Lecture 5: Global Freshwater Fishes

• Discuss notable features of Freshwater Diversity?

  FW = 1% of earths surface

  • Abt 15000 species (1° and 2 °)
  • Asia, South America, and Africa are most diverse in Fresh Water fishes
  • 40 – 45% of all fishes

  Few orders dominate

  • Tetras
  • One of the most diverse
  • Minnows
  • One of the most diverse
  • Catfishes
  • One of the most diverse
  • Knifefishes
  • Lesser Extent
  • Perches
  • Tooth carps
• What are the 7 Freshwater Biogeographic Regions?

  1. Nearctic (US, Canada, Greenland, North Mexico)
  2. Neotropical (S. America, Central America, Mexico)
  3. Palearctic (Europe, Russia, N. Asia, Mid-East, North Africa)
  4. Tropical Africa (Africa)
  5. South-east Asia (South-East Asia, India)
  6. Australia (Australia, New Zealand, Papua New Guinea)
  7. Oceania (Oceanic islands in the Pacific)

  
• Discuss Biodiversity in the Nearctic?

  US, Canada, Greenland, North Mexico

  1,500+ species

  • 500 species in South East US

  Appalachian mountains are high diversity

  North and West of North America is less diverse

  Freshwater Dispersers (93% Species)

  • Percidae (Perch, darters)
  • Suckers
  • Guppies
  • Splitfins (Mexico only)
  • Killifishes
  • Bullhead catfishes
  • Centrarchidae (sunfishes, basses)

  Marine Dispersers

  • 6% Diadromous
  • Salmon
  • Smelt
  • Lamprey
  • Herring & Shad

  Some freshwater species of primarily marine families (3%)

  • Sculpins
  • Burbots

  
• Discuss biodiversity in the Mississippi Province?

  Part of the Nearctic

  Largest river basin in North America

  375 species

  • 40% of species are endemic (old region)
  • Even with glaciers not all the fresh water in the area was covered by ice
  • Glaciers created many interconnected channels
  • Most are freshwater dispersers
  • Marine dispersers and marine derived species in the Mississippi delta

  
• Discuss biodiversity in the Appalachian province?

  Part of the Nearctic

  Highly diverse

  High endemicity

  Formerly connected to Mississippi drainage

  Mountainous

  Coastal streams get marine dispersers

  North was glaciated but the South was not

  
• Discuss biodiversity in the Laurentian Great Lakes?

  Part of the Nearctic

  Includes Great Lakes, St. Lawrence River

  Recently glaciated and glaciated many times

  Once connected to Mississippi

  • artifical connections are present

  73% FW dispersers

  17% Marine dispersers

  6% Marine derived

  Higher proportion of marine dispersers and marine derived than elsewhere in N.A.

  • Glaciers killed old fish and continually allowed marine fish to colonize the area
  • Can move from the St. Lawrence River to the coast
  • All lakes are interconnected, allowing marine taxa to move between them

  
• Discuss the Great Basin Province?

  Part of the Nearctic

  Bounded by mountains on the west, south and east

  Currently very arid

  • Historically contained large lakes and was notably wet

  Highly Isolated water bodies

  • Endorheic basins (don’t drain into rivers or oceans)
  • Outflow not connected to other water bodies

  50 species, 80% endemic

  • Low diversity due to harsh conditions
  • Cyprinidae, Catostomidae, Cyprinodontidae, Goodeidae
  • Endangered pupfishes

  Great deal of human interference

  
• Discuss biodiversity in the Neotropics?

  South and Central America

  • South = older taxa
  • old continent separate from the other continents for a long time
  • Central = Newer Taxa
  • geologically new, thus newly colonized

  Over 4000 species

  • These species not affected by the last glacial cycle
  • Many species undescribed
  • Total # could be over 8000
  • Fauna reflect different histories of the Americas

  
• Discuss biodiversity in the Neotropical region of South America?

  FW dispersers over 95%+

  • Tetras
  • Catfishes
  • Knifefishes
  • Killifishes, guppies
  • Cichlids
  • Bony tongues
  • South American estivating lungfish

  Marine dispersers (S. America)

  • Very low numbers of individuals present
  • Galaxiidae
  • Gobies
  • Both are amphidromous (need marine and fresh water)

  Marine Derived (~30 species)

  • Most in the Amazon where there is a lot of habitat to take advantage of
  • Stingrays
  • Sole
  • Herring
  • Anchovies
  • Drum

  
• Discuss biodiversity in the Neotropical region of Central America?

