Strip-spawned juveniles (March 17, 2019) from ambient or varibable low pH exposed broodstock

  • Matt had turned pump up to 140rpm because the draw rate out of the algae header has been slower
    • lines may need to be cleaned out!
  • measured shell lengths (width - the shortest distance on their shell) of animals in a ~2 mL grab sand/seawater from H2_T2
    • Measurement protocol:
      • turned a 3mL plastic transfer pipette into a spoon by cutting the bulb in half to get the grab
      • put grab into a petri dish and added ~ 3ml more seawater
      • used another 3mL transfer pipette that I cut the tip to be wide to transfer individual animals onto a sedgewick slide wiht 1mm grids
      • took pictures of each animal (pictures here)
    • OBSERVATIONS: 18 animals were ~1-2mm
    • CONCLUSION: they are too small to be seived on the 3mm mesh, which is the minimum size Matt sends to growers

  • guts of many H2_T2 animals seem lighter in color than they did in the past

    May 9

    May 29

    today

    • CONCLUSION: feed them more; this is most likely an animal density to algal density issue
    • see Marshall et al. 2014 paper
      • low density animals have to move more to search for food, using more energy requiring more food
    • At 12pm, I turned pump up to 180 rpm
    • Plan is to swap out the 6402-14 skinny tubing for wider tubing when it arrives tomorrow. Matt will do this.

Plans:

Last week of June:

  1. measure and count animals
    Counting protocol:
  • rinse seed to one corner of screen
    • can shake screens in water bath
  • rinse seed off screen into beaker with seawater
  • measure a sample in a graduated cylinder
    • pour seed from beaker spout into a graduated cylinder
    • tap cylinder to get animals to lay flat and packed with siphons receded
    • measure 25-50mL
    • pour cylinder contents onto dark plastic surface
    • spread animals into a circle about 3 ‘rows’ of animals wide
    • mark starting position and count all animals with clicker to get # animals/mL
  • pour animals remaining in beaker into same graduated cylinder, again tapping to compress animals
    • Matt counted around 500 animals in 50mL.
  1. Prepare for thermal and pH stress experiment:

Sam’s experiment: March 1, 2019 ambient broodstock volitional spawn

Water Chemistry:

  • took discrete measurements
  • poisoned TA samples and stored them under the counter where the titrator is here: