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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Perch

Perca fluviatilis

Common name:

Perch

Scientific name:

Perca fluviatilis

:

Perch live in schools, usually in the top 50 metres of water, and often mix with other species of fish. Redfin perch are a popular sport fish with some anglers because of their fighting qualities and taste. However, they are also voracious predators of other fish and invertebrates. They can destroy recreational fisheries in enclosed waters by stunting the growth of other fish species or eliminating them.

Additional Info

  • Where does this species come from?

    Eurasia

    What is its invasive status in South Africa?

    Category 1b (National Parks, Provincial and Forestry Reserves; Category 3 (all other discrete catchment systems in which they occur).

    Where in South Africa is it a problem?

    Western Cape and Florida Lake in Gauteng.

    How does it spread?

    The sticky, ribbon-like structure of the eggs is responsible for the spread of this fish to most bodies of permanent water; the eggs are transferred to other environments when they become entangled around the legs of wading birds.

    Why is it a problem?

    As predators upon zooplankton, macroinvertebrates and fish, perch have the potential to significantly alter native freshwater communities and can devastate native fish populations by carrying the Epizootic Haematopoietic Necrosis Virus (EHNV).

    What does it look like?

    Description: The perch is a distinctive fish with a deep greenish body marked with dark vertical bands and the dorsal fin is stiffened with spines. The tail and anal fins are orange and the gill covers are tipped with a sharp spine. The erect dorsal fin has a noticeable black spot at the rear. They can weigh up to 4kg and reach up to 25cm in length. Habitat: This species prefers slow-moving rivers, deep lakes and ponds, where it stays close to patches of vegetation and submerged objects. Perch require well-oxygenated water to survive. Breeding: Spawning takes place in April, and the very sticky eggs are produced in bands. Females twine these bands around submerged vegetation or between rocks, and the males follow them and fertilise the eggs. The young fish hatch after about three weeks and remain amongst the egg bands until the yolk sac is exhausted. They then venture into more open water and feed on planktonic animals. As they grow, they begin to form shoals close to the bank. Males mature when they reach 7-8cm in length, females when they are 10cm.

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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