Local scientists are keeping a close eye on waterways with the help of the North Carolina Ferry system. Ferries involved in the water-testing program can help detect fish kills and cold stuns, like the one that happened to Spotted Sea Trout this past week.
The program is called FerryMon. It was started 10 years ago by local UNC Institute of Marine Sciences researcher Hans Paerl after Hurricane Floyd contaminated sound waters with mud. It consists of two ferries, one that runs from Minnesott Beach to Cherry Branch, and one that runs from Cedar Island to Ocracoke Island and on to Swan Quarter. Those two ferries are specially equipped with sensors to test water that cleanly streams through the bottom of the boats.
"Each of these sensors is measuring a different thing. you have temperature, salinity, and turbidity of the water," says Paerl.
If the sensors detect something suspicious, they will automatically trigger a carousel to start collecting water samples to take back to the lab when the ferry docks. This way scientists can test the water for dangerous toxins or algae blooms.
"Well if we get a fish kill and there's no obvious low oxygen event going on, then you start suspecting other things." says Paerl.
After looking at this past week's data, Paerl can confirm the problem reported with the Speckled Sea Trout was caused by quick temperature changes, and not toxins. He says the ferries recorded water temperatures close to 70° before last weeks storm, and a quick drop to 40° just after (4° Centigrade).
"When we get down below 4°C (40°Fahrenheit) we have problems with cold stun and of course that has been recorded in Pamlico Rivers and Cape Fear." says Paerl.
The system is very efficient, testing water quality almost continuously. Paerl says it is very important to continue the FerryMon project because the state is unable to test nearly as much as the ferries are. State testing is only performed once a month. This makes it difficult to spot problems in the water that could eventually lead to dangerous algae blooms, or fish kills. That's why the state helps to fund the project through grants. Much of the funding for FerryMon is currently provided by the Coastal Recreational Fishing License, or CRFL, a program by the Department of Marine Fisheries.
"I always like to say that the program is almost free because the ferries don't cost anything!" says Paerl.
To learn more about the project, click here.