The Nova Scotia government says it miscalculated figures in a report that showed the quantity of shellfish caught off the province's shores plunged by more than half over a three-year span.

On Wednesday, the government delivered a report that said the quantity of harvested shellfish plummeted from 317,556 tonnes in 2003 to 127,969 tonnes three years later.

But Justin Huston, a coastal zone co-ordinator for the Department of Fisheries and Aquaculture, said Thursday the drop is much smaller.

Huston said the actual catch of shellfish in 2003 amounted to 155,338 tonnes and the inaccurate figure included all harvested fish.

"It was a simple but very major mistake," he said, adding he believes the mistake was made when the authors of the report were analyzing spreadsheets.

"The authors just got the wrong line."

The department will correct the error on its website later Thursday, he said. No other mistakes have been found

Huston said the error doesn't change the report's conclusion that shellfish closures are increasing and it doesn't dampen the department's commitment to protect coastal waters.

The report, the first of its kind in Atlantic Canada, gives an overview of the current state of Nova Scotia's coast.

It says the province will suffer physical, ecological and economical consequences without the co-ordinated participation of governments, residents, academics and businesses, among others.

The government says it will use the report and public feedback to develop a strategy to address coastal issues, expected in 2011.