Transcript VII. Zoogeography of fishes

Zoogeography of Fishes
Zoogeography of Fishes
 Patterns and processes in the distribution of fishes
(i.e., what causes certain fish species to be where
they are?)
 Global
 Regional
 Local
 Successively smaller sieves that determine fish
distribution
 Predictability of fish assemblages
Global
 Plate tectonics
 Rearrangement of
land masses
 sunfishes restricted
to N.A. (arose
following split of land
masses, temperate,
freshwater)
Regional - Historic
 Drainage Divides
 Broad drainages
isolate aquatic
communities
(Mississippi vs.
Atlantic Slope)
Regional - Historic
 Drainage Divides
 Drainage
rearrangement (stream
capture)
 Populations of
Mississippi R. fishes on
Atlantic slope
 Etheostoma blennioides
(Potomac captured
Mississippi)
Regional—Historic
 Glaciation
 Mississippi Drainage oriented N – S
 Fish disperse south
 Atlantic Drainage oriented E – W
 Teays R was the major N-W flowing river
 Ice sheets dams caused it to flow S through the
small Mississippi R.
 Melt water cut through central highlands making
Mississippi R the major river
 Ancient Teays River Valley near present-day
New and Kanawha Rivers
Pre-Pleistocene
Pleistocene
SE Fish Richness
•Tennessee
River most
diverse
•Atlantic slope
least diverse
•New /
Kanawha
River basin
“relatively
diverse”
Warren et al. 1997
Regional - Local
 Geology (regional characteristic that
influences local conditions)
 Habitat
 Water Flow
 Chemistry
 Alkalinity - Hardness
 Productivity
Regional - Local
 Spatial Position
 The position of a stream segment in a stream
network influences species found there
(distance from a species pool).
Influence of Barriers
Influence of Stochastic Events
Local
 Competition / Predation
 Water Chemistry
 Water Flow
 Productivity
 Habitat
 Gradient
 Stream Size
25
Species Richness = -5.16 + 4.6 x (Basin Area) + 0.39 x (Link Order Diff)
R2 = 0.79
df = 17
p < 0.0001
Observed Richness
20
15
10
5
0
0
5
10
Expected Richness
15
20
Zoogeography of Marine
Fishes
Barriers to Dispersal in Marine
Systems
 Continents - e.g. Atlantic vs. Pacific
faunas
 Temperature - e.g. tropical vs.
temperate vs. polar
 Salinity - e.g. estuaries, freshwater
(Panama Canal)
 Depth - deep-dwelling fishes can be
isolated by submerged mountain ranges
Mechanisms for Dispersal in
Marine Fishes
 Directed movements (e.g., with
changes in temperature; migrations)
 Pelagic eggs/larvae - current-born
dispersal
 Human action - transplants (e.g.,
striped bass, American shad in Pacific
Ocean; 250 species introduced into San
Francisco Bay)
Zoogeographic Groupings of
Marine Fishes
 Continental Shelf (neritic)
 Pelagic
 Abyssal
Zoogeographic Groupings of
Marine Fishes
 Continental Shelf (neritic)  45% of all fishes
 Tropical Zone
 Temperate (North & South) Zones
 Arctic/Antarctic Zones
 Pelagic
 Abyssal
Zoogeographic Groupings of
Marine Fishes
 Pelagic  Epipelagic (1.3% of all fish species)
 Meso- & Bathypelagic (5% of all fish
species)
 Arctic
 Temperate
 Subtropical
 Tropical
Zoogeographic Groupings of
Marine Fishes
 Continental Shelf (neritic)
 Pelagic
 Deep benthic (abyssal)
 6.5% of all fish species
 little known about these
Example: Distribution of
pelagic piscivores in north
Pacific Ocean
 Arctic:
 Arctic char, pink salmon, some cods
 distributed north of 0° isotherm
 North Temperate:
 North Subtropical:
 Tropical:
Example: Distribution of
pelagic piscivores in north
Pacific Ocean
 Arctic:
 North Temperate:
 coho, chinook, steelhead, sockeye, chum
salmon
 north of 14° isotherm, south of 0°
isotherm
 North Subtropical:
 Tropical:
Example: Distribution of
pelagic piscivores in north
Pacific Ocean
 Arctic:
 North Temperate:
 North Subtropical:
 some tunas, marlins, basking sharks,
mackerel sharks
 north of 20° isotherm, south of 14°
isotherm
