This document summarizes fish migration. It defines fish migration as seasonal movement that implies returning to the starting point. It discusses different types of migratory fish species and patterns of migration including diadromous, potamodromous, and oceanodromous. The causes of migration are to avoid unfavorable conditions and exploit food sources. Physical, chemical, and biological factors influence migration. Advantages include access to more food, breeding places, and distribution while avoiding competition. Conservation of migratory fish is important for sustaining fisheries and coastal communities.

1. FISH MIGRATION
Submitted by :-
ANURADHA NASKAR
(MFSc. 1st Sem.)
DEPARTMENT OF ZOOLOGY AND APPLIED AQUACULTURE
BARKATULLAH UNIVERSITY, BHOPAL
MADHYA PRADESH, 462026

2. CONTENTS
▪ INTRODUCTION
▪ DEFINITION OF MIGRATION
▪ MIGRATORY SPECIES
▪ TYPES OF FISH MIGRATION
▪ PATTERNS OF FISH MIGRATION
▪ CAUSES OF FISH MIGRATION
▪ FACTORS INFLUENCING MIGRATION
▪ ADVANTAGES OF MIGRATION
▪ CONCLUSION

3. INTRODUCTION
Generally fishes restrict their movements within small territorial limits
and do not go out of their home range. Some species travel long
distances moving from place to place for food or for breeding. Migration
may take place in vertical direction or horizontal direction. Some species
are able to attain great speed, others swim slowly but travel long
distance. Some species migrate within the fresh or marine water, others
may move from fresh water to marine water and vice versa.

4. DEFINITION OF MIGRATION
 Thompson (1952) – “A true migration as seasonal movement that implies
return to the starting point.”
 Baker (1978) – “ The act of moving from one spatial unit to another.”
 Dingle (1980) – “Specialized behavior especially evolved for the
displacement of the individual in space.”
 In general – Migration of fish defined as a class of movement which
involves a long journey to a definite area for some purpose and impels
the migrants to return to the region from which they have migrated.

5. MIGRATORY SPECIES
▪ The cod (Gadus morhua)
▪ Herrings (Clupea harengus)
▪ Salmon (Salmo sp.)
▪ Pacific salmon (Oncorhynchus)
▪ TheTunnas (Thunnus thynnus)
▪ Eel (Anguilla sp.)
▪ Hilsa (Hilsa ilisha)

6. TYPES OF FISH MIGRATION
Migration can be any one of the following types :-
 Climatic migration, undertaken to search better climatic and
environmental conditions.
 Gametic migration, is undertaken for spawning.
 Alimental migration, is undertaken in search of food and water.

7. PATTERNS OF FISH MIGRATION
The following terms are generally used to describe the patterns of
migration :-
 Diadromous migration : In this type of migration pattern fishes
move between sea and freshwater and can
be of 3 types :-
1. Anadromous migration
2. Catadromous migration
3. Amphidromous migration

8. 1. Anadromous migration :- In this type of migration fishes are migrate
from marine water to fresh water. e.g.
Hilsa ilisha, Salmo salar, Oncorhynchus nerka.

9. 2. Catadromous migration :- In this type of migration, fishes are
migrate from fresh water to marine water.
e.g. Anguilla anguilla, Anguilla rostrata.

10. 3. Amphidromous migration :- In this type of migration fishes are
migrate from freshwater to marine
water or vice versa. e.g. mountain mullet, sirajo goby, river goby etc.

11.  Potamodromous migration : In these type of migration pattern
migratory fishes remain confined to fresh water. e.g. carps and trouts
etc.

12.  Oceanodromous migration : In this type of migration pattern
migratory fishes live and migrate
in the marine water. e.g. cod, herrings, mackerels and tunnas.

13. CAUSES OF MIGRATION
Fish appear to migrate
 to avoid unfavourable conditions,
 to enhance the chances of survival of the offsprings, and
 to exploit the available food in feeding areas.
 Population pressure is also considered a possible cause of migration.
The fish migrate in search of new suitable areas where food is
abundant and competition is minimum.

14. FACTORS INFLUENCING MIGRATION
 Physical Factors – bottom materials, depth of water, temperature,
light intensity, turbidity etc.
 Chemical Factors – salinity, pH, smell and taste of water.
 Biological Factors – food, sexual maturity etc.

15. ADVANTAGES OF MIGRATION
 Advantages :- 1) Fish get more food, better climatic condition
and breeding place.
2) Fish gets better adapting in new places.
3) There will be wide distribution.
4) Less competition.

16. CONCLUSION
The migration route and pattern is now clearly known to us. Fishes
generally employment and income for millions of people in world. Fish
remains a subsistence food for many poor coastal communities. That’s
why we must save this resources by stopping to capture this fish species
during migration periods. We must give chance to fish species to grow
up willingly. So we can enrich with this natural resources and can able to
export fish species by fulfilling our countries demand. That help us in
future implementation.

17. Thank You