Invasive Species Flashcards
What is the biggest source of biological invasion in aquatic ecosystems worldwide?
Aquaculture (Gozlan, 2008)
What is biological invasion?
Introduction of a non-native species
What is the most invasive fish species in Europe? Describe it
Topmouth gudgeon (P.parva)
- Small Cyprinidae native to Asia
- max size circa 9cm
- Early maturity
- Batch spawner
- Nest guarder (male)
- Longevity 4 years
Facts about Europe’s most invasive fish species
Rapid invasion since 1960s
32 countries invaded in less than 50 years
Every decade 5 new countries report occurrence
Resulting from the movement of Chinese carps for fish farming
How do biological invasions occur?
Accidental - Ballast from transoceanic vessels - hitch hikers on boats - aquatic birds Intentional - aquaculture - angling/sport - ornamental - biological control
What attributes make for a “good” invasive species?
High phenotypic plasticity High growth rate Early maturity Fecundity and reproductive behaviour Ability to cope with novel pathogens Ability to cope with fluctuating temperatures or a wide temperature range
What are the main points with regards to economy vs ecology?
Large number of freshwater fish (31%) have high market price and low ecological risk
Assessing ecological risk can be difficult due to lag phase
Mean detection rate for introduction of Topmouth gudgeon is 4 years
Once detected can be some time before ecological impacts are seen
What negative impacts can an invasive species have?
Decline in native species
Habitat availability
Fisheries
Ecosystems goods and services
What value can invasive species have?
Support valuable fisheries
Rare and endangered species
High recreational value
What leads to the decline in native species due to invasive species?
Disease Predation Hybridisation Diet overlap Habitat modification
What intracellular parasite was first identified in 1984 in Chinook salmon and why is it a problem?
Sphaerothecum destruens
- Rosette-like agent
- problem for aquaculture salmonids
- infects other species of fish
- new pathogens introduced to naive populations can cause substantial problems
- S.detruens associated with topmouth gudgeon (healthy carrier)
What fish has been highly impacted upon in Europe due to the introduction of the topmouth gudgeon? Facts
Sunbleak (Leucaspius delineatus)
- Small Cyprinidae native to central Europe
- Max size circa 6cm
- Early maturity
- Batch spawner
- Nest guarder (male)
- Longevity
- Listed on IUCN red list of threatened species 1996
- Considered an invasive species in UK
Why has the sunbleak been soo heavily affected?
Sunbleak is highly susceptible to S.destruens, particularly during reproductive period
- high cost of parental care, high cost of courtship behaviours and defence territory can lead to immunocompetence
- Cohabitation of topmouth and sunbleak, sharing only water, showed high infection of sunbleak
Why are the topmouth gudgeon and the sunbleak such effective invaders?
Short maturation rate - 1 year Spawn just once a year Broadcast spawners Batch spawners (several between April and July) Parental care
Why is the topmouth gudgeon soo detrimental?
Competes for food with native and farmed species
Eats invertebrates and fish fry/eggs
Eats zooplankton (leading to phytoplankton and eutrophication)
Vector of infectious diseases in Europe
- S.destruens
- Anguillicola crassus
- Carrier of Pike Fry Rhabdovirus (PFR)
Can hybridise with other species (only non-native species to do so thus far/ or can only do it with non-native species (unclear))
What animal was introduced into Lake Victoria in the 1960s as an experiment?
The Nile Perch (Lates niloticus) - voracious predator, extinguished almost the entire stock of native fish species
Give an example of a successful introduction of a non-native species
Lake Tanganyika sardine (Limnothrissa miodon)
impacted little on pre-existing fish community
Thriving fishery
Give an example of how an invasive species effectiveness depends on the introduction site
Small-mouth bass (Micropterus dolomieu) into Ontario Lakes
- If lakes contained pelagic prey (e.g Coregonus sp. (Salmonidae)) then there was no effect on native top predator (Lake trout)
- If lakes lacked pelagic prey then bass fed on littoral fish and directly competed with lake trout
Give an example of a beneficial introduction into the Great Lakes
Zebra mussel (Dreissena polymorpha)
- Reduced eutrophication
- Provides a food source for migrating birds
