Acknowledgements 5 Glossary 6 List of Tables 8 List of Figures 9 List of Boxes 10 Pakistan Fact Sheet 11 Executive Summary 12

Major Threats to Marine Ecosystems

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7.3 Major Threats to Marine Ecosystems

The major threats to marine ecosystems in Pakistan include pollution, decreased river flow, urbanisation, and sea level rise (Table 7.1). Marine ecosystems in Sindh face all nine issues mentioned in the table, whereas Balochistan’s marine ecosystems face fewer threats. For instance, pollution, urbanisation, and the decreased flow of river water are not problems in Balochistan where the marine environment is presently pristine.

One of the biggest environmental problems in the Indus Delta region is the drastically reduced river discharge caused by the construction of dams further upstream. The discharge is presently around 5 percent of what it used to be before the construction of the dams. This has seriously affected the Biodiversity of the region, especially that of the mangrove forests. Only four out of eight mangrove species now survive, and the total area covered has undergone significant reduction.

The construction of dams has also affected the stocks of palla fish and the Indus dolphin, whose populations have declined significantly. Along with the reduction in the Indus’ flow, there has been a sharp reduction in the annual discharge of alluvial sediments. The reduction in sedimentation has had an adverse affect on mangrove populations and other soft bottom biota, and has been responsible for shore erosion, since sediment is no longer deposited along the shoreline.

Urban and industrial pollution is the next serious problem-threatening marine Biodiversity. There are more than 5000 industrial units in Karachi. Approximately 262 million gallons of sewage are generated each day; half is of municipal origin and the other half of industrial origin. Only a fraction of this sewage is treated before being dumped into the sea.

There is significant oil pollution along Pakistan’s coastline. According to one estimate, some 90,000 tons of oil find its way to the Pakistani coast each year, due to the clearing of bilge and other oil refuse. Other major pollution sources in Karachi include steel mills, power plants, and refineries. Due to the increased turbidity caused by the discharge of pollutants, the large edible oyster Crassostrea sp. is on the verge of extinction.

Table 7.1: Threats to Marine Ecosystems


Management Strategies

Mangrove deterioration

  • Hypersalinity

  • Overexploitation

  • Pollution

  • Soil erosion

  • Increased flow of the Indus

  • Reforestation

  • Ban on 'Katra11' nets

  • Regulate harvesting

  • Strict adherence to NEQs

  • Assessment of annual loss


  • Industrial

  • Eutrophication

  • Sewage

  • Oil

  • Agriculture

  • Toxic waste

  • Thermal

  • Radioactive

  • Pre-treatment of effluents

  • Monitoring

  • Clean-up operations

  • Ship waste processed or eliminated

  • Multi purpose numerical modelling

  • Reduction of harmful compounds

Decreased Flow of the Indus

  • Soil erosion

  • Hypersalinity

  • Restoration of flow

  • Strict adherence to NEQs

  • Decrease silt deposition

Threats to Biodiversity

  • Disappearance of species

  • Loss of sanctuaries

  • Improved habitat

  • Reintroduction of extinct species

  • Marine parks

  • Eco-tourism


  • Dredging

  • Channelisation

  • Solid wastes

Rising sea level

  • Loss of land and biota

  • Economic losses

  • Estimation of accretion and sea-level rise

  • Conservation of mangroves

Socio-economic aspect

  • Poverty

  • Illiteracy

  • Lack of municipal facility

  • Socio-economic uplift of fishermen

  • Education

  • Alternative livelihoods

  • Marine parks

  • Apiculture

  • Mariculture

Lack of public awareness and people participation

Lack of harmonisation and enforcement of legislation

  • Central, provincial and local government co-operation

  • Penalties

Source: Saifullah, S.M. University of Karachi

The over-exploitation of natural resources (e.g. over fishing) also poses a considerable threat to marine Biodiversity. Unsustainable harvesting has resulted in the extinction of certain species, and a significant reduction in the populations of others. Certain crab, oysters and gastropods like ficus, murex, tibia, bullia and olivia are reported to be disappearing as a result of over-exploitation. Mangrove forests are used as a source of fuel wood and fodder, which has resulted in a decrease in shrimp catch from 25,000 tons to 14,000 tons. Green and olive ridley turtles were also killed indiscriminately in the past, but are now the focus of conservation efforts around Karachi. Over-fishing is a major problem in Pakistan's coastal waters. The Exclusive Economic Zone is frequented with illegal foreign trawlers, poachers and even the licensed trawlers resort to over fishing. Sawfish, hammerheads, sardines and sharks are the fish most affected by this illegal practice. RS. 22 million was accumulated as penalties during the year 1998-99 from foreign vessels involved in illegal fishing in the Exclusive Economic Zone of 35 nautical miles.

