Exotic fish species Merits and demerits of exotic fish species

1. TOPIC– INTRODUCTIONOF EXOTICFISH SPECIES.
SUBMITTEDTO - DEPARTMENTOF
ZOOLOGYANDAPPLIEDAQUACULTURE,
BARKATULLAHUNIVERSITY,BHOPAL,
MADHYAPRADESH.
SUBMITTEDBY – SMRITIBISWAS
M.F.ScAPPLIEDAQUACULTURE
4th semester
Enrollment No – R218099020003

2. Contents
 INTRODUCTION.
 HISTORY.
 TRAITSOF EXOTICSPECIES.
 EXOTICSPECIES IN INDIANAQUACULTURE.
 REASONFOR INTRODUCTIONOF EXOTICSPECIES.
 MERITSOF EXOTICSPECIESINTRODUCTION.
 IMPACTSOF EXOTICSPECIES.
 CONTROL ANDMANAGEMENT.
 CONCLUSION.

3. INTRODUCTION
 Exotic species is any species, including its seeds, eggs, spores, or
other biological material capable of propagating that species, that
is not native to that habitat.
 Exotic species belonging by nature or origin to another part of the
World or brought in from abroad.
 Various exotic species have been introduced in the Indian water
bodies and some are now well established too with varying
experiences.
 Accidental escapes and even purposeful releases of aquaculture
species that are not native to a country create biological pollution
with irreversible and unpredictable ecological impacts.

4. Sir, Francis Day, the author of the “Classical work on the Fish fauna of Indian
region”, was probably the first person who tried to introduce the brown trout, Salmo
trutta fario in the Nilgiri waters in the year 1863, but his attempt was unsuccessful.
This was followed by introduction of several exotic fish species from various parts of
the world to different regions of India for augmenting fish production through
aquaculture, for sport fishery, for mosquito / weed control, for ornamental purpose etc
with successes and failures.
The larvicidal fishes, such as, Poecilia retiuculta and Gambusia affinis were
introduced in the year 1908 and 1928 respectively, to contain mosquito larvae in
confined waters.
There are hundreds of ornamental fish species being imported to our country since
the aquarium trade is in progressive growth stage/ insecticidal value of these species is
not well established.
HISTORY

5. TRAITS OF EXOTICSPECIES
Many features have been attributed in invasive species and invaded
ecosystem.
The common invasive species traits include:
Fast growth.
Rapid reproduction.
Phenotypic plasticity.
Tolerance of a wide range environmental condition.
Ability to live of a wide range of food type.

6. EXOTICSPECIES IN INDIANAQUACULTURE
SL. NO. Common Name Scientific Name Year of
Introduction
Source
1. Common carp Cyprinus carpio 1980 Srilanka
2. Bighead carp A. nobilis 1959 Bangladesh
3. Golden carp C. carassius 1968, 1970 England
4. Doctor fish Tinca tinca 1974 England
5. Tilapia O. mossambica 1972 Bangkok
6. Nile Tilapia O. niloticus 1952 Thailand, Israel
7. African Catfish Clarius gariepinus 1978 Thailand
8. Brook trout Salmo fontinalis 1959 Canada
9. Pangasius sutchi Pangasius
hypophthalamus
1997 Vietnam
10. White leg shrimp L. vennamei 2010 USA
[Source – NBFGR, Lucknow]

7. List of restricted, banned and not approved Exotic
Freshwater Ornamental fish species.
SL.NO. SCIENTIFIC NAME COMMON NAME CATEGORY
1. Astronotus ocellatus Oscar Restricted
2. Aequidens rivulatus Green terror Restricted
3. Labeo chrysophycon Black shark minnow Banned
4. Leptobarbus hoeveni Maroon shark Banned
5. Osteoglossum bicirrhosum Arowana Banned
6. Haplarchus psittacus Acara Restricted
[Source – NBFGR, Lucknow]

8. INTRODUCTIONOF NEWSPECIES
Artificial
Introduction
Superior
Competition
Occasional
Introduction
Species Based
Mechanism
Conditions that
lead to
establishment of
exotic species

9. ARTIFICIAL INTRODUCTION - The introduction of new species to specific
habitats or reintroduction of species to the place where it was once common, in
order to restore natural balance to gain commercial profit.
OCCASIONAL INTRODUCTION - Many times species are introduced unconsciously
or by accident. The occasional introduction has severe impact on local community structure
and balance of ecosystem.
CONDITIONS THAT LEAD TO ESTABLISHMENT OF EXOTIC SPECIES – These
mechanism generally fall into two categories. One mechanism focus on the exotic species and
other one focus on the invaded ecosystem.
SPECIES-BASED MECHANISM - Species based characteristics focus on competition
among different fish species. All fishes are able to compete in some manner in order to
survive and persist, invasive species have specific trait or combinations of specific traits that
make them especially good competitors.
SUPERIOR COMPETITON - Invasive species can coexist with native species for an
extended time and only gradually does the superior competitive ability of an invasive species
become apparent, as population grow larger and denser, and slowly increases the risk of
extinction to other species.

