The Penobscot receiver network is a collaborative effort between NEFSC, the University of Maine, and the U.S. Geological Survey (USGS). The University of Maine and USGS maintain freshwater and some estuarine receivers, while NEFSC maintains the majority of the estuarine receivers and all those in marine areas. Biologists download data monthly by tending the receivers by boat.
Once data is downloaded for the season, biologists can learn which route each fish took, how long it took to get to the Gulf of Maine, and most importantly, which fish survived and where fish that did not exit the Penobscot River may have died. This information can help uncover the causes of mortality.
Kocik says the establishment of the Halifax array by the Ocean Tracking Network as a distant receiver line on the Atlantic shelf affords a new opportunity to detect U.S. salmon on their migration to the Labrador Sea. Other NEFSC biologists have been tagging about 250,000 salmon annually since the 1980s using traditional external tagging methods, which help determine survival but don't provide the level of detail about fish movements that the acoustic tags do.
The Ocean Tracking Network array works like the coastal network in Penobscot Bay. Once the tagged fish swim near passive acoustic receivers on the ocean floor, which are about 800 meters (2,500 feet) apart in a line 22 kilometers (about 14 miles) long, information is transmitted to the receivers and then downloaded via modem to computers on nearby research vessels tending the array. The first tagged salmon crossed the Halifax line in early June.
|Contact: Shelley Dawicki|
NOAA National Marine Fisheries Service