PORTLAND, Maine (AP) - Marine authorities in the U.S. and Canada say they will marshal resources to try to find out what's behind a string of deaths of endangered North Atlantic right whales.

Representatives of the National Oceanic and Atmospheric Administration and Fisheries and Oceans Canada announced the effort on Friday.

David Gouveia of NOAA says the countries will collaborate on a report about why 13 of the whales have been found dead this year.

The report could help craft future regulations that protect the vulnerable whales.

Officials with both countries say ship strikes and entanglement in fishing gear have played roles in the deaths of the whales.

Officials say the report will take months to assemble. It will involve collecting data on each whale that died and considering factors such as changes to the environment and habitat.