Monitoring at MacMillan Wharf, Provincetown, MA

Monitoring at MacMillan Wharf, Provincetown, MA
Marine Invasive Species (MIS) Monitoring at MacMillan Wharf, Provincetown, MA.

Friday, December 30, 2011

Marine Event of the Year - 2011 Tropical Storm Irene

Tropical Storm Irene hit New England on August 28th, 2011 with onshore winds on the east side of the storm battering coastal areas with large waves and a destructive storm surge.  After the storm, I traveled to Provincetown during calm weather and monitored the docks at Provincetown and Wellfleet on August 31st and September 1st.

Tropical Storm Irene Hits New England
 Tropical storm Irene over New England brought onshore easterly winds
 and turbulent waters to the Massachusetts coastline.  
Satellite view over the Northeastern US with outlines of the states superimposed. The image was taken when the eye of the storm was near New York City.

  Left, projected path of Hurricane Irene when it was in the Carribean.  Irene started its journey as a hurricane in Puerto Rico, made landfall over eastern North Carolina's Outer Banks, and was downgraded to a tropical storm as it passed over Long Island, NY.  Right, it continued through western New England battering CT and VT.  The threat level through the Northeast was extreme with widespread damaging winds through August 29th.

The storm had a significant effect on marine life on the sides of docks, scouring off loosely attached organisms and battering firmly attached species.  Most of the colonial species and algae that extended away from their attachment site were pruned or torn off and some species appeared bruised or damaged.  Firmly attached species like Styela clava and Codium fragile survived the storm, but filamentous and leafy algae were washed away or pruned shorter taking with them the species (e.g., amphipods) that grew on or among them. Outgrowths of Didemnum vexillum were torn off at the base, as were large colonies of Botryllus schlosseri and Botrylloides violaceus.  In Wellfleet, an almost solid covering of a spring cohort of Molgula sp.(manhattensis?) on portions of the seasonal docks was decimated resulting in large areas of the docks being cleared of the ascidian.

Monitoring at MacMillan Wharf, Provincetown, 2 Days after the Storm
Inspecting colonial organisms on August 31st using the palm of my hand to make a small pool of water and preparing to magnify the field with a jeweler's loupe. 

A month later, by the September monitoring visit, there was a clear re-colonization of the depleted areas in Provincetown by algae, ascidians, and other invertebrates.  Didemnum vexillum grew up the sides of the dock from established areas lower on the dock, and Diplosoma listerianum, not found at the beginning of the season, surged in its colonization from its first sighting in August.  Botryllus and Botrylloides repaired their torn edges and resumed their previous growth.  Near the water line, small individuals of Styela clava (under 1 or 2 inches) were scattered along the dock on newly exposed substrate.  In Wellfleet, there was no noticable re-colonization of cleared surfaces by Molgula, but Botryllus schlosseri growing on the remaining Molgula continued to grow and spread, and there was some regrowth of algae and other attached species along the water line. 

Thursday, December 22, 2011

Striped Anemone at Wellfleet Marina

Wellfleet Harbor and Marina
Wellfleet Harbor is located on the west side of the Cape Cod Peninsula (see satellite images of Cape Cod along sidebar at right) and is home to the renown Wellfleet oysters.  The town marina is located at the north end of the harbor and was built over a natural strip of land at the mouth of Duck Creek.  A long permanent dock is located on the north side of the marina that I monitored during the summer of 2011 (see satellite image and photo of the marina, below).  The dock rests on concrete covered polystyrene floats similar to those found in Provincetown.  Virtually all the boats moor rear-first at the dock, but there is a perpendicular, seasonal dock with wood sides near or at the end of the long dock for side boat-entry.  During the winter, I am told that the individual sections of the permanent dock are brought to the west end of the bay for protection against winter storms.
Wellfleet Marina North and South
The North Marina features permanent docks with concrete-covered floats for fishing and recreational boats.  The South Marina features the harbormaster seasonal docks and public docks that rest on modular floats composed of polyethylene plastic shells encasing polystyrene cores. 

Wellfleet Marina North Facing the Mouth of Duck Creek
Permanent docks at the mouth of Duck creek provided a substrate for settlement by Diadumene lineata. The water was turbid with sediment, ranged 70-80 degrees in temperature, and had a favorable bay salinity of 32 parts per thousand.

