Chapter 3: Aquatic Life

Context

Healthy ecosystems, including healthy aquatic communities, provide significant social and economic benefits, contributing to a high quality of life for the people of Ontario. Currently, aquatic communities and habitats in Lake Simcoe are stressed by degraded water quality, unsustainable land uses, and pressures from other human activities.

Improving and restoring the health of aquatic life within the Lake Simcoe watershed will depend on successfully implementing the policies of this chapter, as well as those related to water quality, water quantity, shorelines and natural heritage, invasive species, and climate change that are outlined in the other chapters of this Plan. This Plan will seek to improve habitats for aquatic life and help to protect and restore aquatic communities throughout the watershed by improving our overall management and stewardship of these resources.

The health of the coldwater fish community, specifically the lake trout, is a good indicator of environmental quality and the overall health of the aquatic ecosystem. The health of the warm-water and tributary fish communities and their ecological functions are also important in determining how well the aquatic ecosystem is functioning. Additional indicators of environmental quality include the biodiversity of aquatic life within the watershed and the presence of species that are rare, threatened, or endangered.

Excessive phosphorus loads to the lake from changes in watershed land use and associated activities is perhaps the most significant stressor. Excess phosphorus has led to the depletion of dissolved oxygen in deep waters of the lake that provide essential habitat for coldwater species such as lake trout and lake whitefish.

This flowchart shows that the Key Objective of the Lake Simcoe Protection Plan as it relates to Aquatic Life is to restore a self-sustaining coldwater fish community in the Lake. To do this, a key habitat requirement of 7 milligrams per litre of dissolved oxygen in the deepwater of the Lake must be achieved. This in turn relies on limiting the total Phosphorus load to the lake. The modelled relationship will be validated as the Plan moves forward to allow us to enhance our understanding and address emerging issues through an adaptive management approach.

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Key Facts

  • 35 rivers flow into Lake Simcoe, including the Holland River, Black River, Beaver River, Pefferlaw River and Uxbridge Brook, which in total comprise almost 4,000 kilometres of streams.
  • Lake Simcoe supports a wide variety of aquatic animals including:
    • coldwater fish such as lake trout and lake whitefish;
    • warmwater fish such as bass and perch;
    • invertebrates including crayfish, insects, snails and clams;
    • amphibians and reptiles;
    • benthos and plankton.
  • 65 species within the watershed ecosystem are rare and 33 of these are species at risk, including the Jefferson salamander and the spotted turtle.
  • Current conditions do not fully support the natural production of lake trout and whitefish, therefore, a hatchery stocking program exists that annually releases approximately 100,000 yearling lake trout and 140,000 fall fingerling lake whitefish to support rehabilitation of these native species.
  • Since 2001, there has been evidence that natural reproduction of lake trout and lake whitefish has increased, consistent with water quality improvements.
  • Degraded water quality is believed to have been the primary cause of population failures of lake trout and other coldwater fish species.

Lake Simcoe supports a significant winter fishery for lake trout, lake whitefish, and perch with considerable socio-economic benefits. It is also a year-round destination fishery for perch, which attracts tourists from Canada and the United States and is also known for its world-class bass fishing. The fact that Lake Simcoe is the most intensively fished inland lake in Ontario may add significant stress to the aquatic communities of the lake. Properly managing these additional pressures will be key to restoring a self-sustaining coldwater fish community while maintaining a sustainable recreational fishery and its associated social benefits.

This Plan supports the development of fish community objectives specific to the Lake Simcoe watershed that will be used to inform land use and watershed planning and management activities. Monitoring and research will be conducted to further our understanding of the lake and its watershed, their aquatic communities, and the way they function, which in turn will improve our ability to manage its resources. The Plan will also support the review of Lake Simcoe’s coldwater fish stocking program to ensure that stocking targets continue to assist in restoring a self-sustaining coldwater fish community. It will also support an evaluation of the ecological and socio-economic value of the aquatic life resources within the watershed.

