Since arriving in Bangladesh, field visits have been made to the two main shrimp growing areas: the region south of Khulna and Satkhira, and the peninsula from Cox's Bazar to Teknaf. The Khulna-Satkhira region was visited from the 17th to the 21st April 1988. Whilst in the area, the site of the proposed Brackishwater Station (BS) at Paikgacha was visited on the 18th April with the appointed CSO, Dr Aminullah Bhuiyan. The Cox's Bazar-Teknaf coastal area was visited from the 24th to the 30th April 1988. A summary of the various field trips appears in APPENDIX D.
The following synopsis of the present status of the shrimp farming industry in Bangladesh has been based to a large extent on the excellent sectoral review prepared by Karim (1987) together with personal observations made during the field visits during the first part of the assignment in 1988.
Fisheries production in Bangladesh is extremely important to the economy. Although the capture and culture fisheries contribute about 2.9 % of the GDP and 9 % of foreign exchange earnings, fisheries products account for 6 % of the total per capita protein intake and about 80 % of the per capita animal protein intake. The estimated total fisheries production in Bangladesh during 1983–84 was 751,000 t. The production from inland waters was about 577,000 t (77 %), of which 118,400 (21 %) was contributed by aquaculture. In recent years fisheries production has declined from about 822,000 t in 1974– 75, whilst daily per capita fish consumption has fallen from 33 g in 1963–64 to 21 g in 1983–84 (a decrease of 36 %).
Even if per capita fish consumption is to be maintained at the current level, fisheries production will need to be increased to 1,100,000 t by the year 2005 in order to keep pace with the projected population growth. If daily per capita fish consumption is to reach 38 g (recommended by the Institute of Nutrition and Food Science) then production will have to be increased to 1,900,000 t. This represents an increase of about 150 % above present fisheries production levels. The Government of Bangladesh has therefore introduced an ambitious fisheries development programme in the Third Five Year Plan (Anon, 1985a), to increase production from both inland and saline waters for both domestic consumption and for export (Rahman, 1986; Anon, 1985b).
At the present time brackishwater aquaculture is virtually limited to shrimps of the genera Macrobrachium and Penaeus. Penaeid shrimps (mostly Penaeus monodon) currently provide an increasing source of foreign currency through exports to the USA, Europe and particularly Japan. Brackishwater aquaculture production for local consumption is minimal. Smaller, commerically less important penaeid shrimps (Metapenaeus brevicornis and Metapenaeus monoceros) and some Macrobrachium rosenbergii are consumed locally. Small quantities of mullet (Mugil spp) are also produced as a by-product or secondary crop in some shrimp ponds.
Shrimp culture in Bangladesh started to develop in the early 1970s. At that time there was little local demand and the price of shrimp was consequently very low. The potential of farmed shrimp as a hard currency earner was quickly realised by the private sector, and within 10 years more than 26,000 ha of shrimp ponds were under cultivation. During this period the shrimp farming industry received little or no support from the Bangladesh Government. Only since 1980 with the introduction of the Second Five Year Plan (1980–85) has brackishwater aquaculture been given official recognition by the Government.
The Directorate of Fisheries has estimated that by the beginning of 1986 more than 115,000 ha had been turned over to shrimp farming activities in the whole of Bangladesh. Shrimp farming takes place in the districts of Satkhira, Khulna, Bagerhat, Barisal, Patuakhali, Bhola, Chittagong and Cox's Bazar. The two most important areas lie to the north of the Sunderbans (ca 90,000 ha) and in the vicinity of Cox's Bazar (ca 24,000 ha).
Most shrimp farming has developed within polders created by the Bangladesh Water Development Board (BWDB) in low-lying coastal flood plains. Often these activities have been started without the consent of the BWDB, and one of the major concerns has been the creation of unauthorised sluice gates or channels through the perimeter dykes of the polders. Only those areas that are low enough to permit inundation of the land by at least 0.5 m of water at spring tides have generally been used for shrimp farming.
Only two species are deliberately stocked in ponds: P monodon and M rosenbergii. Of these P monodon is by far the more important. Other species of penaeid shrimps are also cultivated, through the accidental introduction of their fry when the ponds are filled or water exchange takes place. These include: Penaeus indicus, Penaeus merguiensis, M monoceros and M brevicornis.
Shrimp farming in Bangladesh relies entirely on the supply of wild fry for stocking purposes. It has been estimated that 1–3 billion fry of P monodon were harvested in 1985. The main collection centres are Satkhira, Khulna, Bagerhat and Cox's Bazar. At present, most fry collection for P monodon is conducted within the rivers and creeks of the coastal flood plain. It has been suggested that there may be a huge unexploited resource within the Sundarbans.
