Four days after the oil spill from MSC Chitra, an exact assessment of the impact on marine life cannot be done for lack of systematic data on the biodiversity off the Mumbai coast. Monsoon adds to the existing woes.
“One thing is sure, the spill will have an amplified impact on the sedentary marine animals like shells, lobsters, crabs, oysters, shrimps and mudskippers,” said Deepak Apte, Assistant Director, Bombay Natural History Society (BNHS). Considering that they form the base of the marine food pyramid, this will have a larger impact on life forms outside the sea as well, including shore birds. “When oil settles on the rocks, in the rock cracks, on the sand or on mudflats, it will create a sheath, thus asphyxiating all life forms under it.”
The impact on fish will be known only in the fair season between December and March. “It will not be clear right now how many larvae or eggs have been affected in the current season. Also, there are some species which breed only once in six years. We have no way of measuring the impact on them till we see them out in the sea,” said Mr. Apte. The impact could be measured on the basis of available ‘natural recruitment data' (the pattern of natural reproduction).
Mangroves will also be affected as this is their peak fruiting season. The mangroves in Vashi have already turned black due to an accumulated oil slick. “But it will not be much of a problem if oil accumulates on the barks of the mangroves,” Mr. Apte said. “The real problem is when the oil settles on aerial roots [also known as pnematophores] or affects their seeds.”
Places on the Mumbai-Raigad coastline like Mandwa and Sasawne have a thick oil deposit on the shore. “They will take a very long time to recover. At other places, depending on the seepage, the recovery may take anything from five months to five years,” said Mr. Apte, who has surveyed all affected sites on the Mumbai-Raigad coast.
Some environmentalists have suggested that fishermen be engaged in clearing the slick and assessing the impact. “They have huge manpower. They know the sea like no one else does. They can be very effective controllers,” Mr. Apte said. The fishermen could be involved in assessing the damage as well. “They know the places where they usually get a good catch.”
Seepage in slums
Colaba and Sewri, where substantial oil leakage was spotted on Monday, were found comparatively clean on Tuesday. But the slum-dwellers near these coasts complained of oil seepage in their homes during the high tide.
“Everything is ridden with oil in the house now. The rice sack was lying on the floor. Oil entered the house during high tide. How are we supposed to clean this now,” asked Vijayabai from the Geeta Nagar slums at Colaba.
Reports say a fresh oil leak has started near the Gharapuri and Pirwadi beaches here. Fortunately, there is still time for migratory birds to arrive. Flamingos will start coming in two months. If the contamination is not contained by then, the ill-effects will spread to wider life cycles, warn experts.
The environmentalists have anyway repeatedly said the most important concern is the long-term implication which can be gauged only after a systematic study.
“There is no need to get panicky. The destruction is hazardous, for sure. But we also need to understand the dynamics of nature. We have to keep watching how our shores behave over the next few months. This story cannot be forgotten after the heat of the breaking news is over,” Mr. Apte said.
