freshwater fishes of australia - amazon s3...fossil records pre-date fragmentation of gondwana few...
TRANSCRIPT
Freshwater fishes of Australia
Stephanie Januchowski-Hartley
Australia!
Image credits: V Hermoso
Today’s talk!
Origins of Australia’s freshwater fishes
Biogeography of Australia’s freshwater fishes
Ecology of Australia’s freshwater fishes
Humans and freshwater fish
Credit: SRJH
Entire evolutionary history restricted to freshwater
Fossil records pre-date fragmentation of Gondwana
Few of these species in Australia
Freshwater fish origins
Primary freshwater species
Gondwanaland: geos309.community.uaf.edu
Derived from marine fishes/ ecosystems
Ancestors from tropical Indo-Pacific
Majority of Australia’s freshwater fishes
Freshwater fish originsSecondary freshwater species
Today’s talk!
Origins of Australia’s freshwater fishes
Biogeography of Australia’s freshwater fishes
Ecology of Australia’s freshwater fishes
Humans and freshwater fish
Credit: SRJH
Rainfall and catchment size influence biogeography
BiogeographyThe distribution of species through space and time
Species richness - the number of species in a defined area
driven by river discharge and perennial stream flows
Richness
Map: peter.unmack.net
Endemism - unique occurrence of a species to a single area
47% of freshwater species endemic to a single region
Driven by isolation due to aridity and drainage divides
Biogeography
Map: peter.unmack.net
Today’s talk!
Origins of Australia’s freshwater fishes
Biogeography of Australia’s freshwater fishes
Ecology of Australia’s freshwater fishes
Humans and freshwater fish
Credit: SRJH
Lepidogalaxias salamandroides (Salamanderfish)
Primary freshwater species
Endemic to peat lands between two riversMap: peter.unmack.net
Lepidogalaxias salamandroides
Inhabits small (2-600 m2) acidic ephemeral ponds
Aestivation - is a state of animal dormancy due to arid conditionsWhere are the fish?
Fishes remain in burrows
(up to 1m below) until rain returns next
yearImages: australianmuseum.net.au
Adapting to life under pressure
Performs internal fertilization
Wedged-shaped skull resists weight of wet sand
Vertebrae gaps and reduced abdominal ribs allow burrowing
Cannot move eyes; flexible vertebrae allows head to turn
Tropical river diversity
8,000 km2 supports >50% of Australia’s freshwater fish
11 rainforest endemics - perennial flow and riffle habitats
Rainforest vegetation important role in fish diets
Credit: SRJH
Kuhlia rupestris(Jungle Perch)
Feeding adaptations
Cairnsichthys rhombosomoides(Cairns rainbowfish )
Feeding adaptations!CREDIT: National Geographic
Toxotes chatareus(Seven-spot archerfish)
Amphidromy
Adult spawn in fresh waterLarvae pass to sea to feed and grow Young of year return to fresh waters
Image: hawaiiwatershedatlas.com
What are amphidromous fish adaptations?
Where would amphidromy be advantageous?
Image credit: D. Hogan
Amphidromy in Australia’s streamsAmphidromy sparse on continents
Conditions similar to island streams
Small coastal drainages poorly sampled
10 new amphidromous species recorded (2011)
many species found on nearby islands
Amphidromy in Australia’s streams
doi:10.1371/journal.pone.0026685.g002
Today’s talk!
Origins of Australia’s freshwater fishes
Biogeography of Australia’s freshwater fishes
Ecology of Australia’s freshwater fishes
Humans and freshwater fish
Credit: SRJH
Humans and fishesWhat types of human disturbances do you think could threaten
Australia’s fishes?
Thank you for listening!Related reading:
Biogeography of Australian Freshwater Fisheswww.peter.unmack.net/biogeog
Freshwater Fishes of Northeastern AustraliaPusey, Kennard and Arthington 2004
Amphidromy Links a Newly Documented Fish Community of Continental Australian Streams, to Oceanic Islands of the West
Pacificjournals.plos.org/plosone/article?id=10.1371/journal.pone.0026
685