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

Estimation of Maximum Sustainable Yield (msy) of Hilsa ( Tenualosa Ilisha Ham.) in the Meghna River of Bangladesh

M.S. Miah
Bangladesh Fisheries Research Institute, Riverine Station, Chandpur-3602, Bangladesh

M.A. Mazid
Bangladesh Fisheries Research Institute, Riverine Station, Chandpur-3602, Bangladesh

G.C. Halder
Bangladesh Fisheries Research Institute, Riverine Station, Chandpur-3602, Bangladesh

M.A. Rahman
Bangladesh Fisheries Research Institute, Riverine Station, Chandpur-3602, Bangladesh

Abstract/ Executive Summary:

MSY per recruit of Tenualosa ilisha in the Meghna river was predicted as 112 g per recruit at the F msy=0.6 /yr and at T c=0.6 /yr. But Y/R=95 g per recruit was obtained at the existing fishing level, F=1.14 /yr and at T_c = 0.6 /yr. Existing F level was nearly double than the F msy level. Fishing pressure should be reduced immediately from F=1.14/yr to Fmsy=0.6/yr. Fmsy=1.14/yr was the same at first capture,Tc=1.0, 1.2 and 1.4 /yr, and MSY could be obtained as 142 g, 162 g and 176 g per recruit respectively. It is easier to change the first capture age (T c) ratherthan changing off level. So, hilsa fishery manager may adopt Fmsy=1.14/ yr while age at first capture must be increased from Tc==0.6 /yr (3 em size group) to Tc=1.4 /yr (25 cm size group), by which 1.8 times production could be increased than the present production. MSY also possible to obtain as 201 g and 210 g per recruit at Fmsy=2.0 /yr and 4.0 /yr at Tc=1.7/yr and 1.9 /yr respectively. Under both the situations, hilsa production could be increased 2 times than the present production. To obtain the MSY=21 0 g per recruit the fishing level could be increased upto F = 4.0 /yr at T c = 1.9/yr (34 em size group). Economic point of view, hilsa fishery managers may choose to obtain the economic MSY as 201 g per recruit at F msy=2.0 /yr and Tc=1.7 yr (31 em size group) in the Meghna river of Bangladesh.

Keywords: MSY, Hilsha, Meghna River

Location: Bangladesh Fisheries· Research Institute, Riverine Station, Chandpur

Start Date: 00-07-1993

End Date: 00-06-1995

Program Area: Socio-economic and Policy

Non-commodity: Profitability

Objectives:

Estimation of MSY helps to indicate the present fishing level of any fish population either the fishery is under fished or over fished and deals with the MSY per recruit

Methodology:

The research program was designed for the estimation of maximum sustainable yield per recruit following the Beverton and Holt model. The experiment was undertaken at the Bangladesh Fisheries Research Institute, Riverine Station, Chandpur, during July 1993 to June 1995. For the estimation of MSY of hilsa population in the Meghna river, length-frequency data were collected through experimental fishing as well as from commercial fishing. The Meghna river was selected under this study as the Meghna river is a major migratory route and nursery ground of T. ilisha in the riverine system of Bangladesh. Length frequency data of 8040 specimens of hilsa of the river Meghna were analyzed for the estimation of maximum sustainable yield (MSY) per recruit. Length frequency data were randomly collected in each month during the period of study. Sample was collected by using 1F.B. ilish gobeshona1 boat of FRI, Chandpur. Mesh sizes of the experimental fishing gear were 8.5 em, 10.0 em and 11.0 em which are usually used by the commercial fishermen. Samples were collected from both day and night fishing. Commercial jaggat ber jal with mesh size of 0.5 to 1.5 em and experimental ber jal with mesh size of 1.0 em were used to catch jatka (juvenile hilsa). Samples from artisanal fisherman 1S net (a kind of monofilamentous gill net locally called current jal with mesh size 3.5 em to 7.0 em) were also considered for the purpose. Length-frequency data of the specimens of hilsa were analyzed through length-based stock assessment method with the help of computer package programme of XL-staistica and Microstate Data management. The results of the growth parameters (L, k,& t 0), mortality parameters (Z, M,& F), asymptotic weight (W), relative condition factor (K_n), recruitment age (T_r) and age at first capture (T_c) are necessary to calculate the yield per recruit (Y/R). So, the growth parameters were calculated by using formula. L(t) = La*( 1 -exp (-K* ( t-t₀)) ------------------------------(i) Here, the model expresses the length L, as a function of the age of the fish t, K is the curvature parameter and La is the asymptotic length of fish. Total mortality (Z) was calculated by Length Converted Catch Curve method. Natural mortality (M) was estimated by following Pauly's empirical relationship of La, k and mean annual temperature, T⁰C. In M = -0.0152 - 0.279*1n La+ 0.6543*ln T ---------------(ii) Asymptotic weight was calculated by using the following formula. Wa = K_nx L³ ----------------------------------------------(iii) Recruitment age (T_r) and age at first capture (Tc) were also calculated by the Inverse von-Bertalanffy growth equation model. t(L) = t₀ - 1/k*ln(1-L/La )------------------------------(iv) The yield per recruit (Y/R) were calculated by using the model such as : Y/R = F * exp.(-M *(Tc-Tr)*Wa *(1/z-3S/(z+k) +3S²/(z+2k)-S³ /(z+3k).-------------(v)

Where S= exp.(-M*(Tc-t₀) and Z=F+M. Finally, the Y/R and MSY per recruit under various fishing levels (F) and age at first capture (Tc) of T. ilisha in the Meghna river were calculated.

Source of Information: Bangladesh J. Fish. Res., 2(2):177-182, 1998

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Fishing maintained at the level of F msy=2.0 /yr and the probable MSY would be obtained in MSY=201 g per recruit at the age of first capture T c =1.7 yr, which will be more economically viable level off msy for hilsa fishing at the same time hilsa production will be double.

Knowledge Management: Journal