A "stressful" afternoon

Got the oysters into pH treatments today! This, after a couple surprises…

Arrived at the hatchery in the afternoon and found that all 3 header tanks were nearly empty. I unplugged all the pumps and refilled the headers. The 3 ambient tanks, which held the Pacifics had not warmed, so the water had likely drained fairly recently. Interestingly the low pH tanks (no animals yet) were warm, ~13degC. The reason for the drain was a partially-clogged 1um filter. I removed that, and plan to go without during this phase of the experiment. Now the water is filtered down to 5um.

Last Saturday I moved the large Pacific oysters into the 3 ambient tanks, 60 oysters per tank. They drove the pH down from ~7.78 to (at times) 7.53, this without my Olympia oysters. Needing to maintain a more reasonable ambient pH, today I dispersed the Pacifics to a stocking density of 20 animals/tank after cleaning the dirty tanks. The rest are being stored/fed on the lower shelf for another use. I increased the flow marginally on all tanks to 1.2 L/min. Also, I moved the set point for the low pH to 7.18-7.22.

Moved Olympia oysters to their new homes! 48 freshly labeled bags. See previuos post for naming convention.

Because of the filter clog and my late start I wasn’t able to take chemistry today. The tanks had all refilled and needed to stabilize, so chemistry samples wouldn’t have been informative. Also, I need to sample during business hours in order to have a NOAA employee present whiel I use the HgCl. The Durafets are capturing continuous pH data. I prepped sample bottles, data sheets, and Tris for PSRF to sample (hopefully) tomorrow or Friday.

That is all.

Written on February 15, 2017