Species Profile

Enos Lake Limnetic Threespine Stickleback

Scientific Name: Gasterosteus aculeatus
Other/Previous Names: Enos Lake Limnetic Stickleback ,Gasterosteus sp.
Taxonomy Group: Fishes
COSEWIC Range: British Columbia
COSEWIC Assessment Date and Status Change: May 2012
COSEWIC Status: Endangered
COSEWIC Status Criteria: A2ace; B1ab(iii,v)+2ab(iii,v); C2a(ii)
COSEWIC Reason for Designation: This small fish occurs in a single lake in south coastal British Columbia where it has now formed a hybrid swarm with a co-existing stickleback. Although it is possible that a small number of genetically-pure fish still exist in the lake, the ongoing presence of an invasive crayfish, and associated habitat degradation, continue to place this species at a high risk of extinction.
COSEWIC History of Status Designation: Original designation (including both Benthic and Limnetic species) was Threatened in April 1988. Split into two species when re-examined in November 2002 and the Enos Lake Limnetic Threespine Stickleback was designated Endangered. Status re-examined and confirmed in May 2012.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2005-01-12

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Enos Lake Threespine Sticklebacks Non-active Threatened

Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | Recovery Team | National Recovery Program | Documents

Image of Enos Lake Limnetic Threespine Stickleback

Enos Lake Limnetic Threespine Stickleback Photo 1

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Description

Enos Lake Benthic and Limnetic Threespine Sticklebacks (Gasterosteus aculeatus) are one of several unique Stickleback Species Pairs that live in sympatry. Two species are sympatric when they exist in the same area and evolved together from a common ancestor. The two species of Enos Lake Sticklebacks descended from the marine Threespine Stickleback and evolved into separate species by living in different habitats. The benthic species lives in nearshore areas. The limnetic species lives in open water. The divergence from their common ancestor is thought to have occurred because of the limited competition and predation in their habitat after the last glaciation. Habitat or environmental changes can disrupt mating barriers within a species pair and lead to a collapse of the pair into a single hybrid population. This hybrid population is sometimes referred to as a hybrid swarm. In Enos Lake, morphological and genetic studies suggest that Benthic and Limnetic Sticklebacks are no longer distinct species. They collapsed into a hybrid population in the late 1990s. This happened because of habitat changes following the invasion of American Signal Crayfish (Pacifastacus leniusculus). The Enos Lake Limnetic Stickleback was a small, streamlined fish with a light-coloured belly and silver sides. It was typically smaller than the Benthic species. During breeding season, males would have red throats and blue backs. Enos Lake Limnetic Sticklebacks were more heavily armoured than the Benthic species. They had more bony rays in their anal fins and a greater number of gill rakers. (Updated 2017/07/19)

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Distribution and Population

The Enos Lake Stickleback Species Pair is found only in Enos Lake on Vancouver Island in British Columbia, Canada. In 2001, a study found approximately 26,000 mature sticklebacks in Enos Lake. There is substantial hybridization between Enos Lake Benthic and Limnetic Sticklebacks. (Updated 2017/07/19)

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Habitat

Enos Lake is a small coastal lake that covers 17.6 hectares. Its maximum depth is 11 metres. There is no permanent surface drainage into the lake. An outlet drains the lake towards the northwest in the rainy season. Enos Lake Limnetic Sticklebacks primarily lived in open water. Both the Limnetic and Benthic species nested in nearshore beaches. However, Enos Lake Limnetic Sticklebacks preferred to spawn in more open areas than the Benthic species. Natural light was necessary for the species to recognize their mates. Once emerging from nests, Limnetic fry used inshore vegetated areas for food and protection. They eventually moved offshore to open water. Both the Limnetic and Benthic species moved to deeper water habitats to overwinter. After the introduction of American Signal Crayfish, inshore habitat changed drastically. The invasive crayfish removed almost all aquatic vegetation. This likely had a significant effect on the mating barriers between the Benthic and Limnetic species and promoted the collapse of the pair into a single hybrid population. (Updated 2017/07/19)

