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Recovery Strategy for the Aurora Trout in Canada [Proposed]

2. Recovery

1.  Recovery Goals Objectives and Approaches:

a)  Recovery Goals:

Although historical data on population and biomass was not available for the native lakes, the recovery team was able to develop recovery goals for aurora trout.  These goals are based on a knowledge of brook trout populations in similar oligotrophic waters, the current population and biomass in the native lakes and a realization that re-acidification is the principle threat to the populations.

The primary long-term goal of this recovery strategy is:

To maintain secure self-sustaining aurora trout populations in both native lakes (Whirligig Lake and Whitepine Lake) at a minimum biomass target of 13 kg/hafor Whirligig Lake and 12 kg/ha for Whitepine Lake; a density of adult fish of 29 fish/ha for Whirligig Lake and 20 fish/ha for Whitepine Lake; and an age class structure that demonstrates no missing year classes.  These targets must be achieved in the absence of any further human intervention (e.g. liming).

The values above represent the lower end of the 95% confidence interval for the biomass and adult population estimates from the 2003 field survey (to recognize statistical uncertainty in the population estimates).  This survey was completed more than 10 years after aurora trout were re-introduced to the native lakes and it is assumed that the populations are now stable.

It is the contention of the recovery team that the above identified targets should be achieved without the requirement for further whole lake liming for at least 10 years.  If this occurs, aurora trout could potentially be considered for down-listing or de-listing by COSEWIC.

In addition to the primary goal, three further secondary recovery goals have been identified:

  1. To establish a secure self-sustaining aurora trout population in one or two non-native, well-buffered lakes to act as a wild brood stock refuge to the native populations in Whitepine and Whirligig lakes;
  2. To clarify the taxonomic status of aurora trout, that is to determine if aurora trout are distinguishable from brook trout at the molecular genetic level
  3. To maintain the captive breeding program.

The recovery team believes it is necessary to establish a viable self-sustaining aurora trout population in a waterbody secure from known threats.  The chosen waterbody will act as a wild brood stock refuge in the event of re-extirpation in the native waters or an unforeseen event that may compromise the captive breeding program.  If no significant genetic differences are found between aurora trout and brook trout, then aurora trout could be considered for de-listing by COSEWIC or could be listed as a specific race or population rather than as a separate sub-species.  Even if no genetic differences are found, aurora trout would still be managed by OMNR as a unique component of Ontario’s biodiversity on the basis of their phenotypic differences.

b)  Short-term Recovery Objectives:

The following short-term recovery objectives provide the focus for recovery initiatives over the next 3 to 5 year period (2005-2010).  These objectives will be accomplished by the formation of a number of Recovery Implementation Groups (RIGs).  The ATRT will continue to act as an overseer RIG, but will establish a number of task-oriented RIGs to assist in implementing the various aspects of this recovery strategy.

1) The RIGs will ensure continuation of the long-term data collection and monitoring of water quality, trophic level food chains and the status of the re-established aurora trout populations within Whirligig and Whitepine lakes. This protocol is to expand to include data collection and monitoring of any future waters where a self-sustaining, non-native population is established.

2) A Genetics RIG will conduct an examination of molecular genetic data utilizing the most advanced techniques and newest molecular markers (such as nuclear ITS region or gene introns).  The purpose of these studies is to determine if aurora trout are genetically distinct from brook trout; to initiate investigations into potential genetic inbreeding depression; and to provide a recommended course of action(s) to reduce impacts if inbreeding is deemed to be a threat.

3) A science-based RIG will:

  1. Ensure that data and analyses for the native lake field assessments are completed and the results are documented in a timely manner to provide guidance for future action planning.  Past data and analyses will be synthesized into a report so that the pertinent information is more readily available;
  2. Complete critical load modeling for sulphate deposition in the native lakes that would maintain a pH above 5.0;
  3. Conduct detailed spawning habitat assessments in Whitepine Lake.  Only general locations are known in Whitepine Lake at the present time.  Groundwater flow measurements are also required for Whirligig Lake;
  4. Develop a suite of criteria based upon the habitat requirements of aurora trout to assist managers in the identification of suitable waters for the establishment of one or two non-native aurora trout populations.  If established such populations could act as a wild brood stock refuge to minimize the risk to aurora trout viability in the event of a catastrophic loss within the captive breeding program or the re-extirpation of the native lakes;
  5. Assist with the establishment of such a wild brood stock population(s);
  6. Develop a breeding strategy which applies knowledge established from Short-term Objective #2 (above). 

