Transcript The Rusty Crayfish By

The Rusty Crayfish
By: Vlad Spirkov, Michael Tsimidis & Matthew Bondi
Ecology STSE
Changes in Stability of Ecosystems
INTRODUCTION
-Rusty Crayfish are a frightening problem to the Great Lakes ecosystems
-Affect all/ most of the ecosystem’s food web
-Affects tourism and fishing in the great lakes
-Rusty Crayfish are competing with the native crayfish species found in the
Great Lakes, which harms the native population
-Rusty Crayfish are also increasing the population of some predators, such
as Bass, which can have both positive and negative consequences
-There are various ways to mitigate the spread of Rusty Crayfish into
further areas of the great lakes
SCIENTIFIC PERSPECTIVE-Matthew
-Name: Rusty Crayfish or Orconectes rusticus
-Rusty Crayfish are an aquatic species of crayfish with a dark red/brown rusty
colour
-Where: The rusty crayfish were first discovered in the Ohio River Basin and quickly
spread at an alarming rate into Kentucky, Indiana, Tennessee, Illinois, and the water
areas of many other states in the Great Lakes section of America (see below). They
have also managed to spread from the USA into Ontario.
-How they grow and reproduce: Mating happens between female and male Rusty
Crayfish. The female crayfish will lay around 80-575 eggs, which hatch in 3-6 weeks,
depending on the water temperature.
TECHONOLOGICAL PERSPECTIVE- Matthew
Rusty Crayfish are multiplying fast, and there is currently no effective or
proven way to reduce rusty crayfish population without harming other
species.
Some ideas for how to reduce crayfish are:
-Having a larger population of bass and sunfish may help rusty crayfish to be less
invasive
-Putting many traps into areas with high Rusty Crayfish populations
-Introduce aquatic species that will lower Rusty Crayfish numbers
-Spread awareness to reduce introduction of rusty crayfish into other areas
Impact On Humans:
SOCIETAL PERSPECTIVE- Michael
Ecological Impact
1) Rusty Crayfish eat an extensive quantity of aquatic vegetation
-Destroys nursery grounds for bass and other fish species living there
-Displaces native crayfish species from sheltered areas into vulnerable areas, which causes predators to kill
the native species more easily
2) Rusty Crayfish compete with native crayfish species which makes it more difficult for native species to survive
-Reduces population of native species
Economical Impact
1)Banning the use of Rusty Crayfish as bait in habitats that do not already have them, cause economic pain to bait
merchants using them as merchandise
-Merchants selling baits therefore have to buy other, more expensive alternatives which cause further
financial loss
2)Hurt market for bass due to declines in bass spawn
3)Extermination of rusty crayfish is expensive and is not always effective
Impact on Tourism
1)Rusty Crayfish destroy nursery grounds of economically valuable fish species such as bass
-Reduces population of these species
2)Reduces the amount of anglers who fish in those waters (No fish to catch=No fish to sell=No money)
SOCIETAL PERSPECTIVE Contd. - MICHAEL
How Rusty Crayfish can be Controlled by Humans:
Impact On Health
1)Harms its new food web
-Kills predators eggs
-Competes with native crayfish for food
-Puts native crayfish into vulnerability
Mechanical
1) Banning use or transportation of Rusty Crayfish as bait
2) Prevention is the best method for dealing with Rusty Crayfish
-Barriers or nets that can prevent the further spread of Rusty Crayfish
-Traps are a simple, yet effective way of removing small quantities of the Rusty Crayfish
Chemical
1) Adding chemicals into aquatic vegetation to change it’s odour
-Turns away Rusty Crayfish into believing that the vegetation is not editable1
Biological
1) Augmenting predators
-Protecting bass’s eggs by putting them into an incubator then releasing them back into their natural ecosystem
Environmental Perspective-Vlad
Effects on Native Crayfish.
The Rusty Crayfish Displaces the Native Crayfish.
The Rusty Crayfish are better hiders then Native Crayfish making them more vulnerable
to predators.
The Rusty Crayfish have bigger claws therefore they can protect themselves from
predators better meaning that the Native Crayfish are a bigger pray for predators.
Control of the species can restore the Native Crayfish.
https://www.youtube.com/watch?v=oVfNcBE2bBQ
https://www.youtube.com/watch?v=oVfNcBE2b
ENVIORNMENTAL PERSPECTIVE-Vlad
Effects on the General Food Web.
The Rusty Crayfish eat large amounts of aquatic plants witch indirectly reduces natural
habitats for other species.
When removed from areas certain areas, species effected by them have had their population
increased significantly.
Reduce population of some other fish species.
Potential Impacts.
The Rusty Crayfish can easily remove other crayfish from their habitat and they can compete
better with the limited food resources.
Other crayfish eat aquatic plants the Rusty Crayfish eat even more due to their higher
metabolic rate, resulting in even less food for other species.
Conclusion
Rusty Crayfish are destroying our Great Lakes ecosystem and the species living in them
1) Impact all aspects of life
-Impacts economically, ecologically, and affects tourism and health
If Rusty Crayfish are not controlled properly there could possibly be tremendous
consequences
-Native Crayfish may become endangered in some areas of the Great Lakes
-Economical losses in businesses situated in that region
If there is a will to prevent further spread, then there is a way
-Anglers who catch Rusty Crayfish must kill them
-More traps and nets to catch Rusty Crayfish also alleviates some of the
difficulty in this battle to stop the spread.