Washington, March 25 : A biologist has discovered that the shell lengths of northwest Atlantic Ocean snails have increased by 22.6 per cent over the past century.

"We found a dramatic increase in size, which could affect the entire intertidal food chain," said Jonathan Fisher, a Postdoctoral Fellow at the Queen's University in Canada, and the leader of the study.

Until now, this significant change in the marine ecosystem has gone unnoticed.

Previous and continuing research has also found that large snails tend to prey on mussels and barnacles and spend less time resting between feedings, compared to small snails.

Fisher and his team used museum collections from the Academy of Natural Sciences of Philadelphia as a base for their data.

They measured the shells from 19 lots of shells gathered between 1915 and 1922, and compared them with samples from the same 19 locations today.

The researchers are unsure exactly why the snails are growing so large, so rapidly.

"Many documented environmental changes between these time periods could affect snail survival or growth rates," Dr. Fisher suggested.

"We're finding fewer predatory fish now, which would allow the snails to grow," he added.

The temperature of the water today is warmer than 100 years ago, which could also account for faster growth of the snails, he explained.

"But, regardless of the factors that contributed to the size increase, the marine landscape is changing dramatically on a historic timescale. That's what is really important here," said Dr. Fisher. (ANI)