Hilsa( Tenualosa ilisha) Migration
-
Upload
sulav-indra-paul -
Category
Education
-
view
805 -
download
6
Transcript of Hilsa( Tenualosa ilisha) Migration
![Page 1: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/1.jpg)
Bangabandhu Sheikh Mujibur Rahman Agricultural
University
Salna, Gazipur-1706
![Page 2: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/2.jpg)
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 tofreshwater and freshwater to sea.
The fish contributes about 12% of the total fish productionand about 1% of GDP in Bangladesh.
![Page 3: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/3.jpg)
The fish is- Marine; Freshwater; Brackish; Pelagic-neritic; and Anadromous;
It is found in rivers and estuaries in Bangladesh, India, Pakistan andBurma.
Breeds mainly in rivers during the southwest monsoon.
![Page 4: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/4.jpg)
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 reachesof the rivers.
![Page 5: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/5.jpg)
![Page 6: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/6.jpg)
Migration refers to rhythmic movement of animal which involves ajourney from one place to another and come back again.
Hilsa spends the first year of its life in the lower reaches of therivers and goes to the sea in the third year.
![Page 7: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/7.jpg)
![Page 8: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/8.jpg)
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
![Page 9: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/9.jpg)
![Page 10: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/10.jpg)
Two types of migratory pattern are seen for Hilsa shadin Bangladesh.
a. South-west monsoon migration.b. Winter migration.
![Page 11: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/11.jpg)
![Page 12: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/12.jpg)
It has four main spawning grounds in banglades. These are-
i. Dhalerchar of Charfashion in Bholaii. Monpura in Bholaiii. Moulavichar of Hatia in Noakhaliiv. Kalirchar of Sandwip.
![Page 13: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/13.jpg)
![Page 14: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/14.jpg)
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.
![Page 15: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/15.jpg)
November To January
March To May
![Page 16: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/16.jpg)
![Page 17: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/17.jpg)
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.
![Page 18: Hilsa( Tenualosa ilisha) Migration](https://reader033.fdocuments.net/reader033/viewer/2022051009/587a6bc11a28ab8a2a8b6a23/html5/thumbnails/18.jpg)