title: The annual marine feeding aggregation of Atlantic sturgeon Acipenser oxyrinchus in the inner Bay of Fundy: population characteristics and movement.
abstract: Atlantic sturgeon Acipenser oxyrinchus aggregate to feed from May to October in Minas Basin (45° N; 64° W), a large, cul-de-sac embayment of the inner Bay of Fundy. The aggregation consists mainly of migrants from the Saint John, NB and Kennebec Rivers, ME (99%). During 2004-2015, 4393 A. oxyrinchus were taken as by-catch by commercial fish trawlers or at intertidal fishing weirs, and 1453 were marked and/or sampled and released. Fork length (LF) ranged from 458 to 2670 mm, but 72·5% were <1500 mm. Mass (M) ranged from 0·5 to 58·0 kg. The mass-length relationship for fish ≤50 kg was log10M = 3·32log10LF- 5·71. Observed growth of unsexed A. oxyrinchus recaptured after 1-8 years indicated fish of 90-179 cm LFgrew c. 2-4 cm a year. Ages obtained from pectoral spines were from 4 to 54 years. The Von Bertalanffy growth model predicted K = 0·01 and L∞= 5209 mm LF. Estimated annual mortality was 9·5-10·9%. Aggregation sizes in 2008 and 2013 were 8804 and 9244 individuals, respectively. Fish exhibited high fidelity for yearly return to Minas Basin and population estimates indicated the total at-sea number utilizing the Basin increased from c. 10 700 in 2010 to c. 37 500 in 2015. Abundance in the Basin was greatest along the north shore in spring and along the south shore in summer, suggesting clockwise movement following the residual current structure. Marked individuals were recaptured in other bays of the inner Bay of Fundy, north to Gaspé, Quebec, and south to New Jersey, U.S.A., with 26 recoveries from the Saint John River, NB, spawning run. Fish marked at other Canadian and U.S. sites were also recovered in Minas Basin. Since all A. oxyrinchus migrate into and out of the Basin annually they will be at risk of mortality if planned tidal power turbines are installed in Minas Passage.
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada. mike.dadswell@acadiau.ca.
authors: M J
authors: MJ
authors: Dadswell
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: S A
authors: SA
authors: Wehrell
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: A D
authors: AD
authors: Spares
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: M F
authors: MF
authors: Mclean
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: J W
authors: JW
authors: Beardsall
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: L M
authors: LM
authors: Logan-Chesney
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: G S
authors: GS
authors: Nau
authors: Acadian Sturgeon and Caviar Inc., Carters Point, New Brunswick, E5S 1S5, Canada.
authors: C
authors: C
authors: Ceapa
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: A M
authors: AM
authors: Redden
authors: Department of Biology, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
authors: M J W
authors: MJ
authors: Stokesbury
mesh_terms: D025041:Animal Migration; D000818:Animals; D061006:Bays; D002170:Canada; D005247:Feeding Behavior; D005260:Female; D005399:Fishes; D008297:Male; D009026:Mortality; D011156:Population Density; D011157:Population Dynamics; D011792:Quebec; D045483:Rivers; D012621:Seasons
keywords: Acipenseridae; Minas Basin; abundance; growth; mortality; tidal power