Found! UMaine Researchers Re-discover Endangered Sturgeon in the Penobscot
Contact: Michael Kinnison (207) 581-2575; Gayle Zydlewski (207) 581-4365: David Munson (207) 581-3777
ORONO, Maine — Over the past week, UMaine scientists conducting research in the Penobscot River have captured and released nearly a dozen shortnos sturgeon, a bottom-dwelling fish that has been listed as endangered since 1967. Discovered in the waters off Winterport, these sturgeon represent the first confirmed encounters of the unusual fish in the Penobscot since 1978.
Five of the 11 fish captured were implanted with special transmitters to allow researchers to follow the fishes’ movements in the river.
The re-discovery of the species is an important milestone in an ongoing project being conducted by UMaine scientists and the USGS Cooperative Fish and Wildlife Research Unit funded by the National Oceanic and Atmospheric Administration. The discovery of a surviving population in the river, despite the loss of much of the sturgeon’s habitat and serious problems with water quality during the last century, suggests that the Penobscot may be on the mend. The capture also points to the potential of the Penobscot River Restoration Project, which may open the door to lost habitat for struggling species like the shortnose sturgeon.
“Our research is actually designed to find Atlantic sturgeon, but what a bonus,” said UMaine graduate student Stephen Fernandes. “When I saw it, I was ecstatic.”
“This species tends to stay within its home river, unlike the Atlantic sturgeon that wanders along the coast,” said UMaine Biological Sciences Professor Michael Kinnison. “One or two fish could represent strays from another river system, but the numbers we are now encountering bode well for a remnant shortnose population that spawns somewhere in the Penobscot. It’s great!”
The fish captured this past week measured 30 to 42 inches in length, consistent with breeding age individuals.
UMaine School of Marine Sciences Professor Gayle Zydlewski and Dr. Joseph Zydlewski of the USGS Cooperative Fish and Wildlife Research Unit are key players in the project as well, working with Kinnison and Fernandes to gather critical information about the abundance and habitat use of sturgeon populations in the Penoboscot system. A close cousin of the shortnose sturgeon, the Atlantic sturgeon is not currently listed as endangered, but is a species of special federal concern and hence under review.
The first sturgeon captured during the project were implanted with an acoustic transmitter and quickly released back into the river near Winterport. Utilizing an $86,000 grant from NOAA’s Fisheries Service, the UMaine team will track the individuals carrying implants using portable receivers and a new river-wide hydroacoustic telemetry array deployed by the University of Maine, USGS Coop Unit and the NOAA/NMFS Downeast Field Station. By following the movements of these individuals the research team hopes to determine where sturgeon go and what they do in the river, and, hopefully, discover where the rest of the lost shortnose sturgeon population is hiding.
“They are an amazing fish,” said Kinnison of the sturgeon. “It’s really exciting that we were able to find them again in the Penobscot.”
Often referred to as “living fossils,” sturgeons have remained relatively unchanged for millions of years. Both the Atlantic and the shortnose sturgeons are covered with bony plates and are equipped with a highly specialized mouth on the underside of the head for bottom feeding. Surviving on a diet of shellfish and other small, bottom-dwelling creatures, shortnose sturgeon can live for more than 30 years and grow to 25 pounds or more. The larger Atlantic sturgeon can reach lengths of eight feet and weigh in excess of 300 pounds.
The coast-wide plight of these sturgeon species is owed to a number of factors. In addition to problems with water quality and dams, these fish are slow to mature, taking up to 20-30 years before first reproducing. This slow maturation made their populations particularly vulnerable to over-harvesting in the 19th and 20th centuries when their eggs, or “caviar”, became a fashionable delicacy.