Reservoir Fisheries of Asia

socio-economic aspects. These cross-sectoral issues should be accorded equal
importance by incorporating appropriate mitigation measures through holistic
management approaches to maintain the biological, environmental and socioeconomic
aspects of the impacted area in a sustainable manner.
The importance of and need for fisheries resource conservation were realised
quite early in the country. The Aquatic Life Conservation Act 1961 – “JAL CHAR
SANRAKSHAN AIN – 2017” had been adopted, but could not be implemented for
some time. In 1999, the Act was amended (2055 BS). changes included important
aspects such as its scope and the definition of different terms specified in the
Act. The other aspects included in aquatic life conservation act are: restrictions
on killing and capture methods, punishments, citizen’s obligations, role and the
responsibility of local authority and technical authority. However, the Act is not
yet in operation because laws and regulations are yet to be approved by the
government.
Ecological impacts
The damming of river for hydropower/irrigation development converts the
lotic habitats of river into lentic habitats. As a result, some native fish species
are threatened and gradually disappear due to the loss of spawning grounds,
migratory routes, and imbalance of physio-chemical factors and energy flow
mechanisms of flowing river system habitat. Nevertheless, other limnophilic
species flourish. Also, many native fish species are threatened as they are driven
into turbines of hydropower plants. This issue has not been considered in the
basic engineering and design of the project so that mitigation measures have not
been adopted. Hence appropriate mechanisms at the policy level are required to
safeguard the loss of native fish species and other aquatic fauna through suitable
mitigation measures to minimise the biodiversity losses.
Impacts of cross-technological activities/urbanisation
Hydropower and irrigation projects require high investment and long term
service delivery for the recovery of cost. The siltation caused by continued wash
down of loose soil due to haphazard agricultural practices and deforestation
in the surroundings and uplands is a serious problem to reservoir hydrology,
its fishery and other aquatic biological resources. The continued accumulation
of mud in the reservoir bottom diminishes water storage volume and affects
the cost effectiveness of hydropower production. Also, addition of wastes
from urban settlements and industrial wastes have deteriorated the aquatic
environment to some extent in Phewa and Begnas lakes as well as Indrasarovar
reservoir. As such, holistic management approaches are required for lake
and reservoir management focusing prevention of soil erosion through sound
plantation management, maintenance of drainage system through proper
engineering works in the surrounding hills, effective management of sewage/
effluent discharge schemes.
64 | Reservoir Fisheries in Nepal