And Water Quality Parameters Of Beel Fisheries In Assam
and P. K. Goswami3
Institute of Fisheries Education, Versova, Mumbai-400061, India
of Fisheries, Central Agricultural University, Lembucherra, Tripura,
of Fisheries, Assam Agricultural University, Raha, Assam, India
of corresponding author: firstname.lastname@example.org
constitute vitally important fishery resource of Assam. Beels are
wetlands which, if judiciously managed, can furnish unimaginably high
and rich benefits to the people of the state.
fisheries area in the state covers one lakh hectare against 2.30 lakh
hectares being 43% of the country. In Assam two major river systems
namely the Brahmaputra and the Barak are there and the beels are
situated along the tributaries of these two river systems. In
Brahmaputra valley, there exist a total of 1,030 number of beels
covering an area of 92,693 hectares; out of which 306 beels (31,214
ha) are located in central Assam, 409 beels (29,383 ha) are in lower
Assam and 315 beels (32,016 ha) are in Upper Assam. On the other
hand, there are about 167 beels with an area of 8,122 ha in Barak
valley. The potential of these beel fisheries could not be harnessed
so far, as no substantial development effort could be taken up due to
financial constraints. Presently
these beels are under threat from many factors like pollution,
reclamation, habitat degradation etc. These threats cause loss of
important biodiversity of indigenous and migratory flora and fauna.
of the beels
is a highly productive ecosystem which can effectively convert the
solar energy into organic carbon in the presence of rich nutrients
available from natural sources. Thus, growing fish in the beels is an
effective way through which the gap between demand and supply of fish
can be reduced. However, the ecosystem processes in open bodies are
usually very complex due to the interaction of an array of physical,
chemical and biological processes. Because of the combined effect of
these processes on the biotic communities living in these water
bodies, it is often difficult to link their fish production potential
with any particular ecological parameters. The beel ecosystem is
extraordinarily complex with wide temporal and spatial variations of
many key parameters. Some of the important factors that influence the
wetland ecosystem are depth, nature of catchment area or river basin,
precipitation and duration of connection to river etc. Ecosystem
processes in a beel is determined by a number of factors which can be
included under three broad heads.
Morphometry and hydrodynamics
main morphometric features that influence the productivity of beel
ecosystem are shoreline area, depth and slope. These features are
closely linked with the hydrodynamics of wetlands. There are three
main sources of water input into the beel ecosystem viz. overspill
from the river channel, surface flow and regeneration. During the
period April-June heavy rainfall takes place in Assam, due to which
all the beels and low lying areas are flooded with rain water.
Surface run-off and increase in river height due to inflow of rain
water from the upper stretches cause inundation of the floodplains,
often causing resumption of connection between beels and main rivers.
Therefore through the connecting channels the open beels receive the
water from their parent rivers throughout the year. Permanently
closed beels receive water through rainfall and surface run-off.
Thus, flood is the main source of water for the beels of Assam.
recession of flood, connecting channels are dried up due to the
reduction in water level in the rivers. The water depth of the beels
reduces through evapo-transpiration and seepage. In some places,
people practice rabi crop and vegetable cultivation on the banks by
extracting water from the beels. The water loss by various means
causes shrinkage and lowering of depth in the beels. Consequently,
the fluviatile nature of the system is transformed into a lentic and
stagnant water body till next flooding. This seasonal change from a
lotic to lentic condition and vice versa bestows the beels its unique
flow plays a vital role in nutrient dynamics and aquatic productivity
through transport of nutrients to the organisms and removal of waste.
Similarly, temperature, which affects all life processes including
growth rate, lifecycle and overall productivity of the entire system,
is a key physical variable. The flood water and surface run-off carry
huge load of silt and organic matter which render water turbid,
preventing light penetration. After the monsoon, the silt settles at
the bottom making the water more transparent to facilitate light
penetration. This increases effective photosynthetic zone making the
system more productive.
are three basic mechanisms that control the water chemistry of the
beels: precipitation, evaporation and nature of the river basin. The
ionic composition of water is chiefly determined by the rain and the
substrata over which the parent river flows. Secondary influences on
the ionic composition are exerted by macrophytes and phytoplankton.
