Winter residents are returning to or passing by the island and coastal waters. Common Loons share their melodic calls with us in Ryefield Cove in the early morning hours of September 13 (ML). There is silence for several days – perhaps these individual loons are in route to a warmer winter home, south of here. Before dark on October 2nd, as storm clouds rest on the eastern horizon, Northern Gannets feed offshore as noted by their distinctive diving behavior. From great heights they plunge as straight as an arrow released from a bow into the surface waters - their white plumage contrasting against the steel grey horizon. The following evening, with dark clouds still hanging on the horizon, large skeins of Double-crested Cormorants fly over Cliff Island towards Peaks Island and beyond. Dramatic cloud formations exaggerate the elegant silhouettes of more than 200 individual cormorants, as one flock, in single a file. The flock changes shape into an inverted ‘V’ as it passes over the island. The male Common Eiders in their magnificent and newly acquired black and white plumages are less impressive in their flight styles. Perhaps, more importantly they are eagerly welcomed back by their female companions and now grown chicks. A White-winged Scoter, Long-tailed Ducks and several other unidentified sea ducks, grebes and loons are noted the first days of October – and even more are now arriving. Look for large rafts of scoters and eiders, and smaller groups of goldeneyes, buffleheads, long-tails, loons, grebes, and guillemots. We hope the Great Cormorants with their diagnostic white-rump spot will return to roost on Cushing Island’s Whitehead cliffs – sometimes ice covered. Welcome back winter residents.
With all of this bird activity offshore, one might miss the human commotion on Peaks Island’s shore and the ferry-landing floating dock. MIMIC (The Marine Invader Monitoring and Information Collaborative) volunteers finish their third summer monitoring for marine invasive species (For more information about MIMIC and detailed classifications of the below species please see Nov. 2015 blog: MIMIC comes to Peaks Island).
Jeanne 'eye-balling' a tiny invertebrate through a loupe
Jeremy Miller, our leader cherry-picks a tide pool on the corner of the Backshore and South Shore as our second official monitoring site.
Jeremy at new tide pool
Old tide pool
A tide pool nearby, accessible at the lowest of tides, was originally selected by PW, but Jeremy immediately ruled it out as he watched waves breaching its edges - commenting that losing volunteers is not acceptable.
We are left on our own in July – to monitor the floating dock and tide pool.
Jeanne and Jacque comparing notes and having fun
We welcome a new volunteer, Jacque who strives to become an environmental science teacher. She is inquisitive and leans over the side of the dock and probes with her eyes and fingers. She finds a new species – a club tunicate (Styela clava), with the grotesque appearance of a warty club – less than one inch long. Tunicates, are marine invertebrates, also known as sea squirts because they pull in water through an incurrent siphon and squirt it out through the excurrent one. Within its body is a sac with a filter apparatus that collects food. Some tunicates are pretty, others are ugly. Tunicates live as solitary individuals or individuals within colonies (these individuals are referred to as zooids). This club tunicate is solitary, and it is ugly:
Club Tunicate (Styela clava)
As in 2015, many sheath tunicates (Botrylloides violaceus) cover ropes, kelp, and mussles. This tunicate is colonial and the individual reddish-orange zooids might be considered pretty, except for its slimy covering. And, it is an invasive species and we are biased, so we do not flatter it for its beauty.
Sheath tunicates on kelp
(Botrylloides violaceus) Close up of stalk covered with sheath tunicate
Close up of sheath tunicate zooids
The lacy crust bryozoa (Membranipora sp.) is another invertebrate, unrelated to the tunicates, that also feeds by water filtration.
Their filter mechanism differs from the tunicates, though - they use a retractable lophophore - a fancy name for a mouth surrounded with tentacles lined with cilia (tiny hair-like structures). They too, are colonial with individual zooids. A slimy covering does not protect these zooids; instead they produce a box-shaped exoskeleton for protection. These ‘boxes’ line up, side-by-side and end-to-end creating pretty lacy crusts over many surfaces, including kelp. In time the kelp blade is destroyed.
The skeleton shrimp (it is not a shrimp, it is an amphipod within the Subphylum Crustacea: Caprella mutica) that looks like a creature out of the Aliens movie, are rare this year.
Last year this creature, was abundant until the end of the summer when it nearly disappeared from their favorite haunts – end of kelp stalks.
Red arrow -
Blue arrows -
Membranipora sp. zooids lined up on kelp blade.
At the tide pool we find a few colonies of the sheath tunicates, the lacy bryrozoa, and a few green crab shells. And, now that we are fine-tuned to the club tunicate, we find another one – we name it Jacque’s tunicate.
Club Tunicate (Styela clava) Photo © Jeanne Gulnick
Just as we marvel over the unattractive club tunicate, a beautiful native ‘hairy’ nudibranch appears just under the water’s surface traveling over a rock.
Salmon-gilled Nudibranch Photo © Jeanne Gulnick
A nudibranch is a naked snail (mollusk), usually adorned with beautiful color hues. This one is called a salmon-gilled nudibranch. After a photo-op, it disappears into the seaweed-lined pool.
A plankton tow yields native copepods (crustacean), bivalve (mollusk) larvae, and nudibranch larvae. And, we add a curious Spotted Sandpiper to our bird list.
