beneficial-use impairment at
11 of the 17 Areas of Concern identified on the Canadian side
of the Great Lakes, and has also occurred at many locations outside
of Areas of Concern (Kelso and Minns 1996). In most locations
the habitat losses are primarily, if not exclusively, in nearshore
habitats. Randall et al. (1993) have correlated degradation of
nearshore habitats with reductions in the proportion of fish biomass
contributed by piscivores and with increased spatial variability
in species richness and biomass.
7.1.1 Fish Habitat Features of the Nearshore
7.1.1.1 Depth
By definition, shallow habitats are found only in the nearshore
waters. Depth has direct effects on fish distributions; smaller
individuals can occupy shallower depths. Thus, the shallows provide
a refuge for small fish, including young-of-the-year. In addition
to depth per se, fish distributions are influenced by other factors,
individually or in combination, which are related to depth. The
most significant of these-water temperature, substrate, and aquatic
vegetation-are discussed below.
7.1.1.2 Temperature
Temperature influences physiological processes, which affect the
growth, reproduction, and survival of fishes, and can also act
as a proximate factor through its influence on food supply, competition,
and predation (Reynolds 1977). Preferred and/or optimum temperatures
differ between species, with younger individuals of some species,
such as alewife (Alosa pseudoharengus), preferring higher
temperatures than the adults of those species do (Brandt 1980).
Consequently, habitat partitioning among and within species is
affected by temperature, and the amount of habitat available at
different temperatures has a profound influence on fish community
composition.
In the spring, solar radiation causes water temperatures in the
Great Lakes to increase. Water temperature increases most rapidly
in sheltered, shallow habitats, where wind-induced mixing is least.
As the warming continues, a band of warmer water forms along the
shore; this "thermal bar" gradually expands towards
the centre of the lake until the lake becomes thermally stratified.
During the spring, many coldwater species (such as lake trout)
inhabit shallow, warmer water where temperatures are closer to
their thermal optimum. As water temperature increases, these species
migrate to deeper water. In Hamilton Harbour, Lake Ontario, gill
net catches have indicated that warmwater species such as carp
(Cyprinus carpio) and brown bullheads (Ameiurus nebulosus)
are concentrated in the shallow, sheltered inner harbour (Cootes
Paradise) during early spring, when water temperatures there were
higher than in the outer harbour. As temperatures in the outer
harbour increased, these species dispersed (Portt et al. unpublished).
For species that are near the northern limit of their range, such
as largemouth bass (Micropterus salmoides), the availability
of shallow, sheltered habitats that warm early in the spring is
probably essential for survival. For other species, such as lake
trout, using warmer nearshore areas effectively increases the
growing season and may significantly increase production.
7.1.1.3 Vegetation
Of the 133 species examined by Lane et al. (1996a), the young-of-the-year
of 77 are moderately to strongly associated with aquatic vegetation;
more species are associated with submergent than with emergent
vegetation (Table 6). Wetlands provide critical spawning and nursery
habitats for many Great Lakes fish species, and several authors
have reported high species richness of young fishes from wetland
habitats. Chubb and Liston (1986) identified larvae of 18 fish
species in Pentwater Marsh, a coastal wetland on Lake Michigan.
Stephenson (1990) found juveniles of 31 fish species in one or
more of five coastal marshes in the Toronto area of Lake Ontario,
with the number of species at individual sites ranging from 12
to 25. Young-of-the-year of 19 species were present in Second
Marsh, Lake Ontario (OMNR 1980).
Life Stage | Vegetation Type | ||||
adult | submergent | ||||
emergent | |||||
young-of-the-year | submergent | ||||
emergent | |||||
Sources: Lane et al. 1996a, 1996b.
The abundance of young-of-the-year fishes is also often higher
in vegetated than in non-vegetated habitats (Chubb and Liston
1986; Holland and Huston 1984; Leslie and Timmins 1994; Keast
et al. 1978). Chubb and Liston (1986) reported that larval fish
densities were usually 10 times to 100 times more abundant in
the vegetated bayou of Pentwater Marsh, Lake Michigan, than in
adjacent unvegetated bayou mouths or river channels.