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Biology

Reproduction in the two species was separated through different spawning areas and breeding times. Enos Lake Limnetic Sticklebacks tended to spawn later in the season and preferred to nest in more open habitat than the Benthic species. These barriers and mate recognition resulted in little hybridization. Enos Lake Limnetic Stickleback males constructed nests. Females produced several clutches of eggs. Limnetic females produced more egg clutches than Benthic females. Males mated with several females and nested more than once in one breeding season. Eggs took up to one week to hatch into larvae. The larvae were free-swimming after another three to five days. Male Enos Lake Limnetic Stickleback guarded their nests until fry were about one week old. Enos Lake Limnetic Stickleback matured at age one. They rarely lived beyond one breeding season. Adults, with exception of nesting males, fed on zooplankton in open water. Their mouths were adapted for this feeding style. Predators of the Enos Lake Limnetic Stickleback included fish-eating birds such as Great Blue Heron (Ardea herodias) and Belted Kingfisher (Megaceryle alcyon), and Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii). Young Enos Lake Limnetic Sticklebacks were also preyed on by invertebrates. Few, if any, pure Enos Lake Limnetic Stickleback currently exist in Enos Lake. (Updated 2017/07/19)

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Threats

The American Signal Crayfish got established in Enos Lake in the 1990s. Following its invasion, aquatic vegetation disappeared from the lake and the number of Limnetic-Benthic hybrids increased in the lake. The species pair now exists as a single hybrid population. The American Signal Crayfish may have affected the Enos Lake Stickleback Species Pair through changing vegetated habitat, displacement from nesting habitat, predation and competition. Current threats to the species include more invasive species, water use and land use. Additional introductions of species are possible. For example, Brown Bullhead (Ameiurus nebulosus), Largemouth and Smallmouth Basses (Micropterus salmoides and M. dolomieu), Pumpkinseed (Lepomis gibbosus), and Yellow Perch (Perca flavescens) may be spread by anglers and other members of the public. In most regions of British Columbia, the probability of invasive species becoming established after release to a new location is high or very high. Existing water licences allow both water storage and diversion from Enos Lake. These have raised lake levels because of a dam at the outlet and increased annual drawdowns. This could threaten the species by reducing spawning and feeding habitat. Also, the Enos Lake watershed is currently being developed for residential use. Increases in sedimentation and loss of riparian habitat associated with these developments are a concern for the species. (Updated 2017/07/19)

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Protection

Federal Protection

The Enos Lake Limnetic Threespine Stickleback is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.

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Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for Paxton Lake, Enos Lake, and Vananda Creek Stickleback Species Pairs (Gasterosteus spp.) in Canada
Status Final posting on SAR registry

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Recovery Team

Pacific Region Species at Risk Program - Enos Lake Limnetic Threespine Stickleback

  • DFO Pacific Region - MPO région du Pacifique - Chair/Contact - Fisheries and Oceans Canada
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Recovery Progress and Activities

The Enos Lake Limnetic Stickleback was assessed as Endangered in 2002 and reassessed as Endangered in 2012 by COSEWIC. The species was listed under the Species at Risk Act in January 2005. A Recovery Strategy that addresses the Paxton Lake, Vananda Creek, and Enos Lake Stickleback Species Pairs was posted in 2007. The Recovery Strategy identifies threats, population and distribution objectives and broad approaches to recovery for the six species. Researchers have investigated the relationship between American Signal Crayfish and the Enos Lake Stickleback Species Pair. Stewardship groups also contribute outreach and education activities, and management activities to recovery the Enos Lake Stickleback Species Pairs. For example, the Nanoose Naturalists developed and submitted an Enos Lake Water Management Plan to the key landowner in the watershed. They also developed a management plan that addresses water quality for the Enos Lake Stickleback Species Pair. (Updated 2017/07/19)

Documents

PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

25 record(s) found.

