LONDON: Scientists found further evidence that large scale commercial fishing has driven some species of deep sea fish to near extinction. A report in the latest issue of the journal Nature shows declines of up to 98% in the population of five species of deep sea fish.
The report authors - researchers from Canada's Memorial University had studied the catch data of trawlers fishing in the Canadian Atlantic waters. Trawlers operate out at deep sea using the 'bottom trawling' method where a huge trawl net is dragged across the ocean floor. The net is usually 50m – 60m wide and scoops up not just deep sea fish but also destroys coral and other ecosystems.
The Canadian scientists studied the logged entries of catches between 1978 and 1994 and identified five species whose populations had declined by 89-98%. These are: the blue hake, spinytail skate, spiny eel, onion-eye grenadier and round-nose grenadier.
The declining numbers are of great concern as they occurred in “a single generation of theses species” according to Jennifer Devine, the leader of the MU research team. She explained that the species her team identified were known to live up to 60 years and can grow up to a yard in length.
What makes them particularly vulnerable to over-fishing is that these species mature late in their teens and have a low fertility rates. Some species could become extinct in just three generations, according to the researchers' projections.
These species were actually accidental catches and not meant for dinner plates, which makes the study results even more significant. The declining numbers in these species represent a threat to the marine ecosystem, the scientists said.
These five species can be regarded as “critically endangered” – a classification based on conditions specified by the UN-appointed World Conservation Union. This group identifies and lists endangered and threatened species.
The MU team leader says in her report that “urgent action is needed for the sustainable management of deeps-sea fisheries”, a sentiment echoing the concerns of conservation groups. In recent times, various conservation groups and environment campaigners have lobbied hard for a global moratorium on commercial deep sea fishing. Last November, they tried to persuade the UN assembly to adopt a moratorium.
Commercial fishing started concentrating on deep sea fishing in the 1960s, after coastal areas started yielding a poorer catch year after year.
Devine urged for more conservation measures which include “the establishment of deep-sea protected areas”.
Another study some time ago had found an alarming increase in commercial fishing. It warned that traditional fisheries had grown to a scale that is 30 percent more than what the world's oceans can provide.