Vegetation is also an important component of adult habitat. Adults
of nearly one-third of the fish species in the Great Lakes are
strongly associated with submergent vegetation, while adults of
one-quarter of the species are strongly associated with emergent
vegetation (Table 6).
7.1.1.4 Substrate
Table 7 indicates the wide diversity of substrates used by both
adult and young-of-the-year fish species of the Great Lakes. Gravel,
sand, and silt are the most preferred materials, with more than
three-quarters of young-of-the-year fish species and two-thirds
of adult species using at least one of them. These substrate types
are often found within vegetated habitat, and the strong association
is certainly related. Coarse substrates such as rubble and cobble
also provide important nursery and adult habitat (Lane et al.
1996a, 1996b). In addition, many species of Great Lakes fishes-such
as lake trout, lake whitefish, walleye, bass, and most sunfish-spawn
on gravel, cobble, and rubble. In the nearshore, many features
are actively forming at present lake levels, the continued extension
of Long Point, Lake Erie, being one example. Glacial, glaciolacustrine,
and lag or relict beach deposits have been described over a wide
range of depths at many locations in the Great Lakes (Sly and
Prior 1974; Sly and Sandilands 1988; Thomas et al. 1976). These
deposits can be subject to degradation due to infilling and/or
burial by finer sediments and/or particulate organic material.
In the nearshore, wind-generated currents determine the size distribution
of particles that are transported. In some areas, accretion of
fine sediments occurs; in others, these materials accumulate.
This accumulation leads to a diversity of substrates that is not
found in the deeper portions of the Lakes.
Adult | boulder | 8 | 12 | 5 | 108 |
cobble | 12 | 13 | 3 | 105 | |
rubble | 24 | 24 | 7 | 78 | |
gravel | 68 | 26 | 12 | 27 | |
sand | 90 | 18 | 6 | 19 | |
silt | 71 | 16 | 6 | 40 | |
clay | 6 | 9 | 8 | 110 | |
Young-of-the-year | boulder | 11 | 2 | 1 | 113 |
cobble | 12 | 2 | 3 | 110 | |
rubble | 19 | 9 | 5 | 94 | |
gravel | 43 | 25 | 2 | 57 | |
sand | 84 | 17 | 3 | 23 | |
silt | 65 | 15 | 5 | 42 | |
clay | 10 | 14 | 2 | 101 | |
Sources: Lane et al. 1996a, 1996b.
7.1.2 The Significance of Water-level Fluctuations
Variation in Great Lakes water levels is generally identified
at three temporal scales, which we define here as short-term,
seasonal, and year-to-year. Short-term cyclical fluctuations-with
periods measured in hours, and amplitudes typically measured in
centimetres or tens of centimetres-occur due to seiche activity.
Occasionally, larger short-term fluctuations-with amplitudes in
excess of 1 m-occur as a result of cells of low barometric pressure
and/or high winds. Seasonal changes in water levels occur largely
in response to seasonal patterns of precipitation and temperature
in the drainage basin. The amplitude of these seasonal fluctuations
varies between the lakes, as does the time of maximum and minimum
levels. On average, water levels rise during a five-month period
in the spring and early summer and recede during the remaining
seven months of the year. The annual minimum and maximum occur
approximately two months earlier in Lake Ontario (where they
occur in late January and mid-June, respectively) than in Lake
Superior (where they occur in mid-March and late August, respectively).
Superimposed on the seasonal cycles are year-to-year fluctuations
in water levels, which occur primarily as a result of year-to-year
variation in precipitation within the drainage basin. These fluctuations
can cause substantial deviations from the "normal" seasonal
pattern. The amplitude of the year-to-year variations differs
between the lakes. The extreme highs and lows for the period of
record differ by approximately 2.0 m in Lake Ontario and Lake
St. Clair; 1.8 m for Lakes Michigan, Huron, and Erie; and 1.2
m for Lake Superior. The locations of the "shoreline,"
depth contours, and the thermocline vary over time because of
these water-level fluctuations. Where bottom slopes are gentle,
the migrations can be large. Such changes illustrate the dynamics
of nearshore habitats and the direct influence they have on the
fish community.