Reports on the Progress of Recovery Document Implementation

  • Report on the Progress of Recovery Strategy Implementation for the Paxton Lake, Enos Lake, and Vananda Creek Stickleback Species Pairs (Gasterosteus aculeatus) in Canada for the Period 2007 – 2015 (2016-10-12)

    The Paxton Lake and Vananda Creek Stickleback Species Pairs were assessed as Endangered in 2000, and again in 2010 by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC 2010a and 2010b). The Enos Lake Stickleback Species Pair was assessed as Endangered in 2002, and again in 2012 (COSEWIC 2012). The Enos Lake, Paxton Lake, and Vananda Creek Stickleback Species Pairs were listed under the Species at Risk Act as Endangered in June of 2003. In October of 2007 the final Recovery Strategy for Paxton Lake, Enos Lake, and Vananda Creek Stickleback Species Pairs (Gasterosteus spp.) in Canada (NRTSSP 2007) was posted to the Species at Risk Public Registry. Fisheries and Oceans Canada, in cooperation with the Province of British Columbia’s Ministry of Environment, is developing an Action Plan for the Paxton Lake and Vananda Creek Stickleback Species Pairs as part of the Government of Canada’s ongoing commitment to the conservation of species at risk through the implementation of the Species at Risk Act.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Enos Lake Benthic and Limnetic Threespine Stickleback Species Pair Gasterosteus aculeatus in Canada (2013-01-03)

    The Enos Lake Benthic and Limnetic Threespine Sticklebacks were small-bodied (up to about 60 millimetres total length) freshwater fish species derived from the marine Threespine Stickleback. They were one of a handful of sympatric, reproductively isolated species pairs that occur in lakes in a restricted area of the Strait of Georgia, southwestern British Columbia. Limnetics primarily exploit plankton, and had traits that are considered adaptations to a zooplankton-consuming lifestyle. Benthics had traits that are considered to be advantageous in benthic feeding.
  • COSEWIC assessment and update status report on the Enos Lake stickleback species pair Gasterosteus spp. in Canada (2002-12-24)

    Sticklebacks in Enos Lake independently evolved into limnetic and benthic populations. Populations in four other lakes near Georgia Strait similarly possess limnetic/benthic species pairs. Those in Hadley Lake have already become extinct. Historically, Enos benthic and limnetics typically exhibited <1-2% hybridization. During 1999 or 2000, hybridization rates reached 12%. Unpublished data of University of British Columbia researchers suggest hybridization could have approached 20%. Limnetics are more slender and have longer gill rakers adapted for capturing plankton than have bottom feeding benthics. Gene loci and associated allozyme frequencies distinguish these populations and suggest distinct Evolutionary Significant Units. Although other Gasterosteus populations may share similar morphology and feeding strategies, none have trophic or reproductive isolating mechanisms allowing such close sympatry as those described in this report. Instances of hybridization were deduced in large part on morphological traits that are found in limnetic/benthic species pairs. Allozyme frequencies and mitochondrial DNA demonstrate genetic differences between limnetic and benthic populations. D. Schluter, University of British Columbia, provided much of the significant information. Some genetic analyses on Enos stickleback hybridization were not available or complete at the time of writing this report.

Response Statements

  • Response Statement - Enos Lake Limnetic Threespine Stickleback (2013-01-03)

    This small fish occurs in a single lake in south coastal British Columbia where it has now formed a hybrid swarm with a co-existing stickleback. Although it is possible that a small number of genetically-pure fish still exist in the lake, the ongoing presence of an invasive crayfish, and associated habitat degradation, continue to place this species at a high risk of extinction.
  • Response Statements - Limnetic Enos Lake Stickleback (2004-04-21)

    A response statement is a communications document that identifies how the Minister of the Environment intends to respond to the assessment of a wildlife species by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The document provides a start to the listing and recovery process for those species identified as being at risk, and provides timelines for action to the extent possible.

