Algae

Chlorophyta (Green Algae)

Codium fragile subspecies tomentosoides
Common Name:  Green Fleece Alga
This alga is green, spongy and finger-like with branches that can grow up to 36 inches in length (91 cm).  Originally introduced from Asia, it has invaded North America from the Gulf of St. Lawrence (New Brunswick side of Chaleur Bay) to North Carolina, establishing populations in bays and subtidal zones. It attaches itself to hard surfaces, rocks, shellfish, and snails such as crepidula which allows it to grow in sandy areas. 
Codium also is a substrate for other invaders such as compound ascidians (Botrylloides violaceus and Botryllus schlosseri) and bryozoans (Membranipara membranacea).

Codium fragile

Codium fragile ssp. tomentosoides
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Photo Source: MIT Sea Grant College Program

Heterokontophyta phaeophycae (Brown Algae)

Melanosiphon intestinalis, formerly Myelophyais intestinalis  

Common Name:   Brown Alga
This brown alga appears to have originated in the North Pacific.  It is easily overlooked and confused with other species.  To view a photo visit:    www.botany.ubc.ca/Biol320/algae/species/b15.html. 

Rhodophyta (Red Algae)

Bonnemaisonia hamifera
Common Name:  Red Alga
This bright pink or red alga, originating from Asia, has small, hook-like appendages on its branches.  It attaches to rocks and shells, is most prominent seasonally, and appears to be restricted by cold climates.  It alternates its form with a tetra sporophyte generation “
Trailliella intricata.”

Bonnemaisonia hamifera

Bonnemaisonia hamifera
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Image used with permission of:
National University of Ireland, Galway, Seaweed Site.

Grateloupia turuturu (formerly Grateloupia daryphora)
Common Name:  Red Alga
This red algae can grow four to five feet in length.  It has been introduced from Asia to the North Atlantic (mainly Rhode Island) and has been found in southern U.K.  In 2007 it was found on either side of the Cape Cod Canal (Bourne and Sandwich, Massachusetts) and in Boston Harbor, Massachusetts.  This species can block sunlight to other organisms, thereby competing with other alga species, and reproduces easily.  Fouling on ships and recreational boats is one possible mechanism that aids its spread.  Warming sea temperatures may also facilitate a northward movement.

Grateloupia turuturu

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Photo Source:  R. Gladych, University of New Hampshire

Lomentaria clavellosa
Common Name:  Red Alga
This alga, which originated from Europe, can grow up to 15.75 inches long (40 cm) and has a hollow main stalk, which is soft and gelatinous.  It is bright to dark red in color and is found in shallow waters, and occasionally on mussels or other seaweeds.  To view photos visit:  http://seaweeds.uib.no/?art=787.

Lomentaria orcadensis
Common Name:  Red Alga
This red alga originated from Europe.  This species grows to approximately 3 cm (2 inches), has a flat thallus, and is found subtidally.  To view a photo visit:  www.habitas.org.uk/marinelife/species.asp?item=ZM7530.   

Neosiphonia harveyi (formerly Polysephoria harveyi)
Common Name:   Filamentous Red Alga
Neosiphonia is a bushy red alga growing up to 16 inches in length (40.5 cm) and most likely originated in Japan.  Its current range is from Newfoundland to South Carolina.  This species is a weedy, fouling species associated with boating and aquaculture and is present in the majority of marinas in New England.  Although it is one of the most prolific filamentous red alga, it is difficult to identify in the field and often is mistaken for native filamentous alga.


Porifera (Sponges)

Halichondria bowerbankia sp.
Common Name:  Bread-Crumb Sponge
This sponge usually forms colonies south of Cape Cod, Massachusetts.  It exhibits s a wide variety of colors and may be brown, yellow, olive green, or bronze.  Older colonies have finger-like projections that are ~8 mm long.  Colonies will form on rocks, algae, and pilings in the intertidal and subtidal zones.  To view a photo visit:   www.habitas.org.uk/marinelife/species.asp?item=C4810.

Halichondria bowerbankia

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Photo Source:   Used with permission of P. Drynda

 


Cnidaria (Hydroids (Anemone-like Animals), Anemones, and Jellyfish)

Hydrozoa

Cordylophora caspia
Common Name:  Colonial Hydrozoan

This light brown hydrozoan colony can grow up to 10 cm and lives in fresh to brackish (0-20 psu salinity) waters.  Global distribution has expanded, presumably due to increased boat travel and ballast water exchange.  Cordylophora alters community structure, and negatively affects populations of ciliates and bryozoans, while attracting barnacles, amphipods, and polycheates.  By clogging pipes and filters, Cordylophora has also become a problem for power plants and irrigation systems.   To view a photo visit:  www.marbef.org/modules.php?name=Photogallery&album=6c&pic=8961.  

