Intertidal Dredging and Data Analysis

This week we started the second phase of the Yaquina Bay intertidal population study. If you think way back to the first week I was here in Newport, you might remember that I had to wake up really early to do RAM surveys. We took sediment samples, temperature readings, and counted the visible clam siphon holes at random points in different sand/mud flats in the Bay. Now we are going back to these same locations and dredging them to find out exactly how many clams are at each site.

Intertidal dredging is very similar to the subtidal dredging we have been doing, except we get to dredge this time, not divers. Surprisingly, the system is pretty easy to use and the most difficult part seems to be staying in one place when holding the bag end of the dredge. Because of the air in my drysuit a lot of times I just start floating away. Luckily we can only sample when the water isn’t very high (between 2 and 3 feet) so I can get myself back in the right spot fairly quickly.

To work the intertidal dredge requires 3 people: 1 person mans the dredge and sucks up the sediment/clams, 1 person mans the bag and makes sure that the bag doesn’t get clogged and that sediment/water isn’t going towards the dredge head, and the final person is on the boat manning the motor and sorting samples.

I very quickly learned how to do all 3, but I think it was very helpful that I already has indirect experience from all the subtidal work we have done. I was familiar with the data sheets and how the dredge system as a whole worked, so I only needed to learn the exact method of how to use the dredge in the water – and how to efficiently move around in a bulky dry suit.

Next week is more dredging, and at the end of the week we will prep for yet another week of work in Tillamook  – and you thought I was done! hah!

While not out doing fieldwork (we can only dredge a few hours at a time during low tide), I have started a new data analysis project. This will incorporate the historical data I entered over the last few weeks, and some of the data we have been getting this summer. Hopefully I will be able to incorporate all of this together in a cohesive way so I have something to add to my presentation other than 15 slides of our various projects and methods. But don’t get too excited, it will probably just be comparisons of size frequency and abundance. I also don’t think I will have time to run any statistical analysis so I won’t be able to say whether any of the trends we see are significant or not.

During my free time, I have been attempting to enjoy the decent weather we have been having in Newport by surfing a lot, playing beach volleyball, and watching LOTS of Olympics. I feel like all the students here have really started to get along well, and it is a shame we only have 3 short weeks left before we all must continue our journeys elsewhere. Until next time!

 

Print Friendly, PDF & Email

One thought on “Intertidal Dredging and Data Analysis

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.