This document discusses fish migration and different types of fish passes. It introduces various reasons for fish migration including food gathering, breeding, and temperature adjustments. It then describes the main types of fish migration such as spawning migration, diadromous migration between fresh and salt water, and potamodromous migration within freshwater systems. The document focuses on anadromous migration patterns in salmon and catadromous migration in eels. It also discusses oceanodromous migration over long distances in oceans. Finally, it covers factors influencing migration and designs of fish passes to help fish migrate upstream over barriers.

1. Fish migration and
different types of fish
passes
PRESENTED BY- MANISH KUMAR
ID NO- 40024

2. Introduction
Migration - The movement of large number of
animals from one place to another for various
reasons like
1. Food Gathering
2. Breeding
3. Temperature Adjustments

3. Causes
I. To avoid unfavorable conditions
II. To enhance the survival of offspring's
III. To exploit the available food in feeding areas
IV. Population pressure (competition and
predation)

4. Types of Migration
SPAWNING MIGRATION
DIADROMOUS
ANDROMOUS CATADROMOUS
POTAMODROMOUS OCEANODROMOUS
 From sea
water to
Fresh water
 From fresh
water to
sea water
 From one
freshwater
habitat to
another fresh
water
 From sea
water to
sea water

5. • Diadromons fishes – migrate between sea
& fresh water
– Anadromous – major part sea but fresh water
during breeding season e.g. Salmon & Hisla
– Catadromous – major part fresh water but sea
during breeding e.g. Anguilla (eel fish)
– Amphidramons – fresh water to sea & vice
versa. Eg. Gobies
• Potamodromons – migratory, confined to
fresh water eg. Corps and trouts, Mahasees
move up stream along Himalaya rivers
• Oceanodromons – migratory, confined to
sea only eg. Tunnas, Mackerels

6.  Causes of migration in fishes
 Heape (1961) – 4 primary reasons of fish migration
 Gametic migration (Spawning/breeding migration)
◦ Better survival & proper development of egg/larva
◦ Stop feeding prior to migration or reduced drastically
◦ Energy requirement (fat deposit) e.g. Chum salmon spp. 25,810 Ca &
28,390 cal by male and female respectively
 Alimental of Feeding Migration
◦ Due to shortage of food (Suitable/wintering/spawing)
◦ Better food facilities, better survival & fast growth
◦ Grow fast in size & mature & produce more eggs.
 Climate or Wintering Migration
◦ Due to inactive physical condition and low BMR (Basic Metabolic rate)
◦ Depends on fish condition and environment
◦ Achieved by hormonal and physiological changes
◦ Deposit mainly as fat deposits
◦ Among freshwater species (Grass corp.) more to wintering grounds.
 Osmoregulatory or Protective Migration
◦ Spwing, feeding & wintering migration can all be regards as protection
migration as they ensure further life of fish
◦ These migration are not cyclical

8. Anadromous Migration

9. Anadromous
• Fishes which migrate from the sea into fresh water to
spawn
‘OR’
• Ones which stay entirely in sea water and migrate
upstream to spawn
• An Anadromous fish, born in fresh water, spends most
of its life in the sea and returns to fresh water to spawn
• Adults usually die after spawning
• Their adaptations to conditions of different habitats are
particularly with regard to salinity of the water
• Common examples - Salmon, Trout, Hilsa, striped bass,
Sea lamprey and sturgeon

10. Anadromous adaptations by salmon
• Salmon hatch in small freshwater streams
• From there they migrate to the sea to mature (1
to 5 years)
• When mature, the salmon return to the same
streams where they were hatched to spawn, this
homing behaviour has been shown to depend on
olfactory memory
• Salmon are capable of going hundreds of
kilometres upriver, and humans must install fish
ladders in dams to enable the salmon to get pass

11. Salmon Life Cycle

12. Death
Egg
Alevin
Fry
Parr
Smolt
Adult
Spawner
SPAWN IN
Redd
Spawning beds in FW
Adults change
significantly once they
enter freshwater. They
change color, stop
eating, males develop a
kype (hooked jaw), and
they stop drinking
Entering fresh water
After spawning spawners die
Average number of eggs
deposited per female is
around 3,000 eggs,
Remain in the gravel for
another 1-2 months, yolk sac
2-3 months for hatching
Young free-
swimming, 1-2
inches, learn to
feed
2-5 inches, Parr marks, As
salmon mature into a smolt,
the Parr marks disappear
When salmon prepare
to migrate from
freshwater to the
ocean, they become
smolts, spend some
time in estuaries
before heading to
the ocean
Salmon spend 1-5
years in the ocean,
80% of their life cycle
Entering into Sea water

13. CATADROMOUS MIGRATION

14. CATADROMOUS
• Catadromous fishes are ones which migrate
from fresh water into the sea to spawn
‘OR’
• Ones which stay entirely in fresh water and
migrate downstream to spawn
• Best examples - eels of the genus Anguilla,
numbering 16 species, the best-known of
which are the North American eel (A. rostrata)
and the European eel (A. anguilla)

15. Cont’d…
• It travels several thousand km starting from rivers
reaching spawning grounds in sea
• After spawning adults die
• Larvae of eel drift from spawning grounds, takes
several months to 3 years, to reach river &
undergo metamorphosis to become adults
• Young ones are born in the ocean, mature in
freshwater or estuarine habitats, and return to
the ocean to spawn
• This makes them Catadromous fish

16. Eel life cycle

17. POTAMODROMOUS
MIGRATION

19. POTAMODROMOUS
• Truly migratory fishes
• The movement is confine to fresh water
• Some examples- carps, trouts, catfishes etc.,
• Travels long distances in rivers to locate
suitable spawning grounds (Some migrates
Upstream and some downstream)
• After laying eggs, the parents return to the
feeding area as food is available only for the
young ones & cannot support the adults

