Gretchen and Charles Lambert

12001 11th Ave. NW, Seattle, WA 98177

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Number 65                                                                                                     December 2009


   We greatly appreciate the many contributions for this issue: Work in Progress articles, meetings abstracts, two Ph.D. thesis abstracts (significantly, both are on invasive species), and the citations for 116 new publications. In fact, this is probably the longest newsletter we have ever put out.

   We taught another intensive two week ascidian workshop with Rosana da Rocha in June at the Smithsonian Tropical Research Institute, Bocas del Toro, Panama. We had a full class of 16 hard-working and dedicated participants, from many countries.  Rosana was just finishing a full year’s sabbatical at Bocas, preparing a large monograph of the ascidians of the area that will include a number of new species. We spent several weeks at the Univ. of Washington Friday Harbor Labs during July and August, followed by the 6th Intl. Conference on Marine Bioinvasions Aug. 24-27 in Portland, Oregon. There were an amazing number of talks on invasive ascidians; see the Meetings Abstracts section of this newsletter. In addition to these, ascidians were mentioned in a number of other talks and posters.

   In October we led a 5 day ascidian workshop in Quebec, at the Institut Maurice Lamontagne in Mont Joli and enjoyed a week of sightseeing in this beautiful and historic province. The next workshop will be a short half day one in April 2010 at the next Invasive Sea Squirt Conference (see below), then a 5 day workshop in Singapore in May. 


*Ascidian News is not part of the scientific literature and should not be cited as such.




1. From Mary Carman, Woods Hole Oceanog. Institution, Woods Hole, MA     The next Intl. Invasive Sea Squirt Conference, IISSC-3, will be held at WHOI, April 27-29, 2010. See the website for further information and registration:  Oral and poster presentations will be considered for Taxonomy and Genetics, Biogeography, Ecology, Risk Assessment and Management. On the 27th there will be a morning field trip to various sites in Woods Hole, followed by an afternoon taxonomic workshop presented by Gretchen and Charley Lambert. This workshop will be quite different from the last one at the PEI IISSC-2 meeting, with a number of different species to examine. The journal Aquatic Invasions has agreed to publish the special issue of the IISSC-3 conference papers; the proceedings of IISSC-2 appeared in vol. 4 (1), January 2009 issue of AI.


2. Taken from the following website:

“An experiment in the kitchen is a blessing in disguise.”

 Meonggae bibimbap (Mixed rice with sea squirt) Provided by Korea Tourism Organization


“If Peking duck is the signature food of Beijing, China, and kebabs stand out as the cuisine of Bursa, Turkey, then the dish Geoje Island in South Gyeongsang is best known for is its meonggae bibimbap, or sea squirt mixed with rice. Meonggae bibimbap is a variation on traditional Korean bibimbap, which is usually rice mixed with vegetables and meat and seasoned with hot pepper paste. The dish originated at the Baek Man Seong Restaurant on Geoje Island. One afternoon in the 1990s, a tourist from Japan visited a small restaurant near the city hall on the island. He ordered a bowl of rice topped with sea cucumber intestines. Unfortunately, or perhaps fortunately for us, the kitchen was short on sea cucumbers that day. In a sudden act of consternation, the chef replaced the main ingredient with salted sea squirt, or jeotgal, and brought it out to the table, feeling perplexed and apologetic. To the surprise of the anxious chef, the tourist gave it a thumbs up and exclaimed it was better than his original order. The success of the dish is a boon for experimentation. Meonggae bibimbap is now a popular dish and the restaurants that serve it are now a common sight in tourist areas. Meonggae has been enjoyed by Geoje Island dwellers for a long time, especially in its salted form as meonggae jeotgal. If eaten raw, the dish has a piquant sweetness. To make it, the meonggae is cut into pieces, mixed with condiments and marinated for some time at a low temperature. Sea squirts are abundant from April to June on the southern coast, especially off of the Geoje shore. During that time, the people of Geoje make enough jeotgal so that it can be eaten year round. Meonggae bibimbap is easy to make and can be served in minutes. The steamed rice topped with dried seaweed and sesame oil mingled with the half-frozen meonggae jeotgal is a refreshing summer dish from the sea.”  By Yim Seung-hye contributing writer.


Tunicate delicacy:  Here’s an actual video of someone eating (though not necessarily enjoying) raw sea squirt: Halocynthia roretzi, at a seafood market in Korea. Check it out! If you just can’t wait for that segment in this 9 minute video, you can move the round dot forward to 3:45 minutes.

Thanks to Mary Carman and her son Zac for that submission!


Editor’s note: Please send me ascidian recipes for my “sea squirt cookbook” which I am (very) slowly compiling and will share with AN readers eventually.


3. From Teruaki Nishikawa: In September I moved from Nagoya University to Toho University in

Chiba Prefecture, near Tokyo, a private small  university having faculties of Medicine, Pharmacology and Science. My department (Dept. of Biology) has 15 teaching staffs (including 7 professors) with 100 students per year. I do hope to have far more time to spare for ascidian taxonomy and for making ascidian (or some marine invertebrate) taxonomists.

Professor Teruaki Nishikawa, D. Sc., Laboratory of Taxonomy, Dept. of Biol., Faculty of Sci., Toho Univ., 2-2-1 Miyama, Funahashi, Chiba 274-8510, Japan.


4. From Rosana da Rocha : The journal Aquatic Invasions is trying to get supporters to enter the Thompson database and get impact factor. Go to their website and scroll to the bottom, click on the link. It takes just 2 minutes to fill and submit (you will need the journal information - thus maintain both windows open).

  Editor’s note: A number of us involved in research on invasive species use and publish in this journal now and would like to see it included in the Thompson database.




1. From Lauren Stefaniak:  We recently discovered Clavelina lepadiformis (Müller, 1776) in two harbors on the southern New England shoreline (New London, CT and Stonington , CT).  A post hoc investigation led us to photographs taken by local divers dating the presence of C. lepadiformis in New London back to at least December 2008. This is the first time this species has been reported in the northwest Atlantic.  A manuscript is in preparation.

James Reinhardt, Lauren Stefaniak, David Hudson, Becky Gladych, Robert Whitlatch.

Department of Marine Sciences, University of Connecticut, Avery Point, Groton, CT 06340


2. From Mary Carman, Woods Hole Oceanographic Institution, Woods Hole, MA.   

    We have recently observed the invasive species Didemnum vexillum, Botrylloides violaceus and Ascidiella aspersa utilizing seagrass as substrate in a few protected marine ponds in southern New England.  In addition, Ben Becker with Point Reyes National Seashore found D. vexillum on eelgrass in Tomales Bay, California last fall.  We think that this occurrence of invasive species of tunicates in eelgrass habitat is representative of what may be happening elsewhere.  Before 2008, D. vexillum had not been previously recorded as inhabiting eelgrass habitat; it has been documented as using fucoids and macro-algae as substrate.  Botrylloides violaceus, Molgula manhattensis and Ciona intestinalis have been documented as using eelgrass as substrate.  However, I have not found a reference that specifically cites A. aspersa as utilizing eelgrass as substrate.  The spread of invasive tunicates into habitat not commonly used is perhaps an indication of their ability to adapt and continuing ability to increase in abundance locally.  I am seeking information on this topic and would appreciate hearing from tunicate workers about similar observations. 


3. Perforation with and without vinegar injection as a mitigation strategy against two invasive tunicates, Ciona intestinalis and Styela clava.  Parent, Marianne, Paetzold, S.C., Davidson, J., Pedro, Q. Atlantic Veterinary College, Univ. of Prince Edward Island, Canada.

    This study addresses invasive tunicate mitigation by assessing the applicability of two related approaches: tunicate perforation and vinegar injection. Healthy adult Ciona intestinalis and Styela clava were perforated using nails (small, medium, large and carpet nails) or hypodermic needles (20G, 25G and 28G). Tunicates were either treated with individual perforations (0-100), or simultaneous perforations using low, medium and high density perforation devices (0.5 needles/cm2, 1.1 needles/cm2 and 2.4 needles/cm2, respectively).  Some of the perforation treatments were combined with simultaneous vinegar injections (0.05, 0.20, 0.50, 1.00, 2.00, 3.00 and 4.00 mL injection volume). Underwater perforation treatments were also considered. Treated tunicates were observed for one week and assessed for morbidity (sickness) and mortality (death). Moreover, the high density perforation device was tested under field conditions for the treatment of mussels socks fouled with C. intestinalis in the Georgetown River, PEI. In the laboratory, mortality of C. intestinalis was observed at 100 % efficacy for 60 individual perforations, or with an injected volume of vinegar of 0.05 mL. Similarly, 100 % mortality of S. clava was achieved through 100 individual perforations.  Two applications of the high density perforation devices resulted in 80 % mortality of C. intestinalis. Preliminary field results indicated no difference in C. intestinalis biomass between sock sections treated once with the high density perforation device or with the device dipped in vinegar after one week.  However, C. intestinalis covering the socks were smaller than in lab trials and the perforation device may not have been able to reach many of the tunicates.