Recovery Strategies

  • Recovery Strategy for Paxton Lake, Enos Lake, and Vananda Creek Stickleback Species Pairs (Gasterosteus spp.) in Canada (2019-08-21)

    The fish known collectively as “stickleback species pairs” are small, freshwater fish descended from the marine threespine stickleback (Gasterosteus aculeatus). Their recent and unique evolutionary history has been of considerable scientific interest and value. Stickleback species pairs were known to exist in four watersheds in the Georgia Basin, British Columbia: two watersheds on Texada Island, and one each on Lasqueti and Vancouver Islands. Within the last decade the species pair on Lasqueti Island has been declared extinct, and the species pair in Enos Lake has collapsed into a single hybrid swarm. The present global range is therefore restricted to four small lakes in two watersheds on northern Texada Island.

Orders

  • Order Acknowledging Receipt of the Assessments Done Pursuant to Subsection 23(1) of the Species at Risk Act (2004-04-21)

    This Order acknowledges receipt by the Governor in Council of the assessments of the status of wildlife species done pursuant to subsection 23(1) of the Species at Risk Act (SARA) by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The purpose of SARA is to prevent wildlife species from being extirpated or becoming extinct, to provide for the recovery of wildlife species that are extirpated, endangered or threatened as a result of human activity and to manage species of special concern to prevent them from becoming endangered or threatened.
  • Order Amending Schedule 1 to the Species at Risk Act (volume 146, number 14, 2012) (2012-07-04)

    The purpose of the Order Amending Schedule 1 to the Species at Risk Act is to add 18 species to Schedule 1, the List of Wildlife Species at Risk (the List), and to reclassify 7 listed species, pursuant to subsection 27(1) of SARA. This amendment is made on the recommendation of the Minister of the Environment based on scientific assessments by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and on consultations with governments, Aboriginal peoples, stakeholders and the Canadian public.
  • Order Amending Schedules 1 to 3 to the Species at Risk Act (volume 139, number 2, 2005) (2005-01-12)

    Schedule 1, the List of Wildlife Species at Risk of the Species at Risk Act (SARA), is amended by Order of the Governor in Council (GIC), on the recommendation of the Minister of the Environment, by the addition of 73 species. This Order is based on scientific assessments by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and follows consultations with provincial and territorial governments, Aboriginal peoples, stakeholders and the public, and analysis of costs and benefits to Canadians.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2003 (2003-10-01)

    May 2003 Annual Report to the Canadian Endangered Species Conservation Council by the Committee on the Status of Endangered Wildlife in Canada.
  • COSEWIC Annual Report - 2011-2012 (2012-10-05)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (September 1, 2011 to September 30, 2012) from November 21 to 25, 2011 and from April 29 to May 4, 2012. On February 3, 2012, an Emergency Assessment Subcommittee of COSEWIC also assessed the status of the Tri-colored Bat (Perimyotis subflavus), the Little Brown Myotis (Myotis lucifugus), and the Northern Myotis (Myotis septentrionalis). During the current reporting period COSEWIC assessed the status or reviewed the classification of 67 wildlife species. For species already found on Schedule 1 of SARA, the classification of 32 species was reviewed by COSEWIC and the status of the wildlife species was confirmed to be in the same category (extirpated - no longer found in the wild in Canada but occurring elsewhere, endangered, threatened or of special concern). The wildlife species assessment results for the 2011-2012 reporting period include the following: Extinct: 1 Extirpated: 4 Endangered: 29 Threatened: 10 Special Concern: 15 Data Deficient: 2 Not at Risk: 6 Total: 67 Of the 67 wildlife species examined, COSEWIC reviewed the classification of 49 species that had been previously assessed. The review of classification for 26 of those species resulted in a confirmation of the same status as the previous assessment (see Table 1a).

