Update on Green Crab Monitoring Site 277

It took awhile, but I was finally assigned a monitoring site. For those of you just catching up with the story, this is the effort by the Washington Sea Grant Crab Team to monitor for the invasive European Green Crab (Carcinus maenas). The delay was two-fold; we were waiting for the necessary permits from Tacoma Parks, and the fact that the team was busy with the large influx of European Green Crabs that were found early this summer near Dungeness Spit. But finally we’re assigned Site 277 for our surveys.

Site 277 – Titlow Beach

Titlow Beach is an area I’m very familiar with as I’ve taught numerous kayak classes there. Our monitoring site is the lagoon which is open to the sound just behind new water park.

Our first monitoring was last month when we met with Dr. Emily Grason. Our team is 4 strong; myself and Theresa as well as Denise and her husband Don. We’re so lucky to have Denise as she’s complete the shoreline observation course and brings a tremendous amount of identification expertise with her.

We spend the day going over the protocols with Emily. The whole monitoring process is a 2 day affair involving both paperwork and photographing the specimens. It was some time since I had taken the class, so I was appreciative of the refresher.

Protocol

So here’s a rundown of the process and protocol we follow. On day 1 we lay out a tape measure 50 meters long just along the wrack line. 6 random numbers are selected and a 1 meter square is laid out on the corresponding number on the tape. We then inventory everything within the quadrants within the square; ground cover, floating debris, rooted planted, other debris, etc. All of this is recorded on our data sheet. That’s our Transect survey.

Next up is the Molt Survey. Here we all stand by the official site stake, set a timer for 20 team minutes. What i mean here is if there’s only 2 of us we would search for 10 minutes; 4 would be 5 minutes and so on. During that time we look and collect as many crab molts as we can. Once the timer goes off we then sort the molts by type and identify each. This is record on the data sheets as well.

Traps

The final step is of day 1 is to set the 6 baited traps in just enough water to cover them (we time this as low tide so as not to expose the trapped critters to other terrestrial critters that would love to snack on them). We stagger our Minnow traps with the Fujitsu traps spaced 10 meters between them. We let them soak till the next day when we return and collect any specimens that are present.

Fish and snails are identified then tallied. Crabs get the same treatment but we sex them as well. The final step is to measure the carapace of a random 10.

Everything is photographed and then returned to the water with as little handling as possible. Everything is collected, cleaned and stored for next them.

Tally

We done 2 monitoring so far with one more schedule for September. Here’s are tally so far:

2 Replies to "Update on Green Crab Monitoring Site 277"

  • comment-avatar
    Stacy Frazer August 17, 2017 (7:12 pm)

    Sounds like really interesting work!

    • comment-avatar
      Steve Weileman August 18, 2017 (7:23 am)

      It has been. I’ve also learned quite a bit about this whole eco-system. And, it gets us outdoors! 🙂

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