Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Availability of Vulnerable Elasmobranches in the Marine Water of Bangladesh

Roy Bikram Jit
Marine Fisheries Survey Management Unit, C.G.O-2, 6th floor, Agrabad, Chittagong, Bangladesh.

Nripendra Kumar Singha
Marine Fisheries Survey Management Unit, C.G.O-2, 6th floor, Agrabad, Chittagong, Bangladesh.

S. M. Hasan Ali
Marine Fisheries Survey Management Unit, C.G.O-2, 6th floor, Agrabad, Chittagong, Bangladesh.

Md. Gaziur Rhaman
Marine Fisheries Survey Management Unit, C.G.O-2, 6th floor, Agrabad, Chittagong, Bangladesh.

Abstract/ Executive Summary:

A study was conducted about vulnerable shark and ray species availability and their percentage composition in two fish landing centers at Fishery ghat, Chittagong and BFDC fish harbor, Cox’s Bazar district during April 2006 through March 2012. A total of 35 species (11 shark and 24 ray species) was identified within these six years. Out of 35 species, only one vulnerable shark species, the silky shark Carcharhinus falciformis (Muller and Henle, 1839), was not abundant all the year round and three were vulnerable ray species, Javanese cow ray Rhinoptera javanica (Muller and Henle, 1841), banded eagle ray Aetomylaeus nichofii (Bloch and Schneider, 1801) and white spotted shovelnose ray Rhynchobatus laevis (Bloch and Schneider 1801) were found throughout the year during the study period. The average percentage composition by weight of C. falciformis was 1.38 and the availability of average number was 3202. The average percentage contribution and the landed average number of vulnerable R. javanica, A. nichofii and R. laevis species were 1.46% (948 numbers), 0.61% (554 numbers) and 0.54% (298 numbers), respectively of the total catch.

Keywords: Vulnerable elasmobranchs, Percentage composition, Total catch, Abundance, Sharks, Rays.

Location: Chittagong and Cox’s Bazar districts, Bangladesh.

Start Date: 00-04-2006

End Date: 00-03-2012

Program Area: Conservation and Biodiversity

Commodity: Aquatic animal

Objectives:

To find out the abundance of total sharks and rays, availability of vulnerable shark and ray species in the Bay of Bengal and their contribution to the total marine catch.

Methodology:

The survey work was carried out in Chittagong and Cox’s Bazar districts of Bangladesh. Data were collected from two major fish landing centers which are located at i) Patarghata and Fishery ghat, Chittagong, and ii) BFDC fish Harbor in Cox’s Bazar. Maximum sharks and rays caught are sold at these two landing centers. Data have been collected according to moon month in the period of new moon, full moon, 1st quarter and last quarter with field visits from April 2006 to March 2012 by Marine Fisheries Survey Management Unit (MFSMU), Chittagong. The primary data were assembled through field survey at the landing centers using a prescribed questionnaire by MFSMU. The questionnaire form was filled in by interviewing the organizers, aratdars (assembler) and fishermen directly from the field. All the collected data were analyzed and the shark and ray grouped were identified up to species level by using (i) Field guide to sharks, rays and chimeras of Malaysian and Neighboring countries; (ii) Field Identification Guide to the sharks and rays of the Red sea and Gulf of Aden; and (iii) FAO identification sheet and all the collected data were analyzed by the profiteer.

Source of Information: Bangladesh J. Zool. 40(2): 221-229, 2012

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Major findings from this study are that the average weight of each landed C. falciformis was 1.339 kg; and R. javanica, A. nichofii and R. laevis were 2.992, 2.928 and 5.227 kg, respectively. In this study it is observed that the harvesting of shark fishery was over exploited and these vulnerable shark and ray species are harvested mainly in small sizes, but suddenly caught large in size with few numbers and their catch rates (catch per unit effort) reduce day by day. Total catch increased due to the increasing of active fishing days, number of fishing boats, gears; and new fishing techniques indicated that all shark and ray species were in fishing pressure. As human pressures increase many shark and ray populations have declined where they were once common. It is expected that the statistical interpretation would rightly focus on the status of vulnerable shark and ray species and contribute towards any national management plan for the shark fishery of Bangladesh.

Knowledge Management: Journal