  South America, Central America, Mexico

  Larger number of freshwater dispersers because Central America is a recent disturbance by the continent raising

  • 59% FW dispersers
  • 13% Marine derived
  • 28% Euryhaline marine fishes

  Low representation of Otophysan fishes

  • Catfishes
  • Cichlids
  • Guppies
  • Meso-American killifishes
  • Tetras

  
• Pt. 1 Discuss background for the biodiversity in Africa?

  About 3,000 species

  • Includes many ancient lineages (lungfishes, bichirs, bony tongues)

  Stable landmass for 600 million years (good environment for FW fishes)

  40% of families are endemic (ex: Mormyridae)

  Shares families with South America, South East Asia, Australian regions

  • Formerly attached to South America & Australia
  • Near South East Asia

  
• Pt. 2 Discuss biodiversity in Africa?

  95% are FW dispersers

  • Cichlidae (900+ species)
  • Cypriniformes (~500 species)
  • Characiformes (~200 species)
  • Siluriformes (~450 species)
  • Bony tongues
  • Bichirs
  • African estivating lungfish
  • Closest relative to the South American estivating lungfish
  • Gouramis
  • Annual killifishes

  Few Marine Dispersers

  • None reach inland very far
  • Catadromous eels
  • Amphidromous gobies

  Marine Derived

  • Few Species
  • pufferfish
  • pipefish
  • Mullets
  • Herring
  • Barramundi

  
• What is notable about Cichlids in regards to African and South American biodiversity?

  Distributed in Africa and South America

  • Assumed that they arose when continents were together (120 million years)
  • Fossil and genetic evidence shows that cichlids are only 65 million years old.
  • Indicates cichlids dispersed through the ocean to colonize South America from Africa prior to the ocean gap getting too wide

  
• South East Asia biodiversity?

  2 Subregions

  • India
  • Independent island continent 100 mya – 50 mya
  • Mostly Otophysans of Asian/African origin
  • Fossil evidence suggests that Cyprinids from Asia dispersed to India and overwhelmed the original fish fauna
  • FW Dispersers
  • No endemic genera of minnows/catfishes
  • All from South East Asia or Africa
  • Southeast Asia
  • About 2,000 species
  • Complex distribution patterns
  • Especially with connections to islands via the sea
  • Sub-regions hard to define/not well understood
  • Geology and lack of study

  About 3000 species

  High number of families (121)

  
• Discuss biodiversity of the Indian Subregion of South East Asia?

  700 species of FW dispersers

  • Cyprinidae (53%)
  • Siluriformes (25%)
  • Cobitidae (loaches)
  • Balitoridae (river loaches)
  • Channidae (snakeheads)
  • Anabantidae (gouramis)
  • Cichlidae
  • Notopteridae (old world knifefishes)

  Few Marine Dispersers

  
• Discuss the biodiversity of the South East Asian subregion of South East Asia?

  70-80% are FW dispersers

  • Cyprinidae (39%)
  • Siluriformes (18%)
  • Cobitidae (loaches)
  • Balitoridae (river loaches)
  • Osphronemidae (gouramis)
  • Osteoglossiformes (bonytongues)

  Marine Derived

  • Dasyatidae (stingrays)
  • Engraulidae (anchovies)
  • Polynemidae (threadfins)
  • Gobiidae (gobies)
  • Syngnathidae (pipefishes)
  • Tetraodontidae (puffers)

  
• Discuss biodiversity in the Paleoarctic?

  Europe, Russia, North Asia, Mid-East, North Africa

  In past Europe, Russia, Northern Asia Region largely under glaciers

  Low Diversity

  Freshwater Dispersers

  • minnows
  • Loaches
  • Catfish
  • Asian catfish (Sisoridae & Bagridae)
  • Sucker
  • Perches
  • Pike

  Marine Dispersers

  • High diversity of trout, grayling, & whitefish
  • Many do not go to sea but rather lakes and rivers
  • Gobiidae

  Marine Derived

  • Sculpins
  • Large radiation in Lake Baikal, Russia
  • Oldest lake (65 mya)
  • Largest lake (20% of worlds surface freshwater)
  • Deepest lake in the world – 5,300 ft deep

  
• Discuss biodiversity in the Australian subregion?