Maynard and Wilcox (1996) discuss the well-documented importance
of water-level fluctuations for healthy wetlands. Effects on other
fish habitats has not been researched as extensively; however,
Henderson (1985) showed that yellow perch reproduction improved
in high-water years in South Bay, Lake Huron. He attributed this
improvement to the increased availability of vegetation along
the shoreline. Strong year classes of northern pike have been
attributed to rising water levels that have flooded vegetation
in impoundments (Bodaly and Lesack 1984; Nelson 1978). Similar
effects would be expected in Great Lakes wetlands.
7.1.3 Types of Nearshore Habitats
The nearshore waters have been defined as including the portion
of the lakes from the shore, or the outer edge of coastal wetlands
where these are present, to the intersection of the late-summer
thermocline with the bottom. Also included are the connecting
channels, as well as tributaries upstream to the point where lake
levels affect flow. These habitats can be divided into five general
categories: wetlands, embayments, connecting channels, tributaries,
and exposed coastline and offshore shoals.
7.1.3.1 Wetlands
Wetlands are defined as areas that are covered by shallow water,
either seasonally or permanently, as well as areas where the water
table is at or near the surface (OMNR 1992). Wetlands comprise
different types of ecosystems and serve a number of functions,
including maintaining and improving water quality, providing erosion
and flood protection, and providing fish and wildlife habitat
(Maynard and Wilcox unpublished).
Along the Great Lakes shoreline, coastal wetlands provide an important
link between aquatic and terrestrial systems. These wetlands differ
from inland wetlands in a number ways. Water levels in coastal
wetlands are dependent on lake water levels, which fluctuate over
a period of years. Because of this long-term fluctuation, coastal
wetlands do not exhibit the gradual senescence that occurs with
inland wetlands (Herdendorf et al. 1986).
Coastal wetlands are formed by a diversity of landforms, including
barrier bars, deltas, lagoons, and natural levees (Jude and Pappas
1992). These characteristics provide the extensive zonation that
results in diverse habitat structures. These areas, in turn, promote
the formation of complex food webs and diverse community structure.
The role of coastal wetlands in fish production relates primarily
to providing both nursery and spawning habitat (Stephenson 1990).
The fundamental prerequisites for nursery habitat of virtually
all larval fish species are abundant food supply and protection
from predators. The proliferation of aquatic macrophytes in coastal
wetlands provides microhabitat for both eggs and larvae, the necessary
cover from predator species, and the storage and release of nutrients
(Petering and Johnson 1991). In addition, higher water temperatures
promote higher growth rates for larvae, as well as providing favourable
conditions for all life phases of certain warmwater fish species.
Another result of the profile of favourable characteristics common
to wetlands is the species diversity found in both pristine and
degraded areas. Stephenson (1990) found 31 species of juvenile
fish in the combined sampling sites of marshes around the Toronto
area. Individual marshes supported 18 taxa, a similar number to
that found by Chubb and Liston (1986) in their study of Pentwater
Marsh on Lake Michigan. Species abundance, however, tends to be
lower in degraded wetlands, with one species-often carp-being
dominant (Chubb and Liston 1986).
7.1.3.2 Embayments
Embayments represent another diverse array of sheltered habitats
for fish species in the nearshore areas of the Great Lakes. Although
many embayments contain wetlands (abundant submergent and emergent
vegetation are typically present), they also include areas of
open water. Often they represent a transition between open water
and riverine habitats. The Bay of Quinte (Lake Ontario), Long
Point Bay (Lake Erie), and Saginaw Bay (Lake Michigan) are examples
of embayments. Field studies in Muscote Bay, Bay of Quinte (Leslie
and Moore 1985), and Hog Bay, Severn Sound (Leslie and Timmins
1995), both Areas of Concern, showed 24 and 31 taxa, respectively.
7.1.3.3 Connecting Channels
The Great Lakes connecting channels are also important spawning
and nursery habitats. Leslie and Timmins (1991a) captured 21 species
of fish larvae in the St. Clair River proper, but captured more
than 60 species in waters connected to and adjacent to the river.
Young-of-the-year of 48 species were captured in tributaries of
the St. Clair River (Leslie and Timmins 1991b). Liston and McNabb
(1986) reported larvae of 33 species and juveniles of 27 from
Munuscong Bay on the St. Marys River. The St. Marys River, downstream
from the dam at Sault Ste. Marie, and the Niagara River provide
spawning habitat for Pacific salmon and for rainbow trout, which
also spawn in many of the tributaries of the Great Lakes. Connecting
channels also have an important role in the transport of water,
sediments, nutrients, and contaminants (Sparks 1995).