In comparison to the other bays studied, Wellfleet marina had a relative low diversity of species on its docks.  The dominant, year-around species was the common oyster, Crassostrea virginica which covered the intertidal rip rap and grew to mature size on the underside of the dock floats.  The sides of the permanent docks also had a few mussels and empty shells, but not a new cohort of young oysters.

The Wellfleet oyster industry dates back prior to the Revolutionary War.  In the 1700's, native oysters were harvested.  During the mid 1800's, young oysters were shipped in from Chesapeake Bay and grown to maturity in Wellfleet Bay.  During the late 1800 and 1900's, aquaculture techniques were developed, and today the bay is home to a thriving oyster industry that celebrates each fall with its Wellfleet OysterFest.  The shallow bay that is so favorable to oyster beds is also probably one of the features that make it a favorable environment for the orange-striped anemone, Diadumene lineata (also listed as Haliplanella lineata).   

Diadumene lineata - the orange striped anemone
Diadumene lineata is a small anemone about 3 cm in diameter, with a smooth, brown or green-gray body, with or without vertical orange stripes.  The crown is topped with 50-100 slender, tapered, fully retractile tentacles that are transparent, pale yellow, beige, or light green.  It is native to northeastern Asia but has spread around the world to temperate climates in both the northern and southern hemispheres.  It is commonly found on pilings or floating docks of protected shallow waters such as harbors and is often associated with mussels or oysters.  It is extremely tolerant to extremes in temperature, salinity, and water quality.  This tolerance probably explains its distribution in Wellfleet in an area that is generally unpopulated by other attached and encrusting species. 

Diadumene lineata - Portrait by Underwater Photography
A view of Diadumene as seen in the literature. This image by R. Manuel is from A Guide to Invasive Marine Species of Hawaii by Eldredge and Smith, 2001. 

Within my monitoring areas in the Gulf of Maine, Wellfleet was the only site where we saw Diadumene, and within the Wellfleet Marina, it was most common along the long permanent dock in the north, protected bay.  The permanent docks of Wellfleet Marina are dominated by oysters, in contrast to Provincetown Marina or Salem Sound where the mussel Mytilus edulis is the common bivalve.  Diadumene is relatively inconspicuous to the eye but can been seen growing at moderate density in social groups on the vertical dock surfaces and on oyster shells.  

Diadumene lineata Growing on Oyster Shell
Individuals were photographed shortly after collection (9/1/2011).  Most individuals were fully open, but one is closed at the bottom center revealing the orange stripes. 

Under the stereomicroscope, Diadumene took on a new look.  The light colored tentacles had a luminescent glow, and with menthol anesthesia, the tentacles moved around in slow motion.   The anemones were partially immobilized, and the tentacles appeared shorter and more stout (compare the length of the tentacles of the anemones below to the ones in the photo above). Two color variants were seen, a majority with light yellow tentacles and a less frequent variant with light brown tentacles.

Diadumene lineata Growing on an Oyster Shell
Diadumene lineata viewed with a stereomicroscope using fiber optic lighting.
The specimens were collected in July 2011 and anesthetized with menthol crystals.
The light colored tentacles had a luminescent glow.  2X zoom x 10X objective.

Diadumene lineata with Brown Translucent Tentacles
Diadumene lineata viewed from above showing the mouth and orange stripes.  This individual was also anesthetized with menthol crystals.  2X zoom x 10X objective.

Color Variants of Diadumene lineata
The two color variants of Diadumene lineata detached from the substrate
after menthol relaxation.  1.5X zoom x 10X objective.

View of the Mouth of Diadumene lineata
Beige colored mouth surrounded by rings of brown tentacles 
(above mouth, a small piece of adhering debris).  4X zoom x 10X objective.

Distribution of Diadumene in New England marinas (RI to Maine):
Pappal, A, Pederson, J, and Smith, JP.  Marine Invaders in the Northeast.  Rapid Assessment Survey of non-native and native marine species of floating dock communities. 7/25/2010 - 7/31/2010

Special thanks to Adrienne Pappal and Niels Hobbs for confirming the species identification of Diadumene from sterezoom micrographs.

