Untitled - WWF - Pakistan

Detailed Ecological Assessment Report 2008 – Keenjhar Lake
Tahir, Chandio, Abdullah, & Rashid,1998; Sajjad & Rahim,1998; Hussain &
Mateen, 1998; Sial & Mehmood,1999; Latif, Akram, & Altaf,1999; Chandio,1999;
and Tahir, 2000). In addition, excessive monsoon rains, floods, herbicides,
fungicides, untreated municipal waste, sewage breakdowns, and coastal water
pollution due to waste discharges and oil spills are extremely hazardous which
pollute water.
An abundant supply of good, clean water must support a variety of beneficial
uses. These include drinking water for domestic use and stock watering;
industrial, commercial, agricultural, irrigation, and mining use; fish and wildlife
maintenance and enhancement; recreation; generation of electrical power; and
preservation of environmental and aesthetic values.
Water quality factors are important in freshwater aquaculture systems. Water
quality determines not only how well fish will grow in an aquaculture operation,
but whether or not they survive. Fish influence water quality through processes
like nitrogen metabolism and respiration. Some water quality factors are more
likely to be involved with fish losses as dissolved oxygen, temperature, and
ammonia. Others, such as pH, alkalinity, hardness and clarity affect fish, but
usually are not directly toxic.
Fish are important not only for ecosystem function, but also may provide
socioeconomic value in the form of fishery resources for people. Loss of fish
species due to changes in water quality or over-fishing may result in dramatic
shifts in ecosystem dynamics, as grazing pressure on invertebrates and algae
can be released, enabling rapid growth and potential blooms of algal populations.
The majority of the subtropical and tropical coastline is dominated by mangroves,
estimated to cover an area of 22 million hectares. However, over the past several
decades, the global area in mangroves has increasingly diminished as a result of
a variety of human activities, such as over harvesting, freshwater diversion and
conversion to other uses" (Snedaker, S. C.,1993).
Pakistan is largely arid and semi-arid, receiving less than 250 mm annual rainfall,
with the driest regions receiving less than 125 mm of rain annually. It has a
diverse landscape, with high mountain systems, fragile watershed areas, alluvial
plains, coastal mangroves, and dune deserts. The flora and fauna are mainly
Paleartic and Indo-malayan. Forests cover approximately 4.58 million ha (5.7
percent) in Pakistan. (Government of Pakistan, 1996) Of these, 0.132 million ha
(less than 3 percent) are coastal mangrove forests. Pakistan is divided into 18
habitat types, among them mangrove forests, which occur mainly in the Indus
Delta and in a few patches westward along the Baluchistan Coast.
There has been considerable qualitative and quantitative loss of mangrove forest
in Pakistan over the last 50 years. A significant reduction in the river water supply
and increased marine water pollution in the Indus Delta as well as over
harvesting of mangroves by the local communities, sedimentation, and coastal
erosion are generally considered to be the proximate causes of this loss. Another
threat is emerging in the form of over harvesting of fish resources, largely
provoked by increased pressure for exports with little or no consideration for the
existing environmental laws and regulations. Policies and decisions made at the
national and international levels have determined these proximate causes.
WWF Pakistan – Indus for All Programme Page 21 of 165