7.1.3.4 Tributaries
The principal spawning and nursery habitats for one-third of the
fishes in the Great Lakes are located in the tributaries (Lane
et al. 1996a). Many of these species spawn further upstream than
the area that has been defined as nearshore habitat (the furthest
distance upstream that water levels are affected by lake levels).
Other species, however, spawn within the lower reaches of the
tributaries. Temperatures sufficiently high to trigger spawning
often occur in streams before they occur in lakes, thus providing
a longer growing season. For example, spottail shiners spawned
one month earlier in a tributary to Lake Michigan than they did
in the lake (Mansfield 1984). Productivity also tends to be higher
in streams than in pelagic lake areas, probably as a result of
the allochthonous input from terrestrial areas (Mansfield 1984).
Floodplains also enhance productivity and maintain diversity.
At drawdown, nutrients are mineralized and accumulation occurs;
during flooding, the nutrients are dissolved and high primary
production and decomposition rates occur (Bayley 1995). The result
is a high turnover rate and optimum conditions for spawning and
nursery grounds for many species of fish.
7.1.3.5 Exposed Coastline and Offshore Shoals
Exposed coastline and offshore shoals have been the subject of
less sampling effort in the Great Lakes than have the other nearshore
habitats. This neglect is probably due both to the fact that such
areas are perceived as being less important in terms of fish habitat
than are most other nearshore habitats and to the fact that they
are more difficult to sample. Macrophytes are typically not present,
with the exception of deeper beds in some locations. Wave-induced
mixing inhibits thermal stratification, and upwelling of water
from the hypolimnion occurs in many areas. Although total fish
numbers are generally lower than in sheltered habitats, these
areas present unique features that are optimum for certain species,
particularly those adapted to turbulent environments. Upwelling
also affords coldwater species with periodic access to shallow
littoral habitats.
Fish habitat problems related to power production, dredging, transportation,
and boating have been mentioned earlier in this report. This section
covers problems associated with other types of activities.
7.1.4.1 Shoreline Modification
Portions of the Great Lakes shoreline have been modified during
the course of industrial, commercial, and residential development.
Except where diking of coastal areas for agricultural purposes
has occurred (primarily along the shores of Lakes Erie and St.
Clair), the extent of these modifications is roughly proportional
to the population along the shoreline. Shoreline modifications
range from simply infilling the shallows to erecting sheet steel
and concrete walls. In Hamilton Harbour, a major industrial port,
filling the nearshore areas, along with straightening and hardening
the shoreline, reduced the shoreline's length by 36 percent between
1808 and 1992. Only about 6 percent of the original shoreline
remains in an unaltered state. In Severn Sound, which represents
an intermediate case, 15 percent of the 325 km of shoreline that
has been inventoried has been altered. The alterations include
nearly 9.7 km of concrete walls and 3.4 km of sheet steel piling.
Not surprisingly, the modifications are concentrated in sheltered
embayments that are surrounded by the most intense development.
Along the north shore of Lake Superior, where there are relatively
few communities, most of the shoreline is still in its natural
state.
Hardening the shoreline eliminates the migration of the nearshore
with changing water levels. Indeed, such modifications are often
motivated by the desire to eliminate such migration. Their effect,
however, is to reduce the amount of fish habitat available, especially
in relation to what would be available during high-water years.
Usually, such modifications also straighten the shoreline. Because
irregularities in the shoreline cause local variations in alongshore
currents, which in turn cause local variation in substrate, straightening
results in a loss of habitat diversity.
Other examples of shoreline modification are accumulations of
wood fibre and bark near some pulp mills and accumulations of
wood scraps from lumber operations in Penetang Harbour.
