128 native, 19 introduced fish species in Ontario. ..

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Biodiversity of Fishes on the Boreal Shield in
Ontario

• Class 10
• Presentation 1

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Thanks to

• Nicholas E. MandrakResearch Scientist
• Great Lakes Laboratory forFisheries and Aquatic
  SciencesDepartment of Fisheries and
  OceansBurlington, ON

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Outline

• Defines some of the biological diversity of fresh
  water fishes in Ontario
• What are the threats to fish biodiversity?

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Biodiversity Includes

• Species
• Subspecies
• Populations / Evolutionary Significant Units
  (ESUs)
• Morphotypes
• Assemblages / Communities

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Species
What is Biodiversity?

• 128 native, 19 introduced fish species in
  Ontario.
• Of the 128 species in 24 families, 5 were endemic
  to the Great Lakes
• No species endemic solely to Ontario.
• Greatest fish species richness south of the
  Shield.

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What is Biodiversity?
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Great Lakes Ciscoes
What is Biodiversity?
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Freshwater Fish Richness
What is Biodiversity?
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Species
What is Biodiversity?

• Greatest fish species richness south of the
  Shield. Why?
• Combination of what happened following the last
  Ice Age, current climate and water chemistry.

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evolutionary processes
North America 600 spp.
postglacial dispersal, climate, water chemistry
Northern North America 130 spp.
morphometry, water chemistry
Shield 60 spp.
biotic interactions
Shield Lakes lt30 spp.
modified from Tonn 1990
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Postglacial Dispersal
What is Biodiversity?
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Postglacial Dispersal
Some genes from fish that survived in Beringia
refugia
What is Biodiversity?
Mandrak and Crossman 1992
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Mean Annual Air Temperature
What is Biodiversity?
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Productivity
What is Biodiversity?
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Species
What is Biodiversity?

• Few species found in northern Ontario that are
  not found in south.
• Few exceptions

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What is Biodiversity?
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What is Biodiversity?
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What is Biodiversity?
1 cm
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What is Biodiversity?
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What is Biodiversity?
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Subspecies
What is Biodiversity?

• No longer used by ichthyologists.
• None listed in official names list by American
  Fisheries Society.

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Populations / ESUs
What is Biodiversity?

• Population - group of individuals of single
  species inhabiting specific area, limited gene
  flow with other populations.
• Many populations restricted to single lakes (e.g.
  headwater lakes).
• Evolutionary Significant Units (ESU)
  population, or group of populations, that is
  substantially reproductively isolated and
  represents an important component in the
  evolutionary legacy of the species.
• Populations/ESUs of only a few species in Ontario
  identified, none comprehensively.

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Distributions of mtDNA lineages among lake trout
populations
Wilson and Hubert (1996)
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Morphotypes
What is Biodiversity?

• Individuals of a species may exhibit variation in
  physical characteristics phenotypic variation.
• May be result of
• adaptation to
• different habitats (e.g. sunfishes)
• different prey to minimize competition (e.g.
  ciscoes developing different gill rakers
  depending on food source)
• predation (e.g. sticklebacks with different
  plates on their backs)
• genetic drift caused by
• isolation (founder effect) (e.g. Aurora trout
  isolated in 5 lakes)
• limited gene flow (e.g. lake trout, little
  migration)

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Algonquin Ciscoes
What is Biodiversity?
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Aurora trout
What is Biodiversity?
Aurora trout
Brook trout
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Communities
What is Biodiversity?

• Communities group of interacting species living
  in a specific area, or all species living in a
  given area.
• Assemblages limited to specific taxon (e.g.
  fishes)
• Fish assemblages on Shield
• simpler than south of Shield
• fewer warmwater predators (e.g. basses)

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What are the threats to fish biodiversity?

• Habitat alteration, loss
• Overexploitation
• Introduced species
• Atmospheric pollution

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1. Habitat alteration and loss
Threats to Biodiversity

• Habitat is the physical, chemical and biological
  components in a species environment required for
  survival.

