Download Freshwater Fish Richness

Biodiversity of Fishes
on the Boreal Shield
in Ontario
Class 10
Presentation 1
Thanks to
Nicholas E. Mandrak
Research Scientist
Great Lakes Laboratory for
Fisheries and Aquatic Sciences
Department of Fisheries and Oceans
Burlington, ON
Outline
 Defines
some of the biological diversity of
fresh water fishes in Ontario
 What are the threats to fish biodiversity?
Biodiversity Includes
 Species
 Subspecies
 Populations
/ Evolutionary Significant
Units (ESUs)
 Morphotypes
 Assemblages / Communities
What is Biodiversity?
Species
 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.
What is Biodiversity?
Minnows
Salmons and Trouts
Perches
Suckers
Sunfishes
Catfishes
Sculpins
Lampreys
Sticklebacks
Gars
Herrings
Pikes
Gobies
Mooneyes
Temperate Basses
Topminnows
Bowfin
Cods
Drums
Eels
Mudminnows
Silversides
Smelts
Sturgeons
Trout-perches
Paddlefishes
Native
Introduced
0
5
10
15
20
No. of Spp.
25
30
35
40
What is Biodiversity?
Great Lakes Ciscoes
What is Biodiversity?
Freshwater Fish Richness
What is Biodiversity?
Species
 Greatest
fish species richness south of the
Shield. Why?
 Combination of what happened following
the last Ice Age, current climate and water
chemistry.
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
<30 spp.
modified from Tonn 1990
What is Biodiversity?
Postglacial Dispersal
What is Biodiversity?
Some genes
from fish that
survived in
Beringia refugia
Postglacial Dispersal
Mandrak and Crossman 1992
What is Biodiversity?
Mean Annual Air Temperature
What is Biodiversity?
Productivity
What is Biodiversity?
Species
 Few
species found in northern Ontario that
are not found in south.
 Few exceptions
What is Biodiversity?
What is Biodiversity?
1 cm
What is Biodiversity?
What is Biodiversity?
What is Biodiversity?
What is Biodiversity?
Subspecies
 No
longer used by ichthyologists.
 None listed in official names list by
American Fisheries Society.
What is Biodiversity?
Populations / ESUs

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.

Distributions of mtDNA lineages
among lake trout populations
Wilson and Hubert (1996)
What is Biodiversity?
Morphotypes
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)

What is Biodiversity?
Algonquin Ciscoes
What is Biodiversity?
Aurora trout
Aurora trout
Brook trout
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
 Communities
 simpler
than south of Shield
 fewer warmwater predators (e.g. basses)
What are the threats
to fish biodiversity?
1.
2.
3.
4.
Habitat alteration, loss
Overexploitation
Introduced species
Atmospheric pollution
Threats to Biodiversity
1. Habitat alteration and loss

Habitat is the physical, chemical and biological
components in a species’ environment required
for survival.
Threats to Biodiversity
1. Habitat alteration and loss

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.
Threats to Biodiversity
1. Habitat alteration and loss
Perched culverts
Turbidity
Mine tailings
Threats to Biodiversity
2. Overexploitation
 Overfishing
exceeds natural mortality of
population, or targets spawning stock
(typically larger individuals).
 Commercial fishing in larger lakes.
 Recreational fishing in smaller lakes.
Threats to Biodiversity
2. Overexploitation
1930s saw demise
of commercial
catch in L Huron
due to over fishing.
Sea lamprey may
have had an effct
as well
1950s saw
demise of
ciscoes due
to over
fishing.
Ciscoes not
affected by
lamprey
Threats to Biodiversity
Great Lakes Ciscoes
Extirpated in GL
Extinct
Extirpated in GL*
* Except Superior
Extinct
Extirpated in GL*
Threats to Biodiversity
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.
Smallmouth Bass
Introduced
Source: Checklist of Ontario Freshwater Fishes Annotated with Distribution Maps
(Mandrak and Crossman 1992)
Threats to Biodiversity
Threats to Biodiversity
May have
been in L
Ontario
spread to
upper Gt
Lakes after
Welland
Canal built
Threats to Biodiversity
3. Introduced Species
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)
Threats to Biodiversity
Threats to Biodiversity

ruffe
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
Threats to Biodiversity
Atmospheric Pollution
 Anthropogenic
contributions to
atmosphere can have far-reaching (e.g.
global) effects on aquatic environments.
 Acid precipitation, climate change.
Threats to Biodiversity
Acid Precipitation
 Direct
effects: loss of fish populations
 Numerous indirect effects.
Threats to Biodiversity
Change in Mean Annual Temperature
1990-2050
+2°C to 5°C
Threats to Biodiversity
Change in Mean Annual Temperature
1990-2080
+5°C to 8°C
Threats to Biodiversity
Climate Change
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.
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.
Conclusions
 Science
Needs
 Identify
biodiversity at sub-specific levels.
 Identify limiting factors and threats.
 Identify mitigation and adaptation strategies.
 Protection
 Identify
and Recovery Needs
gaps in protection .
 Identify and undertake recovery activities.