(AP) — Officials are investigating a rash of deaths among dolphins and sea turtles on the Mississippi Gulf Coast.

WLOX-TV reports nearly 40 dead dolphins and sea turtles have been found in recent weeks.

Two veterinarian pathologists from Mississippi State University have been performing necropsies on dead dolphins at the Institute for Marine Mammal Studies in Gulfport, looking for answers.

The institute’s director, Moby Solangi, says he believes the deaths are linked to floodwater that has emptied into the Mississippi Sound from south Louisiana’s Bonnet Carre Spillway. The spillway opened Feb. 27 to alleviate Mississippi River flooding, sending freshwater coursing through Lake Pontchartrain into areas that are normally brackish or salty.

Floodwaters from the spillway are also known to kill oysters in the Mississippi Sound.