Freshwater Fish (lecture 2)

Question 1

freshwater fish

Answer 1

occupy freshwater habitat for a significant part of lofe cycle

Question 2

freshwater evolutionary perspective

Answer 2

only four fish follow it (lungfish, north and south saratoga, and salamanderfish)
-all evolved in freshwater

Question 3

Gwandan relic(only live in freshwater)

Answer 3

lungfish, saratoga, and salamander

Question 4

Marine colonizer(marine ancestors)

Answer 4

catfish, eel, rainbowfish, galaxiids, blackfish, lampreys, and murray cod

Question 5

reason for few Australian species

Answer 5

-fish need water(Australia is highly variable and pretty dry and arid)
-runoff (low runoff since Australia is 80% arid)
-not looking hard enough
(neglected group of Australia wildlife)
-not looking in the right places (KImbley region have found incredibly new species, but not visited)

Question 6

types of habitats

Answer 6

torresian, eyrean, bassium

Question 7

torresian

Answer 7

• monsoonal, warm
• north coast
• wet/dry season
• wide flood plain

Question 8

eyrean

Answer 8

• arid, ephemeral bodies water bodies
• inland
• source on West of Great Divide
• fluctuating, unpredictable levels
• warm, slow and turbid
• massive floodplain
• salt lakes

Question 9

bassium

Answer 9

• high rainfall, cooler, permanent water
• east coast
• source on East of Great Divide
• fall rapidly to the sea
• clear and cool
• relatively stable flow
• mountain lakes

Question 10

Australia’s hydrologic background (time series of flow)

Answer 10

gauged streams

• nationally-80% of stream do not flow continuously over time
• victoria-50%

much greater percentage in ungauged catchments

high inter-annual variability in duration of zero flows

challenging environment for fish to persist in

many exploit refuges

Question 11

Australia’s specie richness of freshwater fish compared to the rest of the world

Answer 11

• low
• 206 exclusively freshwater native species
• about 70% endemic, especially in Tasmania, south-west WA and the Kimberly region
• 71 non freshwater dependent species
• 26 exotic or introduced species

Question 12

migration patterns during life cycle

Answer 12

diadromous
-anadromous, catadromous,
amphidromous

obligate freshwater
-potamodromous

Question 13

diadromous

Answer 13

• using two different habitats

- fresh and salt water

Question 14

anadromous

Answer 14

-type of diadromous
-sea to stream
-spends adult life in marine then move to freshwater to spawn
-ex.
lampreys, Tas whitebait

Question 15

catadromous

Answer 15

-type of diadromous
-stream to sea
-spend adult life in freshwater then moves to marine to spawn
-ex.
eel, barramundi

Question 16

amphidromous

Answer 16

-type of diadromous
-non-breeding migration, both ways
-dont move to spawn, but move to take on new food source
-ex.
Australian bass

Question 17

potamodromous

Answer 17

-type of obligate
-freshwater migration
-dont experience environment stress from salt to freshwater
-move during spawn
-ex.
silver perch

Question 18

threatening procesess

Answer 18

habitat change and introduction of exotic species

Question 19

habitat change

Answer 19

• river regulation

- salinisation, pollution, and eutrophication

Question 20

river regulation

Answer 20

a habitat change

dams

• Australia has variable rainfall
• used for human

consumptions
barriers from moving to freshwater
-lead to fragment
population (higher chance of extinction)

prohibits the nutrients for down stream food chains

alter flow regimes

high flows occur in the summer instead of the environmental spring due to dams
-effects fish spawn

cutting down brush

• bringing more salt to the surface
• loss of habitat

Question 21

salinisation, pollution and eutrophication

Answer 21

• a habitat change
• 95% of Australia’s original wetlands degraded or lost due to rural development and mining
• particularly severe in heavily populated coastal areas and farming areas
• salinisation is caused by land clearing resulting in a rise of the salt-laden water table
• agricultural chemicals

Question 22

introduced or exotic species

Answer 22

trout, mosquito fish, and carp

Question 23

trout

Answer 23

• introduce specie
• introduce for angling to feel like the old country
• preservation of trout fishery is strong
• predators of native fish

Question 24

mosquito fish

Answer 24

• introduce specie
• used for mosquito control but failed
• competes with natives

Question 25

carp

Answer 25

• accidental
• number one pest
• impact debated
• bottom feeder
• destructs habitat beds
• shear biomass