Links providing further information on Diadumene lineata:

References on the history of Wellfleet:
1.  Wright, D.B. The Famous Beds of Wellfleet.  A Shellfishing History.The Wellfleet Historical Society, 153 pp., 2009. 
2.  Lombard, D.  Wellfleet, A Cape Cod Village.  Arcadia Publishing, 128 pp., 2000.  

Friday, December 9, 2011

New Ascidian Images on Tunicarium

Botryllus schlosseri is another beautiful colonial ascidian whose single and multi-color variants make for an amazing number of color morphs.  These colorful ascidans, like Botrylloides violaceus (Nov. 11 Post), make for terrific underwater photographs that I thought would transcend directly to the stereomicroscope.  It did to an extent; however, like with Botrylloides, structural detail was easier to capture with the lighter color variants.  Some of the stereomicrographs from this summer's monitoring of Cape Cod and Salem Sound marinas are now featured on Tunicarium, including images of the invasive ascidians Botrylloides violaceus, Botryllus schlosseri, and Didemnum vexillum.  

Botryllus schlosseri was a challenging colonial to capture under fiber optic lighting. The variants with dark-colored zooids blended in with the backgrounds making difficult the photography of structural detail.  With the light color variants against a darker background, the two-toned beige, which formed a mosaic-patterned colony, and single-colored orange colonies proved to be highly photogenic.

To capture the zooids with open siphons, I tried Gretchen Lambert's technique for relaxation with menthol crystals.  It was terrific for relaxing ascidians as well as other invertebrates.  But as with any approach, I found relaxation had its pros and cons for viewing as well as photomicrography.  Relaxation greatly reduced contraction ability, but also inhibited the ability of zooids to fully expand. Lack of anesthesia was challenging under bright light because individual zooids reacted to the light independently, each zooid in a cluster randomly closing and re-opening during photography.  My objective was to obtain images where all the branchial siphons in the field of view were fully open.  It made for some interesting and entertaining time-sequence shots.    

The images below are two of my favorites.  They demonstrate the difference between the information revealed capturing images of light vs. dark Botryllus color variants and show zooid structural and pigment cell details that cannot be seen solely by underwater photography.  The 40X original magnification generated images with the greatest resolution and zooid detail (4X zoom + 10X objective lens).  These details can also be seen out in the field with the 30-40X jeweler's loupe magnifying glasses that I discussed in the Nov. 25 Post.  The beige variant gave vivid zooid detail, whereas the typical white star on dark purple was outstanding for showing cells in the pigment bands.

Botryllus schlosseri Beige-Rust Mosaic Variant
Botryllus schlosseri growing on the green algae Codium fragile collected from MacMillan Wharf, Provincetown, MA. Zooids have a translucent beige color revealing the tips of the branchial tentacles and pale rust-orange cells in the pigment bands. 

Botryllus schlosseri White Star Variant with Parallel Pigment Bands.
Botryllus schlosseri growing on Codium collected from MacMillan Wharf, Provincetown, MA.  Four branchial openings are seen at the top with 4 pairs of white pigment bands leading to the single, common atrial aperture at the bottom center.  

The full collection of images on Tunicarium can be seen all together on Google Images that has been web-searched using the word "Tunicarium".  The photos are featured in thumbnail view and can be "double-clicked" to see the jpg files saved on the website.  Larger sized micrographs can be obtained from me by request at

Friday, November 25, 2011

Helpful Monitoring Accessories

At the beginning of the summer, I got supplied with the usual set of monitoring supplies: Clipboard, Thermometer, Refractometer, Collection Trays, and a Pocket 6X Magnifying Glass.  I was all set, but when I arrived out in the field, the 6X magnification left me poorly equipped to make species determinations of the colonial species, and it was also difficult to distinguish the red bryozoan Bugula neritina from some filamentous red algae.  Back at home, under the stereomicroscope, I could easily make species determinations magnifying specimens 20-40X.  It was then that I realized I needed magnifiers at this range of magnification.
Off I went to the internet and found a terrific line of magnifiers at Amazon.  I purchased several, but the jeweler's loupes were the most helpful.  Some magnifiers are made for viewing details of photographs and the plane of focus is right against the glass, but the jeweler's loupes are designed to be held away from the subject and this feature keeps the lens clean and dry in the field.  