4. Mrs. D Shanmuga priya, Lecturer,  Dept. of Chemistry, A.P.C.Mahalaxmi College For Women,  Tuticorin, India is doing her Ph.D.,  under the guidance and supervision of Dr. S Gopalakrishnan, Prof. And Head, Dept of Pharmaceutical Chemistry, Manonmaniam Sundaranar University and Dr. V.K.Meenakshi, Associate Prof., Dept of Advanced Zoology and Biotechnology, A.P.C. Mahalaxmi College  For Women, Tuticorin.

    The thesis plan includes Five chapters.  In the first chapter a survey of the Tuticorin harbour area was  carried out for a period of one year (August 08 – August 09). This revealed the occurrence of the following 24 species of ascidians – Aplidium indicum, Aplidium multiplicatum, Polyclinum madrasensis, Polyclinum nudum, Distaplia nathensis, Didemnum viride, Didemnum perlucidum, Trididemnum cerebriforme, Trididemnum clinides, Trididemnum sp., Diplosoma similis, Lissoclinum fragile, Lissoclinum abdominale, Ecteinascidia diaphanis, Phallusia arabica, Phallusia nigra, Ascidia sydneiensis, Rhodosoma turcicum, Styela canopus, Eusynstyela tincta, Symplegma oceania, Botrylloides magnicoecum, Microcosmus exasperatus and Microcosmus helleri.  Among these, Phallusia arabica, Phallusia nigra, Ascidia sydneiensis, Styela canopus and Microcosmus exasperatus were the simple ascidians most common and found throughout the year.  In the second chapter a few chosen ascidians were collected and exhaustively extracted using solvents like petroleum ether [40 to 60˚C], benzene, chloroform,  methanol, methylene chloride and water.  The crude extracts were concentrated using rotary evaporator and screened for steroids,  triterpenoids, reducing sugars, phenolic compounds, alkaloids, flavanoids, catechins, saponins, xanthoproteins, tannins, aminoacids, anthroquinones and aromatic acids.  The third chapter deals with screening of antimicrobial activity of the extracts to five human gastro intestinal pathogens – Salmonella typhi, Vibrio cholerae, Bacillus subtilis, Shigella flexneri and Enterococcus faecalis obtained from MTCC, Lucknow.  Pharmacological studies like determination of LD 50, CNS activity, local anaesthetic activity, histopathological studies, electrical activity of heart, antipyretic, anti-inflammatory and analgesic activity will be carried out with  the crude extracts in  the fourth chapter.  Isolation , purification, characterisation and structure determination of the compounds with biomedical properties using column chromatography, HPLC and spectral studies forms the fifth chapter.  The thesis is proposed to be submitted by August, 2011. 




1. 14th Intl. Conference on Biological Inorganic Chemistry, July 25-30, Nagoya, Japan.

a. A novel vanadium reductase, vanabin2, forms a possible cascade involved in electron transfer.  1 Norifumi Kawakami, 1 Tatsuya Ueki, 2 Yusuke Amata, 2 Kan Kanamori, 3 Koichi Matsuo, 3 Kunihiko Gekko, and 1Hitoshi Michibata*.  1Dept. Biol. Sci. and 3Dept. Math. Life Sci., Grad. Sch. Sci., Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, and 2Dept. Chem., Grad. Sch. Sci. Eng., University of Toyama, Gofuku 3190, Toyama 930-8555, Japan.

    The unusual ascidian ability to accumulate high levels of vanadium ions at concentrations of up to 350 mM, a 107-fold increase over that found in seawater, has been attracting interdisciplinary attention for a century. Accumulated V(V) is finally reduced to V(III) via V(IV) in ascidian vanadocytes. Reducing agents must therefore participate in the reduction. Previously, we identified a vanadium-binding protein, Vanabin2, in which all 18 cysteines form nine disulfide bonds. Here, we report that Vanabin2 is a novel vanadium reductase because partial cleavage of its disulfide bonds results in the reduction of V(V) to V(IV). We propose that Vanabin2 forms a possible electron transfer cascade from the electron donor, NADPH, via glutathione reductase, glutathione, and Vanabin2 to the acceptor, and vanadium ions conjugated through thiol-disulfide exchange reactions.

b. A novel vanadium transporter of the Nramp/DCT family from a vanadium-rich ascidian Ascidia sydneiensis samea.  Tatsuya Ueki1,*, Nobuaki Furuno2, Hitoshi Michibata1. 1Dept. Biol. Sci., and 2Amphi. Inst., Grad. Sch. Sci., Hiroshima University, Hiroshima 739-8526, Japan.

    Vanadium is one of essential transition metals in biological systems. Several key proteins such as vanadium-binding proteins (Vanabins) related to vanadium accumulation have been isolated, but transporter for vanadium ions has not been identified. Here we report the identification and cloning of a Nramp/DCT family of membrane metal transporter (AsNramp) from an ascidian Ascidia sydneiensis samea, which can accumulate extremely high levels of vanadium in the vacuoles of signet ring cells, which are one type of blood cell called vanadocytes. By using Xenopus oocyte expression system, we revealed that AsNramp transported VO2+ into oocyte at pH>6, while no significant activity was observed at pH<6. Sodium ions inhibited the AsNramp-dependent transport of VO2+. Western blot analysis showed that AsNramp was localized on the vacuolar membrane of vanadocytes. These results indicated that AsNramp is a novel VO2+/H+ antiporter. We propose that AsNramp mediates vanadium accumulation coupled with the electrochemical gradient generated by vacuolar H(+)-ATPase.


2. 44th European Marine Biology Symposium (Liverpool, UK) September 2009.

 Genetic differentiation at small geographical scales: Population genetics and phylogeography of the colonial ascidian Pycnoclavella communis.  R. Pérez-Portela1  & X. Turon2.  1Eco-Ethology Research Unit, Instituto Superior de Psicologia Aplicada (ISPA), Rua Jardim do Tabaco, 34, 1149-041 Lisboa, Portugal. .  2Centre d’Estudis Avançats de Blanes (CEAB, CSIC), Accés a la Cala St. Francesc 14, Blanes, Girona E-17300, Spain. 

   Recent studies revealed an unexpected species richness of the genus Pycnoclavella in the Atlanto-Mediterranean region. One of those species, Pycnoclavella communis, showed high variability including several colour morphotypes. In order to explore geographical patterns and evolutionary events that can explain the distribution of genetic diversity of P. communis we performed a study of population genetics and phylogeography. Variation in the mitochondrial gene cytochrome c oxidase subunit I (COI) was studied for 135 individuals from eight Mediterranean populations of the species. Three haplotypes from Atlantic locations were also included in the study. The study revealed 32 haplotypes, 29 of them grouped within two Mediterranean lineages of P. communis (divergence between lineages 8.55%). Phylogenetic and network analyses suggest the possible existence of cryptic species corresponding to these two lineages. Further population genetic analyses were restricted to the five populations belonging to the main genetic lineage, and for these localities we compared the information gleaned from COI sequence data and from eight microsatellite loci. A high genetic divergence between populations was substantiated using both kinds of markers. There were high numbers of private haplotypes (COI) and alleles (microsatellites) in the populations studied. Microsatellite loci showed a strong incidence of failed amplifications, which we attribute to the marked intraspecies variability that hampered the application of these highly specific markers. Our results show important genetic variability at all levels studied, from within populations to between basins, possibly coupled to speciation processes. This variability is attributable to restricted gene flow among populations due to short-distance dispersal of the larvae.


3. 6th Intl. Conference on Marine Bioinvasions. Portland, Oregon USA, 24-27 August 2009.

a. Establishment and dispersal of invasive ascidians on urban structures.  Marc Rius a,b, Shimrit Perkol-Finkel c, Xavier Turon d and Laura Airoldi c.

a Departament de Biologia Animal, Universitat de Barcelona, Av. Diagonal 645, 08028, Barcelona, Spain; b Present address: Centre of Excellence for Invasion Biology, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa; c Scienze Ambientali, Universita di Bologna, Via S. Alberto, 163, I-48100 Ravenna, Italy; d Centre for Advanced Studies of Blanes (CEAB, CSIC), Accés a la Cala S. Francesc 14, 17300 Blanes (Girona), Spain.

