MIMIC comes to Peaks Island
Female Common Eiders (eider ducks) circle the Peaks Island public dock next to the ferry landing. They watch curiously four humans sift through dangling seaweeds. Kelp and other marine algae hang on the docksides – some kelp species growing into long fragments. The eider ducks regularly feed along the dock, picking through the marine algae for invertebrates such as crabs and mussels. Now there is competition, it seems.
Female Common Eiders at dock Photo © Patty Wainright
Part 1:
MIMIC volunteers! What is MIMIC and who are these volunteers? The Marine Invader Monitoring and Information Collaborative – MIMIC - is a network of trained volunteers, scientists, and state and federal agency workers who monitor marine invasive species throughout the northeast United States. The collaborative provides an opportunity for the general public to actively participate in an invasive species early detection network. Participants identify new invaders before they spread out of control and they help to improve our understanding of the behavior of established ones. Monitoring, for the presence and abundance of invasive marine invertebrates, is done in three different habitats: docks, rocky intertidal areas, and tide pools.
An invasive species is any non-native species that is introduced to an area by human activity such as aquaculture, foreign shipping (including the release of ballast water in our nation’s harbors), and in some cases - the pet industry. These species are harmful as they ‘push out’ native species by occupying similar habitats and competing for food resources.
Volunteers search for these marine species not to eat or compete with these eider ducks, but instead, to identify them, to provide data, to educate, and of course, to have fun!
Kathy, Jeanne, and Susan preparing to sample Photo © Patty Wainright
On May 23, 2014, MIMIC arrives on Peaks Island at Peaks Island Elementary School where eager volunteers gather. Jeremy Miller, a Research Associate at Wells National Estuarine Research Reserve (Wells NERR; Casco_Bay_Island_Invasion Blog) introduces us to MIMIC. Curtis Bohlen, the Director of Casco Bay Estuary Partnership (CBEP) discusses its role in Casco Bay and how it overlaps with MIMIC goals. Mr. Bohlen and CBEP provided funding in 2014 to assist in establishing MIMIC sites on the islands of Casco Bay. Adrienne Pappal of the Massachusetts Office of Coastal Zone Management, who started MIMIC in 2007, also outlines overall goals of the organization. Cindy Nilsen, Principal of Peaks Island Elementary School, states that it is our goal to protect and preserve island habitats and while doing so instill interest in young students.
Jeremy and PI Elementary School Students Photo © Jeremy Miller [Wells NERR]
Potential volunteers are now wide eyed, and interested. We introduce ourselves and Jeremy gives each of us laminated identification cards (Guide to Marine Invaders in the Gulf of Maine [1]) that provide an abundant amount of information and photographs of invasive species in New England. These identification cards are available in the Peaks Island Library. Data sheets are also provided:
Jeremy and colonial tunicates on rope in Wells Harbor
Photo © Jeremy Miller [Wells NERR]
Jeremy, a charismatic fellow, now takes the bull by the horns and teaches us how to be citizen scientists. Tricks used to identify these species - without the luxury of a sophisticated laboratory and a fine line of classy instruments – is initiated. First we will use a hand lens to determine the shape of the organism. Body color is variable, as it readily changes according to habitat, so Jeremy recommends it as an unreliable characteristic. Then the yuk factor is presented. We are instructed to feel the creature’s body for texture, and for its sponginess or sliminess. We are asked to learn the scientific names; it reduces confusion and redundancy of common names. We learn new terms and how to classify these organisms:
Zooid: An individual animal that is not fully independent but lives, within a colony of organisms like itself (such as colonial tunicates, bryozoans, corals) that replicates by budding.
Crustacea: Animals within the Phylum Arthropoda, Subphylum Crustacea, which includes such invertebrates animals as crabs, lobsters, shrimp, krill, barnacles, amphipods, and isopods. [2]
Amphipod: Phylum Arthropoda, Subphylum Crustacea, Class Malacostraca:
Order Amphipoda. [3a] Featuring two skeleton shrimps (amphipods):
Caprella mutica (invasive) and Caprella penantis (native).
Order Decapoda. [3b] Featuring the green crab - Carcinus maenas
Tunicates or sea squirts: Phylum Urochordata. Tunicates can be solitary or in colonies (referred to as zooids). They are built like barrels covered in a tunic. Two siphons connect the inside barrel (branchial basket) where food and oxygen is trapped. [4] Featuring the star tunicate - Botryllus schlosseri; the mystery tunicate - Didemnum vexillum; and the red-sheath tunicate - Botrylloides violaceus
Bryozoa: Phylum Bryozoa. This group of animals lives in colonies usually forming a calcium carbonate (lime) skeleton. The colonies are formed by tiny zooids that are less than 0.2mm. [5] Featuring the lacy crusty bryozoan - Membranipora membranacea
Botryllus schlosseri, star tunicate Photo © Patty Wainright
Jeremy then introduces each invader by its scientific name. We may encounter Botryllus schlosseri. It is a colonial ‘star’ tunicate (or sea squirt) – that is, many little tunicate animals, called zooids, living together as one cooperative unit – held together with a translucent type of ‘gel’. As the name implies, each zooid looks like a star. Each one of these zooids has two siphons, one pulling water into the digestive system and one pushing it out, filtering out tasty plankton in its branchial basket. It’s sponge-like appearance is deceiving as it is not spongy, but rubbery.