4)    An approved recovery strategy will allow the continuation of the limited recreational angling opportunities, as well as any lethal sampling that may be required for either scientific or for fish health purposes (for additional details, see Section 12 – Activities Permitted by the Recovery Strategy). 

5)    A communications based RIG will:

  1. Develop and implement a communications plan to engage the cooperation of potential stakeholder partners including other government agencies, industry, environmental groups and the public;
  2. Revise, deliver and monitor an educational campaign to measure the success of maintaining the specially regulated recreational angling opportunities for aurora trout.  This is a means of increasing public awareness and generating support for species at risk in general;
  3. Update existing and create new brochures, videos, displays and websites as necessary to facilitate recovery messages;
  4. Review and update the provincial aurora trout policy and legislation to provide protection to all aurora trout populations and the watersheds they inhabit.

c)  Approaches for Recovery:

The broad approaches identified for recovery efforts include Legislation and Policy, Research, Habitat Management and Population Management.  Proposed actions related to each approach are detailed in Table 2.

2. Critical Habitat:

a) Identification of the Species’ Critical Habitat: 

This recovery strategy identifies both native lakes, Whirligig Lake and Whitepine Lake, as the Critical Habitat for the recovery of aurora trout.  A whole lake approach has been taken, rather than a habitat feature-based approach, given that the habitat requirements of the species depend on the lakes being treated as a holistic system.  This approach is prudent due to the small size of the native lakes and is reasonable given that they are located in a protected area – Lady Evelyn-Smoothwater Provincial Park (a wilderness class park).

b) Examples of Activities Likely to Result in Destruction of Critical Habitat:

The two native lakes are located within the boundaries of a wilderness class park so they are protected from land use activities (e.g. resource extraction such as forestry or mining, road building, urban development, etc.) that would otherwise be of concern due to potential negative impacts to critical habitat.  They do, however, continue to remain susceptible to acidification due to industrial emissions and this must be monitored closely.

Both lakes are also provided some protection through the application of the Timber Management Guidelines for the Protection of Fish Habitat.  In addition, the Federal Fisheries Act provides general fish habitat protection.  All lakes are protected from the harmful alteration, disruption or destruction of fish habitat under this Act. 

c) Schedule of Studies:

In the opinion of the recovery team, sufficient information exists to warrant the proposal of identifying whole waterbodies as critical habitat for the native lakes (Section 6 (a)).  However, studies are required to fully document the spawning habitat location(s) in Whitepine Lake and to identify ground water flow rates in both native lakes.  Additional consideration related to defining critical habitat for the non-native lakes needs to be given, particularly for lakes that are expected to be maintained through natural reproduction.  Monitoring for natural reproduction in any newly introduced lake will be required.  If natural reproduction is found in one of the non-native lakes, critical habitat components such as spawning sites could be added as an amendment to this strategy as the location of these sites are identified.  If it is determined that the designation of critical habitat is advantageous in the stocked lakes, habitats within these lakes could also be added through an amendment to this strategy.

Alexander Lake and the other lakes that are to be used for the establishment of self-sustaining, non-native populations (e.g. Southeast Campcot Lake and/or Northeast Campcot Lake) will not be identified as critical habitat for the species at this time  As additional studies are completed to determine the specific habitat requirements of aurora trout, habitat components in the non-native lakes can be identified as critical habitat through an amendment to this strategy.

3. Effects on Other Species:

Prior to extirpation, but during the latter stages of decline, Sale (1964) noted that aurora trout in Whitepine Lake co-existed with brook trout and white sucker (Catostomuscommersoni) and only with white sucker in Whirligig Lake.  No other fish species were apparent.  He reported the invertebrate fauna to be typical of lakes in the area with Chironomidae, Trichoptera, Odonata, Notonectidae and Gyrinidae present; however, zooplankton (Copepod and Cladocera) were present in only small numbers and Gammarus were missing.  Crayfish (Orconectes sp.) were also present. 

Presently, the self-sustaining re-introduced aurora trout populations are the only fish species within the two native lakes.  Assessments of invertebrate communities were conducted after each liming treatment in Whirligig Lake to determine the impacts of the treatments on the biota.  Species richness and abundance increased after each liming treatment, but overall the species composition reflects that of low productivity environments (E. Snucins, pers. comm.).  The number of phytoplanktontaxa almost doubled by the mid-1990s, while zooplankton species have only slightly increased compared to their pre-liming abundance.  Known acid-sensitive species are rare or absent, but acid-tolerant species, especially larger cladocerans, which are preferred prey for planktivorous species like aurora trout, are present in large numbers.  Odonata have declined.  Ephemeroptera on the other hand have increased due to an increase in the abundance of an existing species (Leptophlebia sp.) and the successful colonization of an acid-sensitive species (Stenacron interpunctatum) (Carbone et al. 1998). 