In recent years, human factors related industrial, agricultural and
urban activities started playing an increasingly important role in
determining the chemical quality of water. The chemical and physical
load brought in by rain water or surface run-off gets concentrated by
evaporation and altered by chemical and biological interaction within
the system, causing seasonal variations of various parameters.
living part of the ecosystem or the biotic communities in water is
governed by the variations of physical and chemical features of the
water body and trophic interactions associated with it. Biotic
communities of the ecosystem can be catagorized broadly as autotrophs
and heterotrophs. The autotrophs include photosynthetic pigment
bearing microscopic plants, plankton and macrophytes; whereas
heterotrophs include consumers and decomposers. Beels are generally
considered as highly eutrophicated system with high rate of primary
productivity. The energy produced at the primary stage i.e.
phytoplankton and macrophytes are transformed into higher trophic
levels through food chains. In beels, two main pathways viz. the
grazing chain and the detritus chain are found. In the absence of
fish feeding on macrophytes, the plants die and settle at thebottom
which is later consumed by the detritivorous fishes.
A beel infested with water-hyacinth (Eichhornea spp.)
quality of the beels in Assam
is vital in maintaining the productivity of any water body and water
quality is vital for metabolic process of plants and animals living
within the water body. The soil and water conditions of the beels in
Assam are mentioned below.
Organic carbon (%)
6.40 - 7.60
Social, economic and policy respects of Fisheries
yield and fish yield potential of the beels
of upper Assam has the highest average yield potential (1245
kg/ha/yr) followed by the lower (1221 kg/ha/yr) and central Assam
(1060 kg/ha/yr). Barak valley beels with yield potential of 1093
kg/ha/yr was poor compared to upper and lower Assam areas of
of fish yield from beels of Assam is very difficult task due to the
unorganized marketing activities and dissipation of catch. CIFRI have
made some assessment of the fish yield on the basis of enquiries from
the beel sites. According to CIFRI, fish yield are in the range of
14-488 kg/ha/yr with an average of 173 kg/ha/yr.
and control of beels
Assam, normally, the beels or low lying wetlands are under the
control of Revenue Department. Since 1977, about 182 beels have been
handed over to the Assam Fisheries Development Corporation (AFDC) for
maintenance and development of fisheries. As such under the present
system, both the Revenue Department and AFDC lease out the beels for
a period ranging from 5 to 7 years at a time. The prime objective of
leasing beels is to earn revenue for the state’s exchequer. The
protection of the interest of traditional fishermen is not given much
attention under the existing policy. The system allows rich middlemen
to obtain the lease. The leasees hire fishermen to do the netting and
fishing. In most cases, fishermen of adjacent villages are hired at
very low wages or on a shared-harvest basis mostly in the ratio of
70:30 or 60:40 between the lease and the fish catcher. The marketing
of the fishes is totally controlled by the leasees. The fishermen are
not allowed to sell their share of fish in the market. They have to
sell their share of fishes to the leasee at a low price fixed by
the lease period is short and fixed, the leasees maximize income by
catching the entire stock of fish from the beel. To achieve this, the
water level is often reduced by pumping it out. The fishermen also
helped the leasee to maximize the catch, especially those fishermen
who work on the share-harvest system. The provisions of the Fisheries
Act, 1897 enacted for the protection and conservation of fish-biota
are meaningless under existing management system.
of Assam are rich in fish diversity and it harbours almost all
freshwater species available in the North Eastern region. Due to
improper fishing, lack of proper planning and proper conservation
measures fish species are depleting very rapidly in the state. If it
continues for another few years most of these indigenous fishes will
extinct. So, immediate attention from government agencies, NGOs,
researchers, planners and policy makers, local people etc. is
required in this regard.
Acharjee, B., 1997. Ecological
Status and Productivity Potential of Some Beels
in lower Brahmaputra Basin, Assam. Unpublished
Gauhati University, Assam. p. 206.
on various species of fishes and strategy for development of Fishery
sector in N.E. region: A report by AFDC.
Deka, T. K., 1999. Present
Status of Beel
and its Impact on Socio-economic Condition of Fishermen Community of
University, Assam. p. 122.
Seafood — Fish — Crustacea
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