    One of the largest human induced alterations along coastal areas is the establishment of urban structures such as coastal defences, harbours and marinas. Aside from seriously altering the dynamics of marine ecosystems, these structures can facilitate the establishment and spread of invasive species, acting as stepping stones for organisms with restricted dispersal capabilities and increasing the connectivity between remote hard bottom habitats separated by extensive soft bottom areas. However, little is known about why invasive species establish and proliferate so successfully

on urban marine structures, and what the role of these structures is in the large scale dispersal of these species. We carried out a study aimed at analysing the effects of urban marine structures in the establishment and spread of invasive tunicates, which are known to have considerable impacts on human activities. The study was done along the coast of the North Adriatic Sea. This region is amongst the most urbanized marine areas in the world, and coastal-defense structures which run almost uninterrupted for hundreds of kilometers have promoted the expansion of some introduced species. We carried out an extensive field sampling at 15 sites along ca. 400 km of coastline to assess the distribution and community composition of ascidian species. The abundance of these species and other dominant space occupiers was recorded directly in the field, while several specimens were also collected to be identified to species level after a detailed taxonomic examination. Through comparisons between urban structures and natural reefs we tested whether assemblages of tunicates on urban structures include a greater proportion of invasive species than those on natural reefs. A greater abundance of invasive species has indeed been reported on a variety of artificial structures compared to natural reefs; however, little is known about the extent to which these patterns can be generalized. We finally examined the relationships between assemblages on urban structures that were built or maintained at different time periods and possible source populations (sampled in nearby harbours and marinas), in order to get insights into the modalities by which these organisms reach urban structures. This information is fundamental to develop models aimed at predicting the rates and pathways of dispersal of invasive species

that can result due to the proliferation of urban structures along large stretches of coastline.


b. First Pacific record of the north Atlantic ascidian Molgula citrina—bioinvasion or circumpolar distribution? Gretchen Lambert1, Noa Shenkar2. Billie J. Swalla2.  1Univ. of Washington Friday Harbor Labs, Friday Harbor, WA 98250 U.S.A. 2Dept. of Biology, Univ. of Washington, Seattle, WA 98195 U.S.A.

    The small brooding ascidian Molgula citrina Alder and Hancock, 1848 has long been known as a common inhabitant of shallow waters on both sides of the north Atlantic on subtidal natural hard substrates and also as a fouler of floating docks. There are published records from the White Sea (NW Russia), but none from the north Pacific. In May and August 2008 a number of adult specimens were collected from floating docks at the small fishing village of Seldovia on the Kenai Peninsula at Kachemak Bay, Alaska. Morphologically these individuals exactly match Atlantic specimens of Molgula citrina in all characters. The unique constellation of characters for this species differentiates it from all other Molgula species, as was noted by Van Name (1945). In addition, the full-length 18S and 28S rDNA sequences are nearly the same for both the Alaska specimens and New England M. citrina.  Is this a new invasion, or is M. citrina another of a number of northern circumpolar ascidian species that somehow got overlooked? If this new record indicates a natural distribution, why has it not been collected before now? The north Pacific is a vast region, with many thousands of miles of undersampled coastline especially in northern British Columbia, Alaska, and NE Russia, and thus its invertebrate fauna and distributions are still poorly known.  If it is a recent introduction, it is unlikely that M. citrina, an inhabitant of cold waters, could survive in sea chests of ships from the N. Atlantic arriving in Alaska via the Panama Canal, but the intriguing idea exists of transport from Atlantic to Pacific through the Northwest Passage. The tadpoles of this small brooder are retained for some time after hatching, resulting in an extremely short free larval life, but could survive as metamorphosed juveniles attached in sea chests or free-floating in ballast water. They have a wide temperature tolerance and once they metamorphose can live free-floating in sea water for weeks.  They become very sticky and will ultimately stick to whatever they contact (BJS, pers. obs.).  Thus they could conceivably live for many generations in sea chests and sustain a viable population from which to invade new habitats. As global warming increasingly diminishes the ice cover in this region, more and more ships are traversing the Northwest Passage across northern Canada and represent a significant new route for anthropogenic transport of marine species.


c. The effects of Didemnum vexillum overgrowth on Mytilus edulis biology and ecology.
Linda A. Auker and Larry G. Harris, Dept. of Biological Sciences, Univ. of New Hampshire,
Durham, NH 03824

    Didemnum vexillum is an invasive tunicate that has been observed overgrowing several species of sessile marine animals, including the common blue mussel Mytilus edulis. It is clear that this overgrowth negatively affects the retrieval and processing of farmed mussels. However, the effects of overgrowth on mussel biology has not been extensively quantified. Therefore, this study aims to compare growth, reproduction, and predator preference for mussels not covered by D. vexillum, and those that are overgrown. Mussels are maintained in triplicate cages at the University of New Hampshire pier in Newcastle, NH, where D. vexillum is a dominant fouling species. Each month, thirty mussels from each set of cages are measured for height, length, and width. Every three months for a year, a set of each clean and overgrown mussels are retrieved and measured in the lab to calculate shell thickness index, tissue index, lip thickness, and reproductive output (measured by gonad weight and from histology samples). From the first two sets of data, it is evident that D. vexillum, when healthy and thriving in the late fall (November 2008), may cause a decrease in M. edulis tissue index and lip thickness. When the tunicate enters a senescent period during the winter (February 2009), it appears to have no effect on the mussel. In both November 2008 and February 2009, there was no difference in shell thickness. This presentation will also cover results from the remaining trials in the growth experiments, as well as the results of our other experiments testing the effects of this epibiosis completed during summer 2009.


d. Larval competency period and natural dispersal potential of the invasive colonial ascidian Didemnum vexillum. 1Lauren Fletcher, 2Barrie Forrest and 1James Bell. - 1Victoria Univ. of Wellington, New Zealand; 2Cawthron Institute, Nelson, NZ.

    One of the major human-associated threats to ecosystems and their biodiversity is biotic invasion. In New Zealand, invasive biofouling organisms have resulted in considerable economic and ecological impacts at local scales and as such there is increased interest in the management and control of marine pest species. This research focuses on one such pest species, the colonial ascidian Didemnum vexillum, a highly invasive biofouling organism whose presence in the Marlborough Sounds region poses a considerable threat to the New Zealand aquaculture industry. Although present in the Marlborough Sounds region since 2001, the rate of spread and dispersal capacity of Didemnum is not well understood. Marine pests undergo secondary spread through either natural mechanisms (e.g. passive transport of propagules in water currents) or by association with human transport vectors. Recent studies have shown that natural dispersal phases can facilitate spread in the range of metres to hundreds of kilometres depending on the duration of the planktonic phase and hydrological conditions encountered. Here we incorporate the results of a widespread monitoring programme, estimates from the recorded distribution of this species, and measurements of larval recruitment in field experiments to estimate the natural dispersal potential of Didemnum larvae. These estimates are supported by an assessment of the larval competency period and description of larval behaviour in a laboratory reared population of this species. Results have shown Didemnum larvae can survive up to 24 hours in the plankton while retaining the ability to metamorphose and settle successfully, indicating a relatively limited natural dispersal capacity of this species likely to be hundreds of metres to kilometres depending on water currents in the area. The lifespan presented for these larvae can now be used to predict dispersal under current regimes at other at risk locations within New Zealand and abroad. This information will assist managers in the implementation of effective eradication and control efforts, as understanding the importance of natural dispersal relative to human mediated dispersal is critical to the management of marine pests.



e. Reproductive seasonality of Didemnum vexillum: mitigating impacts on the New Zealand mussel industry. 1Lauren Fletcher, 2Barrie Forrest and 1James Bell. - 1Victoria Univ. of Wellington, New Zealand; 2Cawthron Institute, Nelson, NZ.

    The introduction of a number of high profile invasive fouling species to commercially important aquaculture regions globally poses a significant practical and economic barrier to the development of competitive shellfish aquaculture. New Zealand, even though geographically isolated from other problem areas, is not immune to these difficulties. Currently several introduced ascidians threaten New Zealand’s highly valued shellfish aquaculture industry, and as such efforts to control and manage these species are ongoing. This has led to an increased demand for tools to mitigate the effects of biofouling pests, including knowledge of the biological characteristics of fouling species that underpin management. Avoidance of crop and equipment infection through the utilisation of pest windows is an example of one such management tool. Most pest species have a fixed reproductive season, often regulated by water temperature, during which eggs or larvae are released and dispersed. Industry can therefore manage their activities to avoid deploying vulnerable life-stages (such as mussel or oyster spat) during high risk periods. We recently assessed the reproductive seasonality of the colonial ascidian Didemnum vexillum, in order to determine the duration of the reproductive season of this species and the presence and timing of associated pest windows. Although present in New Zealand since 2001 there are still considerable knowledge gaps surrounding the key biological attributes and ecology of Didemnum, in particular how these relate to its presence in the New Zealand environment. Weekly recruitment levels have been measured and correlated with environmental parameters (water temperature and salinity) over a 12 month period at two sites. Results indicate that although recruitment levels vary considerably between sites they follow a similar seasonal pattern. Didemnum recruits were detected between late November 2007 and early July 2008, a period of 7 months, with a recruitment peak in late January to early February 2008. This shows a 5 month period during the colder months where Didemnum populations are not producing larvae. This information on the reproductive seasonality of Didemnum is vital as it can be applied to the management of this species through industry avoidance of spat seeding at high risk periods to maximise the growth of these vulnerable small size classes before Didemnum populations spawn and larvae are present in the water column.


f. Integrating genetic and vector analysis to assess invasion pathways of the clubbed tunicate Styela clava in the northeastern Pacific. 1John A. Darling, 2L. Matthias Herborg & 3Ian Davidson.  1US Envl. Protection Agency, Cincinnati, OH 45208 USA; 2BC Ministry of the Environment, Victoria, BC V8W9M1 Canada; 3Aquatic Bioinvasions Research & Policy Institute, Portland State Univ., Portland, OR 97297 USA.

