Procedure

Here are some growth and survival measurements for our outplanted oysters at Westcott. We now have some initial growth measurements and a few weeks of survival data.

Growth

Average growth effort B

Average growth effort D

Looks like growth is similar between treatments for both efforts so far. Doesn’t seem to be a huge difference in the rate of change of height and width in comparison to length, at least for this first set of measurements. This graph doesn’t have standard error bars, but I did another graph with them and the standard errors were so small you couldn’t see the bars (they weren’t bigger than the points themselves), so I just opted to include this original graph.

Survival

Mean live oysters per treatment

In tipping the bags out to do some labeling when we first outplanted the oysters, I lost some oysters out of one of the weekly control bags (effort D), which you can see in the “live oysters per bag effort D” graph (larger standard error and lower mean). There wasn’t a huge death, I just fumbled the bag (literally).

Live oysters per bag effort B

Live oysters per bag effort D

Because of losing a bunch of the oysters in one of the bags, we are now much more careful about tipping out the bags and in closing them back up (using more zipties, closing them more tightly, being more strategic about ziptie location).

Other than that though, live oyster numbers seem to be pretty static. Next season, I will do initial counts of oysters and then just count the number dead so that I don’t have to count live oysters every time. Although it might make sense to still count live oysters; there’s some variability in counts each week. Sometimes the counts rise artificially just because we’re getting better at thoroughly counting how many oysters are in there.

Cumulative dead oysters effort B

More “daily” conditioning bags have lost an oyster than “control” bags thus far, but it’s early in the season.

Cumulative dead oysters effort D

I tried jittering the points horizontally to no avail, so this is the best we have. In effort D, there are about the same number of control and weekly conditioning bags that have lost an oyster, just from looking at the raw data (can share if needed, can also access by using my code.)

Future measurements

Apparently there was some death this weekend, according to the staff at Westcott. We plan to do survival measurements tomorrow to see whether our outplanted seed weathered the heat.

Additional thoughts

New shell growth can be very delicate, so we’re trying not to push down on the calipers so much when getting size measurements (i.e., I am trying not to push down as hard as I was when getting initial sizes).

I’ve also lost some tags on some of the oysters, so we can track individuals for at least 8-10 oysters per bag (originally tagged 15, and most bags still have that number), but we’ll see how the labels stick throughout the summer. I think in an effort to deal with some tag loss at the beginning of the summer, I also gave some oysters the same number tag. In data entry, I have been able to figure out which oyster is the original tagged oyster or not just by looking at sizes (if it’s smaller in any size metric compared to the original measurement, it’s probably not the right one), but for some I haven’t been able to figure it out. Therefore, they will remain duplicates.

Feedback?

Let me know if you want to see the data a different way.