Marine biodiversity in Pakistan
WELL WE all know about terrestrial ecosystems but we still know little about marine ecosystems. Hence I thought it would be interesting to discuss something new today.
So put on your goggles and get ready to dive in the cool, refreshing waters of our country.
We will first swim in the inland water resources of Pakistan. Yup!
You guessed it right! The inland water resources comprise of the Indus, Jhelum, Chenab, Ravi, Sutlej rivers, all originating in Western Himalayas and then along the flow of the rivers we will drain into the Arabian Sea where we will study marine and coastal biodiversity. By the way, did you know we have huge deposits of coral reef there too?? Dont worry we will give them a special visit too!
Coming back to the rivers, Pakistan has 198 freshwater species of fish including 15 introduced species. The fish fauna is predominantly South Asian, with some West Asian and high Asian elements. Among these are the nine species of snow trout (sub-family Schizothoracinae) that are found up in rivers of the northern mountains. These fish are representatives of an ecologically interesting group of fish confined to (only present in) snow fed rivers and lakes of the high Asian region. Species richness is highest in the Indus river system, in the Kirthar Range and in the Himalayan foothills, while the river systems of north-east Balochistan have the highest levels of endemism.
Some species of fish such as Tor (Tor putitora), migrates from flood plains to the Himalayan foothills for breeding, but the construction of the Mangla and Tarbela Dams has blocked its migration. The other species is Palla (Tenualosa ilisha), which requires a 200 km northward run for spawning from the coast to the Indus River. The migration of this fish too has been blocked by the construction of dams and barrages. Though Fish ladders have been provided for this purpose but they have been proven ineffective.
The Indus River dolphin (Plantanista gangetica minor) is one of the worlds rarest mammals and the second most endangered minor freshwater river dolphin. Approximately, 1,275 specimens of this species exist today in the lower reaches of the Indus River in Pakistan. However, the population of these species has gradually declined because of various factors, including water pollution, poaching, fragmentation of habitat due to barrages etc. But do not be sad animal lovers! Irrespective of these facts active efforts are being done to conserve their population and as a result their population has increased a lot. In 2001 their population was estimated to be only 1,100 and in 2006 their number was estimated to be 1400-1600.
Indus River Dolphins travel either as couples or individuals. Since these dolphins do not have a crystalline eye lens they are effectively blind; all they can do is detect the direction and intensity of light. Navigation, therefore, is entirely by a sophisticated echolocation system. This blindness is one of the reasons why these dolphins swim on one side underwater, with one flipper trailing in the muddy riverbed. The physical touch gives the dolphins important information about their surroundings and helps them find food. They feed on small fish and crustaceans.
Now coming to the marine and coastal biodiversity in Pakistan, Pakistan has a coastline that stretches to over 1,050km along the Arabian Sea, 990 km when measured in a straight line. The coast of Pakistan consists of sandy beaches that are interrupted by rocky protruding points. According to the reports available, gastropods dominate the rocky shore fauna followed by decapods, crustaceans and polycheate worms. There are occurrences of approximately twenty-one intertidal (between high tide and low tide) seaweeds. As many as 15 green seaweeds and 6 brown red marine macro algae are found from sandy shores.
Almost 800 species of marine fish have been recorded in Pakistans coastal water. Large pelagics (fish living in open sea) such as the tuna are common in the waters of Balochistan. Palla fish (Tenalosa ilisha) which is considered a delicacy, is an anadromous fish that swims up the Indus River to breed.
The green turtle (Chelonia mydas) and the olive ridley turtle (lepidochelys olivacea) are found in Pakistan. Eight species of oyster occur here and squid are also abundant.
Last but not the least, corals. It was widely believed that corals do not occur in Pakistan. A preliminary survey of four areas along the Balochistan coast of Pakistan found 25 species of scleractinian coral and 77 species of reef fish. Astola (Jezira Haft Talar) Island situated approximately 37 km off the Balochistan coast stood out for its diversity of corals and fish. Soft coral such as seafan and brain coral are also present south of Astola Island.
The Writer Is A Student Of Bio Sciences, Comsats Institute Of Information Technology.