It's a new summer season in New England and the CZM launched its Marine Invasive Species Program for 2012. This summer, I'll be working with the Provincetown Center for Coastal Studies monitoring marinas in Provincetown and Wellfleet. There are no new species classified as invasvie this year. The collection of MIMIC ID Cards gives detailed descriptions of the 16 marine invasive species and the 7 potentially new species that have not yet reached the New England coast. Guidelines are listed for distinguishing MIS species from related native species.
MIMIC ID Cards for MIS Species (16 ID cards)
MIMIC ID Cards for MIS Species (16 ID cards)
MIMIC ID Cards for Potential Invasives whose geographic ranges are spreading (7 ID cards)
Recently, I was searching the internet for information on invasive species and I came across several Wikipedia listings that described some of the issues around terminology for invasive species. They contrasted the terms "invasive, introduced, immigrant, naturalized, exotic, alien, foreign, non-native, and non-indigenous". For example, "invasive" and "alien" have unintended negative connotations that may not apply to all species, and "exotic" is also used for rare or unusual pets. Many native and formerly invasive species are also "fouling" organisms that have spread beyond their native habitat (usually because of human activities). Many invasives are simply in the process of geographic range enlargement or globalization because of new opportunities created by humans. Marinas help facilitate the spread of MIS, especially for species that prefer quiet waters, because they are so numerous along the coasts of many countries. At some point in time, the invasive species will most likely reach an equilibrium and at some point may be considered established.
Here is this year's list of species featuring images from recent web searches, a few of my own micrographs, and my impressions of the species from last season's monitoring:
Ascidians:
- Didemnum vexillum (beige colonial tunicate). This species aggressively grows over everything - any flat surface including docks, solitary ascidians, mussels, algae blades. Have I forgotten anything? If so, include it too.
- Diplosoma listerianum (grey/green colonial tunicate) - Diplosoma is also a rapid grower and shows seasonal and regional variability with Didemnum. It is also a member of the Didemnidae family but lacks spicules. It is distinguished by its smooth, slimy texture - like the body of an anemone, but it grows in a flat sheet.
- Ascidiella aspersa (translucent solitary tunicate) - The translucent, bumpy solitary ascidian. Distinct from Ciona, another related species, and distinguished by its placement of siphons, which are far apart. Ascidiella and Ciona can easily to distinguished from Molgula by the internal organs which can be seen through the tunic in young specimens.
- Styela clava (club solitary tunicate) - Very common but can be missed when small and large individuals are frequently covered by Didemnum with only the brown Styela siphons sticking out.
- Botryllus schlosseri (star colonial tunicate) - Probably the most commonly studied adult ascidian as a model for colonial growth and tissue rejection. Numerous color and pattern variants.
- Botrylloides violaceus (orange colonial tunicate) - One of the most beautiful invaders/foulers. Comes in many different shades of red/orange/peach. Not as aggressive as the Didemnid colonials.
Bryozoa:
- Membranipora membranacea (lacy encrusting bryozoan, posted Feb 12, 2012) - common on any flat, sturdy surface. Co-exists with the native encrusting bryozoan. Helpful to have a 30X magnifier.
- Bugula neritina (purple bushy bryozoan) - Similar to red algae in growth form but calcareous and distinctly different in structure. Individual zooids may be discerned with a 30x magnifier.
Anemones:
- Diadumene lineata (orange striped anemone, posted Dec 22, 2011) - seen in the "murky" waters of Wellfleet but not in the "sparkling" waters of Provincetown. They're tiny gems.
Bivalves:
- Ostrae edulis (European oyster) - Not likely to be seen on docks.
Crustacea:
- Carcinus maenus (green crab) - Vary in size on docks - usually smaller than the size of a quarter. It is distinguished from the Asian crab by its color, shape of the carapace, and solid coloring on its legs.
- Hemigrapsus sanguineus (asian shore crab) - Easily identified by its striped legs and body.
- Palaemon elegans (European rock shrimp) - Present in Salem Sound. Difficult to distinguish from native shrimp, especially when small before the blue bands on its legs and body fully develop. Best to confer with the crustacean or MIMIC experts.
- Caprella mutica (Caprellid amphipod a.k.a. skeleton shrimp) - Very common living on algae and bryozoa. These small amphipods look and act like miniature preying mantis. They hold tight to surfaces and do not "swim around" like typical amphipods and shrimp. Not very compatible with fine nets where they need to be hand-picked off.
Algae:
- Codium fragile (green fleece) - Common in mid-late summer along dock water lines where they grow in masses. Characterized by branching growth pattern (right).
- Grateloupia turuturu (leafy red algae) - Arrives late season in the Gulf of Maine due to cold temperatures.
Links:
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.
Non-Native Species Invasions, Marine Biodiversity Wiki
Invasion Biology Terminology, Wikipedia
Invasive Species, Wikipedia
Introduced Species, Wikipedia