Garveia franciscana
Common Name:  Hydrozoan
First identified in 1902,
Garveia franciscana has only recently been found in New England.  Its ecological impacts include competition, habitat change, and predation.  This fouling amphipod may cause economic damage through water-pump failures, increases in cleaning frequency at inlets, and decreasing efficiency of deoxygenating towers.  To view a photo visit:  www.solpugid.com/cabiota/garveia_franciscana.htm. 

Anthozoa

Diadumene lineata
Common Name:  Orange Striped Green Anemone
The striped anemone has 50-60 tentacles, displays orange or white stripes against a greenish body, and can grow up to 1.5 inches (<4 cm).  It was introduced from the Pacific Ocean, and has established itself from Maine to Florida.  It lives attached to hard surfaces in protected areas of the subtidal zone.

Diadumene lineata
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Photo Source:  R. Buchsbaum

Sagartia elegans
Common Name:  Purple Anemone
With up to 200 purple or pinkish tentacles, the Purple Anemone can grow up to 8 inches in diameter (roughly 20 cm).  It lives in the protected areas of the subtidal zone up to 30 ft (9 m) deep.  It was introduced from Europe.  This anemone is difficult to find during the winter, but re-grows in warmer weather at the single location in Massachusetts where it was first observed.

Sagartia elegans

Sagartia elegans
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Photo source: J. Pederson, MIT Sea Grant College Program


Polychaeta (Segmented Worms)

Information and descriptions from Marine Polychaete Worms of the New England Region by Marian H. Pettibone, 1963 and A Practical Guide to the Marine Animals of Northeastern North America by Leland Pollack (1997).

Janua pagenstecheri (formerly known as Spirobus pagenstecheri)
Common Name:  Polychaete
This is a relatively small polychaete (worm) that lives in a spiral calcareous tube.  Because it is a very small, obscure species, it is difficult to identify in the field.  In New England it is often found on eelgrass blades and other hard surfaces.  Because it is not a well-studied species, there is relatively little information on its ecology and impacts.  To view a photo visit:  www.marlin.ac.uk/species/januapagenstecheri.htm.


Mollusca

Nudibranchia (Sea slugs)

Thecacera pennigera
Common Name:  Sea Slug
This species was originally found in the Atlantic coast of Europe, and it is now seen in Africa, the Middle East, Japan, Brazil and Australia.  Its size ranges from is usually 15 mm to 30 mm in length with a spotted, brown and orange appearance.  This mollusk has been spotted in warmer weather and is reintroduced each year from the Caribbean.  It prefers to feed on the
Bugula sp., a bryozoan.

Thececera pennigera

Thececera pennigera
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Photo source: D. Woods, A. Shepard, and C. Ranney

Gastropoda (Snails)

Littorina littorea
Common Name:  Common Periwinkle Snail
This snail was introduced from Europe in the 1840s and spread from Pictou, Nova Scotia to Boston, Massachusetts by the 1850s with its range now extending to Virginia.  It is the most prolific snail in the intertidal and is easily identified by its dark shell and transverse black strikes on its tentacles.  Two other common littorinid species are
L. saxatilis which is found high in the intertidal, near the splash zone, and L. obtusata which is yellowish and greenish in color and does not have a pointed whorl.  Recent molecular studies have confirmed L. littorea’s European origins.

Littorina littorea

Littorina littorea
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Photo source: J. Pederson, MIT Sea Grant College Program

Bivalvia (Clams, Oysters and Mussels)

Ostrea edulis
Common Name:  European Oyster
This oyster has a shell that is wider and rounder than its Virginian counterpart and can grow up to 8 inches (20 cm).  It has a grayish white shell that is slightly scalloped with a white muscle scar (the native oyster usually has a distinct purple muscle scar).  This species was introduced from Europe for aquaculture throughout New England and has been observed from Maine to Rhode Island in estuarine habitats, in the intertidal and subtidal zones.

Ostrea edulis

Ostrea edulis
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Image used with permission of Kelly Galway Oysters.


Arthropoda

Mysidacea (Mysid shrimp)

Praunus flexuosus
Common Name:  Mysid Shrimp
This small shrimp grows to about 0.75 inches (20 mm) and lives in the lower shore in pools and in shallow water, especially over sandy substrates.  It is often found “hanging” vertically in the water around pilings and docks.