An even more sinister name is presented – Didemnum vexillum, another colonial tunicate. A description of this beast includes such words as mystery tunicate, aggressive, and moving into the Gulf of Maine. Didemnum vexillum resembles a sponge and it too is rubbery as is Botryllus schlosseri, but it is slimy too. It forms beige undulating mats or long rope-like lobes of rubber and slime, often fouling fishing gear as well as habitat for commercially important species like sea urchins.
Didemnum vexillum attached to tide pool rock Photo © L. Stefaniak, UConn
And, we are likely to face Caprella mutica; it looks like a shrimp and it is called a skeleton shrimp, but it is not a shrimp, it is an amphipod – another type of crustacean critter with a more laterally flattened body shape than a shrimp. The males of this invading amphipod can reach the size of two inches, with long necks and spines on its back. This Halloween character attaches itself to substrate with back legs, dangles in the currents, and ‘waves’ its front claws – reaching for delicacies. Jeremy describes in detail another twelve marine species. He emphasizes again, that we are required to learn their scientific names and identification characteristics.
Red Arrow - Caprella mutica Photo © Curtis Bohlen [CBEP]
Blue Arrows - Membranipora membrancea
Our eyes squint as we absorb this information, but we eagerly assemble at the dock for our first field lesson. There we find the waving shrimp – whoops - amphipod. We now see why we need to use scientific names, as common ones are confusing, so we learn to call it Caprella mutica. We find Membranipora membranacea on stacked lobster traps. It feels crusty, yet its appearance is like delicately woven white lace (hence the common name of “lacy crusty bryozoan”). With a hand lens we see rectangular zooids lined up, giving it the lace-like appearance. This colonial animal is not a tunicate, but a vastly different animal - a bryozoan in its own Phylum Bryozoa. We are hooked.
Once a month in the summers of 2014 and 2015 Peaks Island volunteers collect data at the public dock, next to the ferry landing. And we add a new location in 2015 - a tide pool on the corner of the Backshore and South Shore – near the 2015 ‘boat wreck’.
Backshore/South Shore Tidepool Photo © Patty Wainright
On different occasions we have guest appearances by three scientists, a phycologist or seaweed specialist - Margaret Carroll, PhD (Framingham State University), and two marine biologists Marina Penalver (King Middle School Science) and Sam Wainright, PhD (US Coast Guard Academy), come to our aid teaching us new identification skills.
September 27 was the last sampling day for 2015. Caprella mutica is less abundant than in our early summer observations. The native species Caprella penantis (males are small at ½ inch long, with no spines, and short necks) that once was common, appeared to be pushed out by this invasive species (Caprella mutica) earlier in the season, but now it is more abundant in September. Good news.
Botrylloides violaceus, red-sheath tunicate Photo © Patty Wainright
But the bad news is - Botrylloides violaceus is gaining speed. This colorful colonial red sheath tunicate, with many zooids, is also confused with a sponge, especially orange and red ones. It is not spongy, it is rubbery with a coarse and rigid feel. This pretty tunicate attaches to about anything – any stationary structure, algae, and slow moving invertebrates or stationary invertebrates, including mussels.
Kathy reaches over the dock ...
... and finds Botrylloides violaceus, and more. Photos © Patty Wainright
As Kathy casually reaches over the dock, she finds a treasure trove of this Botrylloides violaceus (blue arrows above) attached to kelp, mussels, and ropes. Now grotesque in appearance, no longer pretty, it nearly covers the mussels, perhaps smothering them in the end. Also noted near the clump of thriving tunicates are kelp blades covered in Membranipora membranacea (red arrows above), its pretty lace-like zooid colonies reducing the kelp blade to a brittle and vulnerable sheet that will eventually break into scattered pieces. These pieces of kelp can no longer sustain a habitat for the lump fish (Cyclopterus lumpus [6]) that relies on this floppy seaweed (and other substrates) for its living quarters:
Cyclopterus lumpus, lump fish Photos © Patty Wainright
We also discover Botrylloides violaceus at our new tide pool site. This colonial red sheath tunicate us growing in sheets on the veritical sides of the tide pool. Here, too this invader is increasing in abundance since early summer. The European green crab, Carcinus maenas, is found in this pool, but not in great abundance as found elsewhere along the coast [7]. Perhaps the Common Eider flocks that routinely feed at this tide pool at high tide keep their numbers from escalating.
Botrylloides violaceus, red sheath tunicate at tidepool (red arrow)
Disguised native Atlantic Rock Crab (blue arrow) Photo © Patty Wainright
Finally, after our last day of monitoring, Peaks Island volunteers add new species to the final data sheet, their relative abundance, and the temperature and salinity of the water. Jeanne and Susan compile all data sheets and photographs and send them to Jeremy at Wells National Estuarine Research Reserve. He will compile this data from Peaks Island and compare it to Chebeague and Long Islands, and other Maine locations (see below – Results of Casco Bay Monitoring Program).
