by prachee rajput B.U Bhopal (IND) 462026

1. Migration in fishes
BY
prachee rajput
2nd SEM Zoology
Dept. Of Zoology and Applied Aquaculture
Barkatullah University Bhopal

2. SYNOPSIS
Introduction
Types
a) Diadromous
b) Anadromous
c) Catadromous
d) Oceanodromous
e) Potadromous
 Causes of migration
 References

3. Introduction
• It is sometimes the case in fishes that the life history
needs a population ( e.g, foraging and reproduction)
cannot be met by a single habitat . This is due to
variability in the habitat conditions (e.g, temperature), or
to the changing needs of the population itself (e.g,
foraging habitat vs. Spawning habitat). In such cases the
fitness of individuals benefits from movement to an
alternate habitat. As a result, many fishes have evolved a
life history that includes coordinated movement from
one habitat to another . This synchronous, directed
movement of part or all of a population between discrete
habitats is called “migration” .

4. TYPES
Fish migration are typically grouped into five
categories, based somewhat arbitrarily on their
relationship to the seawater/freshwater boundary.
a) Diadromous
b) Anadromous
c) Catadromous
d) Oceanodromous
e) Potadromous

5. Diadromous:
It is derived from the classical Greek word where
“dia” means “through” and “dromous” means
“running”. In this type the fishes migrate between
fresh water and sea water e.g, pacific salmonids

6. Anadromous:
It is derived from a Greek word where “ana” means
“up” and “dromos”means “course” . In this fishes
migrate from the sea up into fresh water to spawn,
or stay entirely in sea water and migrate upstream to
spawn e.g, pacific salmon species such as Chinook
(king), Coho (silver) etc.

7. Catadromous:
It is derived from a Greek word where “kata” means
“down” and “dromos” means “course”. In this type
the fishes migrate from fresh water into the sea to
spawn, or stay entirely in fresh water and migrate
downstream to spawn e.g, eels of genus Anguilla.

8. Oceanodromous:
In this type fishes live and migrate only in sea
water e.g, Atlantic herring, sardines etc. These
fishes nearly migrate to colder water regions
for the purpose of spawning and then return
to their parental area.

9. Potadromous:
Migrations that occur entirely within freshwater are
classified as Potadromous. Potadromous migrations
can occur solely in lakes e.g, lake trout, salvelinus
namacycusb.

10. Causes of migration
According to some scientists the migration in fresh water
fish arise basically as a result of insufficient food supply
in rivers, whereas in marine fishes, it is more favourable
condition and better protection for developing eggs in
the rivers than in open sea. there are three mechanisms
on which migration can brought among these fishes.
a) Gametic migration
b) Alimental or Feeding migration
c) Climatic or wintering migration
d) Osmoregulatory or protective migration

11.  Gametic migration: This type of fish migration is
brought for better survival and proper development of
their eggs and larvae.
 Alimental or Feeding migration: This is one of the
important migration which is brought about mainly due
to shortage of suitable food supply in the wintering or
spawning ground.
 Climatic or wintering migration: Such type of migration
can help to survive in a protective area which depend
on environmental changes.
 Osmoregulatory or protective migration: Spawning,
feeding and wintering migration can all be regarded as
the protective migration as they ensure the further life
of fish.

12. THANKYOU