PORTLAND, Maine (AP) A report about a critically endangered whale authored by federal scientists says some regulations that are supposed to protect them aren’t working and might have unintended consequences for the animals.

The report is a National Oceanic and Atmospheric Administration technical memo and it concerns the North Atlantic right whale. The right whale is one of the most endangered marine mammals in the world, numbering only about 450.

Lobster fishing rules are designed to protect the whales by requiring fewer trap lines that can ensnare the giant animals. But the NOAA report asserts that some lobstermen have adapted to the rules by putting more traps on a single line, and using stronger rope.

Maine Public reports that combination may have actually contributed to an uptick in the severity of whale entanglements.