Population trends and status of the PGT fishery

There are no known self-sustaining, naturally reproducing native trout or salmon species (with the exception of lake trout – see Lake Trout Management Strategy Section) in FMZ 18, and as a result, all other coldwater fisheries in the zone are managed as PGT (see Fish Stocking Approach Section for more details), dating back multiple decades.

FMZ 18’s PGT fisheries provide a variety of alternative fishing opportunities. Angler effort and harvest, as well as fish survival and growth rates from formal assessment activities are currently lacking on most PGT waterbodies. A number (n=11) of PGT coldwater fish populations were surveyed from 2003 to 2009 using various index netting methodologies, yielding insufficient information for management purposes. However, recent (2013-2015) modified index netting methods have provided useful information to inform the management strategy for some of these species.

Over the last 200 years, habitat loss, pollution and alteration of natural flow regimes from dams, channelization and various land uses have had catastrophic impacts on biotic and abiotic components of streams (Reid, 2001), and other cold waterbodies. Many of the stresses on these waterbodies are directly related to continued growth in human populations. Some coldwater streams flow through urban centres (e.g. Stittsville and Greely (Ottawa)) and many smaller communities or through significantly altered landscapes. Stream reaches within these developed areas are significantly degraded and with increased population growth it is anticipated that they will be increasingly affected.

In summary, coldwater PGT fisheries in FMZ 18 require more assessment to determine the amount of fishing pressure, as well as angler success rates and the general survival, growth and abundance of stocked fish, in most populations. The management focus for these PGT fisheries is to continue to provide a variety of additional fishing opportunities.

Population trends and status of the lake whitefish fishery

Lake whitefish populations across FMZ 18 were surveyed from 1996 to 2009 using FWIN and SLIN methodologies. There were a total of 12 surveys that captured lake whitefish on 9 lakes. In addition, BsM was conducted on 5 lakes in FMZ 18 from 2008 to 2010.

Lake whitefish abundance is impacted by harvest and quality of habitat and is estimated by the average number of lake whitefish per net (CUE). The catch rate of lake whitefish did not vary across FMZ 18. The mean catch rate was identical for each individual survey type (incl. 5 BsM surveys) at 0.3 lake whitefish/net in FMZ 18. A greater number of age classes and high maximum age are indicative of successful recruitment and adult survival. The assessment data, although limited, show that many lake whitefish are reaching the maximum age of up to 40 years (FMZ 18 data) suggesting high survival. 25% of the population was 20 years or older.

In summary, lake whitefish populations in FMZ 18 require more assessment to determine the general status of the populations and the fishery they support, although the limited data currently available suggests that most populations have high proportions of fish at, near and beyond the age of maturity. The management focus for this species is to fully determine the status of the populations and supporting fishery.

Coldwater species management in FMZ 18

The lack of coldwater species assessment data in FMZ 18, especially given the amount of resources invested in maintaining PGT fisheries, has been recognized as a concern and a priority in the fisheries management plan. MNRF and the Advisory Council identified a number of challenges to managing coldwater species populations in FMZ 18.

Management challenges:

  • habitat degradation and destruction caused by shoreline development; increased nutrient levels from faulty septic systems or shoreline erosion; and climate change causing an increase in thermal regime
  • fish introductions (into simple fish communities) creating competition for limited resources
  • lack of effective, standardized assessment protocols for assessing many of the (smaller lacustrine and riverine) coldwater PGT fisheries
  • potential over-harvest and high natural mortality rate of fish, in coldwater PGT fisheries

The MNRF with the advice of the Advisory Council developed objectives and strategies to address the challenges and help reach the following coldwater species management goal.

Goal:

To maintain, and where possible, improve coldwater fish populations supported by PGT stocking to provide diverse angling opportunities.

Objective 1:

Maintain or increase coldwater fish abundance and the number of sustainable populations (lake whitefish).

MNRF and the Advisory Council agreed that assessing and monitoring our coldwater fish populations in FMZ 18 is a priority, given the level of resources invested in this type of fishery. Information on the zone’s coldwater streams is outdated and many data gaps exist. Many agencies have databases with stream data that would assist in making management decisions. A mechanism and process for sharing expertise and information between organizations and agencies is not well established, in most cases. Databases are not comprehensive, are limited in scope, and the data is not easily accessible to all partners that need it.