In instances where aurora trout are being considered for introduction into non-native waters it is anticipated there will be some level of impact.  It is recommended in each instance that a pre- and post-assessment of the abiotic factors and biotic community be completed in order to determine if any negative impacts resulted and their extent.  Prior to any future introduction, a Class EA for Resource Stewardship and Facility Development Projects will have to be completed for any lake situated on Crown Land, or the Class EA for Provincial Parks and Conservation Reserves would have to be completed for any lake within a Provincial Park or Conservation Reserve.  As well, the risk assessment screening process outlined in the National Code on Introductions and Transfers of Aquatic Organisms would have to be completed.  Class EA’s have been completed for all recent introductions of aurora trout.  As of the writing of this report, a Class EA and risk assessment screening is currently being completed for one new aurora trout lake (Timmins #57 Lake).  No other introductions have occurred since the inception of the National Code in September 2003.

4. Recommended Scale for Recovery:

The aurora trout is ideally suited to an individual species recovery planning effort since it has a very restricted native range and occurred naturally within simple fish communities.  There is no other ‘at risk’ or rare species occupying the same lakes or watershed to permit consideration of a multi-species recovery planning process.  Since Lady Evelyn-Smoothwater Provincial Park is in the process of developing a management plan there will be opportunities to compliment recovery actions (related to the two native lakes) with park activities and policies.

5. Statement of When One or More Action Plans in Relation to the Recovery Strategy Will Be Completed:

An action plan, in the form of the provincial aurora trout Management Plan, has been guiding recovery actions since 1983.  This plan, produced by the aurora trout Management Committee, has been revised twice - once in 1993 for the operating period 1994 - 2004, and a second time in 2000 for the period 2000-2010.  The current Management Plan is to be reviewed and updated to ensure that it meets the requirements of a Recovery Action Plan under theSpecies At Risk Act within one year of the approval of this Recovery Strategy.  The Recovery Action Plan will provide additional details on the recovery tasks to be completed, the sampling and management protocols to be followed and the timing and frequency of the tasks such as monitoring and assessment.

Since the inception of the first aurora trout Management Plan in 1983, the aurora trout Management Committee (referred to as the ATRT in this strategy) has operated similar to an overseer RIG.  The current structure and role of the ATRT is expected to continue for decision-making and guiding management actions with respect to recovery initiatives.  Given the recovery direction identified within this strategy, it is likely that the ATRT will continue to act as an overseer RIG, but will establish task-oriented RIGs to deal with each of the broader approaches identified in Section 6 (b).

6. Evaluation:

Success of this recovery strategy will be evaluated through the establishment of specific lake monitoring programs and through the results of applied research.  The evaluation will be carried out by the appropriate RIG, but must achieve the following:

  • long-term maintenance of self-sustaining aurora trout populations attaining stated biomass, year class presence, and spawning age density targets in the goal statement;   
  • no further human intervention required to manipulate water quality within the native lakes.  Specifically, intervention in the form of further liming treatments to ensure a pH of at least 5.0 should not be necessary;
  • successful establishment of one (or more) self-sustaining, non-native aurora trout populations;
  • clarification of the taxonomic status of aurora trout;
  • success in achieving further reductions in sulphate and other industrial emissions;
  • development of a captive breeding strategy, including potential solutions for reducing the threat of inbreeding depression and maximizing the reproductive fitness potential of aurora trout; and
  • reporting on the establishment of new recovery partners and partnerships, general public awareness of aurora trout, number of media contacts, anglers utilizing the limited recreational angling opportunities, etc.

7. Activities Permitted by the Recovery Strategy

As set out in subsection 83(4) of the Species at Risk Act, a person can engage in an otherwise prohibited activity if the activity is permitted by a recovery strategy and the person is authorized under an Act of Parliament to engage in that activity.

a)  Continuation of Limited Sport Angling Opportunities

This recovery strategy permits holders of a sports fishing license issued under the regulations of the Fish and Wildlife Conservation Act to participate in the trophy sport fisheries for Aurora Trout as per the regulations set out under theOntario Fishery Regulations, 1989 pertaining to the recreational fishery of Aurora Trout.