    Recognizing the patterns by which estabilshed invasive populations expand their ranges is crucial to understanding the risks posed by those species. Here we integrate two methods commonly adopted to assess likely pathways of invasive spread: genetic inference of connectivity between established populations and analysis of anthropogenic vector movements between potential recipient regions. We employ these methods to reconstruct the expansion of the clubbed tunicate Styela clava in the northeastern Pacific. Styela clava has become a common component of fouling communities from northern Mexico to British Columbia, and has proven a costly nuisance species where found in high densities. Mitochondrial cytochrome c oxidase subunit I (COI) sequences and multilocus genotype data from 12 polymorphic nuclear microsatellite loci were generated for a total of 433 individual tunicates from thirteen populations. Descriptive statistics indicate that levels of genetic diversity range broadly, with some populations showing signatures of strong founder effects. Significant genetic structure is observed across the introduced range, with particularly strong differentiation observed between samples in southern California and those in Puget Sound/Georgia Strait. We utilized data on the strength of commercial ship traffic between ports in our study area to test the hypothesis that movement of these vessels explains the observed genetic structure. Results of these analyses indicate that connectivity between samples via commercial shipping is a poor predictor of genetic structure, suggesting that alternative hypotheses must be explored. In particular, our data indicate the likelihood of multiple independent introductions to the Pacific coast of North America.


g. Trophic level response of native predator and prey populations to invasive colonial ascidians. Jennifer A. Dijkstra1, Larry G. Harris2, Cameron C. Brooks2, Walter L. Lambert3.    1Wells Natl. Estuarine Research Reserve, Wells, ME 04090,; 2Univ. of New Hampshire, Durham, NH 03824; 3Framingham State College, Framingham, MA 01701.

    Invasive colonial ascidians have become a new source of prey for some species e.g., Henricia sanguinolenta (blood star) and a competitor for others e.g., sponges, in New England.  However, it is unclear how this new food source affect densities of H. sanguinolenta and whether changes in density coupled with competition from an aggressive space occupant would then have an impact on historical prey (sponge) populations. Using a combination of laboratory and field studies, we present a conceptual model describing the relationship between invasive colonial ascidians, a native predator, H. sanguinolenta and its native prey species, sponges. Laboratory experiments and field surveys were used to determine prey choice of H. sanguinolenta among invasive colonial ascidians (Diplosoma listerianum, Botryllus schlosseri, Botrylloides violaceus and Didemnum vexillum). Long-term changes in the abundance H. sanguinolenta populations were established through field surveys while changes in sponge populations were determined through a study comparing succession in a marine fouling community between 1979 to 1982 and 2003 to 2006. Photographs taken from several areas in the Gulf of Maine were analyzed to assess frequency of overgrowth of sponges by colonial ascidians and of overgrowth of colonial ascidians by sponges. Since the introduction of invasive colonial ascidians, we have seen a decline in sponge populations. Results suggest the presence of invasive colonial ascidians had a cascading effect in subtidal communities, facilitating a build-up of predator populations and a decline in sponge populations.


h. A tale of two seas: ecological aspects of non-indigenous ascidians along the coast of Israel. Noa Shenkar, Dept. of Biology, Univ. of Washington, Seattle, WA 98195 U.S.A.

    One of the most extensively documented marine bioinvasion phenomena is the invasion of Red Sea species to the Mediterranean Sea through the Suez Canal (known as “Lessepsian migration). However, little is known about Lessepsian migration of ascidians (Phylum Chordata, Class Ascidiacea). The uniqueness of the Israeli coast line, namely the combination of a coral reef environment and a Mediterranean rocky shore only few hours apart, together with the recent (in evolutionary terms) opening of the Suez Canal, provides fertile ground for comparative studies of ascidian distribution and migration. The present study reports the occurrence of seven non-indigenous ascidian species (NIA’s) along the Mediterranean coast of Israel: Ecteinascidia thurstoni, Ascidia cannelata, Phallusia nigra, Rhodosoma turcicum, Symplegma brakenhielmi, Microcosmus exasperatus and Herdmania momus.  Five of these species (excluding P. nigra and R. turcicum) probably reached the Mediterranean via the Suez Canal, since they have an extra-tropical Indo-Pacific distribution and a restricted distribution in the eastern Mediterranean. E. thurstoni is reported for the first time in the Mediterranean, and H. momus and M. exasperatus were recorded mainly on artificial substrates. In addition, in order to understand parameters that may lead to species invasions, a comparative study of the ecology of the solitary ascidian H. momus was conducted simultaneously in the Red Sea and the Mediterranean coast of Israel revealing marked differences in H. momus populations. Increased recreational sailing and the proliferation of marinas and artificial marine structures in recent decades, provide additional sites for colonization of NIA’s, especially those with low dispersal abilities. The accumulating evidence for the negative impact of NIA’s on local species and habitats raises the necessity for long-term studies that will combine regular monitoring of natural versus artificial habitats, and the use of molecular genetic tools that will allow the identification of sources and patterns of dispersal.


i. Molecular identification and population genetics of a colonial ascidian (Didemnum vexillum) in New Zealand. Kirsty F Smith*, Lauren Stefaniak1, Chrissen EC Gemmill*, S Craig Cary*, Andrew E Fidle*. *Cawthron Institute, Nelson & University of Waikato, Hamilton, New Zealand; 1 Dept. of Marine Sci., Univ. of Connecticut, Groton, CT USA.

    Determining whether a putatively newly-introduced species is indeed non-native or rather a previously unreported indigenous species is sometimes problematic, particularly if taxonomic assignments are based solely on highly variable morphological characteristics. Correct identification of new species is critical for a rapid response and possible prevention of spread if a new species is considered potentially invasive. In the marine environment new colonizers may often go unnoticed in benthic environments particularly if the species is morphologically indistinguishable from a native species or lacks obvious morphological characteristics affording easy identification.

    Ascidians are common invasive species in marine environments around the world, including New Zealand. The ascidian Didemnum vexillum was first identified in New Zealand in 2001 in ports in the North Island. Soon after, the same species was reported in the Marlborough Sounds (South Island) where it quickly spread to mussel aquaculture areas. The species was identified, using morphological characteristics, as Didemnum vexillum and declared a native species, a status disputed by many at the time. Identification of ascidians in the genus Didemnum is problematic due to the small sizes of zooids, larvae and spicules of most species, as well as poor preservation techniques and inadequate sampling. This work describes the use of the ‘barcoding’ mitochondrial gene, cytochrome oxidase 1 (mtCO1), for the unambiguous identification of the D. vexillum in New Zealand. Associated molecular phylogenetic analyses placed populations of D. vexillum in New Zealand in the same clade as other populations around the world and confirmed that D. vexillum should be classified as a non-indigenous species in New Zealand. This interpretation receives additional support from the relatively low mtCO1 haplotype diversity amongst D. vexillum in New Zealand indicating a ‘genetic bottleneck’ possibly associated with recent colonization. These findings have significant implications for any efforts to mitigate negative effects that D. vexillum may have on the New Zealand aquaculture industry.

4. AMSA (Australian Marine Sciences Assoc.) Intl. Conference 2009: Marine Connectivity. Adelaide, Australia 5-9 July.

Cryptic species associated with marine biogeographic provinces within Australian and South African lineages of the low-dispersal ascidian Pyura stolonifera. Teske P, Rius M, Styan C, Piggott M, McClusky C, Rhamdhani S, Barker N, Banks S, McQuaid CD, Beheregaray L.

     Pyura stolonifera is a large, solitary ascidian that dominates rocky shore communities along the coasts of Australia and South Africa. As the species has very low dispersal potential, its disjunct distribution is believed to be the result of the break-up of Gondwanaland during the Mesozoic. Using DNA sequence data from four independently evolving loci, we show that both lineages are comprised of a number of highly distinct regional genetic lineages that are in most cases confined to single marine biogeographic provinces. Many of these can also be distinguished morphologically, suggesting that each is a cryptic species that may be adapted to the environmental conditions characteristic of its region. We discuss the observed genetic patterns in the light of the species’ low dispersal potential.


5. EMBO Workshop “EvoDevo meets marine ecology”,  S. Angelo d’Ischia 9-11 October 2009.

POU genes and the differentiation of nervous sytem in the ascidian Ciona intestinalis.
R. Pennati1, G. Zega1, S. Candiani2, R. Manenti1, M. Pestarino2, F. De Bernardi1.

1Dept. of Biologia, Università degli Studi di Milano, via Celoria 26,20133 Milano; 2Dept. of Biologia, Università di Genova, v. le Benedetto XVI, Genova, Italy.