10. MERITSOF EXOTICSPECIES INTRODUCTION
 Improve production and economic benefits from fisheries
and aquaculture.
 Use of exotic species for fisheries and aquaculture
diversification deal with rising demand for food and
nutritional security.
 The development of aquaculture Worldwide.

11. IMPACTS OF EXOTICSPECIES
Economic
Impacts
Ecological
Impacts
Genetic
Dilution
Transmission
of Diseases
Impacts on
Biodiversity

12. ECOLOGICAL IMPACTS
 Competition of exotic species with the native species
for living space with same niche preference.
 For food with fishes of similar types of feeding habits,
or of omnivorous feeding habits or predation on native
fishes by these, spreading parasites and pathogens.

13. IMPACTS ON BIODIVERSITY
 Habitat destruction.
 Invasive species cause loss of
biodiversity including species
extinction and changes in
hydrology and ecosystem
function.
 The impact on global
biodiversity of human
introduction of non-native
species that have subsequently
become invasive is subjective.

14. TRANSMISSION OF DISEASES
 Particular concern to exotic species is that the level of
uncertainty will be higher with new introduction on what
pathogens may be present and may cause problems in the
new environment.
 The diseases which comes from other country to India is –
 Epizootic ulcerative syndrome.
 Epizootic haemorhagic necrosis.
 Taura syndrome.
 Yellow head disease.

15. GENETIC DILUTION
 The genetic impact of introduction of exotic fishes on native
fishes can be classified into two categories:
1. Reduction of effective population size by the ecological,
biological and genetic effect of introduction.
2. Alteration/extinction of gene pools of the species /stocks by
cross breeding or hybridization and backcrossing.

16. ECONOMICAL IMPACT
 The economical impacts can be seen at two levels –
Capture fisheries and Aquaculture.
 Economic costs due to invasive species can be separated into
direct costs due to production loss and management costs of
invasive species.
 Since the exotic fish species never fetch higher price than the
native varieties and also the decline of native fish production is
observed in the presence of exotic species in natural waters,
the total economic returns declined for the stakeholders of the
capture fisheries.
 In aquaculture however it provided immediate gain, in most
cases without consideration of the long term ecological
consequences.

17. STRATEGIESFOR INTRODUCINGEXOTICFISHSPECIES
 Introduction of fishes should be avoided and attempt should be made to
enhance the production of native species by biomanipulation or
biotechnological means.
 If the introduction is essential, highest precautions should be taken
before introduction and should not be allowed in the natural water
before proper study of long term impact on the ecosystem.
 A nodal agency or panel should be made responsible to study the
impacts and risks or benefits of the proposed introduction.
 The import and cultivation of broods or seeds of certain species which
have proved as harmful to the native fauna and ecosystem as a whole
should not be permitted at all.
 Stringent quarantine measures should be followed for the imported live
specimen consignments in ornamental fish trade. It should be ensured
that they don’t escape into natural waters, even accidentally.
 Banned or unofficial / illegal introduction or trade of fishes should be
penalised by law. A comprehensive legislation needs to be introduced.

18. CONCLUSION
Introduction of exotic fish species would be a threat to
the existing species diversity.
The introduction of species have greater adverse
impact on aquatic ecosystem and also on culture
practices.
Species introduction result in competition for limited
food, space, ecological niche and may results in genetic
erosion , predation and pathogen entry.
Introduction of exotic species can be used for broadening species
diversity in aquaculture systems of a particular country and also
for economic benefits.
The recent action by the government of India to introduce only
SPF L. vennamei and controlled culture of P. hypophthalamus are
the new steps in this direction.

19. References
Handbook of fisheries and aquaculture, ICAR.
Mishra et al. (2013) Introductions of exotic fish species
into Indian waters: an overview of benefits, impacts, issues
and management.
Sambid (2017) Exotic Fish Species Introduction in India
and Its Impacts.