Migratory Pattern, Route & Abundance of Hilsa Shad

Bangabandhu Sheikh Mujibur Rahman Agricultural University

Salna, Gazipur-1706

Migratory Pattern, Route & Abundance of

Hilsa Shad ( Tenualosa ilisha )

Introduction:

Hilsa is considered as one of the tastiest fish due to its-

Distinctly soft oily texture, Mouth watering flavour and Superb mouthfeel.

During entire life, Hilsa shad migrates both from sea to freshwater and freshwater to sea.

The fish contributes about 12% of the total fish production and about 1% of GDP in Bangladesh.

The fish is- Marine; Freshwater; Brackish; Pelagic-neritic; and Anadromous;

It is found in rivers and estuaries in Bangladesh, India, Pakistan and Burma.

Breeds mainly in rivers during the southwest monsoon.

Habitat of Hilsa:

During the breeding season they ascend the rivers and

After spawning, return to the original habitat.

Eggs, larvae and juveniles have been found in the upper reaches of the rivers.

Distribution of Hilsa:

Figure 01: Hilsa Habitat in Bangladesh.

Migration of Hilsa:

Migration refers to rhythmic movement of animal which involves a journey from one place to another and come back again.

Hilsa spends the first year of its life in the lower reaches of the rivers and goes to the sea in the third year.

Figure 02: Migration Route of Hilsa.

Reasons Behind Migration:

Physical factors• Temperature, Current and tide,

turbidity, and light intensity

Chemical factors• Salinity, alkalinity, dissolved gases,

odor, tastes, and pollutants

Biological factors• Sexual development, blood

pressure

Figure 03: GIS Mapping for Water Quality in the River System.

Migratory pattern, route and abundance of Hilsa shad:

Two types of migratory pattern are seen for Hilsa shad in Bangladesh.

a. South-west monsoon migration. b. Winter migration.

Figure 03: Migratory Pattern of Hilsa.

Hilsa Spawning Grounds in Bangladesh:

It has four main spawning grounds in banglades. These are-

i. Dhalerchar of Charfashion in Bhola ii. Monpura in Bhola iii. Moulavichar of Hatia in Noakhali iv. Kalirchar of Sandwip.

Figure 04: Breeding Areas of Hilsa.

Feeding and growing grounds:

Juvenile Hilsa spends about 1-1.5 years in the Bay of Bengal for further growth and development.

After becoming sexually mature, they begin their journey to the estuary and river for spawning.

Figure 05: Migratory Route and Abundance of Hilsa Shad

November To January

January To March

March To May

Recommendations:

The migration route and pattern is now clearly known to us.

We must save this resource by stopping to capture this fish during migration periods.

We need to break all the water barrage system, which affects in Hilsa Migration.

We should avoid Jatka for Capturing during migration period.

So, we can ensure Sustainable Hilsa Stock in the River.