Collection of shrimp fry is carried out using either a fixed bagnet which relies on tidal streams in small rivers and creeks to carry postlarval shrimp into the codend, or alternatively triangular (or less frequently rectangular) nets which are pushed or pulled along the bed of the river or creek. In Cox's Bazar shrimp fry collection is also carried out along the beach. In the Khulna-Satkhira area the peak season for shrimp fry is February-May, whilst at Cox's Bazar it is April-June.
Shrimp fry collectors transfer their catches to earthenware bowls which are then carried back to the villages where the fry are sorted and counted by children using white enamelled plates. This undoubtedly results in a very large wastage of fry of both penaeid shrimps and other commercially important species including fish. The shrimp fry then pass through a chain of middlemen before reaching the shrimp farmers, during which the fry are usually transported in 20–30 l aluminium vessels using every conceivable form of transport.
Shrimp fry mortality is believed to be very high, due to extreme water temperature and salinity fluctuations, low dissolved oxygen levels, and even the use of table salt used in the mistaken belief that it will provide the right salinity for the fry.
The price of P monodon fry in the Khulna-Satkhira area has risen dramatically from about Tk 40–50 in 1980 to Tk 400–600 per thousand (postlarvae of ca 15 mm total length) in 1988. The price of shrimp fry is much lower in the vicinity of Cox's Bazar being only Tk 40–100 per thousand for fry of a similar size.
Macrobrachium fry (postlarvae and juveniles) are collected in the Khulna region for stocking freshwater or low salinity brackishwater shrimp farms. There are no estimates available of the number of fry collected annually. Fry are available in the Khulna area from April onwards with the peak demand occurring in July. The price of Macrobrachium fry in the Satkhira area in 1986 was Tk 500–1,000 per thousand (25–50 mm total length), although at Paikgacha prices were only half this figure. Hatchery reared Macrobrachium fry produced in Cox's Bazar were being sold in 1988 for Tk 440 per thousand (15–20 mm total length).
In the Khulna-Satkhira area the shrimp farming pattern, often in rotation with agriculture, reflects the ambient seasonal salinity fluctuations in response to the monsoon:
January-July [high salinity season]:
August-December [low salinity season]:
In the Cox's Bazar area this pattern may be reversed due to the generally higher ambient salinities. Therefore some farmers produce salt during the the dry season and brackishwater shrimp during the rainy season.
Most of the shrimp farming is carried out within large dyked areas (polders or ghers). Transplanted aman rice can be grown from August-December, when water and soil salinities are low. Agricultural crop production from January to July is difficult due to the shortage of freshwater and increased salinities in the soil. Acid sulphate soils may also present special problems in some areas.
Before the recent and rapid growth of shrimp farming, the land used to be left fallow during the dry season and used instead for grazing cattle and water buffalo. Animal dung remaining on the land, if not collected for fuel, would help to increase the production of aman rice in the following rainy season. The loss of grazing has resulted in very serious conflicts in land use in some areas.
Until recently all shrimp farmers, either individually or in groups, have leased land within BWDB polders. In some cases the land has been re-leased from the rightful leaseholders by force. The BWDB perimeter dykes are deliberately breached and wooden sluice gates or reinforced concrete culverts installed before repairing the dykes. The ponds which may extend up to 500 acres (200 ha) or more are usually allowed to remain dry during January after havesting the rice. The stubble is left in place. The ponds are then flooded during spring tides.
Since the early 1980s the Government of Bangladesh has played an active rôle in improving the level of shrimp farming husbandry and technology. Screens to prevent the entry of predators and competitors have become much more widespread, in combination with the selective stocking of fry. Simple nursery production methods have been introduced in some cases through the construction of a shallow nursery pond within the confines of each growout pond. Pond preparation, liming, fertilisation, pest control, nursery production, supplementary feeding and water management have only started to be introduced during the last five years, and even now are employed in only a few areas.
Recently P monodon production has been increased by the more enterprising farmers from <50 kg ha-1 yr-1 to >300 kg ha-1 yr-1. In the case of the Allah-Wala shrimp farm at Cox's Bazar (see APPENDIX D) a production of up to 900 kg ha-1 yr-1 was claimed during 1988.
There are plenty of signs that shrimp production levels in Bangladesh will continue to rise as a result of the gradual introduction of more intensive practices. At the present time, however, most farms are operated on an extensive basis, with relatively few examples of semi-intensive production.