7.1.4.2 Water-quality Degradation
The impaired beneficial uses of many of the 17 Areas of Concern
in the Canadian waters of the Great Lakes all relate in some way
to eutrophication. The cycle of eutrophication begins with the
enrichment of water as a result of nutrient loading and, subsequently,
increased algal blooms. Eutrophication causes a shift in community
to a species profile that can better tolerate the conditions of
impaired visibility and variations in dissolved oxygen (Severn
Sound RAP Team 1993). Often these species are less desirable-for
example, carp (Cyprinus carpio), alewife (Alosa pseudoharengus)
and brown bullhead (Ameiurus nebulosus). Sewage plants,
septic systems, urban storm water, and agricultural sources-both
livestock and crops-all contribute to the eutrophication problem
in the Severn Sound AOC (Severn Sound RAP Team 1993). In the Bay
of Quinte AOC, six municipal sewage treatment plants bordering
the area are mainly responsible for phosphorus loadings (Bay of
Quinte RAP 1996). Discharges from the Domtar liner-board mill
on Nipigon Bay and from the two local sewage treatment plants
are responsible for eutrophication problems in that AOC (Nipigon
Bay RAP Team 1995).
7.1.5 Fish Habitat Policy and Current Initiatives
7.1.5.1 Department of Fisheries and Oceans (Canada) Policy for the Management of Fish Habitat
The habitat protection provision of the Canadian Fisheries Act
provides the legislative mandate for the management of fish habitat
in Canada. This Act prohibits any work or undertaking that is
likely to result in the harmful alteration, disruption, or destruction
(HADD) of fish habitat without the implementation of compensatory
measures. The Department of Fisheries and Oceans (DFO) policy
for the management of fish habitat establishes an overall objective:
to "increase the natural productive capacity of habitats
for the nation's fisheries resources, to benefit present and future
generations of Canadians" (DFO 1986). The first goal of this
policy is to maintain the current productive capacity of fish
habitats. The guiding principle for achieving this objective is
no net loss of the productive capacity of habitats. Simply stated,
the DFO will seek to balance any unavoidable habitat loss with
habitat replacement on a project-by-project basis (DFO 1986).
Other goals include rehabilitating the productive capacity of
fish habitats in selected areas where economic or social benefits
can be achieved through the fisheries resource, and improving
and creating fish habitats in selected areas where the production
of fisheries resources can be increased for the social or economic
benefit of Canadians.
In Ontario, the DFO and the Ontario Ministry of Natural Resources
(OMNR) work together to protect fish habitat. The provincial agency
is responsible for enforcing the habitat protection provisions
of the Fisheries Act. Applications for activities that will affect
fish habitat are reviewed by OMNR field offices. If a HADD is
anticipated, the project is normally referred to the DFO for authorization.
The major decision criteria for the authorization of a HADD are
the significance of the habitat and the possibility of compensation.
Typically, the creation of new habitat or the modification of
existing habitat that will increase fish productive capacity is
considered acceptable. Table 8 provides information on some projects
assessed by the DFO under the "no net loss" policy.
Less than 5 percent of the shoreline referrals were dedicated
to restoration. Close to 50 percent of the projects affect between
0 m and 1,000 m of shoreline each, yet the cumulative effect of
these projects is significant. The development of long-range habitat
management plans that deal effectively with these issues is essential.
Variable | Count (Number of Projects) | Percent | |
Project | Marina | ||
Dock | |||
Water Intake | |||
Industrial Wastewater | |||
Storm Sewer |
|||
Sewage Treatment | |||
Water Course Diversion | |||
Armourment |
|||
Restoration/Cleanup | |||
Infilling |
|||
Dredging |
|||
Other | |||
Shore Affected (m) | 0 | ||
> 0-10 |
|||
10-100 | |||
100-1,000 |
|||
1,000-10,000 | |||
> 10,000 |
|||
Unknown |
|||
Area Affected (m2) | 0 | ||
> 0-10 |
|||
10-100 | |||
100-1000 |
|||
1000-10,000 |
|||
> 10,000 |
|||
Unknown |
|||
Effects | Construction | ||
Permanent |
|||
Both | |||
None | |||
Unknown |
|||
Source: Minns et al. 1995.
7.1.5.2 Current Initiatives
The ecosystem approach to nearshore fish habitat management has
been adopted for the Canadian waters of the Great Lakes. In this
approach, which recognizes the link between the natural ecosystem
and human activity, the effects of shoreline development are assessed
with respect to their impact on fish habitat (Minns et al. 1995).
