Over the weekend Ian and Elliot monitored the sea stars, performed water changes, and monitored nutrient levels in the tanks. One of the most difficult part of sea star husbandry is keeping ammonium – which is toxic to marine life – low. In an ideal situation, nitrifying bacteria and archaea form biofilms on our filters and do the work for us. However, this does take a bit of time, especially when you have a lot of animals in a small space.
Friday evening Ian noticed a few of the Evasterias were looking not great, including one that had dropped an arm, so we moved it and another lifeless animal to our quarantine tank to see if it would recover. By Saturday evening unfortunately 2 more had croaked, probably just in rough shape after transit. However, the remainder looked OK, moving around the tanks fast. None of the stars were up to eating shrimp yet (they’re very particular about eating only when they’re comfortable), so we’ll wait a couple of days and try again.
So what we have now are 11 Solaster stimpsonii (we’d misidentified them during collection), which seem to be doing alright. These belong to the Solasteridae, a group of coldwater sea stars which lack pedicellaria (claw-like structures) on their surface. Normally they consume small holothurians (sea cucumbers) and barnacles. They are a species which has been subject to wasting disease in the Pacific Northwest.
We have 7 (eek! need minimum of 6!) Evasterias troscheli left, but they seem to be doing OK, minus one small individual, Joclyn, which seems to be having a rough time.
Let’s see how they do over the next few days. We’re hopeful that our collaborator, Lesanna, can ship us some Pycnopodia from the Pacific Northwest sometime this week! Then the experimental fun begins…