Atlantic Sturgeon Use of the Penobscot River and Marine Movements within and beyond the Gulf of Maine

Abstract

Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus were recently listed as threatened in the Gulf of Maine and endangered in the rest of their U.S. range. Continued research priorities include long-term population monitoring, identifying the species’ spawning and nursery grounds, and determining its use of estuaries and marine coastal waters. Although recent and ongoing research is filling in knowledge gaps, the Atlantic Sturgeon’s life history and its severely depleted populations make this a challenging species to fully characterize. Our goal was to compile data collected over 7 years from fish captured in the Penobscot River estuary, Maine, to inform management decision making. Atlantic Sturgeon were captured (n = 199), recaptured (n = 16), and passively telemetered (n = 32 that were analyzed here) from 2006 to 2013. Captured individuals were predominantly subadults, and data from telemetry indicated repeated use of a 5-km reach of the mesohaline portion of the estuary. Subadults predictably emigrated from the river each fall (mean date ± SD, August 31 ± 43.5 d) and immigrated back each spring to early summer (May 15 ± 27.8 d), with most individuals (>95% [31 of 32]) returning one or more years after tagging. Marine detections of these subadults were common (81.25% [26 of 32]) and spanned the geographic extent of both the threatened and endangered U.S. distinct population segments and into international waters, e.g., from the Hudson River, New York, to Minas Basin, Nova Scotia. However, they were more typically detected by receivers in the Gulf of Maine; 77% (20 of 26) were only detected in the Gulf of Maine when not in the river. These data indicate that, based on the temporal and spatial predictability of habitat use, the estuary of the Penobscot River is important for subadult Atlantic Sturgeon of the Gulf of Maine. The wider movement patterns emphasize the need for conservation and management across regions and international boundaries.

Received June 23, 2016; accepted January 4, 2017

Acknowledgments

We thank Steve Fernandes, Phillip Dionne, Matthew Wegener, Kevin Lachapelle, Matthew Altenritter, and Catherine Johnston for capturing and tagging the Atlantic Sturgeon and maintaining the receiver array as part of their graduate work and Joseph Zydlewski for his contributions on graduate student committees and supply of field assistance and infrastructure.

We also thank the following Gulf of Maine Coastal Tracking Network, Atlantic Cooperative Telemetry Network, and Dalhousie University Ocean Tracking Network (OTN) researchers, staff, and partner organizations that maintained receivers outside the four study rivers and provided data: Jay Barthelotte, Duncan Bates, Rod Bradford, Robert Branton, Jeremy Broome, Nicholas Buchan, Michael Dadswell, Keith Dunton, Michael Frisk, Graham Goulette, James Hawkes, William Hoffman, Adrian Jordaan, Richard Karsten, Micah Kieffer, John Kocik, Matthew Litvak, Kim McKown, Paul Music, Anna Redden, Peter C. Smith, Michael Stokesbury, and James Sulikowski, as well as Acadia University, Dalhousie University, Department of Fisheries and Oceans Canada, Massachusetts Division of Marine Fisheries, Mount Allison University, National Marine Fisheries Service, New York Department of Environmental Conservation, OTN field and data teams, Stony Brook University, University of Massachusetts–Amherst, U.S. Geological Survey Conte Anadromous Fish Research Center, and University of New England.

This project was conducted under the University of Maine Institutional Animal Care and Use Committee protocols A2008-07-01, A2011-06-11, and A2014-05-06. The research was funded by NOAA-Fisheries award NA07NMF4720053 to the Maine Department of Marine Resources. This is Maine Agricultural and Forest Experiment Station publication 3526. All procedures were conducted under NOAA ESA Section 10 permits 1595 and 16526 for taking protected species for scientific purposes. The views expressed herein are those of the authors and do not necessarily reflect the views of the Penobscot River Restoration Trust, NOAA, USGS, or any of their members or subagencies.