Strategies to address the objective include:

  • monitor coldwater fish populations to assess the growth and survival of stocked fish and share information among agencies
  • monitor lake whitefish populations to assess the status of the fishery
  • develop public/partner opportunities to measure fishing pressure and harvest rates via public reporting (e.g. volunteer angler diary program)

Objective 2:

Maintain coldwater fish angling opportunities.

PGT stocking only occurs on waterbodies where there is no reliance on natural reproduction. It provides alternative angling opportunities on waterbodies where there are no or minimal naturally reproducing populations, it is also used as a management tool to divert fishing pressure away from stressed lakes.

Strategies to address the objective include:

  • determine if water quality and habitat variables are sufficient to support PGT coldwater fisheries
  • maintain existing PGT coldwater fisheries where effective, and explore options for creating new ones
  • prioritize and where appropriate, rehabilitate coldwater habitat (recognizing limited opportunities)
  • maintain existing season (open all year)

Objective 3:

Increase the quality (i.e. larger fish) of coldwater fish angling opportunities.

Currently, very little data exists on the coldwater lake, river and stream fisheries in FMZ 18. Increased understanding of resource use contributes to effective long-term management of the resource. Additional assessments of PGT fisheries will help determine if these fisheries are meeting management objectives, and if they need to be enhanced.

Strategies to address the objective include:

  • see Objective 1 strategies – monitor coldwater fish populations
  • explore management actions (e.g. catch limits, size limits) to increase the quality (i.e. larger fish) of coldwater angling opportunities

Objective 4:

Maintain suitable coldwater habitat of PGT coldwater fisheries.

Coldwater fisheries are vulnerable to a high number of stressors in southern Ontario. Habitat destruction and alteration caused by the prevalence of shoreline alteration and development; industrial and agricultural contamination; increased nutrient levels from faulty septic systems or shoreline erosion; and climate change, all negatively impact the quality of coldwater habitats, and in some cases, increasing the thermal regime.

Managing various detrimental impacts such as limiting the amount of shoreline development (via Provincial Policy Statement) to reduce the input of nutrients may prove to be the most effective technique for managing critical coldwater habitat for coldwater species.

Strategies to address the objective include:

  • share fishery management objectives, and coldwater habitat information (e.g. LIO) with partner agencies to enable the protection of these important areas through land use planning and application of their regulatory mandates (e.g. DFO and Fisheries Act)
  • engage stakeholders to increase awareness, promote and undertake rehabilitation to enable natural shorelines

Objective 5:

Prevent the introduction of spiny-rayed fish into PGT coldwater fisheries.

Many spiny-rayed fish (e.g. yellow perch, smallmouth bass, pumpkinseed) are native to lakes within FMZ 18, and others are not (e.g. bluegill, black crappie, largemouth bass) but have become well established throughout a significant portion of the zone. These populations are now considered naturalized and it is unrealistic to expect a significant reduction in these populations at current levels of angler harvest. However, the introduction and establishment of these species in PGT coldwater fisheries should be prevented as they pose detrimental risks to the viability of these stocked fisheries.

Strategies to address the objective include:

  • see Invasive Species and Diseases Management Strategy Section

The goal, objectives and strategies have been summarized in Table 7.

Table 7: coldwater species management summary

Adapted from tabular format.

Coldwater species management goal:

To maintain, and where possible, improve coldwater fish populations supported by PGT stocking to provide diverse angling opportunities.

Objective 1.

Maintain or increase coldwater fish abundance and the number of sustainable populations (lake whitefish).

Strategies
  • Monitor coldwater fish populations to assess the growth and survival of stocked fish and share information among agencies.
  • Monitor lake whitefish fisheries to assess the status of the population.
  • Develop public/partner opportunities to measure fishing pressure and harvest rates via public reporting (e.g. volunteer angler diary program).
Progress reviewed by

BsM Cycle 3

IndicatorBenchmarkTarget

Lake whitefish:

  • Median area weighted CUEW (all lakes combined from  from BsM)

Current kg/net

Maintain or > Current kg/net

  • BsM
    Proportion of lakes where biomass ratio (B/Bmax) is > 0.5
  • BsM
    Proportion of lakes where mortality rate ratio (Z/M) is < 2

Current # of Coldwater fish stocked

Maintain or > Current # of Coldwater fish stocked

PGT fisheries:

  • # of Coldwater fish stocked
  • CUE of residual (2+ year old) fish in PGT fisheries

Current CUE of residual (2+ year old) fish in PGT fisheries

Maintain or > Current CUE of residual (2+ year old) fish in PGT fisheries

Objective 2.