Permits and Related Agreements

  • Explanation for issuing permit(#19-PPAC-00007 ), persuant to the provisions of section 73 of SARA (2019-04-01)

    Incidental catch and release of Enos Lake Threespine Sticklebacks (Benthic or Limnetic) during the removal of a sample of 100 hybrid Threespine Stickleback (50 male and 50 female) from Enos Lake for scientific research. The above sampling will be conducted using seine nets, dip nets, or minnow traps.
  • Explanation for issuing permit(#19-PPAC-00019 ), persuant to the provisions of section 73 of SARA (2019-06-15)

    Incidental catch and release of Enos Lake Benthic Threespine Stickleback and/or Enos Lake Limnetic Threespine Stickleback during the removal of a sample of 300 hybrid Threespine Stickleback from Enos Lake for scientific research. Sampling will be conducted using minnow traps and/or dip nets.
  • Explanation for issuing permit(#20-PPAC-00002 ), persuant to the provisions of section 73 of SARA (2020-05-15)

    Incidental catch and release of Enos Lake Benthic Threespine Stickleback and/or Enos Lake Limnetic Threespine Stickleback during the removal of a sample of up to 500 hybrid Threespine Stickleback from Enos Lake for scientific research. Sampling will be conducted using minnow traps and/or seine nets.
  • Explanation for issuing permit(#20-PPAC-00006 ), persuant to the provisions of section 73 of SARA (2020-04-01)

    The activities authorized by this permit consist of incidental catch and release of Enos Lake Threespine Sticklebacks (Benthic or Limnetic) during the removal of a sample of 100 hybrid Threespine Stickleback (50 male and 50 female) from Enos Lake for scientific research. The above sampling will be conducted using seine nets, dip nets, or minnow traps.
  • Explanation for issuing permit(#21-PPAC-00008 ), persuant to the provisions of section 73 of SARA (2021-04-01)

    The activities authorized by this permit consist of: Incidental catch and release of Enos Lake Benthic Threespine Stickleback and/or Enos Lake Limnetic Threespine Stickleback during the removal of 50 male and 50 female hybrid Threespine Stickleback from Enos Lake for scientific research. Sampling will be conducted using seine nets, dip nets, and/or minnow traps.
  • Explanation for issuing permit(#DFO-18-PPAC-00007), persuant to the provisions of section 73 of SARA (2018-04-01)

    Incidental catch and release of Enos Lake Threespine Sticklebacks (Benthic or Limnetic) during the removal of a sample of 300 hybrid Threespine Stickleback (150 male and 150 female) from Enos Lake for scientific research.
  • Explanation for issuing permit(#DFO-PAF SARA 121), persuant to the provisions of section 73 of SARA (2009-03-17)

    Authorized representatives of the University of BC will sample individuals from each stickleback population above for sampling/laboratory testing in order to; understand the impact of alien crayfish on limnetic and benthic nesting behaviour/success; and determine the potential role of macrophytes in spatial segregation and reproductive isolation. Euthanasia of limited numbers of sticklebacks is required for analysis, and to reduce the spread of pathogens potentially acquired in a laboratory setting. The ultimate goal is to aid in the recovery of these species at risk by understanding the cause of hybridization in Enos Lake, which will also help inform appropriate management of other stickleback lakes to ensure that they do not suffer a similar fate.
  • Explanation for issuing permit(#DFO-PAF SARA 190), persuant to the provisions of section 73 of SARA (2010-09-02)

    Authorized representatives of Michigan State University (MSU) will collect individuals from each population above for laboratory testing in order to determine egg fertilization success for sticklebacks within and between species. Euthanasia of limited numbers of sticklebacks is required for analysis, and to reduce the spread of pathogens potentially acquired in a laboratory setting. The ultimate goal of the activities is to assist in the recovery of Enos Lake sticklebacks by informing what maintains this species' reproduction.
  • Explanation for issuing permit(#DFO-PAF SARA 201), persuant to the provisions of section 73 of SARA (2011-03-01)