For a number of years, OMNR has maintained a maximum of nine put-grow-and-take aurora trout lakes to increase public awareness and generate public and stakeholder support for the aurora trout recovery program (and species at risk in general).  These lakes provide limited trophy sport fisheries that are tightly regulated and operate on a seasonal, rotational basis.  Only a maximum of three lakes may be open in any one year and each may only be open once in every three years for the period August 1st to October 15th, with a catch and possession limit of one fish.  The permissible exploitation rate for the aurora trout in non-native lakes should not exceed the catch and possession limit of one per day.  These lakes are maintained by stocking fry, fingerlings or adults fish (depending upon availability) from Hills Lake Fish Culture Station.

The angling opportunities are currently regulated under theOntario Fishery Regulations, 1989 (under the federal Fisheries Act) and are allowed through a sports fishing license issued under the regulations of the Fish and Wildlife Conservation Act.  The sport fisheries utilize surplus hatchery fishes not required for the ‘wild’ brood stock lake or the establishment of self-sustaining, non-native refuge lake (note – the native lakes are supported by natural reproduction and are not presently stocked).  The harvest of fish from the angling lakes does not jeopardize the recovery of aurora trout in the wild because the fisheries are based solely on fish raised in the hatchery and there is no natural reproduction in these lakes.  The two native aurora trout lakes have been permanently closed to angling under the Ontario Fishery Regulations since 1950.

b)  Field Sampling

This recovery strategy permits persons authorized under a Licence to Collect Fish for Scientific Purposes issued under theOntario Fishery Regulations, 1989, and OMNR staff undertaking fisheries management initiatives as part of their job to engage in field sampling of Aurora trout for the purposes described below and in accordance with authorized methods.

A sampling program is necessary to monitor the status and health of aurora trout populations found in both the native lakes and the non-native lakes.  It is recommended that the native populations be sampled at least once ever five years and more frequently if the populations appear to be threatened by re-acidification or some other stress.  Sampling in Whitepine and Whirligig lakes will provide information that is critical to managing and ensuring the viability of these populations.  Parameters monitored include: population estimates, biomass estimates, growth rate, age class structure, sex ratios, etc.  Field sampling is also used to acquire genetic samples for analysis.  In the non-native lakes it may periodically be necessary to complete sampling protocols to ensure that the populations are safe from extirpation or to determine if natural reproduction is occurring.  For example, it will be important to closely monitor the introduced population in Southeast Campcott Lake.  This population was extirpated once before for unknown reasons.  Additional monitoring may allow extirpation to be avoided this time and could assist in explaining the cause of the past extirpation.

Past sampling was completed by OMNR’s partners under the authority of a Licence to Collect Fish for Scientific Purposes issued under the Ontario Fishery Regulations, 1989.  OMNR staff do not require this permit while undertaking fisheries management initiatives as part of their job.  Generally, field sampling has used non-lethal methods of capturing fish so that they can be released unharmed.  Periodically it may be necessary to use lethal sampling methods (e.g. for fish health and disease testing).

c)  Sampling for Genetic Studies

This recovery strategy permits persons authorized under a Licence to Collect Fish for Scientific Purposes issued under theOntario Fishery Regulations, 1989, and OMNR staff undertaking fisheries management initiatives as part of their job to engage in  sampling for genetic studies of Aurora trout for the purposes described below and in accordance with authorized methods.

As mentioned throughout this strategy, there are several important genetic questions that need to be answered to ensure the successful recovery of aurora trout.  First, it is necessary to determine the taxonomic status of aurora trout.  The results of these studies are also important for determining what management options are available to maximize the genetic diversity of aurora trout.  Analyses are required to determine the most genetically diverse fishes for developing a breeding strategy and to determine if genetic diversity is changing over time in the native and hatchery populations.  Generally, genetic samples are taken using non-lethal means under a Licence to Collect Fish for Scientific Purposes issued under the Ontario Fishery Regulations, 1989.  As mentioned previously, OMNR staff do not require this permit.

If aurora trout are not distinct from brook trout, management options such as backcrosses of aurora trout with brook trout may be considered to increase the diversity of aurora trout.  Currently, studies are ongoing to investigate the survival and fitness of backcrosses versus pure strain aurora trout.  To date these studies have been maintained entirely within the hatchery environment, although in the future it may be desirable to determine how these strains perform over several generations in a lake environment.  Another option would be to infuse brook trout genes into aurora trout to increase diversity.  Aurora trout with brook trout genes are to be solely maintained in the hatchery until the taxonomy of aurora trout is clarified.  No matter the taxonomic status of aurora trout, backcrosses and/or aurora trout with infused brook trout genes would not be stocked into the native lakes.