Kaitlyn’s notebook: 20190123 Geoduck histology

We sampled geoduck at the end of January and took some histology samples. I believe only geoduck from tank 4 were strip spawned and we noticed that the treated tanks had poorly developed gonads. I examined the histology slides that we just received from sampling.

I reviewed how Grace staged her geoduck as well as the criteria in the paper Brent sent Shelly and I (Ropes 1968). I talked with Grace a little more about what she did and showed her some slides and we were both having trouble placing the geoduck at different stages. It was hard to decide whether they were producing less, reabsorbing, or just developing gonad more slowly than the other tanks.

I came up with some scoring criteria to get a better idea of how tanks and treatments compared and entered it into this spreadsheet.

Overall, it appears that the ambient tanks were further along in development than the treated tanks. Tank 4 was furthest in development compared to tank 1 which was dominated by early active geoduck.

All treatment group geoducks were early active:

Least developed male 4 with only spermatognium present in tiny acini-

Early active male 1 with dense connective tissue and very low amount of spermatids-

Early active male 018 with less connective tissue previously but is still early active (granted further along than 1) because of the number of acini with less than 30-40% spermatids; also the acini are smaller than seen below in the late active male –

Early active female 006 with dense connective tissue, low volume eggs, and most eggs are on the follicular wall

Early active female 034 with many elongated eggs on the wall of a small follicles however the eggs do have some good volume and roundness. This is a good example of difficulties staging-

While Ambient geoducks looked more like this:

Late active male 41 with visible spermatids covering at least 50% of large acini and all acini contain spermatids; connective tissue is less dense than 018-

Ripe female 045 with little connective tissue and high volume eggs; this female has the most eggs/follicle but it still isn’t a lot compared to a heavily ripe female-

Images are located on the FFAR-Geoduck drive under /Images/20190123-histo and on OWL. I also updated the histology-databank with the slide locations.

Ropes, J. W. 1968. Reproductive Cycle of the Surf Clam, Spisula Solidissima, in Offshore New Jersey. Biol Bull 135:349-365