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Summary of lake sturgeon individuals sampled and comparison of Field sexing with Mo- lecular (Mol) sexing results.
Source publication
The characterization of demographic features in natural populations is important to understand recruitment dynamics, mating systems, and propensities for loss of genetic diversity. The accurate identification of sex can be difficult in sexually monomorphic species. We present a melt curve analysis based on qPCR assays for lake sturgeon (Acipenser f...
Context in source publication
Context 1
... total of 143 adult lake sturgeon, including the 14 used for the initial testing (85 with a field-sex assignment of male and 58 with a field-sex assignment of female), were analyzed using the real-time PCR sexing assay and the AllWSex2 primers [9]. The results are summarized in Table 1 and Figure 2. The sex assignment agreed between the field and molecular methods in 98% (140/143) of the samples, indicating that the assay was successful in two geographically separated lake sturgeon populations. All except for three female field-sexed fish showed a female-specific peak. ...Citations
... It is possible that separating recapture histories by sex would have led to different results; however, sex could not be accurately assigned. Since tissue samples were collected from each Lake Sturgeon, in the future it is anticipated that sex will be assigned using molecular techniques and applied to the upper St. Clair River subpopulation to provide a more precise estimate of population parameters (Kanefsky et al. 2022). For these reasons, the breeding return time model was not suitable for our data, but its use should be reevaluated when additional sex and recapture information becomes available. ...
Objective
The Lake Sturgeon Acipenser fulvescens is listed as threatened or endangered in 15 states or provinces within the species' native range. Accordingly, investments in habitat and population restoration for this species have increased throughout the Great Lakes. To aid in the evaluation of restoration efficacy, robust population parameters are needed to inform management decisions. The St. Clair–Detroit River system (SCDRS) contains one of the largest self‐sustaining Lake Sturgeon populations in the Great Lakes; however, recent estimates of population abundance and growth parameters have not been assessed.
Methods
Our study used baited setline and mark–recapture data collected between 2001 and 2019 to estimate whether the number of Lake Sturgeon captured varied annually and/or with water temperature and whether population abundance and the population growth rate (λ) varied among three subpopulations located in the SCDRS.
Result
Trends in the number of Lake Sturgeon captured on setlines varied among subpopulations and by life stage. Annual trends in the number of Lake Sturgeon captured remained consistent over time in the upper St. Clair River, decreased for adults and increased for subadults in the lower St. Clair River, and increased in the Detroit River. With subpopulation abundances of 20,184 (95% confidence interval [CI] = 12,533–27,816) in the upper St. Clair River/southern Lake Huron, 6523 (95% CI = 5720–7327) in the lower St. Clair River, and 6416 (95% CI = 4065–8767) in the Detroit River, our study confirms that the SCDRS contains the largest Lake Sturgeon population with unimpeded access to the Great Lakes. The geometric mean λ for all subpopulations indicated stable populations and ranged from 1.00 to 1.16.
Conclusion
Our study provides an updated assessment of Lake Sturgeon population parameters that serve as a baseline to evaluate habitat restoration efforts and to inform management of the SCDRS recreational Lake Sturgeon fishery.
