The commercial fishery for Atlantic Sturgeon Acipenser oxyrinchus in the Saint John River, New Brunswick, began in 1880. The early fishery was unregulated, and the adult stock was depleted by 1886 after landings of 712 metric tons. After a 10-year closure the fishery was reopened in 1897 with management regulations, and landings varied from 6 to 20 metric tons/year until 2010. In 2011 an annual quota of 350 adults was established and landings are now stable at 11.3 ± 1.7 (mean ± SD) metric tons/year. Since 2009, fishers have collected biological statistics from adults taken in the fishery and 14-60% of captured individuals have been marked and released each year. During 2009-2015, annual mean values of total length and dressed weight of landed adults were stable, the male : female sex ratio was 1.2:1.0, and mean age of males and females was 27.2 and 34.0 years, respectively. Estimates of instantaneous total mortality ranged from 0.08 to 0.11, and mean annual survival was 90.9%. Of 1,396 marked adults released, 147 were recaptured in the estuary in subsequent years. Tag returns indicated that the modal spawning periodicity of males was 2 years and that of females was 4 years. Valid, modified Schnabel and Jolly-Seber mean annual population estimates for 2013-2015 were 18,179 and 20,798 adults, respectively. The quota in relation to these estimated adult populations represented annual exploitation rates of 1.9% and 1.7%, which are below F 50 and would maintain present stock size. The virgin adult population was determined using 1880-1886 total landings and a mean weight range for adults of 50-30 kg. Estimated range of the 1880 virgin population size was 14,240-23,733 adults. These data suggest that the fishery is sustainable at its current annual yield and that the population is near the carrying capacity of the Saint John River.

As a long‐lived and late‐maturing species, Atlantic Sturgeon Acipenser oxyrinchus are susceptible to overharvest, which makes knowledge concerning their age and growth essential to sustainable management. The Saint John River, New Brunswick, and the St. Lawrence River, Quebec, support the two remaining commercial fisheries for Atlantic Sturgeon in North America; however, the relationship between age and growth has not previously been modeled for the Saint John River population. Ages of Saint John River Atlantic Sturgeon were estimated by using pectoral fin spine sections collected from 262 individuals of known TL. Most (87%) of the pectoral spine sections were aged by two readers to evaluate possible reader bias. An age–bias plot and coefficient of variation (CV) indicated relatively low between‐reader precision (CV = 5.6%) compared with that reported in other studies. Von Bertalanffy growth model (VBGM) parameters were estimated for males (n = 67), females (n = 85), and the combined sexes. Unsexed juveniles and subadults smaller than 150 cm TL (n = 110) were used for the lower part of each curve. The growth models indicated that (1) males reached maximum length sooner than females and (2) females continued to grow more as adults to greater lengths (males: Brody growth coefficient K = 0.06, asymptotic length L∞ = 230 cm TL; females: K = 0.04, L∞ = 264 cm TL). As predicted, the VBGM parameters estimated for combined sexes of the Saint John River stock (K = 0.05, L∞ = 254 cm) were intermediate to those of Atlantic Sturgeon from the Hudson and St. Lawrence rivers, in agreement with a previously observed latitudinal trend in growth.Received June 26, 2014; accepted January 13, 2015

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Summary Natural mortality of Atlantic sturgeon (Acipenser oxyrinchus) has been determined to be low (M = 0.07). Reported herein is the mortality by beach stranding of 11 Atlantic sturgeon in Scot’s Bay, part of the inner Bay of Fundy in Nova Scotia, Canada on 22 June 2014. Genetic analyses, histological analysis and age determination were performed to determine origin, maturity stage and age of the stranded Atlantic sturgeon. Microsatellite and mitochondrial DNA analyses indicated that four of the Atlantic sturgeon (2 males and 2 females) were from the Saint John River, NB population, which was designated as threatened by the Committee on the Status of Endangered Wildlife in Canada. Seven Atlantic sturgeon (1 male, 5 females, 1 unknown) were from the Kennebec River, Maine population, that was listed as threatened under the Endangered Species Act in the U. S. Ageing of A. oxyrinchus by pectoral fin spine analysis determined that the mean age of the individuals from the Saint John River ( truex¯=24.25 years, sd = 5.0) and the Kennebec River ( truex¯=22.7 years, sd = 3.5) were not significantly different. This is the first report of a stranding event of Atlantic sturgeon, and describes a source of natural mortality affecting populations of concern in both Canada and the U. S.

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