 Tropical:
Example: Distribution of
pelagic piscivores in north
Pacific Ocean
 Arctic:
 North Temperate:
 North Subtropical:
 Tropical:
 flying fish, tunas, whale sharks, marlins
 south of 20° isotherm in northern
hemisphere and north of 20° isotherm in
southern hemisphere
Zoogeography of
Freshwater Fishes
Definition & Overview
 Zoogeography - the study of the distributions
of animal taxa over the surface of the earth
 Unique aspects of piscine zoogeography:
 longer period of record (since 350 mybp)
 constraints to dispersal in aquatic habitats (land
masses)
 unique dispersal mechanisms - current movement
of planktonic eggs & larvae
Interpretation of distribution
patterns requires:
 Ecological information - e.g., can the
fish taxa tolerate exposure to fresh
water or salt water
 Freshwater dispersants - e.g., minnows cannot tolerate any salinity
 Saltwater dispersants - freshwater fishes
that can tolerate salinity - e.g., cichlids
Interpretation of distribution
patterns requires:
 Geological information - what have
been the past connections between
water bodies
 past and present watershed configurations
important - e.g., previous connections
between Great Lakes basin and Mississippi
River - 79% of fishes in GL Basin
originated from Mississippi basin
Interpretation of distribution
patterns requires:
 Geological
information continental drift
Interpretation of distribution
patterns requires:
 Geological information - continental drift
 a single continent (Pangaea) existed as
recently as Triassic (200 mybp)
 Pangaea split into two continents at end of
Triassic (180 mybp):
 Northern continent - Laurasia (modern Eurasia
& North America
 Southern continent - Gondwana (modern
Africa, South America, Australia, Antarctica,
India)
Interpretation of distribution
patterns requires:
 Geological information - continental drift
 Gondwana split in Jurassic & Cretaceous
 Australia broke off first
 South America broke off later
 Several fish taxa are present only on southern
continents:
 lungfishes - Australia, S. America, Africa
 cichlids - S. America, Africa, India
 characins - S. America, Africa
Interpretation of distribution
patterns requires:
 Geological information - continental drift
 Laurasia split in Jurassic (120 mybp)
 North America separated from Eurasia
 Several fish taxa are present only on northern
continents:





Cyprinids (also have moved into Africa recently)
Percids - Holarctic (in N. America & Eurasia)
Catostomids - Nearctic (largely in N. America)
Centrarchids - Nearctic (only in N. America)
Cobitids - Palearctic (only in Eurasia)
Mississippi Basin Fauna
illustrate these patterns well
 Contains ~ 330 species, 13 families
 Basin is ancient - present arrangement since
Rocky Mtns. formed in Tertiary (~65 mybp)
 Ancient relics are extant today - have
benefited from persistence of the basin:
 Chondrosteans - sturgeons, paddlefish
 gars, bowfins
 mooneyes, pirate perch, cavefishes - only found
here
Mississippi Basin Fauna
illustrate these patterns well
 New taxa originated and/or flourished here:
 Notropis/Cyprinella minnows (shiners)
 Etheostoma/Percina percids (darters)
 ictalurids (catfishes), especially Noturus madtoms
 centrarchids, especially Lepomis (sunfishes)
 catostomids, especially Moxostoma (redhorses)
Why is the Mississippi fauna
so diverse?
 Provided a refuge
from glaciers, due
to north-south
axis
 Taxa could retreat
south as glaciers
moved south
Why is the Mississippi fauna
so diverse?
 Provides a diversity of habitats:
 Different stream types:
 Coastal plain (Gulf of Mexico margin)
 Interior highlands
 Ozarks
 Tennessee/Kentucky plateau
 Interior lowlands
 Western (Missouri River basin)
 Central (Upper Mississippi River basin)
 Eastern (Ohio River basin)
Why is the Mississippi fauna
so diverse?
