Clam Trials

goals, daily
Author

Megan Ewing

Published

March 17, 2026

Preliminary trials to determine what temp manila seed can take for acute priming.

Trial 1

3/17 tested ~30C, ~36C, ~40C with n=6-7 clams each for 2 hours

Seed were held in 12C, 20ppt prior to elevated temp exposure

Water temps measured with infared thermometer

Clams were placed in plastic cups (1 per treatment) with 12C for recovery after exposure

Observations:

30.2C

30C (n=6)

  • actual water temp upon removal from incubator: 30.2C

  • Upon removal from incubator (prior to transfer to recovery): 3/6 had slightly opened shells. 3/6 had closed shells

  • Immediately following transfer to recovery: 6/6 closed shells

  • 5 min following transfer to recovery: 5/6 feet and siphons partially extended, shells slightly open and moving occasionally. 1/6 closed

  • 20 min following transfer to recovery: 6/6 feet and siphons partially extended, shells slightly open and moving occasionally

  • 90 min following transfer to recovery: 6/6 feet and siphons partially extended, shells slightly open, some occasional movement. Responds to contact w dissection probe along mantle (closing shell, retracting foot or siphon)

  • 18 hr: 3/6 slightly open shells with siphons out and responsive to contact with dissection probe. 3/6 shells closed

  • 24 hr: all slightly open and responsive

  • 48 hr: all slightly open and responsive

33.4C

36C (n=6)

  • actual water temp upon removal from incubator: 33.4C

  • Upon removal from incubator (prior to transfer to recovery): 3/6 had slightly opened shells. 3/6 had closed shells

  • Immediately following transfer to recovery: 6/6 closed shells

  • 5 min following transfer to recovery: 6/6 feet and siphons partially extended and moving occasionally, shells slightly open

  • 20 min following transfer to recovery: 6/6 feet and siphons partially extended and moving occasionally, shells slightly open

  • 90 min following transfer to recovery: 6/6 feet and siphons partially extended, shells slightly open, some occasional movement. Responds to contact w dissection probe along mantle (closing shell, retracting foot or siphon)

  • 18 hr: 5/6 slightly open shells with siphons out and responsive to contact with dissection probe. 1/6 shells closed

  • 24 hr: all slightly open and responsive

  • 48 hr: all slightly open and responsive

40.9C

42C (n=7)

  • actual water temp upon removal from incubator: 40.9C

  • Upon removal from incubator (prior to transfer to recovery): 6/6 had slightly opened shells with feet and siphons partially extruded

  • Immediately following transfer to recovery: 6/6 had slightly opened shells with feet and siphons partially extruded, no change from before. When prodded with dissecting probe, no response from any individuals. Indicates 100% mortality

  • 5 min following transfer to recovery: same as previous

  • 20 min following transfer to recovery: same as previous

  • 90 min following transfer to recovery: same as previous. No response to contact w dissection probe along mantle, feet, or siphon

  • 18 hr: same as previous / no change

  • 24 hr: same as previous / no change

  • 48 hr: same as previous / no change

Trial 2

34.5C

36C target temp. 2 hr exposure then moved to 12C for recovery.

  • actual water temp upon removal from incubator: 34.5C

  • Upon removal from incubator (prior to transfer to recovery): 2/6 had slightly opened shells with siphons out. 2/6 had closed shells

  • Immediately following transfer to recovery: 6/6 closed shells

  • 5 min following transfer to recovery: 6/6 feet closed shells

  • 20 min following transfer to recovery: 6/6 feet and siphons partially extended and moving occasionally, shells slightly open and responds to contact w dissection probe along mantle (closing shell, retracting foot or siphon)

  • 18 hr: 6/6 closed shells

  • 24 hr: all slightly open and responsive

  • 48 hr: _____

37.1C

38C target temp. 2 hr exposure then moved to 12C for recovery.

  • actual water temp upon removal from incubator: 37.1C

  • Upon removal from incubator (prior to transfer to recovery): 3/6 had slightly opened shells with siphons out. 3/6 had closed shells

  • Immediately following transfer to recovery: 2/6 open with foot + siphon out, and non responsive to dissection probe contact. 4/6 closed

  • 5 min following transfer to recovery: 2/6 feet open and non responsive. 4/6 closed shells

  • 20 min following transfer to recovery: 5/6 feet and siphons partially extended and moving occasionally, shells slightly open and responds to contact w dissection probe along mantle (closing shell, retracting foot or siphon). 1/6 closed

  • 18 hr: 6/6 closed shells

  • 24 hr: 5/6 slightly open and responsive. 1/6 closed

  • 48 hr: _____