Event Date: 2017-04-21
Dr. Matt Hare
“Oyster restoration informed by population genomics; Surprises in the Hudson River suggest we don’t know this species as well as we need to”
21 April 2017, 12:00 pm
In the Hudson River Estuary (HRE) of New York improved water quality has motivated the restoration of native eastern oyster (Crassostrea viriginica) populations in order to benefit from their prolific water filtration, habitat provisioning for juvenile fishes, and attenuation of storm surge erosion. We have used genomic ddRADseq analyses and experiments to address several questions that are critical for restoration planning: (1) in the small, nonequilibrium, remnant populations of today, is gene flow low enough to cause or retain genetic structure? (2) If so, has this allowed for an unusual degree of local adaptation for low salinity oyster populations in the Hudson River? More generally, for highly fecund species such as this, (3) how much genetic population structure results from differential viability selection across habitat heterogeneities every generation? Finally, (4) when hatcheries are used to seed restored habitat is there any reduction in oyster fitness as a consequence? Our results demonstrate that phenotypic plasticity in gene expression and natural selection across environmental gradients both contribute to the broad realized niche of oysters within estuaries. We will present genomic patterns of variation consistent with spatially discreet introgression of farmed aquaculture strains into wild stocks. Preliminary results will also be described for experimental comparisons of fitness-related performance among hatchery-produced oyster cohorts with different degrees of genetic bottleneck, relative to an aquaculture strain and wild-set oysters. Many of our results suggest that current hatchery-based oyster restoration practices can be improved to increase success rates.