 Provides a diversity of habitats:
 Speciation requires isolation - offered by
these diverse AND separated habitat types
 e.g., Ozark fauna is unique from the
Tennessee/Kentucky fauna, even though the
habitats are similar - the Mississippi River valley
separates them - no passage possible between
for small taxa like darters, minnows, madtoms
Why is the Mississippi fauna
so diverse?
 Provides a diversity of habitats:
 Species dependent on small, headwater
streams are more easily isolated, and
therefore are the most diverse groups
 shiners
 darters
 madtoms
Fish Fauna of the Great Lakes
1. Who are they?
2. Where did they come from?
3. What is the nature of the
interactions among species?
1. Who are they? - How many
are there?
 Low diversity:
 Native:
157 species
 Introduced: 22 species
 TOTAL:
179 species
Comparison with other fish
faunas
 Laurentian Great Lakes: 179 species
 Coral Reefs: > 150 on 1 coral head
 Mississippi River Basin: > 330 species
 Amazon River Basin: > 2,000 species
 African Great Lakes: > 450 species
ENDEMIC in ONE lake!
Why is diversity low?
Temperature - cold
Why is diversity low?
Temperature
Productivity - low
Why is diversity low?
Temperature
Productivity
Age - young
Why is diversity low?
Temperature
Productivity
Age
Connections to other lake and river basins
- minimal
1. Who are they? - Two
ecological groupings:
 Coldwater, deep
lake group:
 Coolwater, shallow
basin group:
1. Who are they? - Two
ecological groupings:
 Coldwater, deep
lake group:
 lake trout
 lake whitefish
 lake herring
 lake sturgeon
 deepwater sculpin
 deepwater ciscos
 Coolwater, shallow
basin:
1. Who are they? - Two
ecological groupings:
 Coldwater, deep
lake group:
 lake trout
 lake whitefish
 lake herring
 lake sturgeon
 deepwater sculpin
 deepwater ciscos
 Coolwater, shallow
basin:
 yellow perch
 walleye
 white bass
 channel catfish
 northern pike
 smallmouth bass
1. Who are they? - A New
Group: Introduced species
 Intentional introductions:
 Common carp, brown trout, steelhead,
chinook and coho salmon
Introduced species
Intentional introductions:
Common carp, brown trout, steelhead,
chinook and coho salmon
Accidental introductions:
Alewife, sea lamprey, white perch, pink
salmon, rainbow smelt, round goby, ruffe
2. Where did the native
species come from?
 Endemic species
 Immigrant species
2. Where did the native
species come from?
 Endemic species
 species evolved in the system and are
unique to the system:
 Blue pike (walleye subspecies)
 Deepwater ciscos
2. Where did the native
species come from?
 Immigrant Species:
 species that evolved elsewhere and
entered the system from other watersheds:
 Mississippi Basin: 79% of fauna
 Atlantic drainages: 9% of fauna
 Both: 12% of fauna
3. What is the nature of the
interactions among species?
 Predator-Prey relations
 Niche partitioning (generalists vs.
specialists)
 Resilient species (to heavy fishing
pressure or predation pressure)
 Sensitive species (to heavy fishing
pressure or predation pressure)
3. What is the nature of the
interactions among species?
 Effects of introduced species:
 sea lamprey
 Parasites on large fish - lake trout are small
compared with their ocean hosts
 Cause high mortality on lake trout
 Best opportunity for control is in reproductive
and larval stages - concentrated in rivers
3. What is the nature of the
interactions among species?
 Effects of introduced species:
 rainbow smelt and alewife - planktivores
 compete with native planktivores
 prey on larvae of native fish species
 prey on and compete with each other!
3. What is the nature of the
interactions among species?
 Effects of introduced species:
 gobies & ruffe - benthic fishes
 new immigrants to system
 ballast water introductions of 1980’s
 potential to be competitors and predators on
benthic fishes and invertebrates