Abstract:
Haors are very important habitats for the unique and dynamic ecosystems, which have
immense productive or ecological valuc. Importantly, haors provide suitable habitats
for fisheries, a major component of the ecological resources. However, anthropogenic
interfcrenccs, c.g. wetland encroachment and exploitation pressure, and water
management infrastructures are causing decline of wetland habitats, especially during
the dry season. Water management interventions bring about changes in natural
systems of haors, and hence the impact of partial flood protection on the ecosystem of
the haors is emerging as a significant concern.
The study examined the ecosystem of three selected haors subject to varying physical
effects of water management infrastructure. Fish has been selected as an indicator for
ecosystem as fishes arc scnsltive to many changes in natural water quality and habitat
structure caused by anlhrop<lgenic or by natural causes. Based on a set of pre-del ermined
criteria, a tolal of three haors were selected, which represented three distinct physical
characteristics: a relalhely undisturbed state (Chaptir haar), a moderately intervened
state (fangua haor), and an extensively intervened state (Daram haer). A range of
Participatory Rural Appraisal (PRA) tools (e.g. resource mapping, FGDs) were used
in the srndy to obtain data relating to the status of the physical system of the haors and
the status of fisheries ecosystem.
The findings from' the field surveys showed that migration routes and fish habitat
areas have been impacted to different degrees in the three haors by water management
infrastructures. Fish migration routes are better in Chaptir haor, followed by Tanb'tJa
haor. Migration routes in Baram haor are the worst. Habitat depths, e.g. depths of the
river, khals and beels are highest in Chaptir haer, followed by Tangua haor. Habitat
depths in Baram haor arc the lowest. The impact of water management interventions
has also been reflected in the declines in fish catch compared to a period 10 years ago.
A scoring and ranking method was used for analyzing habitat wise fish composition
data obtained from the field survey. This exercise yielded three species (Rui, Catla,
and Boal) which are indicative of different status of ecosystem health in the haors.
