LAHORE, Sept 11: The Indus Delta where the mighty River Indus meets the Arabian Sea is the seventh largest delta in the world.
It is around 200 kilometres long, 50kms wide and extends over 600,000 hectares. It has 17 old and new creeks, and mangrove forests over 80,000 hectares. It produces 96 per cent of country’s total shrimp export — 4.92 billion in Pakistani rupees.
This was learnt during a survey of the Indus Delta organized by the WWF-Pakistan in league with the Forum of Environmental Journalists Pakistan as part of a programme for capacity building of journalists through eco-visits.
The unique Indus Delta is facing numerous threats.
SEA INTRUSION: The biggest of all is reduction in fresh water inflow that has caused major ecological changes, like sea moving into delta channels. In the absence of fresh river water, agriculture in the Indus delta region has widely been affected. The quantity of the Indus outflow to the sea has progressively been reducing, particularly after the construction of more barrages, dams and link canals. Erosion and degradation of the delta have caused shrinkage of the extent and consequent seawater intrusion has resulted in reduction in biodiversity.
POLLUTION: It is another major threat to the Indus Delta. Karachi, being the largest city of the country and having a population of 13 million, produces 50,505 cubic metres sewage per day. It is in addition to the discharge from over 600 industrial units. The industrial units release 687,050 cubic metres effluents daily — 80 per cent of them is untreated.
Being the port city, Karachi harbour and Port Qasim have shipping and fishing traffic rush. Oil discharge from ships pollutes the sea water and causes a great damage to the flora and fauna. Agriculture pesticide and fertilizer run-off also plays a major role in polluting the Indus Delta.
The major effects of pollution on the Indus Delta are degradation of water quality, habitat loss, localized eutrophication, metal accumulation in fish and shrimps.
VANISHING MANGROVES: Mangroves are salt tolerant plants which grow in estuaries along the coastline. Mangrove ecosystem is of great economic and ecological significance. It is a pool of biodiversity and is a habitat consisting of a diverse community of organisms ranging from bacteria and fungi to fish, shrimp, birds, reptiles and mammals. Mangroves are a source of fuelwood for coastal communities, provide fodder to livestock, protect coastline from wind and tidal action, reduce siltation and strength of storm surges and provide massive ecotourism opportunities.
Mangrove ecosystem has been facing continuous human pressures for domestic needs and developmental activities. The indiscriminate exploitation of mangrove forests by coastal communities for fuelwood and fodder has caused an estimated decrease in mangrove forests from about 263,000 hectares in 1977 to about 160,000 hectares in 1991. Following livestock, camel grazing and fuelwood collection, only one of eight species of mangroves is existent — Avicennia marina. This has caused reduction in types of species — tiger shrimp, palla fish and dangri — supported by mangroves.
To deal with the situation, WWF-Pakistan has initiated a project on the conservation of mangroves at three sites — Sandspit in Karachi, and Sonmiani and Jiwani in Balochistan. The aim of the project is to conserve the mangrove forests through the promotion of sustainable management, awareness raising and restore plantation to the degraded areas.
FISHERFOLK COMMUNITY: The fishermen say there used to be a lot of fish in the sea in the past. Now the catch of the fish has drastically reduced. In the past, they say, they could catch 300kgs to 400kgs shrimp per fishing trip. But, now, despite the whole day fishing activity, they can’t catch 8kgs to 10kgs of fish.
They blame deep-sea trawlers for the reduction of fish. They say the trawlers, in the process of taking fish, capture unwanted species and then throw them back into the sea. Known as discards, these unwanted fish are wasted either because they are undersized or a non-marketable species.
According to a WWF official at Keti Bander, the practice of throwing the discards and by-catch into the open sea greatly pollutes the seawater. — Imran Sheikh