Susan taking salinity measurements Photo © Patty Wainright
Meanwhile, the female eider ducks are eager to return to their invertebrate-munching activities along the dock – will they eat the mussels covered in Botrylloides violaceus? No evidence of eider duck beak carvings is seen on these tunicates. Perhaps these tunicates are not as tasty as mussels and crabs that eider ducks favor.
Female Common Eiders returning... Photo © Patty Wainright
Part 2: Results of Casco Bay Monitoring Program (By Jeremy Miller)
Summer 2015 got off to a “chilly” start and the ocean took a considerable amount of time to “warm up” so to speak. This had a big impact on the “timing” and abundance of these marine invaders (specifically the tunicates). One thing that keeps these invaders “at bay” (pun intended) in the Gulf of Maine is our cold water temperatures. Most of these invaders are coming from warmer climates and are not designed to survive the cold Maine winters, hence why we focus our monitoring in the summer months. In 2013 and 2014 tunicates were generally abundant and spreading like crazy by late June. This year we did not see our colonies really take off until late July/early August. This helped many of our other native fouling species (mussels, seaweeds, sponges, etc.) get an early foothold, and at some locations (Wells Harbor, S. Maine Community College Dock) they actually outnumbered the invaders for a change! This was nice to see…. however, in light of what climate science is telling us, it is unlikely that the Gulf of Maine (one of the fastest warming bodies of water on earth! [7]) will get any colder over the next 50-100 years, and this could potentially aid in the spread and ability of these critters to survive and flourish here. Only time will tell…
We also have MIMIC teams on Chebeague Island (Thanks Bev Johnson!) and we just started a team on Long Island this year, that is run by the local Island Institute Fellow, Erin Love. It was very interesting to see the difference in the fouling communities on these different islands. For instance, we could not find a single colony of Botryllus schlosseri (star tunicate) on the docks at Chebeague Island, however they were abundant on the docks at Long and Peak Islands. I’m not sure why this would be but perhaps they have not been introduced to the shores of Chebeague Island yet, or there is something at that site inhibiting their growth. Another year of monitoring at Chebeague Island will either confirm or reject this trend.
Another interesting observation is the presence of Didemnum vexillum at Peaks and Chebeague Island docks, but lacking at the Long Island dock, and our mainland sampling sites (except for a Portland dock site). This tunicate is sensitive to fresh water (low salinities), so it is not surprising that mainland sites where rivers systems (estuaries) and rain fall events lower salinities, that this species is rare in these habitats. And it makes sense that Peaks and Chebeague Islands, as representative of a more off shore site with preferred higher salinities, now show signs of this invasive tunicate. But why is Long Island dock spared from this invasive tunicate?
Didemnum vexillum is one of the species of our greatest concerns in the program, as it grows and spreads at an alarming rate and it is already covering a lot of subtidal urchin habitat in the Gulf of Maine. As a matter of fact the Department of Marine Resources actively collects data on this species abundance and distribution as part of their annual urchin surveys, using sub-tidal scuba divers.
Keep in mind that many of these species (especially colonial tunicates) are much understudied in the scientific literature, so we are still learning about their life histories, reproductive strategies, and habitat preferences. Really cool information is being collected by volunteers; through their sampling efforts, they help to 'verify' where theses invasive species are 'popping up'. MIMIC is a perfect example of how community members working with professionals in the field of marine science can make meaningful contributions to the greater cause!
A big THANK YOU to all of our volunteers on Peaks Island and at all of our MIMIC sites in Maine! Community involvement is critical to this program and I’m continually encouraged by the dedication and commitment of volunteers here in Maine! Cheers to that!
-Jeremy Miller
Wells NERR
342 Laudholm Farm Rd.
Wells, ME 04090
207-646-1555 Ext 122.
Additional Information:
We seek more eager volunteers for next summer – to aid in our quest for those invaders who may out compete our native marine invertebrate animals and algae. Please contact Jeremy Miller at jmiller@wellsnerr.org or 207-646-1555 Ext. 122 if you’d like to start monitoring with us!
Current Volunteers: Jeanne Gulnick, Susan Merrow, Kathy McCarthy and Patty Wainright
Microscope: Donated by Maureen Donahue; MD Micro Solutions, New England's Source for Micro Optics
Part 1: By Patty Wainright and reviewed by Jeremy Miller, Current Volunteers, Michelle Brown, Marty, and Sam Wainright
Part 2: By Jeremy Miller and reviewed by Current Volunteers, Michelle Brown and Marty
References and Extra Information:
1. Guide to Marine Invaders in the Gulf of Maine. Salem Sound Coastwatch. Originally funded by MA EOEEA Office of Coastal Zone Management and US Fish and Wildlife Service.
6. Jeremy Miller, personal communication September 2105. “This fish is called a "Lump Fish" (Cyclopterus lumpus). A neat little fish whose pectoral fins have evolved into a suction disc which they use to attach themselves to hard substrates. Neat little fish for sure!”
7. Mayday: Gulf of Maine in Distress. By Collin Woodard, Portland Press Herald Staff Writer.
