First National Report Of Pakistan to the Convention on Biological Diversity Ministry of Environment Government of Pakistan Contents

Important Marine Species and their Status

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Important Marine Species and their Status

The information on taxonomic assessment of marine fauna and flora is discrete and not readily available. A large number of coastal species had been identified and yet but the work done so far is inadequate to cover the entire range of biodiversity in Pakistan’s marine areas. The studies done so far cover the species diversity of the rocky, muddy and sandy shores. According to the reports available, gastropods dominate the rocky shore fauna followed by decapods crustaceans and polycheate worms. A list of the fauna of the beaches of Pakistan is available as a supplement prepared by the Zoological Survey of Pakistan (1973).

The wetlands of Pakistan along Sindh and Balochistan coasts, harbour mangrove ecosystems rich in biodiversity. The wetlands are of great ecological and economic significance. There is substantial information available on the mangroves of Pakistan. Over 48 species of macro fauna were reported from mangrove forests along the coast of Pakistan. The fauna consist of several species of crabs, polychaetes, molluscs etc.

A number of workshops have been organized by the Government agencies like Sindh Wildlife Department and other organizations including NGOs on protection and promotion of Mangrove forests on the coastal areas. Species diversity is generally a good measure of the Biodiversity index, but cannot be applied in places such as Pakistan, because the flora and fauna has not been adequately studied and documented. In addition, as Pakistan is not a bio-geographic entity and its borders are confluent with other countries, the rate of endemism is very low. However, endemic species do exist in terrestrial flora and fauna, information about endemic marine forms does not exist. Some important groups and species of marine animals are described below.

There are approximately 788 marine fish species in Pakistan’s coastal waters (Ahmed, 1998). Large pelagics such as the tuna are common in the waters of Balochistan. The blind Indus dolphin (Platanista minor) is a resident of the Indus River and estuary. Palla fish (Tenalosa ilisha), considered to be a delicacy, is an anadromous24 fish that swims up the Indus River to breed. However, it can no longer migrate up the Indus River due to the construction of a number of dams, it is found up to the Ghulam Mohammad Barrage. This has seriously affected the reproductive potential and distribution pattern of the species.

The green turtle (Chelonia mydas) and the olive ridley turtle (Lepidochelys olivacea) are both found in Pakistan. Until recently, they were indiscriminately killed on the Makran coast. Eight species of oysters occur in Pakistan. Squid are abundant, but surprisingly echinoderm populations are very small.

Eight mangrove species were reported to grow in Pakistan until recently, but now only four survive. These are Avicennia marina, Ceriops tagal, Aegiceras corniculatum, and Rhizophora mucronata (Saifullah, 1982, 1997).

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 from this area.

Table 7.1: Threats to Marine Ecosystem


Management Strategies

Mangrove deterioration

  • Hyper salinity

  • Overexploitation

  • Pollution

  • Soil erosion

Increased flow of the Indus

  • Reforestation

  • Ban on 'Katra25' 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

  • Hyper salinity

  • 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 mass transport of chemicals within sediments is affected by the physical structure of the sediments (particle size, shape, density, cohesion, bed roughness, porosity, and stratification), the current regime, and shear stress of the overlying water on the sediments, bio-irrigation, and bio-turbation. Benthic animals move particles and water vertically, and larger animals move more sediment and pump more water. Benthic animals transport contaminants to the overlying water by mixing sediments vertically and by irrigating their burrows. The marine fauna can also increase the sediment burden of contaminants by deep mixing of pollutant bearing particles.

The micro-, meio- and macro-benthos that reside in surface and deeper sediments significantly impact the major ecological processes. Benthic organisms contribute in the regulation of carbon, nitrogen, and sulphur cycling, water column processes, pollutant distribution and fate, secondary production, and transport and stability of sediments. Tubes of animals (e.g. Ampeliscid amphipods) and mucous (e.g. motile gastropods) bind particles and stabilize sediments. Thus, destabilizing effects of bioturbation, stabilizing effects of mucous binding, and variable effects of biological sediment redistribution and alteration of bottom roughness influence sediment erosion.

Sediments ranging from gravel to fine mud make the largest habitat in area coverage. Some sediment is uniform in grain size distribution, while others are constituted of mixed particles. On the other hand, sediment also varies in their origin; they may be of biological or geological origins. Sedimentation rate impacts on coastal ecology, circulation and geology (e.g. beach erosion) and elevated nutrients in coastal oceans may lead to algal blooms and associated hypoxia, changes in benthic community makeup, and thus coastal habitat and ecosystem.

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.

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