Low tide is early – 5:30 AM - we set our alarms and blurry-eyed, greet the tide pool and sunrise at 5:30 AM.
We find the usual players, and fortunately with no increase in their abundance. Even in the dim light, Jeannie spots tiny anemones (related to the jellyfish) – a new invasive species for us – a striped anemone (Diadumene lineata).
Striped anemone at end of finger (Diadumene lineata)
Native species are also observed: Jonah Crabs, pink mats of bacterial colonies, a limpet, slipper shells, gastropods, and two species of mussels – the Blue (Mytilus edulia) and Horse mussels (Modiolus modoilus) – favorite Common Eider cuisine.
Returning to the dock we discover our old friends the lacy bryozoan (now nearly covering the kelp blades), the sheath tunicate, and our warty club tunicate. A productive morning.
Colonial lacy bryozoa (Membranipora sp.) completely covering kelp blade
Colonial sheath tunicate (Botrylloides violaceus)
Club Tunicate (Styela clava)
Jeremy returns for a site visit on our last day of the season to monitor the tide pool and dock. He brings with him Alana. She is Jeanne’s student at St. Joseph’s College and she is finishing a summer fellowship with Jeremy at Wells National Estuarine Research Reserve. The tide is rising and we have no time to spare – a few hugs, but nothing more.
We are knee to thigh deep in water, as the waves break over the edges of the pool.
Jeremy finds a new species for the tide pool – Idotea sp. All is well though, it is a native isopod (another crustacean critter related to the above amphipod). Another species very similar to Idotea sp. is an invasive species – Synidotea laevidorsalis (a giant isopod from Asia). The obvious difference between these two species is a point or knob on Idotea’s telson (last body segment) and a concave configuration on Synidotea’s last body segment. Thankfully, this isopod has a point at the end of its telson.
However, we do find a new invasive species for this tide pool – the star tunicate (Botryllus schlosseri) presents itself. As the colonial sheath tunicate, it is colonial with many zooids, but these ones form a star, with usually 5-8 zooids in a cluster.
Star anemone (Botryllus schlosseri)
Jeanne’s striped anemones are gone. Our time is cut short as the waves torment us with the rising tide.
The original tide pool, vetoed by Jeremy, is now just part of the ocean floor.
Sandwiching ourselves back into the Mini we head back to the dock.
At the dock we find fewer sheath tunicates than mid-summer. This time the tunicate comes in two colors – bright red-orange and blood red, or is it purple?
Sheath tunicate colonies (Botrylloides violaceus)
The lacy bryozoa is more abundant, nearly destroying all kelp blades attached to the floating dock.
Lacy bryozoa on kelp blades (Membranipora sp.)
Two new invasive species are discovered, the club and star tunicates. On the dock the sheath tunicate is abundant in mid-summer, but declining in its presence in October. The lacy bryozoa is most abundant at the end of the season, destroying most kelp blades. The Caprella shrimp (amphipod) were abundant in mid-summer in 2015, but rare in 2016. Perhaps without healthy kelp blades, the Caprella’s habitat on the dock is too compromised for their survival. Species found in the tide pool did not increase in abundance over the summer.
Monitoring complete, it is time for lunch - perhaps a sea salad?
We seek more eager volunteers for next summer – to have fun and to aid in our quest for identifying those invaders who may out compete our native marine invertebrate animals and algae. Please contact Jeanne or Jeremy at: Jeanne Gulnick firstname.lastname@example.org or Jeremy Miller email@example.com.
Thank you for your interest in our Peaks Island birds, and if you have any additional bird sightings you would like to share or questions regarding Peak's bird life, you can send them to: firstname.lastname@example.org.
We thank Curtis Bohlen (Director) and members of Casco Bay Estuary Partnership (CBEP) whose funding has made work possible on Peaks Island, Long Island, and Chebeague Island.
We thank Adrienne Pappal of the Massachusetts Boston Office of Coastal Zone Management for establishing this MIMIC organization in 2007.
We thank Maureen Donahue for her generous donation of used compound and dissecting microscopes that I use to identify the small invertebrates. MD Micro Solutions, New England's Source for Micro Optics.
1. W.S. Johnson and Allen, D.M. 2012. Zooplankton of the Atlantic and Gulf Coasts: A Guide to their Identification and Ecology. The Johns Hopkins University Press. Baltimore. (Illustrations by Marni Fylling)
2. Wikipedia, the free Encyclopedia.
Volunteers and Contributors:
Jeremy Miller, Research Associate at Wells National Estuarine Research Reserve (Wells, ME: http://www.wellsreserve.org/blog/554-casco_bay_island_invasion); Jeanne Gulnick, Assistant Professor at St. Joseph’s College and Peaks Island resident email@example.com; Jacque Kutvirt (Graduate student at University of Southern Maine); Alana Dougherty, student at St. Joseph’s College with her major in Environmental Science and Biology, with two minors in Sustainability and Chemistry, and Michael LaCombe (ML), MD (University of New England; MaineGeneral Medical Center).
Photos: © Patty Wainright (except where noted above)
By: Patty Wainright
Michelle Brown, Michael LaCombe, Marty, Jeanne Gulnick, and Jeremy Miller