    Authorized representatives of Michigan State University will collect fish using minnow traps and dip nets in order to understand (1) behavioral observations to study mating interactions and impacts of habitat loss, (2) behavioral observations to study female mate choice based on experience, and (3) artificial crosses to examine gametic and genetic barriers between the species. The ultimate goal of the activities is to assist in the recovery of this species by achieving a better understanding how limnetic and benthic stickleback species pairs diverged and how we can promote conservation efforts.
  • Explanation for issuing permit(#DFO-PAF SARA 282), persuant to the provisions of section 73 of SARA (2013-06-01)

    Authorized representatives of the University of British Columbia will carry out sampling, preservation, and morphological analysis in order to assess the degree of hybridization between Enos Lake Threespine Stickleback benthic and limnetic forms. The ultimate goal of the activities is to assist in the recovery of this species by definitively determining whether hybridization has occurred, creating a more quantitative environment to conduct a status assessment.
  • Explanation for issuing permit(#DFO-PAF SARA 289), persuant to the provisions of section 73 of SARA (2013-04-02)

    Authorized representatives of Michigan State University will collect fish to conduct research to understand plasticity of mate choice and effect of demography, and to measure sexual selection and sexual isolation to understand forward and reverse speciation. The ultimate goal of the activities is to assist in the recovery of this species by achieving a better understanding how limnetic and benthic stickleback species pairs diverged and how to promote conservation efforts.
  • Explanation for issuing permit(#SECT 04 SCI 016), persuant to the provisions of section 73 of SARA (2004-12-10)

    The work involves observations and experiments on foraging, growth, survival, predator evasion, parasite resistance, mating cues, and genetics. Goals are to 1) describe the differences between species in body size, shape, colour, behaviour and environment; 2) identify distinguishing genes; 3) understand mating incompatibilities and the primary barrier to gene flow between sympatric stickleback species; 4) correlate these differences with environmental features; 5) understand the role of natural selection generated by competition, predation, and parasitism; 6) measure environmental features that are necessary for the long-term persistence of species pairs. The work will establish a baseline for management and tracking of future changes to the stickleback species pairs. Field Sampling of wild fish from the lakes using minnow traps, dip and seine nets, followed by laboratory work. Live specimens collected from the field or made from crosses between wild caught fish will be kept in aquaria. Fish will be raised from eggs and those used in genetic studies will be raised to adult size.
  • Explanation for issuing permit(#SECT 08 SCI 002), persuant to the provisions of section 73 of SARA (2008-04-04)

    Goals of 2008 include: 1) laboratory crosses to identify the genes that distinguish populations and species; 2) association mapping in Enos Lake to identify genes that distinguish populations and species; 3) modest field collections to supplement local brood stocks; 4) measurements of body coloration in the visible and ultraviolet range; 5) studies of the adaptive significance of pelvic girdle loss in the benthic species.

Consultation Documents

  • Species at Risk Act - Legal Listing of Aquatic Species, Pacific Region - Consultation Workbook (2004-03-17)

    Your opinion is being sought to assist the government of Canada in making an informed decision on whether to add any or all of the following 10 aquatic species to the Schedule 1 (the List of Wildlife Species at Risk) of the Species at Risk Act (SARA). The species include: Blue Whale, Sei Whale, Humpback Whale, Enos Lake Stickleback, Speckled Dace, Salish Sucker, Cultus Lake Sockeye, Interior Fraser Coho, Sakinaw Lake Sockeye, and Bocaccio. Your input on the impacts of adding these species to the List is important. This workbook has been developed to give you an opportunity to provide Fisheries and Oceans Canada with your feedback, advice, and other comments regarding adding the above mentioned 10 species to Schedule 1 of SARA (Schedule 1 identifies which species are legally protected under SARA).
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