Colin Buxton, the director of the fisheries, aquaculture and coasts centre at the University of Tasmania's institute for marine and antarctic studies, said that the size of the 142-metre Dutch-owned trawler did not mean that it posed any greater environmental risk than several smaller vessels.

''It's just staggering [that] popularism and political expediency is now managing our fisheries,'' he said. ''I think it's incredibly dangerous. It's really sad that the decision has been handed down in this way.''

Professor Buxton said the 18,000-tonne fish quota given to Seafish Tasmania was sustainable according to solid science.

He said that an ecosystem model developed by the CSIRO - regarded as the ''best ecological model available'' - had been used to calculate the total population of fish and any potential impact on the food chain.

Professor Buxton, who stressed he had no connection with any company, industry body or regulator, said that ''localised depletion'' - the danger of emptying out a part of the ocean if a large ship fished too long in one place - was probably less of a risk with the super trawler.

The advantage of the super trawler, which has its own processing facilities and freezers, was that it could fish over a large area without being tied to ports.

''If you had 10 small trawlers tied to a place like Triabunna [in Tasmania], there would be a much, much higher chance of localised depletion,'' he said. ''These same people who are concerned about the … trawler and [are saying] you could take 10 small boats out there and that's a better idea. Based on what?''

He also rejected claims that not enough scientific research existed.

Professor Buxton said that the net size and catching capacity of the Abel Tasman were ''not dissimilar'' to net sizes already being used in waters off the west coast of Tasmania.