Praunus flexuosus

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Photo source:  J. Pederson, MIT Sea Grant College Program

Isopoda (Isopods - relatives of sow bugs)

Ianiropsis sp.
Common Name:  Isopod
This species is a new introduction, although it may have been in Massachusetts and Rhode Island for several years.  It is not easy to identify from available keys and we know very little about its habitat preferences, life history, and interaction with native species.  Isopods are relatives of the terrestrial sow bug.

Synidotea laevidorsalis
Common Name:  Isopod
This isopod has been moving northward from South Carolina to New York where it was introduced through aquaculture.  It feeds on living and dead materials and is often found in shallow, brackish waters.  It is very similar to native isopods.  With warming temperatures, it may continue to spread northward.

Synidotea laevidorsalis

Click image for full size.

Photo Source:  Leslie Harris

Amphipoda (Amphipods - relatives of sand fleas)

Caprella mutica
Common Name:  Skeleton Shrimp
The Skeleton Shrimp is a large amphipod native to East Asia and Siberia.  It was introduced in North America probably by either ballast water or shipments of Japanese oysters.  During the summer months it can be very abundant and preys on small plankton.  To view a photo visit:  http://www.marlin.ac.uk/species/caprellamutica.htm.

Microdeutopus gryllotalpa
Common Name:  Amphipod
This amphipod is found in lagoons, salt marshes, among algae, shells, polzoans, tunicates and in areas with high detritus accumulation.  There is very little information available on this amphipod or its ecological impact.

Cirripedia (Barnacles)

Chthamalus fragilis
Common Name:  Barnacle
Gray, beige or brown in color it can grow up to 1 cm in diameter.  It is common south of Cape Cod, Massachusetts where it lives on rocks and other hard surfaces at high-tide levels.  It is often confused with the native barnacle, S
emibalanus balanoides, which lives lower in the intertidal.

Decapoda (Crabs and lobsters)

Carcinus maenas
Common Name:  European Green Crab
This crab can have a somewhat variable colored carapace (shell), but is usually green, reddish orange, or tan, with darker mottling.  It has 5 marginal teeth and can grow up to 3.6 inches (7.6 cm).  It was introduced from Europe to North America in the 1800s and has been spotted from Gulf of St. Lawrence to Delaware along hard and soft surfaces, in both intertidal and subtidal zones.  It is a major predator of clams, mussels and other animals, causing economic and ecological damage.

Carcinus maenas

Carcinus maenas
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Photo source: P. Erickson for MIT Sea Grant College Program

Hemigrapsus sanguineus
Common Name:  Asian Shore Crab
The Asian Shore Crab can be readily distinguished by its banded legs, red spots its claws, and general square shape.  It is much smaller than the European Green Crab, and only grows up to 1 inch in carapace width (2.5 cm).  Originally introduced from Asia, it arrived in the Cape May, New Jersey area around 1988 and now ranges from Maine to North Carolina.  This crab prefers rocky cobble floors in the intertidal and subtidal zones.  A related species with hairy tufts is present in Europe and may hitch a ride and be the next crab invader.

Hemigrapsus sanguineus

Hemigrapsus sanguineus
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Photo source: P. Erickson for MIT Sea Grant College Program

Insecta (Insects)

Anisolabis maritima
Common Name:  Maritime Earwig
The earwig is brownish to black and up to 20mm in size.  It is common on the shore under rocks.  It is distinguished by its 24 segments, antennae, and lack of wings.  To view a photo visit:  www.ento.csiro.au/aicn/system/c_1082.htm.

Anisolabis maritima
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Image used with permission of: Katsuyuki. Kohno


Bryozoa (Ectoprocta)

Alcyonidium sp.
Common Name:  Bryozoan
An encrusting bryozoan that forms colonies.  The organism was first observed on aquaculture cages in New Hampshire and ranges from Maine to New York City.  It has not been identified to species yet but is distinct from other native Alcyonidium species found in New England.

Alcyonidium sp.

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Photo Source:  B. Toppin

Barentsia benedeni
Common Name:  Entoproct
This small entoproct with creeping growth composed of 5-10 stalks is difficult to see with a magnifying glass or stereoscope.  It is tolerant of pollution and usually grows on piers and harbor pilings in sheltered bays and estuaries.

Bugula neritina
Common Name:  Bryozoan
This bryozoan has flexible, bushy colonies, purplish to purplish brown in color, and can grow up to 4 inches (10 cm).  It is often mistaken for a red alga.  Found in harbors and estuaries, it attaches itself to hard substrata.  Much biochemical research has been conducted on this species as a source of bryostatin, a compound shown to be effective against leukemia.