A problem exists based on the lack of a protocol that would allow
the consistent and quantitative assessment of fish habitat in
its pre- and post-development stages. Current methods do not consider
cumulative impacts, the direct and indirect effects of development,
or the habitat needs of fish (e.g., individuals, communities,
proximity of spawning, and nursery habitats). There is a need
for a common approach to evaluating the effects of habitat modification
on fish productive capacity.
Development of Methods for Pre- and Post-Development Assessment
of Fish Habitat
A prototype methodology has been developed for use with nearshore
fish habitat of the Great Lakes that provides the ability to assess
fish community objectives with respect to proposed development
(Minns et al. 1995). The proposed methodology estimates (1) total
habitat area that will be affected, either directly or indirectly,
by the development; (2) pre- and post-development fish community
productivity area; and (3) suitable area for special habitat (e.g.,
spawning habitat for coldwater piscivores) for pre- and post-development.
These estimations are based on information compiled regarding
life history, life stage, ecology, and fish community objectives.
The result is a pair of scores-one each for pre-development status
and post-development status. The difference between the two scores
is an estimate of the net change in fish productivity that will
result from the proposed development. Refinements to the methodology
are ongoing.
Incorporating Fish Habitat Concerns into Land-use Planning
It is increasingly recognized that fish habitat protection must
be incorporated into traditional land-use planning to be effective.
In Ontario, recent amendments to the Land Use Planning and Protection
Act require that fish habitat be addressed with other natural
features in a Natural Heritage Policy. Management agencies require
ways of providing ecologically sound information, in a form that
can be readily used by planners and other non-fisheries professionals,
for effective habitat management planning.
Initiatives aimed at developing habitat classification systems
for littoral habitats are under way in two Great Lakes Areas of
Concern, the Bay of Quinte (Lake Ontario) and Severn Sound (Lake
Huron), as part of their Remedial Action Plans. Both use Geographical
Information System (GIS) software to integrate habitat data (substrate,
depth, vegetation) with biological information. In the Bay of
Quinte, fish sampling data have been used to calculate an Index
of Biotic Integrity or IBI (Minns et al. 1994) for the various
littoral habitats. The IBI scores, in combination with a rating
of spawning suitability, were used to calculate a community habitat
suitability score for each identified habitat type (MacLeod et
al. 1995). In Severn Sound, knowledge of the habitat requirements
of Great Lakes fishes is being used to predict fish utilization
of different littoral habitats. These results will subsequently
be evaluated by comparing them to field collection data. Making
this information available to planners, developers, and other
agencies will ensure a proactive rather than a reactive approach
to development. Projects will be redirected away from sensitive
habitats before damage occurs and before large amounts of time
and money are invested.
Integration of Coastal Processes and Fish Habitat Management
Nearshore areas of the Great Lakes are highly diverse and are
subject to constant change with respect to both natural and human
forces. Wave action, sediment transport, deposition, and erosion
are some of the factors that induce changes in surficial substrate,
macrophytes, and water depth. Changes in the amount and quality
of fish habitat result. Modelling techniques are currently being
developed that will enable the prediction of wave action and circulation
patterns, along with prediction of the changes in habitat that
may occur as a result (W.F. Baird and Associates 1996). These
techniques are based on documentation of existing morphology,
evaluation of wave dynamics, and current models. Once the techniques
have been applied, the findings can be interpreted to determine
changes in key habitat characteristics (W.F. Baird and Associates
1996). These advancements clear the way for Coastal Zone Management
planning to expand from its traditional area of flood/erosion
control towards the Fish Habitat Management Planning process envisioned
in the Department of Fisheries and Oceans policy.
Canadian Airborne Spectral Imagery Project (CASI)
The purpose of the CASI project is to develop a digital inventory
of habitat types for Lake Erie. An atlas of digital maps will
be compiled using data collected with CASI along with digital
georeferenced data from other sources. The maps will show nearshore
aquatic and terrestrial habitat components on Long Point Bay,
Lake Erie. The atlas will provide an improved technique for assessing
aquatic habitat suitability and influences of terrestrial activity
on aquatic habitats in a consistent and reliable manner. Such
a tool will be key in helping the agencies responsible for making
land-use and resource management decisions.