20. Cont’d…
• Besides spawning needs, this type of
migration may also be due to competition
• Such as increase in population,
• Scarcity of food may also force fishes to
migrate other places, where food is abundant

21. OCEANODROMOUS
MIGRATION

22. OCEANODROMOUS
• These are truly migratory marine fishes
• Travel long distances with in sea to spawn & return to
the feeding areas
• There are no barriers within the sea and fishes have
learned to migrate in order to take advantage of
favourable conditions wherever they occur
• They differ mainly from one another by the extent of
their migration
• Examples- Mackerels, Tunas, Cod, Herrings, etc.,
• During migration these species visit spawning areas,
nursery areas, feeding areas, winter area etc.,

24. Showing pattern of movements in
Oceanodromous fish migration
Spawning
area
Nursery
area
Feeding
area
Winter
area
Winter
area
Feeding
area
Recruitment into
Adult population

25. Migration of Herring
• Herrings are found in the North Atlantic and
North pacific Oceans, and exhibit seasonal
migration covering a large
• Also undertake daily vertical migration (short
distance and for food)
• Also undertakes annual spawning migration
to the spawning ground near the coast (during
this they do not exhibit vertical migration)

26. Cont’d…
• After spawning , the larvae drift along the
water current to wintering area near the
coast, where they feed and grow
• On becoming adult, they join the older fish in
migration cycle
• And return to spawning area when mature
• This takes 4-6 years

27. Factors influencing migration
Influenced by several Physical, Chemical, and
Biological factors
Physical factors
Temperature
Light intensity
Photoperiod
Water current
Turbidity
depth
Temperature is of more importance,
in sea water rise in temperature
provides stimulus to Salmon for
Migration.
In fresh water temperature rise
fishes moves upstream for
spawning

28. Chemical factors
Chemical factors
pH
Salinity
Odour
Taste of water
Salinity of water restricts the movement of fishes.
Freshwater species are stenohaline (intolerant to large salinity changes).
Hence they remain confined to fresh water do not undertake migration involving long
distances
But some species like Salmon, Hilsa, Anguilla etc., are euryhaline and can adjust to
large salinity variations i.e. Diadromous fishes

29. Biological factors
• Biological factors
Food
Memory
Stage of sexual maturity
Predators and competitors
Hormones
 Availability of food is the primary factor for the survival of juveniles
 Memory guides some species during migration e.g. Salmon returns to the same
area of river for spawning, where its own hatching & development took place

30. Role of Hormones
• Observed in Diadromous fishes
• The osmo - and ionic regulation in these species
is controlled by Hormones such Prolactin,
Corticotrophin, growth Hormone, etc., secreted
by the pituitary gland
• Prolactin is the most important hormone that
acts on gills, skin, kidney, urinary bladder and the
intestine and influence the water and ion
regulation
• It also reduces the loss of Na ions in the fresh
water fishes (Eel)

32. • Fish ways commonly called fish ladders but also known as fish passes.
• Definition :
A fish ladder (or fish way , fish pass) is a structure designed to allow
fish the opportunity to migrate upstream over or through a barrier to fish
movement.
• In Australia also referred to as fish steps.

33.  In 1852–1854, the Ballisodare Fish Pass was built in County Sligo,
Ireland, to draw salmon into a river that had not supported a fishery.
 In 1880, the first fish ladder was built in Rhode Island on the Pawtuxet Falls
Dam.

34. • Natural: In this type of fish passes the approach routes of fish may be
strengthened with concrete to the natural rock with the natural rock with the
object of concentrating flows previously diffuse, reducing turbulence and
deepening pools.

35. • The Pool design (Fish ladder) : It consists of a series of pools arranged in a ladder-
like manner from downstream to upstream. The flow of water from pool to pool
may be over solid obstacles or through passages between obstacles or a
combination of two types. Each pool is designed in such a way that it provides
adequate resting grounds for the ascending fishes.

36. Pool-Weir Fish way
The oldest styles of fish ladders.
Series of small dams and pools of regular length.
 Effective for jumping fish.
Create a long, sloping channel for fish to travel around
the obstruction.
Fish must jump over from box to box in the ladder.

37.  Flows.
 Energy dissipation.
 Resting areas.
 Drop between pools (fish way slope).
 Attraction velocities.
 Entrance locations.
 Space in pools.

38. • The Deniel design: It is a narrow channel with closely spaced baffles set at
an angle with the axis of the channel. In this kind of fish way, the force of
fast flowing water is minimized and fishes can negotiate them easily.

40.  The same principle as Denil fish ways.
 Use many baffles to simulate a rapids to a fish and present
the fish with many options with respect to water speeds.
•
 Narrower than Denil fish ways.
 Made up of any metal.
 Work best at small barriers where inexpensive passage is
needed.

42. vertical-slot fish passage
Allows fish to swim upstream without leaping
over an obstacle.
 Tend to handle reasonably well the seasonal
fluctuation in water levels on each side of the
barrier.
 Used by all types of migrating fish.

43. FISH LOCK
• The Fish lock: It is an arrangement for the
regulation of flow of water with the help of
mechanical gates. The inflow and outflow can
be regulated thus providing fishes with the
passage to move either way.

44. Simple sluice or inclined chute
• Simple sluice or inclined chute: The chute is
an inclined channel or a sort of waterfall with
deep descent. The effective width of the
channel is actually much less than the width
of sluice and many sharp turns cause cross
currents that are very difficult to be
counteracted by large fishes.