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1. Habitat alteration and loss
Threats to Biodiversity

• In southern Ontario, agriculture and urbanization
• e.g. habitat loss, runoff effects physical
  (turbidity) and chemical (nutrients) quality of
  water.
• In northern Ontario, direct and indirect effects
  of resource extraction.
• e.g. logging directly affects water supply,
  physical (turbidity) and chemical (nutrients)
  quality of water logging roads have perched
  culverts, increased access leads to spread of
  overexploitation, introduced species.
• e.g. mining tailings directly pollute water,
  smelting can lead to acid precipitation.

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1. Habitat alteration and loss
Threats to Biodiversity
Perched culverts
Turbidity
Mine tailings
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2. Overexploitation
Threats to Biodiversity

• Overfishing exceeds natural mortality of
  population, or targets spawning stock (typically
  larger individuals).
• Commercial fishing in larger lakes.
• Recreational fishing in smaller lakes.

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2. Overexploitation
1930s saw demise of commercial catch in L Huron
due to over fishing. Sea lamprey may have had an
effct as well
Threats to Biodiversity
1950s saw demise of ciscoes due to over fishing.
Ciscoes not affected by lamprey
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Great Lakes Ciscoes
Threats to Biodiversity
Extinct
Extirpated in GL
Extirpated in GL
Extinct
Extirpated in GL
Except Superior
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3. Introduced Species

• Species not native to an ecosystem, introduced
  deliberately or accidentally.
• Deliberately through
• authorized stocking (outdated process)
• illegally to establish glory hole for sport or
  bait fishes (seeding lakes)
• releasing unused bait or unwanted aquarium
  fishes.
• Accidentally by ballast water, bait bucket water,
  boats, movement through canals.

Threats to Biodiversity
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Smallmouth Bass
Introduced
Source Checklist of Ontario Freshwater Fishes
Annotated with Distribution Maps
(Mandrak and Crossman 1992)
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Threats to Biodiversity
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(No Transcript)
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Threats to Biodiversity
May have been in L Ontario spread to upper Gt
Lakes after Welland Canal built
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3. Introduced Species
Threats to Biodiversity

• Potential impacts on native species
• Habitat alteration or destruction (e.g. carp
  uproot aquatic plants)
• Competition with, predation on, native species.
  (e.g. lamprey, ruffe)
• Introduction of diseases and parasites (e.g.
  whirling disease in trout)

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Threats to Biodiversity
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Threats to Biodiversity

• ruffe

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Threats to Biodiversity
Using C13/12 ratio gives us idea of trophic
position of fish. Higher ratio higher trophic
position
Vanden Zanden et al. 1999
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Atmospheric Pollution
Threats to Biodiversity

• Anthropogenic contributions to atmosphere can
  have far-reaching (e.g. global) effects on
  aquatic environments.
• Acid precipitation, climate change.

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Acid Precipitation

• Direct effects loss of fish populations
• Numerous indirect effects.

Threats to Biodiversity
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Change in Mean Annual Temperature 1990-2050
Threats to Biodiversity
2C to 5C
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Change in Mean Annual Temperature 1990-2080
Threats to Biodiversity
5C to 8C
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Climate Change
Threats to Biodiversity

• Potential Effects
• Colonization of Shield by warmwater introduced
  species and associated impacts (N.B. requires
  human assistance).
• Negative impacts on cool- and cold- water fishes
  resulting local and regional decline in
  condition, abundance and range.

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Conclusions

• Biodiversity at sub-specific levels largely
  unknown.
• Threats habitat degradation/loss
  overexploitation introduced species atmospheric
  pollution.
• Synergistic interaction of threats likely to be
  exacerbated by climate change.

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Conclusions

• Science Needs
• Identify biodiversity at sub-specific levels.
• Identify limiting factors and threats.
• Identify mitigation and adaptation strategies.
• Protection and Recovery Needs
• Identify gaps in protection .
• Identify and undertake recovery activities.