Wednesday, 9/7, was a big day at the Shellfish Resilience Lab. Four of us (Chantal, Elin, Mike, and Pauline) went to the lab to do a routine tank cleaning. Cabot, the Lab Labrador, was there as well, “guarding” the loading dock for us. We figured it would take about an hour and a half with all of us experienced tank cleaners there. Not so, it turns out.

A black, older Labrador Retriever sitting in the sun on a loading dock.
Cabot on guard. (photo: Hannah Volk)

There are 8 buckets in Tank 1 now. We separated the clams by size last week, and there are now five buckets of the smaller clams and three buckets of the larger ones. The clams are growing. They are still not big enough to go in the mud, but they are getting bigger every day. 

Cleaning, Tank Emptying, and a Surprise

We clean the tank to remove silt that builds up and to remove barnacles, tunicates, and other sealife that shouldn’t be there. How often we have to do this depends on how much mud and silt is coming in with the water. Lately, we’ve been doing it every two weeks. Here’s the list of steps, along with a note about how each step went.

  • Turn on the water to garden hoses — Check.
  • Turn off the water to the tank — Check.
  • Turn on the pressure relief hose — Check.
  • Hose down all buckets, inside and out — Check.
  • Hose off all aeration stones — Check
  • Hose down all flowerpots and tank supports — Check.
  • Wipe down all pipes, lines, and manifolds in the tank — Check.
  • Remove the plug so the tank can drain — Check.
  • Empty tank — Oops. NO check.

The tank would not drain. After waiting a fair bit of time to see if the high tide was responsible for the slow draining, we started looking more closely. The pipe where it drains into the harbor was clear. It drains above a rock, and the seaweed in the harbor was not a problem. 

So, we started looking inside the lab. We took off the final drain fitting in the tank and found three mussels attached to the edges. Ah!  Were there others IN the drainpipe? Chantal forced the hose as far down the drainpipe as she could–a good 8-9 feet–and we heard a lot of “crunching” sounds. 

A white plastic pipe running beneath a wooden frame that holds a large fiberglass tank.
The drain pipe running along the bottom of Tank 1.

When she removed the hose, some beasties washed back: more mussels and a bunch of really fat tunicates. You can see them in the picture at the top of the page. Those tunicates sure do make trouble

A man wearing a hat bent over and pushing something downward
Mike Cleaning the Drain.

The pipe from the tank to the drain was finally clear–but now the drain was clogged. We had identified the problem but had also pushed it further down the line. Josh got us a drain snake, and Mike went to work on the drain lines outside the lab. More crunching followed, and then a very rewarding sounding “Whoosh.” The drain was clear!  The tank drained! 

As a matter of fact, it drained more quickly than it has in a while. Who knows what is growing in the manifolds and incoming water lines? 

Lessons Learned

  • It is not surprising that things are growing in the lines to/from the tank–we just never thought of it or its repercussions before. 
  • We are thinking that we should find ways to flush the drain lines more frequently. 
  • And we need a drain clean-out. Mike has identified a spot outside the lab where he can put a T and a plug. 

Finishing Up and Photographing

It was time to refill the tank and get the clams back underwater. We turned the pump back on. Since some new pilings were being sunk in the harbor that morning, the water was very riled up. So, we put a double layer of knee-high hose on the water input line to help sift out the initial muck.

We put the buckets back on their spigots, placed flowerpots under their edges to keep them level. Then we plugged in the aerator and made sure the aeration stones were in place and working. 

It was also “pictures to track growth” day, so I took samples of “small” and “large” clams from the buckets and photographed them for our records.

Clams sitting on white nylon mesh
Size of clams separated according to size as of 9/7/2022. The holes in the mesh are1 mm across.

Voila! Done. And it only took 3 hours!

This all sounds very organized in retrospect, but it did take a bit of teamwork, detective work,  trial and error, and laughter. And we have some projects for “winter work.”

All in all, good morning’s work on a lovely day.

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