Green Crab Experiment Part 8

Treatment Days 15 through 17

Day 15

  • Protocol for today
    • Performed TTR for seven randomly selected crabs in a tank. Sexed, gauged color, measured, and weighed each sampled crab, then labelled each crab with a number. Based on weight (20-30 g), we selected crabs for respirometry.
    • Acclimated three selected crabs for one hour
    • Measured oxygen consumption. The goal was to measure consumption until the chambers reached 75-80% oxygen.
    • Removed crabs from the respirometry chambers. Resealed the chamber and measured background respiration for 20 minutes. Empty chambers and wipe down with 70% ethanol.
    • Use refractometer to get salinity measurement for acclimation tank
    • Notes
    • Usually set up acclimation for one tank while performing TTR for the next tank
    • Recalibrated probes before each respirometry run
    • T5: 1 dead yellow male
    • T3: copulation/mate-guarding activity
  • Tank order
    • T2
    • T5
    • T3
    • T6
    • T1
    • T4
  • Salinity
    • T1/T4: 35
    • T2/T5: 36
    • T3/T6: 35
  • Couldn’t check ammonia concentrations since I didn’t have solution 2 in the kit. Performed 60% water change and added 1/2 tsp of conditioner to all tanks
  • Fed crabs 1/4 tsp in all tanks after respirometry
  • T3: front heater malfuction around 1:15 p.m.: reading 48ºC, alarm went off even though back probe was reading 26-27ºC
    • Tried replacing probe, controller box still reading temperature as too hot (36ºC)
    • Replaced controller box and kept original probe: T3 reading in the 30s, but back probe was at 27ºC
    • Replaced probe with new controller box and placed probe in the 10ºC line to confirm probe was reading the correct temperature. Probe read 11.2ºC for 10ºC line which was deemed acceptable, and moved to T3
    • T3 brought back up to temperature
    • Original T3 controller box and probe placed in cold room to determine if the system was malfunctioning. After one hour in the cold room, the probe read 4.5ºC. Kept box and probe as a back up since it was still working. Not sure why it failed in T3. Maybe the probe was touching the immersion heater itself and I didn’t notice?
  • LED lights didn’t automatically turn on, needed to twist cables to get lights to turn on.
    • Unplugged around 1 p.m. and waited for electronics to cool.
    • Inside looked burned/rusted. Sara cleaned with ethanol and bottle brush. Left unplugged to to dry.
    • Plugged in cable and lights after finishing T4 respirometry. Lights did turn on.
    • Confirmed LED light turned off before leaving
  • Obtained HOBO data
    • yrv_9 dead, replaced with yrv_13
  • Purchased new ammonia test kit after leaving lab

Day 16

  • Checked ammonia concentrations in all tanks
    • T1: 0.5
    • T2: 0.25
    • T3: 8.0
    • T4: 0.5
    • T5: 0.25
    • T6: 8.0
  • T3: 2 crabs on top; T6: 1 crab on top
  • Cleaned all tanks, performed water change for T3 and T6, and added 1/2 tsp conditioner to warm tanks
  • Fed ambient and warm tanks 1/4 tsp, cold tanks 1/8 tsp
  • yrv_13 still flashing and recording data, will confirm tomorrow
  • LED lights didn’t automatically turn on, needed to twist cables to get lights to turn on.

Day 17

  • Checked ammonia concentrations in all tanks
    • T1: 2.0
    • T2: 0.25
    • T3: 8.0
    • T4: 1.0
    • T5: 0.25
    • T6: 8.0
  • T6: 1 crab on top
  • Cleaned all tanks, performed water change for T3 and T6, and added 1/2 tsp conditioner to warm tanks
  • Fed ambient and warm tanks 1/4 tsp, cold tanks 1/8 tsp
  • yrv_13 still flashing
  • LED lights turned on automatically!
  • T6 back heater: 62.3ºC alarm when I entered, front probe reading 27ºC.
    • Replaced probe and put old probe in cold room to calibrate. Still read at 62ºC in the cold room. Labelled as “bad probe”.
    • Calibrated spare probe in cold room, reading water temperature around ~3ºC

Going forward

  1. Continue with experiment
  2. Check HOBOs and replace low battery loggers
  3. Update protocols
  4. Organize project repository and datasheets
Written on July 21, 2022