Members of POU gene family play a role in the neural differentiation in vertebrates and invertebrates. Ascidian larvae have a nervous system displaying an organization similar to those of vertebrates even if it is formed by very few cells. The genome of the ascidian Ciona intestinalis contains only three genes that codify for transcription factors of the POU class. We cloned all three genes and studied their expression pattern during the development, in normal conditions and after treatment with retinoic acid (RA). It is known that during the chordate development, this molecule plays a pivotal role in the correct differentiation of nervous system along the antero-posterior axis and in the differentiation of some neuronal populations. Transcripts of the Ci-POU-2 gene are detected during the first phases of cleavage. The expression of Ci-POU-like is restricted to the cells of lateral mesenchime of the larva and to its precursors during the embryonic development. The expression of these two genes is not altered by RA treatment. Instead, Ci-POU IV is expressed in the sensory neurons of the peripheral nervous system and in few cells of the visceral ganglion in the central nervous system. RA treatment dramatically reduces the number of epidermic neurons that express Ci-POU IV and alters their distribution along the antero-posterior axis. To study the role of this gene during the development of the nervous system, we microinjected Morpholino oligonucleotides in eggs. The gene knock down impairs selectively the differentiation of serotonergic neurons, while it has no effects on the  GABAergic ones. Thus, it could be hypothesized that Ci-POU IV plays a role in the terminal differentiation of some neuronal types.

These findings suggest that the close interaction between the morphogenetic action of RA and the expression of POU IV gene is crucial for the correct differentiation of the nervous system in basal chordates.


6. 4th Intl. Conf. of the Intl. Biogeography Society. Merida, Mexico, January 2009.

Biogeography of the cold and cold-temperate ascidian fauna in the southern hemisphere.  Primo, C.1, Hewitt C.L.1, Campbell, M.L.1 & Vázquez, E.2  1National Center for Marine Conservation and Resource Sustainability, Australian Maritime College, Univ. of Tasmania, Launceston, Australia; 2Dept. of Ecology and Marine Biology, Univ. of Vigo, Vigo, Spain.

    Traditional biogeography is important in organisms for which phylogenetic studies are still scarce such as ascidians. The biogeography of the ascidian fauna of the cold and cold-temperate regions of the Southern Hemisphere is described and compared to the biogeography of other fauna in the same regions. Species and biogeographical areas were classified using cluster analysis combined with MDS ordination. The results indicate an association between Tasmanian and Southern African regions, while Southern New Zealand was more related to colder regions (South America, sub-Antarctic and Antarctic). Endemism was high in all the considered regions, but a high percentage of cosmopolitan and widespread Southern Hemisphere species were also identified. Species in the widespread fauna were re-classified using existing invasion criteria (Chapman and Carlton, modified to suit ascidian characteristics) to determine if these species are native, cryptogenic or introduced.




1. Abiotic and biotic drivers of exotic species success in marine fouling communities of Washington, U.S.A. Erin K. Grey, Ph. D. dissertation, Univ. of Chicago. Advisor: Dr. Cathy Pfister.

    Understanding how and why exotic species succeed in new biological communities is vital for both conservation and basic ecology.  Using a combination of surveys, experiments and demographic modeling, I teased apart the abiotic and biotic drivers of exotic species success in marine fouling communities of Washington, U.S.A.  I first documented native and exotic species diversity of fouling communities throughout the region by conducting extensive surveys of floating dock habitats.  With this data I also tested two classical ecological theories, diversity-stability theory and diversity-resistance theory.  I found no support for diversity-stability theory, equivocal support for diversity-resistance theory, and evidence that native and exotic species prefer different abiotic environments.  I then conducted manipulative experiments to test the effects of abiotic environment and direct-contact interactions to the vital rates and population growth rates of the most common exotic species, the colonial ascidian Botrylloides violaceus.  Results showed that both abiotic environment and direct-contact interaction influenced the survival and growth of B. violaceus.  However, abiotic effects on population growth rates were much larger than direct-contact effects.  I subsequently explored the effects of pre-emptive competition for space by testing the effect of natural communities on B. violaceus larval recruitment rates and incorporated this effect into a space-dependent model.  I showed that space-dependent B. violaceus populations are likely to exhibit phase-locked cycles and that dynamics are sensitive to inter-specific space-occupation and the growth rates of medium-sized colonies in the summer.  Finally, I used cage-exclosure experiments to test the enemy-release hypothesis, which posits that enemies limit native species to a greater extent than they do exotic species.  I found that large enemies (>1.3cm) do not limit B. violaceus at any site and that their effect on native species depends on their total biomass at each site.  Thus the enemy-release hypothesis was only supported only at sites with high enemy biomass.  Overall, I conclude that pre-emptive competition for space is the most important biotic interaction to the exotic B. violaceus, but that the abiotic environment is the main driver of the success of this exotic species in Washington fouling communities.    

Present address:  Postdoctoral Research Fellow, Dept. of Ecology & Evol. Biology, Tulane University, New Orleans, LA 70118.


2. An urban estuary in a changing world: diversity, invasions, and climate change in San Francisco Bay.  Andrew Chang, Ph. D. dissertation, Univ. of California Davis. Advisor: Dr. Ted Grosholz.  Present address: Postdoctoral Fellow, Univ. of Calif. Davis and Marine Invasions Research Laboratory, Smithsonian Environmental Research Center, Tiburon, CA      Estuarine and coastal ecosystems face large-scale physical environmental stresses from climate change and local scale community changes including non-native species introductions.  In northern California, USA, climate change projections indicate increasingly severe droughts in the future punctuated by more frequent, intense winter storms, significantly affecting freshwater outflow to estuaries like San Francisco Bay. Using long-term physical and biological data sets coupled with experiments, I found drastic changes in epifaunal communities in the Bay between years with extreme high and low freshwater outflow (Chapter 1).  In dry years (low outflow), competition determines community composition, but in wet years (high outflow), low salinity stress shifts the community to being recruitment limited, with community membership determined by the availability of larvae to recruit.  Shifts in outflow extremes drive changes in the dominant species, resulting in altered community performance (Chapter 2).  I experimentally tested the effect of functional group diversity on community performance in different outflow regimes.  Communities containing more functional groups generally occupied more space, but the strength of this effect varied from year to year.  In the absence of normally dominant species during a wet year, resident community functional group diversity had no effect on subsequent invasion by non-resident species.  These results suggest that outcomes of short-term, unreplicated studies of biodiversity-ecosystem function relationships may thus be contingent on prevailing conditions.

         Finally, I assessed the risk posed by the aquarium fish trade for introducing non-native fish species to the San Francisco Bay­ Delta using an inventory of fish species for sale, a model comparing fish physiological tolerances to environmental parameters, and a telephone survey of store representatives’ knowledge and attitudes toward invasions (Chapter 3).  This analysis showed that the local aquarium trade includes at least five and as many as twenty-seven species that could potentially survive in the Bay­ Delta.  Management efforts for this vector should focus on improving labeling and identification of fish species in stores, expanding available information on fish physiological tolerances, educating customers and store employees about the risks of pet release, and providing better options for responsible disposal of unwanted fish.




Acosta, H. and Forrest, B. M. 2009. The spread of marine non-indigenous species via recreational boating: A conceptual model for risk assessment based on fault tree analysis. Ecol. Modelling 220: 1586-1598.

Aiello, A., Fattorusso, E., Giordano, A., Menna, M., Navarrete, C. and Munoz, E. 2009. Clavaminols G-N, six new marine sphingoids from the Mediterranean ascidian Clavelina phlegraea. Tetrahedron 65: 4384-4388.

Ali, H. A. J., Tamilselvi, M. and Sivakumar, V. 2008. Antibacterial activity of the marine ascidians Phallusia nigra and Herdmania pallida from the Tuticorin coast, India. J. Biol. Res. -Thessaloniki 10: 71-179.

Appleton, D. R., Chuen, C. S., Berridge, M. V., Webb, V. L. and Copp, B. R. 2009. Rossinones A and B, biologically active meroterpenoids from the Antarctic ascidian, Aplidium species. J. Org. Chem. epub:

Bao, B., Dang, H. T., Zhang, P., Hong, J., Lee, C. O., Cho, H. Y. and Jung, J. H. 2009. Bicyclic alpha,omega-dicarboxylic acid derivatives from a colonial tunicate of the family Polyclinidae. Bioorg. Med. Chem. Lett. 19: 6205-6208.

Bensemhoun, J., Bombarda, I., Aknin, M., Faure, R. and Gaydou, E. M. 2009. 5a,8a-Epidioxysterols from the tunicate Didemnum salary. Biochem. Syst. & Ecol. 36: 942–944.

Bishop, C. D., Bates, W. R. and Hall, B. K. 2010. Heat shock protein 90 expression in two migratory cell types of ascidian embryos and larvae: test cells deposit HSP90 on the larval tunic. Intl. J. Dev. Biol. in press:

Boldrin, F., Martinucci, G., Holland, L. Z., Miller, R. L. and Burighel, P. 2009. Internal fertilization in the salp Thalia democratica. Can. J. Zool. 87: 928-940.