30X Jeweler's Loupe Magnifying Glass

The 20X, 30X, and 40X lenses are now permanent supplies in my monitoring bag; however I'd say that I use the 30X lens the most.  I use the 20X when I need a wider field of view and the 40X for the smallest details.  Nonetheless, I've used all of them on my most recent trips. 

Don't depend on these magnifying glasses to help much in image documentation, however.  Feeling in an adventurous spirit, I tried taking an iPhone photo of a small Botryllus schlosseri colony growing on Ulva.  I held the 30X jeweler's loupe lens directly against the iPhone lens, and surprisingly, I was able to obtain focus through the lens.  However, I could not hold the specimen or camera steady enough to take a sharp, in-focus photo.  My best attempt is shown below - not bad for evidence but insufficient for documentation.  At least the Botryllus was fresh!

A Blurry Botryllus schlosseri growing on Ulva Sea Lettuce
Photo taken with a 30X jeweler's loupe held directly against the camera lens
 of an iPhone mobile device. Time to get a macro camera........

Sunday, November 20, 2011

Convergence or Coincidence?

A Lighthearted Comparison & Identification Aid
When identifying Botryllids, I frequently use the suburban housing development as a model for identifying Botrylloides.  This has been especially useful when the colonies are small or when the colors of Botrylloides violaceus and Botryllus schlosseri are similar. The organization of zooids in each species is distinctly different, with Botryllus forming stars and clusters and Botrylloides forming meandering chains of zooids reminiscent of newly constructed southwest housing tracts.

Human Social Organization - Shared Roads and Utilities.
   Botrylloides Organization - Shared Excurrent Canals and Blood Channels

It's fascinating when we see nature's designs show up in human social organization.  And somewhat validating, too, that we're all interconnected.

Friday, November 11, 2011

Marine Invasives Monitoring

My monitoring activities at Provincetown, Wellfleet, Salem, and Beverly Marinas are now completed for 2011 with the Species Reports for Ptown and Wellfleet sent off to the CZM and my marine biologic image collection significantly enlarged.  With 4 months of visits behind me, I obtained a nice selection of photographs of Massachusetts marinas and their marine invasive species (MIS).  After several of the trips, I was able to get brightfield microscopic images of colonial species within a few hours of their collection.  Fourteen of the sixteen species on the list in the August 8th Post were seen this season, all except the European oyster Ostrae edulis and leafy red alga Grateloupia turuturu.  Among the sessile or attached species, Didemnum vexillumStyela clavaBotrylloides violaceusBotryllus schlosseriDiplosoma listerianum, Ascidiella aspersaBugula neritinaMembranipora membranacea, and Codium fragile were commonly observed, whereas Diadumene lineata found a special niche in the Wellfleet Marina. 
The most dramatic event of the summer was the impact of Tropical Storm Irene which had a major erosive impact and removed most of the species that were not strongly attached or that extended out from the docks.  My visits to Cape Cod occurred 2-3 days after the storm, and the storm currents cleared away much of the overgrowth and removed some of the species down to the substrate. 
Perhaps the most impressive and beautiful species to my eye was Botrylloides violaceus, whose bright orange colors could be seen by casual observation walking on the docks and which looked even more beautiful up close when the meandering rows of zooids and their surrounding ampullae could be clearly observed.

Botrylloides violaceus in Clear View at Low Tide on a Pier Piling
 at Fisherman's Wharf, Provincetown, MA
The green alga Ulva lactuca grows above a band of orange Botrylloides violaceus. A colony of Didemnum vexillum can barely be seen below the Botrylloides.

Botrylloides violaceus Orange Colonies on the Sides of Dock Floats
View of the side of a dock at MacMillan Wharf, Provincetown, MA. Looking through the hazy water, light-orange, orange, brick-red-orange, and purple-red-orange color variants of Botrylloides can be distinguished. Also present were mature Mytilus edulis and Styela clava.

Botrylloides violaceus Colonial Organization 
Botrylloides colony showing meandering rows of zooids with open branchial siphons separated by clear tunic containing a border of amplullae.  3X zoom x 10X objective.

Botrylloides violaceus Zooids and Ampullae 
Orange color variant of Botrylloides showing branchial siphons, pigmented body wall, and pigmented ampullae between rows of zooids. Endostyle is in subtle contrast to body wall.
3X zoom x 10X objective.

