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Arican Catfsh

Clarias gariepinus

This is one o the most disastrousinvasive alien sh species (native o

Arica). It eats almost everything it

encounters. They not only eed on

indigenous sh species, but also on

snails, amphibians and juveniles o

natve wading birds, among other

indigenous biodiversity.

Though the species introduction

has been stopped now, popula-

tions rom previous introductions

continue to threaten the continued

existence o many native aquatic

species.

The primary Exotic & Invasive sh species released

into the various reservoirs of Kerala

Prepared byRobin Kurian Abraham

Tilapia

Oreochromis mossambica

This species and a similar but larger

species, the Nile Tilapia (O. nilotica)

have a high ecundity and growth

rate and they can breed naturally.

They are competing with many

smaller native sh species, and

gradually occupying their niches.

They have established populations

in almost all water bodies in Kerala,

even inside protected areas.

Common Carp

Cyprinus carpio

This large-bodied species rom

temperate Asia and Europe has

been widley introduced into the

water bodies o many countries

around the world. They are a prob-

lem species in their introduced

range, causing damage to plant and

animal communities in reshwater

ecosystems. They also negativley

modiy the habitat into which theyare introduced, due to their grub-

bing eeding habits.

Image: A Bijukumar

Image: Robin Abraham

Image: Robin Abraham

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Rohu

Labeo rohita

This species eats mainly

zooplankton, but as it grows, it eatsmore and more phytoplankton, and

as a juvenile or adult is a herbivo-

rous column eeder, eating mainly

phytoplankton and submerged

vegetation. As a result, they come

in competition with many native

species occupying the same

ecological niche.

Mrigal

Cirrhinus mrigala

They are bottom dwellers. It is

an illiophage in its eeding habit,

consuming detritus and decayed

vegetation, which orm its princi-

pal ood components, while phy-

toplankton and zooplankton also

comprise a portion o its diet. theywould come into competition with

native species like Hypselobarbus

spp. and Puntius spp., which use a

similar habitat.

Catla

Catla catla

This species is used as the surace

eeder component in Indian

Major Carp (IMC) polyculture

systems. They can grow to immense

sizes and can cause serious impact

on local reshwater ecology in the

Western Ghats already critically

afected and ragile aquatic

ecosystems.

Indian Major Carps

Image: A Bijukumar

Image: A Bijukumar

Image: A Bijukumar