Went to the hatchery in the morning to check for larvae, clean/replace banjo filters, rinse drippers, and replenish algae. As there was a hatchery-wide mortality event after the temperature drop over the weekend, I started 2 new 100 L larval tanks: SS_Tank2 and HC_Tank2. This is because it’s pretty hard to separate out live from dead larvae until the live larvae have grown up a bit. In case the dead larvae still in SS_Tank1 and HC_Tank1 cause additional mortality, I want to start a 2nd replicate where none of the larvae experienced the temperature drop.

• Checking for larvae in larval catch buckets
  • Maybe/Some larvae: SS1
  • Lots/Noticeable larvae: HC3, HC4, HC1, SS4
  • Also screened NF5 but did not get any larvae
  • Added to HC_Tank2 and SS_Tank2
• Counting larvae
  • need to get better at estimating ~100 per mL. Some of these counts had over 400 per mL which makes it harder to count and more stressful for the larvae when they’re in the tripour beaker

Larval counts data DNA samples

• As per my conversation with S. Roberts yesterday, I’m keeping all of the samples from my larvae counts, including those I don’t think are necessary for future genotyping. I’m trying 2 different preservation methods, and will do test DNA extractions next week to look at quantity and quality.
  • 75%/90% ethanol: this was suggested by Jake Heare. I pipet up one of the 1 mL larvae count samples and put it in a 1.5 mL tube. Since I used ethanol when counting, all of the larvae sink quickly to the bottom and I pipet out as much seawater as I can. I continue adding the other larvae count samples and decanting off the seawater in the same fashion. If needed I spin them down briefly with a centrifuge. Then I add 75% ethanol to the tube. A day or 2 after I take out the 75% ethanol and add 90% ethanol. These are stored in -20C.
  • RNALater: As described above, I take out as much seawater as I can and then add about .75 mL of RNALater to the tubes. These are stored in a -80C freezer.

In the afternoon, I stopped by the Roberts lab on the UWashington campus to find some bench space for the test DNA extractions and pick up a HOBO temperature logger to stick in one of my broodstock buckets so I can get a better idea of what they’re experiencing in case a temperature malfunction happens again.