Each fall, the Phillips Wharf Environmental Center receives bags of spat on shell from the Horn Point Oyster Hatchery through the Marylanders Grow Oysters program. These baby oysters are divvied up into cages and delivered to volunteer oyster growers to host for approximately 9 months.
As part of this program, we collect measurement data to get an average estimated size of the spat at the start of the program and the end. This helps us understand how the oysters have grown during their time with our volunteers. We also collect data to estimate the average number of spat per cultch shell (which is the old, empty oyster shell the spat have attached to). This helps us understand the mortality rate of the oysters during their time with us and helps us estimate the total number of oysters planted in the Harris Creek Oyster Sanctuary at the end of the program.
This year, we received our spat bags in mid-August and the spat were an average of 6.9 mm in size. In comparison, last year’s spat bags were received in late-October and the spat were only 3.7 mm in size. In addition, this year’s cultch had a significant increase in the number of spat on the shells compared to last year. All this data suggests that we’ll be planting a lot more oysters (and that they’ll be bigger) at the end of this season compared to last year. As a reminder, we wrote about last season and how many oysters we planted in the July edition of the Heron Herald. Our hope is that this year, since we’re starting earlier with more oysters, they’ll have lots of time to grow before the winter comes and they stop growing. This gives them a better chance at surviving inclement weather, should we see a lot of ice and very cold temperatures like we did last winter. Overall, we’re pleased with this year’s crop of baby oysters and we look forward to seeing how they did come next May!
If you’re interested in how we collected our measurement data, here’s a more detailed look;