Bonura, A., Vizzini, A., Salerno, G., Parrinello, N., Longo, V. and Colombo, P. 2009. Isolation and expression of a novel MBL-like collectin cDNA enhanced by LPS injection in the body wall of the ascidian Ciona intestinalis. Molec. Immunol. 46: 2389-2394.

Brown, F. D., Keeling, E. L., Le, A. D. and Swalla, B. J. 2009. Whole body regeneration in a colonial ascidian, Botrylloides violaceus. J. Exp. Biol. B 312B: 885-900.

Brown, F. D., Tiozzo, S., Roux, M. M., Ishizuka, K., Swalla, B. J. and De Tomaso, A. W. 2009. Early lineage specification of long-lived germline precursors in the colonial ascidian Botryllus schlosseri. Development 136: 3485-3494.

Brunetti, R. 2009. Pseudodistoma valeriae a new species of aplousobranch ascidian from Mediterranean Sea (Tunicata, Ascidiacea). Boll. Mus. civ. St. nat. Venezia 59: 75-79.

Brunetti, R. 2009. Botryllid species (Tunicata, Ascidiacea) from the Mediterranean coast of Israel, with some considerations on the systematics of Botryllinae. Zootaxa 2289: 18–32.

Bullard, S. G. and Carman, M. R. 2009. Current trends in invasive ascidian research. In: Wilcox, C. P. and Turpin, R. B. (ed.), Invasive Species: Detection, Impact and Control. Nova Science Publishing, pp. 57-79.

Byrnes, J. and Stachowicz, J. J. 2009. Short and long term consequences of increases in exotic species richness on water filtration by marine invertebrates. Ecology Letters 12: 830–841.

Cammarata, M. and Parrinello, N. 2009. The ascidian prophenoloxidase activating system. Invert. Survival J. 6: S67-S76.

Cannon, J. T., Rychel, A. L., Eccleston, H., Halanych, K. M. and Swalla, B. J. 2009. Molecular phylogeny of Hemichordata, with updated status of deep-sea enteropneusts. Molec. Phylogen. & Evol. 52: 7-24.

Carlton, J. T. 2009. Deep invasion ecology and the assembly of communities in historical time. In: Rilov, G. and Crooks , J. A. (ed.), Biological Invasions in Marine Ecosystems. Berlin Heidelberg, Springer-Verlag, pp. ch. 2: 13-56.

Carlton, J. T. and Eldredge, L. G. 2009. Marine bioinvasions of Hawai'i. The introduced and cryptogenic marine and estuarine animals and plants of the Hawaiian Archipelago. Bishop Mus. Bull. in Cultural and Envir. Studies 4: 1-202.

Chavanich, S., Viyakarn, V., Piyatiratitivorakul, P., Suwanborirux, K. and Bussarawit, S. 2009. Two introduced tunicate species, Ecteinascidia thurstoni Herdman, 1891 and Clavelina cyclus Tokioka & Nishikawa, 1975, in Thailand. Aquatic Invasions 4: epub.

Cima, F., Manni, L., Menin, A., Basso, G., Fortunato, E., Accordi, B., Schiavon, F. and Ballarin, L. 2009. Hovering between death and life: Natural apoptosis and phagocytes in the blastogenetic cycle of the colonial ascidian Botryllus schlosseri. Dev. Comp. Immunol. epub:

Damiani, F., Gianguzza, M. and dolcemascolo, G. 2009. Effects of tributyltin chloride in ascidian embryos: modulation of kinase-mediated signalling pathways. Invert. Survival J. 6: S87-S94.

Davis, M. H. and Davis, M. E. 2004. The role of man-aided dispersal in the spread of the immigrant Styela clava Herdman, 1882. J. Mar. Sci. & Environ. 1: 18-24.

de Barros, C. M., de Carvalho, D. R., Andrade, L. R., Pavao, M. S. and Allodi, S. 2009. Nitric oxide production by hemocytes of the ascidian Styela plicata. Cell Tiss. Res. 338: 117-128.

De Bernardi, F. 2009. Professor Giuseppe Reverberi and the ascidian school in Palermo. Invert. Survival J. 6: S3-S8.

De Tomaso, A. W. 2009. Sea squirts and immune tolerance. Disease Models & Mech. 2: 440-445.

Degasperi, V., Gasparini, F., Shimeld, S. M., Sinigaglia, C., Burighel, P. and Manni, L. 2009. Muscle differentiation in a colonial ascidian: organisation, gene expression and evolutionary considerations. BMC Dev. Biol. 9: 48-57.

Di Bella, M. A., Carbone, M. C., D'Amato, M., Alessandro, R. and De Leo, G. 2009. The identification and localization of two intermediate filament proteins in the tunic of Styela plicata (Tunicata, Styelidae). Tiss. & Cell epub:

Dijkstra, J. A. and Harris, L. G. 2009. Maintenance of diversity altered by a shift in dominant species: implications for species coexistence. Mar. Ecol. Prog. Ser. 387: 71–80.

Dolcemascolo, G., Pennati, R., De Bernardi, F., Damiani, F. and Gianguzza, M. 2009. Ultrastructural comparative analysis on the adhesive papillae of the swimming larvae of three ascidian species. Invert. Survival J. 6: S77-S86.

Draughon, L., Scarpa, J. and Hartmann, J. 2009. Filtration rates for the rough tunicate Styela plicata should not be based on weight or size. J. Environ. Sci. Health Part A  45:

Dumont, C. P., Urriago, J. D., Abarca, A., Gaymer, C. F. and Thiel, M. 2009. The native rock shrimp Rhynchocinetes typus as a biological control of fouling in suspended scallop cultures. Aquaculture 292: 74-79.

Edwards, P. K. and Leung, B. 2009. Re-evaluating eradication of nuisance species: invasion of the tunicate, Ciona intestinalis. Frontiers in Ecology and the Environment 7: 326-332.

Epelbaum, A., Pearce, C. M. and Therriault, T. W. 2008. A case of atrial siphon duplication in Styela clava (Tunicata: Ascidiacea). JMBA2 - Biodiversity Records 1-3.

Fujikawa, T., Munakata, T., Kondo, S. I., Satoh, N. and Wada, S. 2009. Stress response in the ascidian Ciona intestinalis: transcriptional profiling of genes for the heat shock protein 70 chaperone system under heat stress and endoplasmic reticulum stress. Cell Stress Chaperones epub:

Fukumoto, M. 2009. Mitochondrial translocation in ascidian spermatozoa and its role in reproduction. Bull. Gifu Univ. Med. Sci. 3: 101-108.

Fukumoto, M. 2009. Morphological changes in ascidian spermatozoa during fertilization. Bull. Gifu Univ. Med. Sci. 3: 1-16.

Gab-Alla, A. A.-F. A. 2008. Distribution of the sea squirt Ecteinascidia thurstoni Herdman, 1890 (Ascidiacea: Perophoridae) along Suez Canal and Egyptian Red Sea coasts. Oceanologia 50: 239–253.

Gissi, C., Pesole, G., Mastrototaro, F., Iannelli, F., Guida, V. and Griggio, F. 2009. Hyper-variability of ascidian mitochondrial gene order: exposing the myth of deuterostome organelle genome stability. Molec. Biol. & Evol. epub:

Godefroy, N., Hoa, C., Tsokanos, F., Le Goff, E., Douzery, E. J., Baghdiguian, S. and Martinand-Mari, C. 2009. Identification of autophagy genes in Ciona intestinalis: A new experimental model to study autophagy mechanism. Autophagy 5: 805-815.

Granek, E. F., Compton, J. E. and Phillips, D. L. 2009. Mangrove-exported nutrient incorporation by sessile coral reef invertebrates. Ecosystems 12: 462-472.

Henrich, C. J., Robey, R. W., Takada, K., Bokesch, H. R., Bates, S. E., Shukla, S., Ambudkar, S. V., McMahon, J. B. and Gustafson, K. R. 2009. Botryllamides: natural product inhibitors of ABCG2. ACS Chem. Biol. 4: 637-647.

Hess, J. E., Swalla, B. J. and Moran, P. 2009. New molecular markers to genetically differentiate populations of Didemnum vexillum Kott, 2002 - an invasive ascidian species. Aquatic Invasions 4: 299-310.

Hirose, E., Oka, A. T. and Hirose, M. 2009. Two new species of photosymbiotic ascidians of the genus Diplosoma from the Ryukyu Archipelago, with partial sequences of the COI gene. Zool. Sci. 26: 362–368.

Hirose, E., Uchida, H. and Murakami, A. 2009. Ultrastructural and microspectrophotometric characterization of multiple species of cyanobacterial photosymbionts coexisting in the colonial ascidian Trididemnum clinides (Tunicata, Ascidiacea, Didemnidae). Eur. J. Phycol. 44: 365–375.

