Spawning Intervals, Timing, and Riverine Habitat Use of Adult Atlantic Sturgeon in the Hudson River

Abstract

The Hudson River currently supports the largest population of Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus) in the United States despite currently supporting less than a percent of historic abundance. Listed as Endangered throughout much of their range, Atlantic Sturgeon are still impacted by multiple threats, resulting in habitat destruction or direct mortality that has inhibited a population rebuild despite 20+ years without directed fishing pressure. To assist in management and reduction in anthropogenic impacts to adult Atlantic Sturgeon in the Hudson River we have examined sex specific patterns related to spawning. Utilizing hundreds of adult Atlantic Sturgeon, telemetered along the Atlantic Coast, and an extensive passive acoustic array from 2010-2016 we were able to estimate arrival, departure, and duration of occupancy for four segments of the Hudson River for male, female, and unknown sex individuals. Male Atlantic Sturgeon arrived above river kilometer 100 at an average date of May 27, 12 days prior to females on June 8. While there were only few significant differences in the timing of departure, the average date from RKM 100 was July 11 for males, June 29 for females and July 23 for unknown sex individuals, as such occupancy was significantly longer for male Atlantic Sturgeon. This study shows female Atlantic Sturgeon often spawn in consecutive years and had much shorter mean intervals between spawning appearances (females 1.66 years, males 1.28 years) than the historical literature suggests. While the timing of spawning is consistent with the historic record, we provide a much greater detail and finer resolution timeline for adults in the Hudson Accepted Article This article is protected by copyright. All rights reserved River as well as update the historic estimate of spawning return rates. Conservation measures to reduce direct impacts to spawning habitat and mature Atlantic Sturgeon would likely provide the most benefit if conducted between mid-May through the end of July.

Long‐Term Trends in Juvenile Atlantic Sturgeon Abundance May Signal Recovery in the Hudson River, New York, USA

“…Spawning periodicity may also play a role in year-class strength. Estimates of spawning intervals for female Atlantic Sturgeon are variable, ranging from 1 to 5 years (Hilton et al 2016;Hager et al 2020;Breece et al 2021). The higher catch rates that have been observed in recent years (2012, 2015, and 2018) occurred in 3-year intervals, and the length distribution in these years indicated a greater proportion of presumed age-3 individuals.…”

“…2020; Breece et al. 2021). The higher catch rates that have been observed in recent years (2012, 2015, and 2018) occurred in 3‐year intervals, and the length distribution in these years indicated a greater proportion of presumed age‐3 individuals.…”

Seasonal migration cues differ for dual‐spawning Atlantic Sturgeon in the Great Pee Dee River

“…Atlantic Sturgeon appear to exhibit a subdivided metapopulation structure along the Atlantic coast, with high philopatry among spawning adults leading to genetically distinct populations among river systems (ASMFC 2017; White et al 2021). Historical accounts suggest that spawning intervals range from 3 to 5 years for females and from 1 to 5 years for males (Smith 1985); however, recent studies suggest that spawning may be more frequent in some systems (Hager et al 2020; Breece et al 2021). Timing of spawning varies latitudinally, with upriver migrations beginning as early as March in southern climates and as late as July for more northerly populations (Dadswell 2006; Hilton et al 2016).…”

A long-term ichthyoplankton monitoring program suggests climate-induced environmental variabilities changed fish communities in the Hudson River estuary

“…The changes in salinity could alter their distribution and spawning grounds as well as larval survival and consequent recruitment. Conversely, Atlantic sturgeon, an endangered species in the HRE, spawn upstream from the tidal salt front as their spawning grounds (Van Eenennaam et al, 1996;Breece et al, 2021) and their early life stages are intolerant to saline conditions (Kazyak et al, 2020). Van Eenennaam et al (1996) indicated that the eggs and larval dispersal strategy of Atlantic sturgeon may require the environmental conditions remain freshwater throughout the spawning season.…”