Study: Whale, Seal Recovery Presents New Problems

Many formerly endangered marine mammals are climbing toward healthy populations, according to a new study. The problem? Local communities don't always welcome them with open arms.

"After generations away, these forgotten species can suddenly be seen as newcomers or even pests," Joe Roman, lead author of the study and professor at the University of Vermont's Gund Institute for Ecological Economics, said in a statement.

Watch divers have a whale of an encounter 0:35

Take the gray seal in eastern Canada. Once hunted in great numbers, environmental protections have caused the population there to jump 1,410 percent since 1977, according to the study.

That has caused tensions with local fishermen, some of whom have complained about lower fish stocks since the seals returned. Similar concerns have accompanied the recovery of gray and humpback whales.

Related: U.S. Proposes Taking Humpback Whales Off Endangered Species List

The study, published in the June issue of Trends in Ecology and Evolution, stressed that more animal populations are declining than growing. But for those species that are recovering, local communities should come up with a detailed a plan on how to deal with them, the study said.

It also recommended publicly celebrating conservation successes and re-thinking "nuisance killing" to weigh the economic benefits of returning animals.