Hirose, M. and Hirose, E. 2009. DNA barcoding in photosymbiotic species of Diplosoma (Ascidiacea: Didemnidae), with the description of a new species from the southern Ryukyus, Japan. Zool. Sci. 26: 564–568.

Ito, M., Yokoi, K., Inoue, T., Asano, S., Hatano, R., Shinohara, R., Itonori, S. and Sugita, M. 2009. Sphingomyelins in four ascidians, Ciona intestinalis, Halocynthia roretzi, Halocynthia aurantium, and Styela clava.  J. Oleo Sci. 58: 473-480.

Johnson, S. L. and Yund, P. O. 2009. Effects of fertilization distance on male gain curves in a free-spawning marine invertebrate: a combined empirical and theoretical approach. Evolution 63: 3114–3123.

Kanda, M., Wada, H. and Fujiwara, S. 2009. Epidermal expression of Hox1 is directly activated by retinoic acid in the Ciona intestinalis embryo. Dev. Biol. 335: 454-463.

Karthikeyan, M. M., G. Ananthan, G. and Ali, A. J. 2009. Food and feeding habits of Herdmania pallida (Heller) (Urochordata: Ascidiacea) from Palk Strait, Southeast of India. World J. Fish & Mar. Sci. 1: 225-229.

Kataoka, Y., Mishina, R. and Fujiwara, S. 2010. Mechanism of DNA replication-dependent transcriptional activation of the acetylcholinesterase gene in the Ciona intestinalis embryo. Develop. Growth Differ. epub:

Kawada, T., Aoyama, M., Okada, I., Sakai, T., Sekiguchi, T., Ogasawara, M. and Satake, H. 2009. A novel inhibitory gonadotropin-releasing hormone-related neuropeptide in the ascidian, Ciona intestinalis. Peptides 30: 2200–2205.

Kitamura, S. I., Ohtake, S. I., Song, J. Y., Jung, S. J., Oh, M. J., Choi, B. D., Azumi, K. and Hirose, E. 2009. Tunic morphology and viral surveillance in diseased Korean ascidians: soft tunic syndrome in the edible ascidian, Halocynthia roretzi (Drasche), in aquaculture. J. Fish Diseases epub:

Konno, A. and Inaba, K. 2008. Comparative studies of cilia and sperm flagella in the ascidian Ciona intestinalis (Urochordata). J. Morph. 269: 1491.

Konno, A., Kaizu, M., Hotta, K., Horie, T., Sasakura, Y., Ikeo, K. and Inaba, K. 2009. Distribution and structural diversity of cilia in tadpole larvae of the ascidian Ciona intestinalis. Dev. Biol. epub:

Koplovitz, G., McClintock, J. B., Amsler, C. D. and Baker, B. J. 2009. Palatability and chemical anti-predatory defenses in common ascidians from the Antarctic Peninsula. Aquatic Biol. 7: 81-92.

Kossuga, M. H., De Lira, S. P., Nascimento, A. M., Gambardella, M. T. P., Berlinck, R. G. S., Torres, Y. R., Nascimento, G. G. F., Pimental, E. F., Silva, M., Thiemann, O. H., Oliva, G., Tempone, A. G., Melham, M. S. C., de Souza, A. O., Galetti, F. C. S., Silva, C. L., Cavalcante, B., Pessoa, C. O., Moraes, M. O., Hajdu, E., Peixinho, S. and Rocha, R. M. 2007. Isolation and biological activities of secondary metabolites from the sponges Monanchora aff. arbuscula, Aplysina sp., Petromica ciocalyptoides and Topsentia ophiraphidies, from the ascidian Didemnum ligulum and from the octocoral Carijoa riisei. Quim. Nova 30: 1194-1202.

Koyano, R., Ishida, S. and Fujiwara, S. 2009. Transcriptional regulation of the retinoic acid receptor in the dorsal midline epidermis in the Ciona intestinalis embryo.  Develop. Growth Differ. epub:

Kremer, L. P., Rocha, R. M. and Roper, J. J. 2010. An experimental test of colonization ability in the potentially invasive Didemnum perlucidum (Tunicata, Ascidiacea). Biol. Invasions epub:

Kubo, A., Imai, K. S. and Satou, Y. 2009. Gene-regulatory networks in the Ciona embryos. Brief. Funct. Genomics Proteomics 8: 250-255.

Kusakabe, T. G., Takimoto, N., Jin, M. and Tsuda, M. 2009. Evolution and the origin of the visual retinoid cycle in vertebrates. Phil. Trans. R. Soc. Lond. B 364: 2897-2910.

Lambert , C. C. 2009. Ascidian follicle cells: Multifunctional adjuncts to maturation and development. Dev. Growth & Differ. 51: 677–686.

Lebrato, M. and Jones, D. O. B. 2009. Mass deposition event of Pyrosoma atlanticum carcasses off Ivory Coast (West Africa). Limnol. Oceanog. 54: 1197-1209.

Lemaire, P. 2009. Unfolding a chordate developmental program, one cell at a time: invariant cell lineages, short-range inductions and evolutionary plasticity in ascidians. Dev.  Biol. 332: 48-60.

Lopez-Rivera, A., Pinto, M., Insinilla, A., Isla, B. S., Uribe, E., Alvarez, G., Lehane, M., Furey, A. and James, K. J. 2009. The occurrence of domoic acid linked to a toxic diatom bloom in a new potential vector: the tunicate Pyura chilensis (piure). Toxicon 54: 754-62.

McClintock, J. B., Amsler, M. O., Koplovitz, G., Amsler, C. D. and Baker, B. J. 2009. Observations on an association between the dexaminid amphipod Polycheria antarctica f. scanthopoda and Its ascidian host Distaplia cylindrica. J. Crust. Biol. 29: 605-608.

Meenakshi, V. K. 2008. A report on the biodiversity of Indian ascidians. In: Natarajan and al., e. (ed.), Glimpses of Aquatic Diversity. Rajiv Gandhi Chair Spl. Pub., pp. 213 - 219.

Meenakshi, V. K. 2009. New records of five species of colonial ascidians of the genus Ecteinascidia Herdman, 1880 from the Gulf of Mannar. J. Bombay Nat. Hist. Soc. 105: in press.

Meenakshi, V. K. 2009. A report on the nutritive value of ascidians. Enrich 1: 58 -- 68.

Meenakshi, V. K. and Senthamarai, S. 2007. New records of two species of simple ascidians - Microcosmus pupa (Savigny,1816) and Microcosmus squamiger, Hartmeyer and Michaelsen,1928 - from  Indian seas. J. Bombay Nat. Hist. Soc. 104: 238-240.

Menna, M. 2009. Antitumor potential of natural products from Mediterranean ascidians. Phytochem. Rev. 8: 461-472.

Minamoto, T., Hanai, S., Kadota, K., Oishi, K., Matsumae, H., Fujie, M., Azumi, K., Satoh, N., Satake, M. and Ishida, N. 2009. Circadian clock in Ciona intestinalis revealed by microarray analysis and oxygen consumption. J. Biochem. epub:

Monniot, F. 2009. Some ascidians from Indonesian marine lakes (Raja Ampat Islands, West Papua). Zootaxa 2106: 13–40.

Murphy, B. T., Cao, S., Brodie, P., Maharavo, J., Andriamanantoanina, H., Ravelonandro, P. and Kingston, D. G. 2009. Antiproliferative bistramides from Trididemnum cyclops from Madagascar (1). J. Nat. Prod. 72: 1338-1340.

Nikitina, N., Sauka-Spengler, T. and Bronner-Fraser, M. 2009. Chapter 1. Gene regulatory networks in neural crest development and evolution. Curr. Top. Dev. Biol. 86: 1-14.

Niwano, T., Takatori, N., Kumano, G. and Nishida, H. 2009. Wnt5 is required for notochord cell intercalation in the ascidian Halocynthia roretzi. Biol. Cell 101: 6456-59.

Noda, T., Hamada, M., Hamaguchi, M., Fujie, M. and Satoh, N. 2009. Early zygotic expression of transcription factors and signal molecules in fully dissociated embryonic cells of Ciona intestinalis: A microarray analysis. Dev. Growth & Differ. 51: 639-655.

Okubo, R., Dauga, D., Robin, F. and Lemaire, P. 2008. Quantitative analysis of morphogenetic change during gastrulation movement in ascidian Ciona intestinalis by constructing 3-D virtual embryo. 83: 502.

Oliveira, F., Almeida, C. and Goncalves, J. M. S. 2009. Ascidonia flavomaculata (Heller, 1864), a new record for the Portuguese marine invertebrate fauna (Decapoda, Pontoniidae). Crustaceana 82: 63-67.

Paix, A., Yamada, L., Dru, P., Lecordier, H., Pruliere, G., Chenevert, J., Satoh, N. and Sardet, C. 2009. Cortical anchorages and cell type segregations of maternal postplasmic/PEM RNAs in ascidians. Dev. Biol. 336: 96-111.

