CC-
I really appreciate you and everyone's thoughts. It sucks to have negative things happen, but if any learning comes from the experience it's a small win.
RE, your questions:
1. Can you check water for something besides low O2 that could have killed (meaning some inflow of some chemical or toxin for example?) That might be good to know before restocking: seems very unlikely to have been a toxin, as we have been frozen up and ground frost still in. The inlet fingers to my pond are flowing now but the fish were dead well before that started based on their decomp level.
2. Did your water level drop a lot that set up concentration of the fish in smaller water meaning less resources or oxygen to go around? We actually had full pool this fall and have kept it all winter. The water control structure I placed on my outflow pipe has been a great tool for controlling water levels and managing run off
and I am able to keep my pond 'topped off' all the time. I actually gained some water depth after I added it (about 8-10 inches).
3. For sure you need to sample your fish to see if it hit a TYPE of fish or a SIZE CLASS strongly. I had been already planning to repeat a shock survey this fall (because I wanted to sample size and class year data). But now it will just be to see who's left and in what age groups. *sad face* We had just started catching bass over 3 lbs with great body shape, so I had modest hopes to push some to 4 lbs by this fall. *sigh* Maybe with the next group. Or may there was a 'freak bass' that tolerated low DO better than the rest, or maybe found some tiny DO refuge.
Overall, it seems most likely I was at high end of carrying capacity due to my growing LMB and that I underestimated the biologic DO demand from bacteria in my old pond. It's a good thing to remember; never get comfortable with your guesses because 'you don't know what you don't know'.
I would love to take you up on the offer of some SFS. Just DM me when the time is right and will work out the details.