Box 10: Marine Turtle Conservation12
Thousands of years of biological and geographic evolution and manipulation have been unable to significantly alter the process of marine turtle nesting on the beaches of Karachi. Out of the eight species of marine turtles known world-wide in tropical and sub-tropical marine waters, two have been positively identified as nesting and lying on the beaches o13f Karachi. These are the green turtle (Chelnoia mydas) and the olive ridley (Lepidochelys olivacea). Pakistan is thus amongst the very few major marine turtle nesting grounds in the world. Over-exploitation for commercial purposes has caused the world-wide turtle population to drop to drastically low levels. Like all other species of turtles, the green turtle and the olive ridley are also endangered and are threatened with extinction due to a number of factors. Observations indicate that poaching, predators and human habitation along the beaches are interrupting the turtle's egg laying process and destroying their nests, eggs and hatchlings. According to observations made by the Sindh Wildlife Department, the peak nesting season is from September to November, although turtles come up at lower densities throughout the year. The nesting process takes about three hours. It begins when the turtles come up onto the sandy shore, find a suitable place, dig a body pit and make an egg pit or nest. This is followed by laying of eggs and the pit is covered by sand. Finally, the turtles go back to the sea. It sheds tears during nesting which serves as an important biological process for balancing the salt concentration in the body. About one hundred or more eggs are laid at a time and hatch after forty to sixty days of incubation, sometimes more, depending on temperature and other environmental factors. The hatchlings are very active and instinctively orient themselves towards the sea, but they must walk on firm sand to reach the waves. This is the time when they can be attacked by birds, dogs and other predators. If they survive, they reach maturity after twelve to fifteen years; when they come back to the same beach to lay eggs.
A pioneering step for conservation was taken by the Sindh Wildlife Department, which passed the Protection Ordinance of 1972. The Act declared harassment or hurting an adult or to steal eggs or disturb nests an offence. A pilot project was started with the resources available from the Government of Sindh and WWF Pakistan in 1979. The project was included by the IUCN/WWF in their global protection programme “The Seas Must Live” (1976). The project proposal for the funding of marine turtle research and conservation programmes was forwarded to the IUCN and the WWF and approved in 1980. Since then, the Sindh Wildlife Department has started a protection and research programme for marine turtles. Protection, research and education are the three main components of this project.
Protection and conservation includes beach patrols, and the occasional prosecution of poachers. Conservation includes the transfer of eggs to protected enclosures, where the natural cycle is observed as much as possible. The eggs are buried in the sand at the same depth at which the mother laid them. A wire mesh bearing a serial number for record covers the nest. After hatching, the young turtles are released into the sea. To date, more than 4 million hatchlings have been released into the sea.
After laying eggs, turtles are marked by monel metal tags on both front flippers. Each tag carries “W” as a code for Pakistan with the return address inscribed on the other side. More than 3,000 turtles have been tagged and 513 have been recovered so far. To minimise the mortality rate of hatchlings, the captive rearing of sea turtles has begun, which after emergence, tiny hatchlings are kept in seawater tanks for a few months. Captive rearing or head starting is the practice of raising hatchlings to make them less vulnerable to the predators than the hatchlings growing in the wild. The aim of this practice is to contribute more to a healthy population.
At times, the turtles are examined for diseases and parasites. Leeches of the species Ozobranchus are usually found as ecto-parasites attached to their necks, eyes and other soft parts. Besides conservation and research, education of the masses is an important aspect of this project for which publicity material has been produced such as posters, T- shirts, stickers, signboards, information hoarding, greeting cards, brochures and documentary films. Guided tours to the beaches are also organised for students and the public to educate them aware of the conservation of this species and the protection of our natural heritage.

7.3.1 Economic Value

Pakistan has a thriving fisheries industry. The annual catch of fish is about 300,000 tons while that of shrimp is 25,000 tons with a cash value (in 1999) of more than US $ 30 million. Pakistan earns US $ 120 million annually from the export of marine fish. The fisheries sector provides employment to whole communities, of which exact estimates are not available.
      1. Institutional arrangements

Excessive mismanagement and ineffective policies have created huge problems within this sector. Firstly, too many agencies are laying their claim to the fisheries such as the Ministry of Food, Agriculture and Livestock (MINFAL) which is controlled through the Marine Fisheries Department, and the Fisheries Development Commission. The Fishermen Co-operative Society, Karachi, looks after the fishermen’s interest and in 1999 a deal for fishing rights worth USD 460 million with a US company was cancelled by the government on protests from the local fishermen.

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