Kerr, Emily

Identifying the population origin of aquaculture-reared caviar is crucial for both conservation and management strategies of farmed fish but could also facilitate international trade of a CITES regulated product. Shortnose sturgeon (Acipenser brevirostrum) is the main source of caviar production in Atlantic Canada, from Breviro Caviar Inc. aquaculture facility. Shortnose sturgeon are also listed as a species-at-risk under the Species At Risk Act. Currently there is no genetic method for delineating wild from aquaculture-reared caviar. By targeting the mitochondrial genome (mitogenome) using novel long-range PCR primers and next-generation sequencing (NGS) methods we have successfully sequenced the full mitogenome of 37 shortnose sturgeon. The purpose of this study was to increase the resolution of diagnostic variation among populations and to validate Canadian aquaculture-reared stock from wild US populations.

Results provided a previously unobserved novel control region haplotype in high frequency within both the aquaculture-reared and Saint John River wild sample sets. Similar frequencies were observed with whole mitogenome haplotypes. Diagnostic mitochondrial lineage found in high frequency within the captive Breviro Caviar Inc. population has the potential to allow caviar product from Breviro Caviar Inc. to be distinguished from protected US shortnose sturgeon populations. The application of full mitogenomic characterization provides the potential to further resolve differences between aquaculture and natural Canadian shortnose sturgeon stocks, US/Canadian populations and to contribute to future conservation strategies. Future research identifying signatures of selection on the mitogenome between captive and wild populations and across latitudinal gradients found within the species range. These novel methods have produced a proof-of-concept to provide a "farm-to-fork" validation and ecobrand of Breviro Caviar Inc. product and its aquaculture origin to support importation into US caviar markets.

Author Keywords: aquaculture, mitogenome, next-generation sequencing, species-at-risk, sturgeon