Dataset: Juvenile oyster expt: recruitment

Site Selection- From Hanley et. al 2019, this was a multi-step process that first involved using ArcGIS to partition the bay’s oyster reefs (commercial and non-commercial) into six zones. Zone assignment was based on the reef’s relative distance by water from the river input (near, mid, far) as well as a reef’s east-west orientation to the river (East Apalachicola and West Apalachicola). Next, we randomly selected three reefs out of all possible reefs (including the experimental reefs) within each zone.

Juvenile Experiment 2013-2016: Juvenile oysters were produced from parental broodstocks at a hatchery in Jupiter, Florida (Research Aquaculture, Inc.). To establish each cohort, we collected 25 adult oysters (shell length >75 mm) from 3–5 reefs of each estuary in July 2014 and shipped them to Research Aquaculture, Inc. At the hatchery, adult oysters and their offspring were held under identical conditions in separate flow-through seawater systems to prevent cross contamination between the two bays. The broodstock from each site was manually spawned on the same day. The larvae were held until they settled (~3 weeks) and then moved to a nursery facility at the hatchery under flow-through seawater conditions with standard food concentrations. In August 2014, the two cohorts were transferred to a common flow-through facility at the Florida State University Coastal and Marine Lab. These individuals were reared in a common environment and represented juvenile oyster cohorts of the same age that had experienced identical conditions. Each experimental unit consisted of juvenile oysters (mean shell length 8 mm) that were attached to a ceramic tile (13 cm × 13 cm) using a marine epoxy, and these tiles were affixed to concrete pavers in a vertical position. Tiles of initial densities of 3 or 12 juvenile oysters in 2013 and in 2014 and 2015, 2, 6, and 10 juvenile oysters, respectively. Juvenile oyster tiles were attached to the three unoccupied posts (experimental units) and then randomly assigned among the experimental treatments of cage, cage-control, and control treatment. When each experiment ended, the control and cage-control were removed, but the cage treatment was left on the reefs to continue to generate data on oyster growth through larger adult sizes.

Juvenile Experiment 2019: Juvenile oysters were collected from Easthole(#12) (29.6803, -84.8696). The oysters had settled on to pieces of rock rubble at the site. We separated the rubble into three piles: 1 spat, 2 spat or 3+ spat. We attached the rubble to bird netting using marine epoxy and then attached them to caging material (Industrial Netting).  The treatments consisted of a full cage (10”X10”X10”), a cage control: a cage with one panel missing, and a control: a (10” X 10”) panel. The number of ruble pieces inside each treatment varied between 3-5 pieces for a low density, medium density and high-density treatment.  Each treatment was attached to a crab trap which had been modified so all the openings were covered with Industrial Netting so fish or other organisms would not get trapped inside.  The treatments were cable tied to the outside of the crab trap. Each trap was made up of one of each treatment with the same density of rubble. In each of the three zones in the bay (ABE1, ABE2 and ABE3) we deployed 5 traps along a 15m rope. A week later we came to count the number of surviving oysters. We repeated this again in September 2019 and December 2019.