PORTLAND, Maine (NEWS CENTER) — Maine hasn't had a shrimp season since 2014. Regulators say the stocks are too low to support the fishery. Shrimp are sensitive to water temperature and, as ocean water has warmed, the number of shrimp has declined.

Scientists at the Gulf of Maine Research Institute (GMRI) in Portland are finishing up a two-year pilot study using sound waves to help determine how many shrimp are below the water and where they are. Ten fishermen from Kittery to Cutler agreed to put acoustic equipment on their boats and gather data from the bottom of the ocean.

Adam Baukus, a senior researcher at GMRI, said the collaboration with the fishermen has been key to the study.

"They have history in the fishery and knowledge of the ocean," Baukus said. "This is hard work, long surveys they are doing in between normal fishing operations, the guys are anxious to be helpful."

Baukus said the sound waves bounce off the bottom of the ocean and go back up to the boat. Different animals produce different sounds. A fish with an air bladder will bounce back differently than a shrimp. When they have the readings, the researchers will do small test tows to prove that there really are shrimp where the sound waves indicate.

"Every year we are able to cover 1,200 miles of ocean and learn what animals are in that stretch of ocean, so it's a powerful tool to see where are we seeing shrimp and where aren't we seeing shrimp and how is that changing over time?"

Researchers say they still have data to collect and numbers to crunch but, overall, they are seeing shrimp in fewer areas this year than they did last year.