Parrinello, N., Arizza, V., Cammarano, M., Vazzana, M. and Vizzini, A. 2008. II scientific meeting of the Italian Ascidiologists, 30 June – 1 July 2008, Palermo, Italy  [abstracts]. Invert. Survival J. 5: 83-96.

Pascoe, P. L., Parry, H. E. and Hawkins, A. J. S. 2007. Dynamic filter-feeding responses in fouling organisms. Aquatic Biol. 1: 177-185.

Passamaneck, Y. J., Katikala, L., Perrone, L., Dunn, M. P., Oda-Ishii, I. and Di Gregorio, A. 2009. Direct activation of a notochord cis-regulatory module by Brachyury and FoxA in the ascidian Ciona intestinalis. Development 136: 3679-3689.

Primo, C. and Vázquez, E. 2009. Antarctic ascidians: an isolated and homogeneous fauna. Polar Research epub:

Raftos, D. A., Nair, S. V., Robbins, J., Newton, R. A. and Peters, R. 2002. A complement component C3-like protein from the tunicate, Styela plicata. Dev. Comp. Immunol. 26: 307-312.

Ritzmann, N. F., Rocha, R. M. and Roper, J. J. 2009. Sexual and asexual reproduction in Didemnum rodriguesi (Ascidiacea, Didemnidae). Iheringia. Série Zool. 99: 106-110.

Rius, M., Pineda, M. C. and Turon, X. 2009. Population dynamics and life cycle of the introduced ascidian Microcosmus squamiger in the Mediterranean Sea. Biol. Invasions 11: 2181-2194.

Rocha, R. M. and Bonnet, N. Y. K. 2009. Ascídias (Tunicata, Ascidiacea) introduzidas no Arquipélago de Alcatrazes, São Paulo. Iheringia. Série Zool. 99: 27-35.

Roper, K. E., Beamish, H., Garson, M. J., Skilleter, G. A. and Degnan, B. M. 2009. Convergent antifouling activities of structurally distinct bioactive compounds synthesized within two sympatric Haliclona demosponges. Mar. Biotechnol. 11: 188-198.

Rottmayr, E. M., Steffan, B. and Wanner, G. 2001. Pigmentation and tunic cells in Cystodytes dellechiajei (Urochordata, Ascidiacea). Zoomorphology 120: 159-170.

Ruiz, G. and Hewitt, C. L. 2009. Latitudinal patterns of biological invasions in marine ecosystems: a polar perspective. In: Krupnik, I., Lang, M. A. and Miller, S. E. (ed.), Smithsonian at the Poles Contributions to International Polar Year Science. Washington DC, Smithsonian Institution Scholarly Press, pp. 347-358.

Rychel, A. L. and Swalla, B. J. 2009. Regeneration in hemichordates and echinoderms. In: Valeria Matranga, V. and Rinkevich, B. (ed.), Marine Stem Cells. Springer, pp.

Sagular, E. K. 2009. Fossil didemnid ascidian spicule records in the Plio-Quaternary marine clastics of the Antalya Basin (Eastern Mediterranean) and their stratigraphic calibration to new nannofossil data. Geosci. J. 13: 121-131.

Saidi, B., Bradai, M. N. and Bouain, A. 2009. Reproductive biology and diet of Mustelus punctulatus (Risso, 1826) (Chondrichthyes: Triakidae) from the Gulf of Gabes, central Mediterranean Sea. Sci. Mar. 73: 249-258.

Sasaki, N., Ogasawara, M., Sekiguchi, T., Kusumoto, S. and Satake, H. 2009. Toll-like receptors of the ascidian, Ciona intestinalis: prototypes with hybrid functionalities of vertebrate Toll-like receptors. J. Biol. Chem. 284: 27336-27343.

Sasakura, Y., Inaba, K., Satoh, N., Kondo, M. and Akasaka, K. 2009. Ciona intestinalis and Oxycomanthus japonicus, representatives of marine invertebrates. Exp. Anim. 58: 459-469.

Sekiguchi, T., Suzuki, N., Fujiwara, N., Aoyama, M., Kawada, T., Sugase, K., Murata, Y., Sasayama, Y., Ogasawara, M. and Satake, H. 2009. Calcitonin in a protochordate, Ciona intestinalis--the prototype of the vertebrate calcitonin/calcitonin gene-related peptide superfamily. FEBS J. 276: 4437-4447.

Silvestre, F., Cuomo, A. and Tosti, E. 2009. Ion current activity and molecules modulating maturation and growth stages of ascidian (Ciona intestinalis) oocytes. Molec. Repro. & Develop. 76: 1084–1093.

Svane, I., Hammett, Z. and Lauer, P. 2009. Impacts of trawling on benthic macro-fauna and -flora of the Spencer Gulf prawn fishing grounds. Estuarine & Coastal Mar. Sci. 82: 621-631.

Tapiolas, D. M., Bowden, B. F., Abou-Mansour, E., Willis, R. H., Doyle, J. R., Muirhead, A. N., Liptrot, C., Llewellyn, L. E., Wolff, C. W., Wright, A. D. and Motti, C. A. 2009. Eusynstyelamides A, B, and C, nNOS inhibitors, from the ascidian Eusynstyela latericius. J. Nat. Prod. 72: 1115-1120.

Teng, L., Wada, H. and Zhang, S. 2009. Identification and functional characterization of legumain in amphioxus Branchiostoma belcheri. Biosci. Rep. epub:

Terakado, K. 2009. Placode formation and generation of gonadotropin-releasing hormone (GnRH) neurons in ascidians. Zool. Sci. 26: 398-405.

Terakubo, H., Nakajima, Y. and Horie, T. 2008. Is the novel structure in the tunic-fin of the ascidian larvae the peripheral neuronal cells? Genes & Genetic Systems 83: 502.

Tiozzo, S., Murray, M., Degnan, B. M., De Tomaso, A. W. and Croll, R. P. 2009. Development of the neuromuscular system during asexual propagation in an invertebrate chordate. Dev. Dyn. 238: 2081-2094.

Tsagkogeorga, G., Turon, X., Hopcroft, R. R., Tilak, M.-K., Feldstein, T., Shenkar, N., Loya, Y., Huchon, D., Douzery, E. J. P. and Delsuc, F. 2009. An updated 18S rRNA phylogeny of tunicates based on mixture and secondary structure models. BMC Biol. 9: 187-.

Ueki, T., Kawakami, N., Toshishige, M., Matsuo, K., Gekko, K. and Michibata, H. 2009. Characterization of vanadium-binding sites of the vanadium-binding protein Vanabin2 by site-directed mutagenesis. Biochim. Biophys. Acta 1790: 1327-1333.

Westerman, E. L., Dijkstra, J. A. and Harris, L. G. 2009. High natural fusion rates in a botryllid ascidian. Mar. Biol. 156: 2613–2619.

Westerman, E. L., Whitlatch, R., Dijkstra, J. A. and Harris, L. G. 2009. Variation in brooding period masks similarities in response to changing temperatures. Mar. Ecol. Prog. Ser. 391: 13–19.

Yoshida, M., Kawano, N. and Yoshida, K. 2008. Control of sperm motility and fertility: diverse factors and common mechanisms. Cell. Mol. Life Sci. 65: 3446-3457.

Yubisui, T., Yamanaka, T., Kurita, K.-I., Fujiwara, S. and Kawamura, K. 2008. Occurrence of NADH-specific and NADH/NADPH-bispecific cytochrome b(5) reductases in the ascidians, Styela plicata and Ciona intestinalis. 44A: 39-44.

Zapata, M., Silva, S., Luza, Y., Wilkens, M. and Riquelme, C. 2007. The inhibitory effect of biofilms produced by wild bacterial isolates to the larval settlement of the fouling ascidia Ciona intestinalis and Pyura praeputialis. Elect. J. Biotechnol. 10:

Zega, G., Candiani, S., Groppelli , S., De Bernardi, F. and Pennati, R. 2009. Neurotoxic effect of the herbicide paraquat on ascidian larvae. Environ. Toxicol. Pharmacol. in press:

Zega, G., Pennati, R., Candiani, S., Pestarino, M. and De Bernardi, F. 2009. Solitary ascidians embryos (Chordata, Tunicata) as model organisms for testing coastal pollutant toxicity. ISJ 6: S29-S34.

Zimmerman, S. and Sutovsky, P. 2009. The sperm proteasome during sperm capacitation and fertilization. J. Reprod. Immunol.

Zlatanos, S., Laskaridis, K. and Sagredos, A. 2009. Determination of proximate composition, fatty acid content and amino acid profile of five lesser-common sea organisms from the Mediterranean Sea. Int. J. Food Sci. & Technol. 44: 1590-1594.

Zucchetti, I., De Santis, R., Grusea, S., Pontarotti, P. and Du Pasquier, L. 2009. Origin and evolution of the vertebrate leukocyte receptors: the lesson from tunicates. Immunogenetics 61: 463-481.