Fish migration and fish passes

Fish migration and different types of fish

passes

PRESENTED BY- MANISH KUMAR

ID NO- 40024

Introduction Migration - The movement of large number of animals from one place to another for various reasons like1. Food Gathering2. Breeding3. Temperature Adjustments

Causes

I. To avoid unfavorable conditionsII. To enhance the survival of offspring'sIII. To exploit the available food in feeding areasIV. Population pressure (competition and

predation)

Types of Migration

SPAWNING MIGRATION

DIADROMOUS

ANDROMOUS

CATADROMO

US

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

• 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

Causes of migration in fishesHeape (1961) – 4 primary reasons of fish migrationGametic 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 respectivelyAlimental 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

Anadromous Migration

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

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

Salmon Life Cycle

Death

Egg

Alevin

Fry

ParrSmolt

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

CATADROMOUS MIGRATION

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)

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

Eel life cycle

POTAMODROMOUS MIGRATION

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

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

OCEANODROMOUS MIGRATION

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.,

Showing pattern of movements in Oceanodromous fish migration

Spawning area

Nursery area

Feeding area

Winter area

Winter area

Feeding area

Egg or larvae

Spent

Brooders

Recruitment intoAdult population

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)

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

Factors influencing migration

Influenced by several Physical, Chemical, and Biological factors

Physical factorsTemperatureLight intensityPhotoperiodWater currentTurbiditydepth

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

Chemical factors

Chemical factorspH SalinityOdour 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 distancesBut some species like Salmon, Hilsa, Anguilla etc., are euryhaline and can adjust to large salinity variations i.e. Diadromous fishes

Biological factors

• Biological factors FoodMemory Stage of sexual maturityPredators and competitorsHormones

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

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)

FISH PASSES

• 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.

Fish passes

HISTORY

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.

Natural Bypasses or Fishways• 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.

Pool-Weir Fishway• 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.

Pool-Weir Fish wayThe 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.

What Factors Need to be Considered When Designing a Fishway

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

DENIL FISHWAY• 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.

STEEP PASS FISH WAY 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.

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.

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.

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.

THANKS FOR KINDLY ATTENTION