FISH!! Flashcards
Why is freshwater important?
Marine - 70% of earths surface
Fresh water 0.5% of earth surface
More fish species in freshwater - the ecosystems are more biodiverse than marine or terrestrial ecosystems with 1/3 of all vertebrates.
Why is there a concern with freshwater species?
The species are declining at twice the rate of those either in marine or terrestrial ecosystems
1/3 of face extinction
21/63 australian vertebrates most likely to go extinct in 20 years - 21 of fish
What do Australians use freshwater for that may impact fish?
Australia - we use freshwater for everything, to drink water and perform most domestic functions
building cities on major rivers - altering their flow to protect people and infrastructure and improve access.
irrigate crops and water livestock for food and textile production
almost all of our energy production needs water
Key element in mining and manufacturing
What effect does using large quantities of water, threats to fish?
Habitat loss and modification
Pressures are exacerbated by the scarcity of freshwater
urban stream lane, pipes - doesn tsupport biodiversity
barriers to movement - damns , preventing fish to breed. Fish ladder - built to help fish move passed these barriers. but specific to certain size fish
altered flows
degraded water quality
overharvesting
changing climate - severe changes in temperatures and droughts. Fires affect water ways - pollutes water and removing tree structures from waterways
introduced species
How do we modify the way water moves through ecosystems?
catchments have different responses to rainfall, depending whats in them. Some ecosystems slow water down - you’ll have trees and grass slowing the process down. However, if we take away these canopies - therefore no delay - this can damage the water way - pushing the banks and causing muddy water.
What affect does water quality have?
Big issue, water deteriorates, an oxygen response - algae blooms, respires at night lowering oxygen.
temperatures can changes in water
fertilisers and pesticides
chemicals in water
altered flows could cause change in organic matter being toxic.
How is fishing/ direct take of fish an issue?
The burnette salmon major food source
collecting fish for food
intensive fish catching - reduce population
What type of introduced species threat australian freshwater fish, and how?z
Gambusia - they are a central american fish and have an advantage as they are live bearers which means they are less susceptible to predation. Government introduction - fail control mechanism to reduce mosquitos. feed off fish eggs. produce large clutches
Swordtails - not as aggressive, many creeks they are dominate
Guppies - more populated in streams
Platies - more aggressive, taking up
Carp - problematic, murry darling - possibly increase due by over fishing of other native fish, tear up substrate and alter the habitat
goldfish - tear up substrate and alter the habitat
Tilapia - africa or south america. Coast in QLD, can survive salt water - mouth breeder (guard in mouth)
Pearl Cichlid - tear up vegetation
Barred Grunter
Redclaw crayfish
Trout - competes on species, faster predator
Common Pleco - got into waterways eat any vegetation
What Australian fish did Brisbane have, that is currently extinct?
Brisbane river Cod - maccullochella sp
What australian fish that are at risks?
species with small distributions
Running river rainbowfish
malanda rainbowfish
bloomfield river cod
daintree rainbow fish
desert springs fish
red-finned blue-eye
edgbaston goby - artesian basin
wallum fish
