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  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)  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)  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)  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  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

Tennessee River most diverse Atlantic slope least diverse New / Kanawha River basin “relatively diverse” Warren et al SE Fish Richness

Regional - Local  Geology (regional characteristic that influences local conditions)  Habitat  Water Flow  Chemistry  Alkalinity - Hardness  Productivity  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).  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  Competition / Predation  Water Chemistry  Water Flow  Productivity  Habitat  Gradient  Stream Size Species Richness = x (Basin Area) x (Link Order Diff) R 2 = 0.79 df = 17 p <

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