Our oceans are running out of fish
June 8 was World Ocean Day, but the Central Institute of Fisheries Education says there’s nothing to cheer about…….Joanna Lobo
June 8 was World Ocean Day, but the Central Institute of Fisheries Education says there’s nothing to cheer about…….Joanna Lobo
According to American editor Ambrose Bierce, author of the Devils Dictionary, an ocean is a body of water occupying about two-thirds of a world made for man… who has no gills. And his 19th Century definition holds true even today.
Oceans provide us with practically everything we need to survive, and yet we treat them as dumping grounds. Waste from industries, factories, and everyday life finds its home in our readily accessible oceans. And the worst affected is the marine life.
In India, particularly along the western coast, some fish like eels (wam), threadfins (dhada) and true perches (karkara) are decreasing in numbers at an alarming rate, and are now on the endangered species list. Even the pomfret is dwindling fast. Earlier, the pomfret catch was 15,000 tons per annum, but this has been reduced to a mere 2,000 tons. These alarming statistics were given by Dr Sushant K Chakraborty, principal scientist at the Central Institute of Fisheries Education (CIFE).
The two major reasons behind this are recruitment overfishing and growth overfishing. Dr Chakraborty explains: In tropical countries, the oceans are home to multiple species. Prawns are the main catch and the use of prawn trawlers results in other fish, especially juveniles, becoming a by-catch. This is called recruitment overfishing. Growth overfishing occurs when fish are caught before they mature, which means they cannot reproduce. Fish should be allowed to reproduce once in their lifetime. This ensures progeny of their species.
CIFE on its part undertakes projects like inland fish resource management and aquaculture. The former deals with management of fish as a natural resource, while aquaculture is cultivation of fish (or fish farming). The institute provides the technology to private hatcheries for the same, and also educates fishermen on the usage of the coden mesh of 30mm instead of the standard 15mm so that juvenile fish can escape being a by-catch. Moreover, the 15mm mesh tends to sweep the coral and other marine biology, leaving nothing for the fish to feed on. Says Chakraborty: We also tell them to throw gravid (pregnant) lobsters back into the sea. Usually, the eggs which are present in the abdomen of these lobsters are brushed off.
Deposit of waste is yet another problem. CIFE recently conducted a research project on Nitrogen Fixing Bacteria and their Nitrogenous Activities in the coastal waters of western Maharashtra. The study showed that the chemicals released into the sea lead to an increase in algae resulting in oxygen deficiency. This in turn either kills the fish or affects their reproductive capabilities.
The fact that fish are declining is a problem that has to be tackled on a large scale. For one, according to CIFE, there should be a limit to the amount of fish that can be caught. A time limit should also be fixed, says Chakraborty. For example, in Australia, one species of fish can be caught only for one week in the year. It is time for desperate measures. Otherwise our fish resources will be depleted.
Dr Pramod Kumar Pandey, a senior scientist at CIFE, suggests steps from the environmental point of view. He says, It is important to treat the waste of pollutants and other effluents before they are released into the aquatic environment. This could be done by using plants like lemna, azolla and duckweed that are capable of extracting heavy metals from the water. This is not only cost effective; it is eco-friendly, too.
A recent study carried out by an international team of ecologists suggests that by 2048 the oceans will be empty of fish because of overfishing, pollution, habitat loss, and climate change. The time has come for a change. The glimmer of hope lies in the fact that if proper steps are initiated, the tide can be reversed.