German wasp | Vespula germanica

German wasp

Vespula germanica

Coral bush | Ardisia crenata

Coral bush

Ardisia crenata

Purple loosestrife | Lythrum salicaria

Purple loosestrife

Lythrum salicaria

Pom pom weed | Campuloclinium macrocephalum

Pom pom weed

Campuloclinium macrocephalum

Canarybird bush | Crotalaria agatiflora

Canarybird bush

Crotalaria agatiflora

Peanut butter cassia | Senna didymobotrya

Peanut butter cassia

Senna didymobotrya

Rubber vine | Cryptostegia grandiflora

Rubber vine

Cryptostegia grandiflora

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Environmental Programmes

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Yabby

Cherax destructor

Common name:

Yabby

Scientific name:

Cherax destructor

Alternative common names:

Common yabby.

This crayfish can grow 10-20cm but some individuals attain a length of 30cm. Colour is variable and depends on water quality, but most take on a greyish-blue to vivid metallic blue colour. This is not an indigenous species and may have negative impacts on our wetland systems by competing against indigenous species. The burrowing activity may cause damage to dams and riverbanks.

Additional Info

  • Where does this species come from?

    Australia.

    What is its invasive status in South Africa?

    NEMBA Category 1a.

    Where in South Africa is it a problem?

    Not yet known to be invasive, but these crayfish are kept in aquaculture facilities, but closely related species have escaped and are proving invasive in some river systems.

    How does it spread?

    Dispersal through aquatic systems.

    Why is it a problem?

    This is not an indigenous species and may have negative impacts on our wetland systems by competing against indigenous species. The burrowing activity may cause damage to dams and riverbanks.

    What does it look like?

    Description: This crayfish can grow 10-20cm but some individuals attain a length of 30cm. Colour is variable and depends on water quality, but most take on a greyish-blue to vivid metallic blue colour. Habitat: A freshwater species colonising rivers, reservoirs, dams and lakes. During drought conditions, they can survive by aestivating down burrows in the mud. Breeding: Eggs are attached to abdominal appendages called pleopods and undergo preliminary development before they swim away as free-swimming juveniles.

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General News Updates

2019 National Symposium on Biological Invasio…

26-02-2019

This is your invitation to South Africa's 2019 National Symposium on Biological Invasions. The convention is hosted by the Centre for Invasion Biology (CIB), University of Stellenbosch, and the Biolo... Read more

2019 Invasive Species Training

22-01-2019

During the past five years (2014-2018), ISSA invasive species trainers have trained 4 000 in the identification of invasive species and laws pertaining to invasive species across South Africa.  ... Read more

Alien Grass Working Group

04-09-2018

Who are we? The South African National Alien Grass Working Group was jointly initiated by the South African Biodiversity Institute (SANBI) and the Centre for Excellence in Invasion Biology (C·I·B) in... Read more

Permits for planting indigenous Cynodon?

01-03-2018

On 16 February, 2018, South Africa's Department of Environmental Affairs issued amendments to the regulations and lists relating to the National List of Invasive Species.  Updates to the draft&n... Read more

Invasive species training 2018 dates released

28-02-2018

Interested in invasive species?  How much do you know about NEMBA invasive species compliance for landowners and organs of state? The South African Green Industries Council (SAGIC) have released... Read more

Communications post for Africa advertised

25-01-2018

The Nature Conservancy has advertised a brand new post:  Communications Manager, Africa Region. Knowledge of invasive species and water would be an asset in this post. See details below:    Job Titl... Read more