Bugula neritina

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Photo Source:  P. Erickson, MIT Sea Grant College Program

Membranipora membranacea
Common Name:  Lacy Crust Bryozoan
This white, lacy bryozoan is often found growing on kelp and other types of algae.  It has been found to have negative impacts on many Gulf of Maine ecosystems and has been associated with the devastation of kelp forests.  It first appeared on the Isle of Shoals, in New Hampshire and Maine.

Membranipora membranacea

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Photo Source:  J. Pederson, MIT Sea Grant College Program

 

 


Tunicata: Ascidiacea (Tunicates)

Ascidiella aspersa
Common Name:  Tunicate
This tunicate, introduced from Europe, grows to about 3-4 inches (8-10 cm).  It attaches by one of its sides to docks, rocks and other substrata.   It is grayish to whitish, with pink tinges and has a rigid, bumpy surface.  This tunicate spread through Massachusetts to Connecticut and is considered a nuisance fouling organism.

Ascidiella aspersa

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Photo Source:  J. Pederson, MIT Sea Grant College Program

Botrylloides violaceus (formerly thought to be B. diagensis)
Common Name:  Orange or Red Tunicate
These colonies are composed of zooids (individual animals) arranged in loose circles, rows, or dense clusters. Coloration may vary between bright orange to reddish or dull purple.  Since being introduced from the Pacific, Botrylloides has been found from Maine to Virginia along protected areas within the shallow subtidal zone.  It is a major fouling organism and a nuisance for marinas, boats, aquaculture and cages.

Botrylloides violaceus

Botrylloides violaceus
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Photo Source: P. Erickson for MIT Sea Grant College Program

Botryllus schlosseri
Common Name:  Golden Star Tunicate
These small zooids are less than a tenth of an inch in length and have white or yellow markings.  They are colonial and form a star-like appearance which as a colony can be up to 3-4 inches long (7.5 - 10 cm).  They were introduced from Europe in 1840 and have expanded from Newfoundland to the Chesapeake Bay. 
Botryllus can be found attached to docks or other hard substrates in protected areas of the subtidal, out to 60 feet deep.  This species is a major fouling organism.

Botryllus schlosseri

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Photo Source:  J. Pederson, MIT Sea Grant College Program

Didemnum vexillum (also called Didemnum sp. A)
Common Name:  Tunicate
This tunicate has cream to white coloration with microscopic individual zooids. The large colonies are gritty and have hanging lobes attached. Overall, colonies may reach 12-18 inches long (30-46 cm).  This species may have been introduced from the Pacific Ocean or Europe and now ranges from Maine to Connecticut.  Most recently it has been found offshore, on Georges Bank where it may threaten ground fish and scallop fishery.  Didemnum alone or with other colonial tunicates may be the dominant fouling organisms in harbors and marinas.  This tunicate attaches to or hangs off rocks, docks and pilings and can be found in protected subtidal areas.

Didemnum vexillum
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Photo source:  J. Pederson, MIT Sea Grant College Program

Diplosoma listerianum
Common Name:  Tunicate
A smooth, encrusting colony with a grayish tinge often has small white spots and can grow up to 8 inches (20 cm). 
Diplosoma listerianum is a native of Northern Europe.  Thus far, it has invaded from New Hampshire to Connecticut, remaining near shore, in protected areas, attached to docks, other organisms and hard surfaces.  This species can be very abundant.

Diplosoma listerianum

Diplosoma listerianum
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Photo source: R. Whitlatch, University of Connecticut

Styela canopus (formerly Styela partita)
Common Name: Rough Sea Tunicate
This tunicate or sea squirt arrived from the Pacific around 1852.  It has a rough, leathery, reddish tunic, is about 1 inch long, and is found in southern New England, generally south of Cape Cod, Massachusetts.  It probably arrived by ship fouling. 

Photo source:  R.M. Rocha

Styela clava
Common Name:  Club tunicate
This stalked tunicate was introduced from Japan, can grow to about 6 inches long, and has been observed from Maine to New Jersey. It is found in shallow subtidal waters attached to docks within protected areas.  It recently invaded Prince Edward Island and fouls mussel aquaculture ropes.

Styela clava
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Photo source: J. Erickson, MIT Sea Grant College Program


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Note: The descriptions provided on this page are the most accurate available to us.  We would appreciate any new or updated information, or corrections that you may have.  We welcome your comments and suggestions as we continue to develop this site.