Relative recruitment success of stocked age-1 vs age-0 lake sturgeon (Acipenser fulvescens Rafinesque, 1817) in the Nelson River, northern Canada

Abstract

Success of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) stocking programmes has rarely been evaluated. As of the early 1990s, Lake Sturgeon populations were nearly extirpated from several sections of the upper Nelson River, Manitoba, at least in part due to historical overexploitation. Between 1994 and 2011, 20 885 fingerlings (age-0, untagged) and 1117 yearlings (age-1, 1014 PIT tagged) were stocked into an upper Nelson River reach. In fall 2012, a Lake Sturgeon population inventory using gill nets assessed postrelease survival/retention of stocked fish. Of 91 unique Lake Sturgeon captured, 67 (74%) possessed PIT tags, signifying they were stocked at age-1. Relative recruitment success was conservatively estimated to be 17.7 times greater for age-1 vs age-0 stocked fish based only on PIT tag recapture data. However, including 19 additional fish identified as stocked at age-1 based on atypical 'first' annuli patterns, the revised relative recruitment success rate was 130 times greater for age-1 vs age-0. An interpreted consensus ageing method produced correct age assignment 97% of the time for juveniles of known age, despite complications caused by overwinter growth in the hatchery.

Evaluating Population Recovery Characteristics and Potential Recovery Actions for a Long‐Lived Protected Species: A Case History of Gulf Sturgeon in the Apalachicola River

“…; Bezold and Peterson ; McDougall et al. ) and White Sturgeon A. transmontanus (Ireland et al. ) populations.…”

“…Initially, this should more quickly augment populations that are below carrying capacity but if lesser selective pressure translates to lower fitness (Camp et al 2013) long-term recovery could be hampered. There is precedent for using stocking in sturgeon recovery, as has been demonstrated for Lake Sturgeon A. fulvescens (Schram et al 1999;Bezold and Peterson 2008;McDougall et al 2014) and White Sturgeon A. transmontanus (Ireland et al 2002) populations. However, the use of stocking may be construed as contradicting the Gulf Sturgeon Recovery Plan goal of having "natural recruitment" maintain the population (USFWS and Gulf States Marine Fisheries Commission 1995).…”

Extrinsic Factors Influencing Somatic Growth of Lake Sturgeon

“…; McDougall et al. ). Juvenile Lake Sturgeon length‐at‐age and density (gill‐net CPUE) components of the current dataset were synthesized from academic, stewardship, and environmental monitoring studies conducted in Manitoba river systems (Winnipeg, Nelson, Burntwood, Hayes, and Churchill rivers) between 2006 and 2014 (Figure ; Table ).…”

“…The locations of hydroelectric generating stations are indicated as per the legend. Site abbreviations are presented in Table 1. FACTORS INFLUENCING SOMATIC GROWTH OF LAKE STURGEON energy to reproduction as fish approach (or after they reach) maturity, analyses were focused on juvenile Lake Sturgeon, which can generally be aged accurately (Bruch et al 2009;McDougall et al 2014d). Juvenile Lake Sturgeon length-at-age and density (gill-net CPUE) components of the current dataset were synthesized from academic, stewardship, and environmental monitoring studies conducted in Manitoba river systems (Winnipeg, Nelson, Burntwood, Hayes, and Churchill rivers) between 2006 and 2014 ( Figure 1; Table 1).…”

Evaluation of four surgical implantation techniques for age‐0 white sturgeon ( Acipenser transmontanus Richardson, 1836) with a new acoustic transmitter

“…Sturgeon populations have declined for several reasons, including overfishing and exploitation (historic and ongoing) and habitat degradation and fragmentation. While much research has been conducted to better understand early life history traits (Bates, Chandler, Lepla, & Steinhorst, 2014;Caroffino, Sutton, Elliott, & Donofrio, 2010;McDougall et al, 2014), many studies have not been able to utilize acoustic telemetry in small (<300 mm) sturgeon. Johnson, Hintz, Garvey, Phelps, and Tripp (2014) implanted miniaturized (0.2 g in air) radio transmitters into age-0 pallid sturgeon (Scaphirhynchus albus; 169-259 mm; 9.7-32.0 g; 0.9%-2.5% transmitter burden [weight of the transmitter relative to the weight of the fish]) and observed a decrease in survival and growth compared to unmarked controls.…”