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.

Movement and Out‐Migration of Juvenile Atlantic Sturgeon in Georgia, USA

“…As the MMJs grow and mature in the marine environment, they may return to natal or nonnatal estuarine or riverine habitats for prolonged periods during the summer months (Dovel and Berggren ; Bain ; Altenritter et al. ; Wippelhauser et al. ).…”

Seasonal distribution and movement of juvenile Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) in the lower Saint John River Basin, New Brunswick, Canada

“…Juvenile Atlantic sturgeon in southern Atlantic states have been observed making more frequent movements during cold-weather months and exhibiting high residency during summer in brackish water near the saltwater interface (Moser and Ross 1995). Similarly, subadult Atlantic sturgeon in the Penobscot River exhibit high residency in mesohaline waters during summer months (Altenritter et al 2017). We predicted that distribution and movement would be similar between fish tagged in the Sant John and Kennebecasis Rivers but different among seasons, with summer exhibiting the highest residencies and lowest movement frequency.…”

“…Subadults remain in marine environments where they continue to grow until reaching maturity at an estimated size of 150-180 cm fork length, depending on sex (Smith 1985). Both subadult and adult fish are known to make long distance migrations along the Atlantic coast (Dadswell 2006;Erikson et al 2011;Altenritter et al 2017). Long lives, complex life history, irregular spawning intervals, and long-distance migrations are characteristic of sturgeon species and contribute to the difficulty of studying sturgeon and the persistence of ecological knowledge gaps.…”

“…There has been some investigation into the movement patterns of Atlantic sturgeon in the Bay of Fundy (MacLean et al 2014;Taylor et al 2016) but there has been no directed research into that of juveniles in the lower Saint John River basin. Investigations into distribution and movement of Atlantic sturgeon juveniles in the northern extent of their range suggest they prefer habitats near the salt wedge and typically remain within a small aggregation or foraging areas for extended periods in warm months (Hatin et al 2007;Fernandes et al 2010;Altenritter et al 2017). Limited observations of juveniles during winter suggest they may form overwintering aggregations in the brackish waters of the lower basin (Bell 2011).…”

Surgical Implantation of Acoustic Tags in American Shad to Resolve Riverine and Marine Restoration Challenges

“…For anadromous species, the technology can be extremely informative because, unlike radiotelemetry, it works across all salinity levels, allowing individual fish to be tracked across coastal waters, estuaries, and freshwater environments during their annual migrations (DeCelles and Zemeckis 2014). The environmental flexibility of acoustic telemetry technology and the rapid proliferation of receiver coverage have led to studies that have better defined the ecology and life cycle requirements of iconic anadromous species, such as Striped Bass Morone saxatilis, Atlantic Sturgeon Acipenser oxyrinchus, and a number of salmonids (e.g., Hayes et al 2011;Goetz et al 2013;Kneebone et al 2014;Gahagan et al 2015;Breece et al 2016;Altenritter et al 2017).…”