Botrylloides violaceus Endostyle and Branchial Features
Light-orange color variant showing branchial tentacles and orange-pigmented endostyle against the more transparent body wall.  3X zoom x 10X objective.
Additional stereozoom micrographs of Botrylloides violaceus and other ascidians can be seen at

Monday, August 8, 2011

Coast Watch 2011

The 2011 Coastwatch season has started and is well under way. In my first year participating in the CZM Marine Invasive Species Program, I am joining the monitoring teams at Salem Sound Coastwatch, coordinated by Barbara Warren, and Provincetown Center for Coastal Studies, coordinated by Beth Larson.  In June, Adrienne Pappal of the CZM hosted a launching workshop in Barnstable for the Cape Cod Group and Barbara organized a workshop on Winter Island for the Salem Sound group. 
Earlier in the season, I made a pre-summer visit to Provincetown and Wellfleet Harbors (late May) to gather information about dock configurations and to assess overwintered and cleaned surfaces. The July surveys have just passed and August monitoring dates are scheduled.  For the 2011 summer season, the CZM designated the following 16 species as Marine Invasive:

Invertebrates (includes Ascidians, Bryozoans, Anthozoans, Molluscs, and Crustaceans):
  • Didemnum vexillum (mystery beige colonial tunicate)
  • Diplosoma listerianum (green/brown colonial tunicate)
  • Ascidiella aspersa (bumpy translucent tunicate) (solitary)
  • Styela clava (club tunicate) (solitary)
  • Botryllus schlosseri (star colonial tunicate)
  • Botrylloides violaceus (orange colonial tunicate)
  • Membranipora membranacea (lacy crust bryozoan) (single layer of zooids)
  • Bugula neritina (purple bushy bryozoan) (branching upright growth)
  • Diadumene lineata (orange striped anemone)
  • Ostrae edulis (European oyster)
  • Carcinus maenus (green crab)     
  • Hemigrapsus sanguineus (asian shore crab)
  • Palaemon elegans (European rock shrimp)
  • Caprella mutica (Caprellid amphipod, skeleton shrimp)
  • Codium fragile (green fleece)
  • Grateloupia turuturu (leafy red algae)
Each location and substrate has a unique distribution of species.  The ascidians Styela clava, Botryllus schlosseri, and Botrylloides violaceus are common invertebrates found in marinas on flotation devices.  Mooring ropes which stay suspended in the water during the summer are prime settlement substrates for algae, ascidians, bryozoans, anemones, and bivalves. 

Styela clava, Botryllus schlosseri, and Botrylloides violaceus
on a rope at MacMillan Wharf, Provincetown, MA

The large, solitary Styela clava and the bright orange colonial Botrylloides violaceus on the rope are instantly recognized, but the colonial Botryllus schlosseri to the left takes closer examination to evaluate the number and size of colonies.

Botryllus schlosseri - Close-Up View
Underwater photograph of Botryllus schlosseri by Rokus Groeneveld -

Botryllus schlosseri - Microscopic View
Botryllus schlosseri zooids are arranged in small, star-shaped groups.
Light and dark-pigmented cells give the colony its dual star-patterned coloration.
Stereomicroscopic image recorded with QImaging 5.0 MicroPublisher Camera
and QCapture software.

Other common invasive ascidians include Didemnum vexillum, Diplosoma listerianum, and Ascidiella aspersa, but these species are not equally present throughout the area (data available at MORIS webpage link).  In addition, Ciona intestinalis (classified by the CZM as cryptogenic, but in some studies included as invasive or non-indigenous) and the native ascidians Aplidium sp. (sea pork) and Molgula sp. (sea grape) have been seen at the monitoring sites, too.  On the other hand, the native stolidobranch solitary species, Boltenia ovifera (sea potato, stalked tunicate) and Halocynthia pyriformis (sea peach) are subtidal in Massachusetts Bays, prefering colder water, and are not usually encoutered in these shoreline studies.
In future posts, I'll take a closer look at some of these species in more detail, and in the process, hopefully we'll learn more about the fauna and flora of our coastline. Additional histologic and stereoscopic images will also be appearing at and

(Photocredits:  Photographs and micrographs by Tom Ermak unless specified here or in the caption. 
Photograph of Tom surveying docks by Carl Johnson)