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close this bookProductivity, exploitation and fishing technology of inland open-water fisheries, Bangladesh. Consultancy report. (1995)
close this folder2. PRODUCTIVITY AND EXPLOITATION OF INLAND OPEN WATER FISHERIES
View the document2.1 Introduction
Open this folder and view contents2.2 Inland Open-Water Fisheries
Open this folder and view contents2.3 Productivity of Inland Open-water Fisheries
View the document2.4 Exploitation
Open this folder and view contents2.5 Management Programmes
View the document2.6 Recommendations for Research Needs
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2.4 Exploitation

During dry seasons, the fishes of different species get concentrated in great number in the permanent waterbodies along with the receding of flood water. This provides an excellent opportunity to exploit them as much as possible. This causes heavy mortality to fish every year. But there is hardly any study on the fish and prawn population and their stock assessment. Consequently, it becomes hard to relate overfishing to the causes of stock declination. However, a few studies on the exploitation of fish population have been made.

Tsai and Ali (1985) had carried out a study on open-water carp fisheries management. They recorded a decline in Padma/ Brahmaputra and upper Meghna stocks of major carps. According to them the reasons for decline are construction of embankments, sedimentation and overfishing for Brahmaputra stock and Farakka barrage, embankments and over fishing for Padma stock, while for the Meghna stocks, overfishing was identified as the main cause.

Tsai and Ali (1987) also recorded overfishing in major carps of Sylhet-Mymensingh basin.

BCAS (1989) reported the mortality and rate of exploitation of hilsa, Hilsa ilisha of Narisha-Padma fishery, Nayabhangni fishery and Meghna fishery.

BCAS (1989) recorded maximum fishing mortality of H. ilisha in Nayabhangni fishery (0.89/year) and lowest of it was recorded in Meghna fishery (0.33/year). The rate of exploitation values recorded in Narisha-Padma fishery (0.64) and Nayabhangni fishery (0.57) were above optimum exploitation level which is about 0.50. But its value as recorded in Meghna fishery was 0.31 which indicated some degree of under fishing in this fishery. Whereas the rate of exploitation of H. ilisha reported by Rahman (1992) is 0.518 and the size of first capture (Lc) is 35 cm. This value is just slightly above the optimum value. The total mortality, fishing mortality and natural mortality values as recorded by Rahman (1992) were 2.411, 1.246 and 1.162 respectively. All these values are higher than the values recorded by BCAS (1989). In Narisha-Padma and Nayabhangni fisheries the present exploitation rate should be reduced for obtaining sustainable yield of fish.

The fish production in the major rivers viz., Meghna, Padma, Jamuna and Brahmaputra have declined greatly. Within 8 years (1984-1992), the fish production has been decreased by about 89.69% in Brahmaputra, 84.35% in Padma and 65.98% in Jamuna. The decline in Meghna (23.38%) is relatively low as compared to other rivers. This may be associated with more or less stable catch of the hilsa fish which comprises highest landing of fish from this river.

To know the present fishing status and fishing intensity as compared to last 8 years position the fishermen and middlemen were interviewed in the fishing spots as well as in the landing sites. About 99.2% of the fishermen reported a decrease in their catch. The average decline of their catch was 41% . Almost all the fishermen and middlemen stated that fishing intensity and fishing unit had been increased by about 37.4% and 33.7% respectively (Table 3).

Table 3 Opinion of fishermen regarding the present status of catch, fishing unit and fishing intensity as compared to last 8 years.

Particulars

Fishermen opinion (%)

Average


Same as before

Increased

Decreased

Increased

Decreased

Status of fish catch

0.8

-

99.2

-

41

Status of fishing unit

5.7

94.3

-

37.4

-

Status of fishing

-

100

-

33.7

-

Intensity






Source: Present survey

All middlemen are of the opinion that the catch of the fishermen has decreased and reduction is about 44.6% by average (Table 4).

Table 4 Opinion of the middlemen regarding the present status of catch, fishing unit and fishing intensity as compared to last 8 years.

Particulars

Middlemen response

Average (%)


Same as before

Increased

Decreased

Increased

Decreased

Status of fish catch

-

-

100

-

44.6

Status of fishing unit

-

100

-

41.3

-

Status of fishing

-

100

-

48

-

Intensity






Source: Present survey

Most of the fishermen (77%) and middlemen (71%) have also stated that the size of the fishes are now smaller than before (Table 5).

Table 5 Fishermen and middlemen views on the present size of the major species of fishes as compared to last 8 years.

Particulars

Fishermen views (%)


Same

Smaller

Much smaller

Bigger

Fishermen views

11

77

9

3

Middlemen views

9

71

20

-

Source: Present survey

Due to adverse effects of overfishing and of FCDI Projects, some of the important species are reported to have either become extinct or at the verge of extinction. These species are, Labeo nandina, Tor tor, Tor putitora, Channa barca, Channa punctatus, Bagarius bola, Bagarius bagarius, Rita rita, Puntius ticto, Silonia silondia, Eutropiicthys vacha, Scatophgus, Scatophgus argus, Labeo pangasia and Pangasius pangasius.

However, from all the above statements it can be concluded that the fish exploitation rate has been increased by now than before. The serious decline of fish stock in the major rivers has created an alarming situation for the sustainable fish production in rivers and other waterbodies.