Target:

  • Mean Volume Weighted Hypolimnetic Dissolved Oxygen Concentration of 7 mg/L on September 15th

Indicators:

  • Natural reproduction and survival of native aquatic communities
  • Presence and abundance of key sensitive species (i.e. lake trout and brook trout)
  • Shifts in cold, warm and tributary fish community composition

Policies:

3.1-SA: Within two years of the date the Plan comes into effect, the MNR will develop Fish Community Objectives for Lake Simcoe and its tributaries. This process will be undertaken in collaboration with First Nations and Métis communities, public bodies, the Lake Simcoe Fisheries Stakeholder Committee, key stakeholders and the general public. These objectives will focus on the warm and coldwater fish communities of Lake Simcoe; however, the objectives will also address the entire aquatic community in both the Lake and tributaries. The Fish Community Objectives will be used by public bodies to inform decisions relating to the management of land, water and natural resources, increase the resilience of Lake Simcoe’s aquatic communities to future impacts of invasive species and climate change, and ensure sustainable resource use and social benefit.

3.2-SA: Within two years of the date the Plan comes into effect, the MNR will initiate, using an adaptive management approach, a review of its coldwater species stocking program, and will establish new stocking targets. This review will be done in collaboration with First Nations and Métis communities, public bodies, the Lake Simcoe Fisheries Stakeholder Committee, and other key stakeholders.

3.3-SA: Within five years of the date the Plan comes into effect, the MNR, in collaboration with First Nations and Métis communities, public bodies, the Lake Simcoe Fisheries Stakeholder Committee, and other key stakeholders, will complete a socio-economic evaluation of the monetary, ecological, social and cultural value and impact of the aquatic life resources within the Lake Simcoe watershed, beginning in the first year with a feasibility study of the socio-economic benefits of maintaining a healthy Lake Simcoe to foster a thriving recreational fishery.

3.4-SA: Beginning the date the Plan comes into effect, the MNR, in collaboration with First Nations and Métis communities, DFO, Parks Canada, the MOE, and the LSRCA, will establish baseline mapping of aquatic habitats in Lake Simcoe and its tributaries building on existing monitoring programs and established databases. The MNR will regularly review and update this information and include, where feasible, shoreline and in-water developments, including in-water structures, tributary barriers, channelizations, and hardened shorelines.

3.5-SA: Beginning the date the Plan comes into effect the MNR, in collaboration with the MOE, the LSRCA and other partners, will undertake research projects on the aquatic communities of Lake Simcoe and its tributaries. The focus of the research will be on filling knowledge gaps associated with the aquatic communities in the watershed that may include recommendations by the Lake Simcoe Science Committee among others. Research projects will be identified and undertaken that examine the biological components of the ecosystem, their processes and linkages. The research projects would build on existing knowledge or address knowledge gaps, and be integrated with existing and any new research programs in the watershed. Collaboration among research groups is encouraged. The focus of initial research projects may include:

  1. production dynamics and ecological function research tied to the coldwater fish community and the function of offshore food webs and ecosystems; or
  2. an evaluation of the impacts of nearshore water quality, nutrients, primary production dynamics, invasive species and climate change on the fish community and the function of the nearshore foodwebs and ecosystems.

3.6-M: Beginning the date the Plan comes into effect, the MNR, in collaboration with the MOE and the LSRCA, shall develop and implement an annual aquatic community monitoring program for the Lake Simcoe watershed. Once the program is fully implemented, it is intended to cover the Lake, the tributaries and other inland lakes in the watershed. The program shall build upon existing aquatic community monitoring programs undertaken by the MNR, the MOE and the LSRCA. This program shall support an adaptive management approach, and may be altered from time to time to respond to changing environmental conditions and land, water and natural resource management needs. The components of the annual aquatic community monitoring program shall include one or more of the following:

  1. surveys of winter and open-water anglers;
  2. fish diet and growth studies;
  3. monitoring of nearshore and offshore fish communities;
  4. monitoring of fish biodiversity;
  5. monitoring of invasive species;
  6. monitoring of benthic invertebrates; or
  7. monitoring of aquatic habitat including macrophyte surveys.