This summer, I will be interning for the South Slough Estuarine Research Reserve (SSERR), near Coos Bay, Oregon. I mainly will be working on monitoring European green crabs (Carcinus maenas), one of the most invasive marine species. Native to the Atlantic coast of Europe and northern Africa, green crabs were first documented on the East coast of the U.S. in the mid-1800’s and in California in 1989. Green crab presence was first documented in Coos Bay in 1998. Green crabs can out-compete juvenile Dungeness crabs (Metacarcinus magister) and disrupt native communities, including negatively impacting commercially important shellfish and eelgrass populations.

The SSERR has continued to monitor the green crab populations in the South Slough and Coos Bay since their discovery. Though the population has cycled through years of high and low abundance since the species was first documented in the region, the last couple years have seen a spike in green crab abundance. Along with other interns and staff, one of my main roles this summer will be to continue monitoring efforts throughout the South Slough, tracking their distribution and abundance at various points throughout the estuary.

This week, after settling in to my housing and meeting the green crab team and the rest of the staff, my first task was to conduct inventory on all the green crab trapping equipment to prepare for the season’s fieldwork. We use two main traps in the green crab research: 1) Fukui traps, and 2) Minnow traps. Fukui traps are intended to capture adult crabs, while minnow traps are aimed at smaller juvenile crabs.

Thursday and Friday were our first days out in the field. Traps have to be set during the morning low tide, and then are left until the low tide the following morning. On Thursday, we set traps at 2 sites in the estuary, and on Friday, we retrieved crabs from the traps.

Setting a fukui trap in the Metfield site in Charleston, OR.

Me holding a green crab caught in one of the traps. All of the green crabs caught are weighed and measured, and their sex, abdomen color, and number of missing limbs recorded. (My eyes were closed in every picture taken.)

Retrieving crabs in a fukui trap at the second site. Dungeness crabs, Oregon shore crabs, and sculpin (a fish) are also often caught in the traps. This site was extremely muddy, and we all got our boots stuck multiple times.

These two days of fieldwork were just a brief start to the green crab project, and we will continue monitoring at several sites throughout the estuary for the rest of the summer. Collecting data on green crab abundance and distribution will help us better understand their population in the region and hopefully mitigate and prevent damage to the native ecosystem.