Maintain coldwater fish angling opportunities.

Strategies
  • Determine if water quality and habitat variables are sufficient to support PGT coldwater fisheries.
  • Maintain existing PGT coldwater fisheries where effective, and explore options for creating new ones.
  • Prioritize and where appropriate, rehabilitate coldwater fisheries habitat (recognizing limited opportunities).
  • Maintain existing season (open all year).
Progress reviewed by

BsM Cycle 3

IndicatorBenchmarkTarget

# of PGT coldwater fish lakes

Current # of PGT coldwater fish lakes

# of PGT Coldwater fish lakes

# of days of the coldwater fish season

Current # of days of the coldwater fish season

Current # of days of the coldwater fish season

Objective 3.

Increase the quality (i.e. larger fish) of coldwater fish angling opportunities

Strategies
  • See Objective 1 strategies – monitor coldwater fish populations.
  • Explore management actions (e.g. catch limits, size limits) to increase the quality (i.e. larger fish) of coldwater angling opportunities.
Progress reviewed by

BsM Cycle 4

IndicatorBenchmarkTarget

% of larger (2+ year old) fish present in PGT fisheries

Current % of larger (2+ year old) fish present in PGT fisheries

Maintain or > % of larger (2+ year old) fish present in PGT fisheries

Objective 4.

Maintain suitable coldwater habitat of PGT coldwater fisheries.

Strategies
  • Share fishery management objectives, and coldwater habitat information (e.g. LIO) with partner agencies to enable the protection of these important areas through land use planning and application of their regulatory mandates (e.g. DFO and Fisheries Act).
  • Engage stakeholders to increase awareness, promote and undertake rehabilitation to enable natural shorelines.
Progress reviewed by

BsM Cycle 3

IndicatorBenchmarkTarget
N/AN/AN/A
Objective 5:

Prevent the introduction of spiny-rayed fish into PGT coldwater fisheries.

Strategies

See Invasive Species and Diseases Management Strategy Section.

Progress reviewed by

BsM Cycle 3

IndicatorBenchmarkTarget

# of PGT fisheries without spiny-rayed fish

Current # of PGT fisheries without spiny-rayed fish

Current # of PGT fisheries without spiny-rayed fish

Coldwater species monitoring and assessment

The provincial BsM program is the primary survey method used to collect fisheries data in Ontario, including certain coldwater species such as lake whitefish, lake trout and brook trout. However, with the exception of lake whitefish and due to various BsM program design factors (e.g. waterbody size and/or type, absence of target species), coldwater species PGT fisheries will not be monitored using the BsM program in FMZ 18.

Strategies:

  • adopt the BsM program as the primary index netting (and effort census) survey to assess lake whitefish population status across the FMZ
  • monitor lake whitefish populations using standard netting protocols (e.g. BsM, SPIN) to assess specific management concerns that arise on lakes not sampled as part of the BsM program
  • develop a monitoring program to determine the state of PGT fisheries
  • implement a monitoring program to assess the status of PGT fisheries across FMZ18
  • support the development of a monitoring program for non-wadeable streams and small rivers
  • develop public/partner opportunities to measure fishing pressure and harvest rates via public reporting (e.g. volunteer angler diary program)
  • determine if water quality and habitat variables in potential FMZ 18 waterbodies are sufficient to support PGT cold or coolwater lakes

Current coldwater species regulations

Regulations for coldwater species in FMZ 18 are consistent with the regulatory guidelines for each species in PGT fisheries, in terms of seasons and catch limits. A year round open season and no size restrictions are currently in place. An aggregate limit of five (5) trout (only two (2) of which can be lake trout) applies to sport licence holders (two (2), with only one (1) of which can be lake trout, for conservation licence holders). As for lake whitefish, a twelve (12) fish limit applies to sport licence holders (six (6) for conservation licence holders).