It is a picture of the pattern of “discharges” we are seeing from one oyster spat that we brought into the house after it fell through the cage onto our dock. We have been “feeding” it with a fresh gallon of bay water each day, which it clarifies. And, each day, it has produced the same pattern of excrement on the container bottom. There is always the same thin, dark line leading away from the same place, and some loose particles on the other side of the oyster from that line. We have never seen the oyster shell open nor anything flowing out of it, so we are not sure whether this is happening as a continuous or episodic process. The dark line does get longer and extend farther from the oyster as time goes on. We just don’t know how it gets added to over time.

The oyster seems to be growing faster than we expected – it is now about 11/16″ across. Since an adult oyster can filter up to 50 gallons of water per day at optimum conditions, which we are providing by keeping it in our house at about 68 degrees F, I am wondering if we can continue this through the winter without starving it. The bay water I am dipping is getting clearer by the day, as bay water temperatures decrease, and this spat might soon be bigger than 1 gallon of it can properly feed.

So, we are currently working on making this little guy his own personal minicage to hang off our floating dock for the winter. We need something that it will not fall through. If we put it back into the Recovery Project cage, it will fall out again and die in the muddy bottom.

We will keep you informed of how our little study project turns out.

Steve Long

November 20 – Update on Oyster spat growth

oyster spat
I am sharing another picture of that oyster spat that I saved after it fell through the regular cage onto our dock.

As you can see, it is now about 1″ across, and is filling the small piece of culch that it is attached to.

It has grown rapidly, probably because keeping it inside at about 70 degrees and giving it new Bay water daily allowed it to metabolize the plankton in the water more rapidly than its siblings out in the colder water.

But, now that the Bay water is getting cold, it is getting much clearer, which means that the oysters are getting less food per gallon filtered. That has been obvious for this particular spat, where we can see the pattern of excrement is much more sparse now than it is in the picture I sent earlier.

I am thinking that I won’t be able to keep feeding this spat over the winter, and it would probably harm it to keep it warm and not feed it. So, I am making it a tiny cage that it can’t fall through, and will be putting it out on our dock with its siblings for the winter.

Steve Long