Invaders on the Move

National Invasive Species Week is this week February 26th- March 4^th. What a great time to raise awareness about some local invaders and how we can help to stop the spread of invasive species. Let me start by answering the question of what exactly is an invasive species? By definition, an invasive species a one that is not native to the ecosystem and when introduced has negative effects. Some invaders in Washington include plants and animals such as Scotch broom, the Wood-boring Beetle, and the European Green Crab.

  The European Green Crab is native to the Atlantic coast of Europe and Northern Africa. It is a relatively small crab with a carapace ( back shell) growing only 3.5-4 inches across. Green crabs  were first documented on the east coast of the US in 1817. They are relatively new to the west coast with their first appearances showing up in the San Francisco Bay in 1989. It didn’t take long for them to make their way up the coast to Washington. In 1997-1998 an El Nino event pushed them north up the coast into Oregon, Washington, and British Columbia.
So what’s the all fuss with a tiny crab? Well, this crab may be small but is quite durable and able to adapt to a number of different environments. It can adapt to many temperatures and enjoys eating and disturbing eelgrass habitat. Eelgrass is a very important nursery habitat for a number of aquatic young animals including salmon and Dungeness crabs. To learn more about the importance of eelgrass check out this blog post by our Marine Exhibit AmeriCorps Educator. Green crabs also enjoy some of the very seafood which humans have a palate for. These crabs love to eat soft shelled clams, scallops, young oysters, as well as native crab species. 

So now that we are up to speed on these little guys takeover of the country’s coastal waters, the next question is, where does that leave us here in the Salish Sea region? On August 30^th 2016, one European green crab was found in Westcott Bay, on the northwest end of San Juan Island. Since then, the crabs have been spotted in Padilla Bay. At this point in time there is no evidence of established green crab communities.

Thankfully, there is a dedicated group of individuals who have made it their mission to help stop this arthropodic invasion. Crab team is a group who partners with Washington Sea Grant, the department of Washington Fish and Wildlife, and numerous citizen science volunteers. They survey a number of different sites in the Salish Sea looking for signs of the European Green Crab. With Crab team working hard, they are on the leading edge of a potential species invasion, which is a good place to be says Emily Grason, the Crab Team’s project coordinator.

European Green Crab  (Carcinus maenas) Photo by Sean McDonald

With this new awareness of the invasive green crab there are some steps you can take to help prevent the invasion in the Salish Sea area. Anytime you are out on a beach walk, take a look at the crabs and crab molts you are seeing.

How to Identify a European Green Crab:

•          5 spines on the outside of each eye
•          Up to 4 inches across the carapace or back shell
•          Wider at the front of the carapace

*The color of this crab can range from dark green to orange or red*

If you find a crab that looks like it could be a European green crab, here are the steps you can take:

1.       Take photos

2.       Record your location

3.       Leave the crab where you found it

4.       Report it to (crabteam@uw.edu)

To find out more about the European Green Crab or how you can become a crab team volunteer visit http://wsg.washington.edu/crabteam.  For some helpful information about other invasive species in Washington visit http://www.invasivespecies.wa.gov/priorities.shtml.

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Sarah Croston, Americorps - Natural History and Volunteer Educator

The Wonders Beneath the Waves

Eelgrass Meadows are an important habitat for many animals in the Salish Sea © PTMSC 1991

When walking on the beach near Fort Worden, I am always on the hunt for Eelgrass (Zostera Marina) to add to our display in the Marine Exhibit. I often find what I’m looking for near the high tide line, in a tangled ball that has been uprooted and washed ashore by the waves. Searching for Eelgrass is like a treasure hunt for me, where each tangled ball I find is a clue that  provides me with insight to the wonders that lie beneath the waves. Adding the Eelgrass to the display transforms it even further. The tangled mass I collected on the beach unfurls. Vertically suspended in the water column the blades of Eelgrass sway as the water circulates throughout the tank.

Eelgrass (Zostera Marina) collected

off of the beach at Fort Worden. Photo by Juhi LaFuente

The Eelgrass tank illuminated by sunlight.
 Photo by PTMSC

At first glance, this tank appears to be filled with Eelgrass and nothing more. However, upon further examination, what I think is a piece of Eelgrass turns out to be a juvenile Bay Pipefish (Syngnathus leptorhynchus) seeking refuge in the tangle of blades. I begin to notice more and more pairs of eyes peering back at me. Tiny Tadpole Sculpins (Psychrolutes paradoxus) dart back and forth, and eel-like fish, called Gunnels, peak their heads out to survey their surroundings. Along the bottom, Crabs scuttle and a Sea Cucumber slowly grazes in search of food. This underwater meadow is, in fact, teeming with life.

A Bay Pipefish (Syngnathus leptorhynchus)
disguises itself as a piece of Eelgrass.
Photo by Juhi LaFuente

The Eelgrass display in the Marine Exhibit provides visitors with a glimpse into an important nearshore habitat that often goes unseen beneath the waves. Eelgrass is a flowering marine plant that is widely dispersed throughout the Salish Sea. Found in tidelands and shallow waters, Eelgrass thrives in soft sediment habitats that receive plenty of sunlight. A network of underground stems, called rhizomes, help stabilize the surrounding sediment and anchor the Eelgrass in place. In dense meadows, blades of Eelgrass also help impede current flow and buffers the shoreline from oncoming waves.  


Many invertebrates and fish depend on and use Eelgrass beds for food and protection from predators. Eelgrass helps ensure the survival of juvenile fish such as Pacific Herring (Clupea pallasii) and Chinook Salmon (Oncorhynchus tshawytscha). These fish are important sources of food for many animals. Chinook salmon are the preferred food of the Southern Resident Orcas (Orcinus orca) residing in the Puget Sound.    

Found in such close proximity to the shore, eelgrass beds do not go undisturbed by humans. Eelgrass beds in the Puget Sound are threatened by shoreline development, including dredging and the construction of over water structures that block sunlight. Boaters also risk damaging these beds by cutting the grass with their propellers and tearing it up with their anchors. In order to protect Eelgrass habitat, boaters are advised to slow down or stop when cruising over Eelgrass beds and encouraged to avoid anchoring in eelgrass altogether.
 

In an effort to protect Eelgrass beds, the Jefferson County Marine Resources Committee established voluntary “No Anchor Zones” along the Port Townsend Waterfront. These zones are marked by special buoys and protect over 50 acres of Eelgrass in the waters off Port Townsend. Since the installation of these buoys in 2004, the Marine Resources Committee has observed a  98% compliance within these no anchor zones.

As the AmeriCorps Marine Exhibit Educator, I enjoy engaging visitors in conversations about our local marine life and important nearshore ecosystems like Eelgrass. Your donations to support the Marine Exhibit help ensure that visitors of all ages will be able to continue to explore, observe and learn about the wonders beneath the waves. The Marine Exhibit plays an integral role in helping us fulfill our mission “Inspiring Conservation of the Salish Sea”, Thank you for making this possible through your continued support.

Please consider donating today. https://ptmsc.org/get-involved/donate

Juhi LaFuente is the Marine Exhibit Educator and an AmeriCorps member serving at the Port Townsend Marine Science Center.