Oysters, Oysters and more Oysters

Removing the heart with tweezers
Photo - NIWA - Kerry Harrison

Dabbing heart cells onto microscope slide

Photo- NIWA - Kerry Harrison

This week I have been working with a team who is testing oysters for the parasite Bonamia. Each year samples of oysters from Bluff are tested to see how much Bonamia is present. Bonamia is not harmful to humans but it can quickly kill a whole lot of oysters.

The process involves measuring the oyster then opening up the oyster with a sharp knife, (I was not very good at this) being careful not to destroy the flesh inside too much. Then you use a pair of tweezers to carefully pull out the heart. The heart is then dabbed on a microscope slide (I was good at this part). After that the heart is placed in a small vial with ethanol. We also cut out gill samples and a cross section of part of the oyster for testing too.

I did feel a bit sorry for the oysters as you could see them contract as you reached for their heart. I guess as a scientist you have to get used to that.

Before the slides are looked at under the microscope they had to be fixed and dyed so the cells could easily be seen.

I got to look at the slides under the microscope to see what Bonamia looks like (small blobs).

As a scientist doing this job you had to work carefully so that the oyster information was not mixed up. All samples had to be clearly labeled and tracked back to the oyster it came from. We used pencils for recording the information because they still worked when wet.

Each day we were able to take home about 2 dozen oysters. Shame I don't like them.