7.1.5.3 New Initiatives for Improving Management
The Lake Superior Bi-national Program provides a more broad-scale
approach to restoration and management planning. The overall objective
of this program is to achieve the designation of Lake Superior
as a zero-discharge area. The need to inventory existing habitat
and to initiate activities aimed at protecting or restoring habitat
resources is also included in the broader program to restore and
protect the Lake Superior ecosystem. More specifically, the Habitat
Committee was established to address issues that relate directly
to wetland, aquatic, and terrestrial habitat. Its direct responsibilities
include (1) developing criteria for identifying areas of important
habitat and identifying sites that meet those criteria; (2) promoting
partnerships aimed at integrating the inventory, restoration,
and maintenance of habitat; (3) developing a system of ranking
habitat restoration and maintenance-a system that involves all
potentially affected individuals at all levels; (4) integrating
long-term habitat inventory, assessment, and restoration efforts
(Lake Superior RAP unpublished).
7.1.5.4 Restoration Examples
In recent years, numerous projects aimed at restoring fish and
wildlife habitat have been undertaken in nearshore areas of the
Great Lakes. Currently, approximately 58 habitat restoration projects
are being supported, in part, by the Great Lakes 2000 Cleanup
Fund. Some examples are discussed below.
Hamilton Harbour and Cootes Paradise Habitat
Restoration
This fish and wildlife project, currently the most ambitious on
the Canadian side of the Great Lakes, is coordinated by the Department
of Fisheries and Oceans and is supported by a broad partnership
of government and private organizations. Project activities include
the creation of islands, shoals, and reefs; the naturalization
of shoreline; and the restoration of wetlands. The project's overall
aim is to restructure the fish community so that instead of being
dominated by carp (as it is now), it becomes a more diverse community
dominated by top-order predators. The projected total cost of
this project is more than Cdn $31 million.
Penetang Harbour
About 63 percent of Penetang Bay wetland has been lost through
development (filling). Wood debris from lumber operations along
a portion of the shoreline at the bay's south end prevented the
growth of aquatic plants; in doing so, it impaired habitat for
waterbased wildlife. Removal of wood debris from the bottom
(4 ha) has allowed colonization by aquatic vegetation. Two hectares
of parkland, which had been created by filling the bay, were recontoured
to create two wetlands containing small, spring-fed watercourses.
Steel half-culverts that had contained two other small streams
were removed to allow these channels to revert to a more natural
condition. The projected total cost of this project is Cdn $260,000.
Restorations of Natural Habitat Structure, Toronto Waterfront
Underwater structural complexity was re-created along the Toronto
waterfront, reducing the extent of habitat impairment caused by
shoreline modifications. This activity will help restore self-sustaining
fish and wildlife populations to the area.
In summary, the nearshore habitats of the Great Lakes have been
significantly affected since 1800, when colonization of North
America expanded. The rate and magnitude of change accelerated
greatly with the increases in population and the increases in
agricultural and industrial development that followed. No comprehensive
documentation of the recent changes in the amount and quality
of nearshore habitats is available, but it is clear that with
the adoption of the "no net loss" policy and with the
efforts directed at habitat restoration, a net gain in the amount
and quality of nearshore habitats has been realized in recent
years. Though the current restoration efforts are improving aquatic
habitat, much of the damage is irreversible. For example, restoration
estimates for northern pike (Esox lucius) habitat in Hamilton
Harbour indicate that 20 percent of the harbour will provide suitable
habitat. In its original state, nearly 50 percent of Hamilton
Harbour provided some degree of pike habitat (Minns et al. 1993).
In addition, the degradation in one area significantly affects
our ability to improve fish and wildlife populations in adjacent
areas. Pressures on nearshore habitat will continue as the population
of the Great Lakes basin increases. Subsequently, demand for water
increases as well, along with demand for sewage disposal, food,
housing, recreation, transportation, and a range of other human
needs and wants that threaten aquatic habitats, especially the
nearshore. Recognizing the unfortunate history of habitat destruction
and degradation and the lost opportunities that have resulted,
and recognizing the high cost of restoration, inspires a commitment
to anticipate future human-induced stressors and to develop strategies
to prevent us from repeating the mistakes of the past.
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