  Australia, New Zealand, Papua New Guinea

  Ancient breakaway from other continents

  • Long time spent being independent

  Only four species of freshwater derived species

  • Australian Lungfish
  • Arowana
  • Salamanderfish

  Remaining species are from Marine families

  • Melanotaeniidae (rainbowfish)
  • Pseudomugilidae (rainbowfish)
  • Geotriidae (pouched lamprey)
  • Anguillidae (anguillid eels)
  • Galaxiidae
  • Gobiidae
  • Eleotridae (sleepers)
  • Kuhliidae (flagtails)
  • Latidae (barramundi

  
• Discuss biodiversity in the oceania subregion?

  Oceanic Islands

  • Mainly in Pacific, and tropical coastal streams in Australia, South East Asia

  Relatively new geologically speaking

  Isolated from continental waters

  Contain small communities of freshwater fishes

  • Gobiidae (gobies) – Mostly sicydiinae
  • Eleotridae (sleepers)
  • Angullidae (angullid eels)
  • Syngnathidae (pipefishes)
  • Ambassidae (glassfish)

  
• Describe notable trends in freshwater fish diversity?

  Old, stable regions = higher amount of freshwater dispersers

  • Geological Stability
  • Climate Stability
  • Ex: Africa, South America, southern North America

  New or recently disturbed regions = higher amount of marine dispersers (if they are connected to the sea!)

  • No connection = no colonization
  • Glaciated areas
  • New geological formations
  • Ex: Central America, Great Lakes region, Oceanic Island

  Regions with large rivers have higher proportion of marine derived species

  • Marine species find niches
  • Ex: Amazon R., Mekong R., Congo R

  
• What processes explain the noted trends in freshwater fish diversity?

  Continental Drift

  Freshwater Dispersal

  Marine Dispersal

  Climatological Events (glaciation)

  Ecological Requirements

  People

  
• What processes led to the distribution of lungfishes?

  Most ancient freshwater fishes

  Not very diverse

  • Evolved to deal with poor quality habitat

  Distributed on three southern continents

  • Previous connection between them
  • CONTINENTAL DRIFT

  
• What processes led to the distribution of Tetras?

  Relatively old group of fishes

  Evolved ~140 mya

  Before SA and Africa separated

  Recent expansion into Central America

  • Continental Drift and Freshwater Dispersal

  Very diverse

  
• What processes led to the distribution of cichlids?

  Recently derived group

  Evolved <65 mya

  • After South America and Africa separated

  Recent expansion into Central America

  Very diverse

  What processes?

  • Marine Dispersal and Freshwater Dispersal

  
• What processes led to the distribution of Cyprinids?

  Relatively old group

  Evolved 250 mya

  • Continents all mushed together

  Not present in Arctic or southern continents (except Africa)

  What Processes?

  • Continental Drift
  • Freshwater Dispersal
  • Ecological Factors
  • Cannot handle cold water
  • Look at saltwater and die

  
• What processes led to the distribution of Killifish?

  Recently derived group

  Evolved ~30 mya

  Continents apart

  Coastal distributions in much of the range

  What processes?

  • Marine Dispersal

  
• Why do Eurasia and northern north America have few species?

  Glaciation

  
• Why does Australia have almost no primary freshwater fish?

  It's the driest continent on Earth so it doesn't meet the ecological and geological requirements of the fish
• Discuss the diversity of Indonesia?

  Catfish and minnows in the east

  Gobies in the middle

  • Mainly marine derived so have newly entered

  Rainbowfishes in the west

  • Marine Dispersal

  This is due to geologic instability in the area

  • Glaciation lowered sea levels globally
  • East Indonesia was attached by land to South East Asia
  • West Indonesia was attached by land to Australia.
  • Central Indonesia has never been attached by land
• Things to note about invasives...?

  Some FW fishes have nearly global distributions now

  • Mosquetofish
  • Everywhere with reasonably warm temperatures
  • Introduced for mosquito control
  • Eat larvae of native fishes & Outcompete them
  • Armored Catfishes
  • Aquarium releases
  • Every continent (except Antarctica), plus oceanic islands
  • Dense populations
  • Absorb all the phosphorus nutrients (a limiting resource)
  • Dig into banks causing accelerated erosion
  • Salmonidae
  • Introduced for sport and commercial fisheries
  • Outcompete or eat the native species

  Hawaii

  • 63 of 68 species are introduced