This year’s Halocynthia roretzi season for research in Asamushi is over. All the remaining individuals in the aquarium tank were dissected to collect the tunics, which are going to be sent to someone in Shizuoka University for cellulose extraction. We will see them again in the next November.

Found a place near the main campus in Sendai (about 400 km away from the marine station) who serves cold ramen with slices of Halocynthia roretzi only in summer.

The course ended successfully today thanks to Daphne-san’s and Sebastien’s great efforts and leadership and to staff members’ generous assistances throughout the course. We are able to tell how excited the students also were from their performances in their presentations and the wrap-up party.

On day 3 of the marine biology course, Dr. Sebastien Darras from Banyuls Marine Station, France, is teaching a course of developmental biology of ascidians. Good to see students working hard to dissect adults and collect eggs and sperm for fertilization from many different kinds of ascidian species.

We are hosting an international marine biology course here in Asamushi. On day two today, Dr. Daphne Munroe from Rutgers University, USA, is teaching students from many countries in Asia and Europe an introductory coastal ecology course.

We are hosting a marine biology course for high school students during this weekend. They are trying to make twins of ascidians by isolating blastomeres of the two cell stage embryos under microscopes.

A PhD student, Huang, and Kumano went to a research workshop “Emerging Model Systems: From Unicellular Holozoans to Non-Bilaterians” held in NIBB, Okazaki. Huang presented his research for the first time on tentacle branch formation in the jellyfish Cladonema pacificum by FGF signaling.

A prospective graduate student Haga-san, who will start next spring, visited the lab and attended our progress report and journal club. We had a welcome dinner in the city center of Aomori.

We went to purchase noon type ascidians from a fisherman in Sanriku coast. We stayed one night in Onagawa Field Center in Tohoku Univ., went to the Karakuwa fishing port next morning, where farming of Halocynthia roretzi started originally, and came back with more than 300 of them in Asamushi.

We went to the Harabetsu fishing port to buy morning type Halocynthia roretzi, a.k.a. White Hoya, from a local fisherman. These ascidians are farmed for several years in the sea, originating from young juveniles grown by a fisheries facility through artificial fertilization and larval attachment.

We hosted a seminar in the station by Dr. Kei Jokura from National Institute for Basic Biology. He was talking to us about his research on the function of cilia in the comb plates and balance organs in ctenophore.

We went out on the boat off the Kominato fishing port to collect morning type ascidians Halocynthia roretzi. Two technicians dived into the sea about 25 m deep twice each and picked more than a hundred natural individuals in total. They will be used for our research in the upcoming spawning season.

As a part of the jellyfish workshop, we got to see the backyard of the Asamushi Aquarium. We were all excited to see how they grow and maintain many kinds of jellyfish they are exhibiting there.

We are hosting a jellyfish workshop here in Asamushi (Oct 5-9). People from Dr. Mark Martindale’s lab in Florida, Dr. Cheryl Ames’ lab in Sendai and Kumano’s lab are gathering all together, and experiencing and discussing jellyfish and other marine animals all day long.

A new student Lu Wang has set up the culturing system for Clytia sp. IZ-D in the lab. She is the first one in the lab to use this species for research. It is a new species recently collected off the coast of Sanriku. It has just started producing medusae so hopefully we can get gametes in ten days.

A PhD student Yuma Miyazawa and Kumano are now in Tutzing, Germany, attending Hydra Meeting 2025. All the participants are staying within the grounds of Evangelische Akademie Tutzing, a historical education and conference center, and discussing biology of basal metazoans all day. Very good meeting.

This is the other one developing. The movie was taken by a student.

We are hosting a marine biology course for Japanese and international students from Kyoto, Tsukuba and Sendai. On Day 3 they tried to collect eggs and sperm from three different animals, starfish, sand dollars and sea squirts on their own, and got two of them fertilized and they are now developing.

We finally got EDOKKO 1 into the sea about 15 and 35 m deep to monitor environmental conditions for the scallop farming in Mutsu bay for the next several months in collaboration with the local government and fishermen. The fishermen and the technicians of the station did great job together.

Kumano visited the Dr. Deguchi’s lab in Miyagi University of Education to collect cleavage-stage embryos of the jellyfish Clytia IZ-D for us to do in situ hybridization analysis. They kindly had eggs and sperm spawned, fertilized them and grew them to the stage of our interest on the spot.

Assist. Prof. Shumpei Morita attended 19th International Congress of Comparative Endocrinology held in Sendai from July 8th to 12th and presented his research on germ cell regeneration mechanisms in the ascidian Ciona robusta.

Assistant Prof. Shumpei Morita was in Noto Marine Station, Kanazawa University, from June 26 to 28 to collect Peronella japonica for his research on germline development in sea urchins. Research with this species could give us an interesting insight into the evolution of germline development.

Technicians Hirabayashi-san and Koyama-san dived and collected for us young ascidian individuals of H. roretzi from the sea around the Hadaka-jima island by the station. The biggest individual in the image is about 5 cm in size (about 2 years old) and the smallest 1 cm (about 1 year old).

Kumano is now in Suwa, attending the annual director meeting of Japan’s Marine and lake stations. They took us a tour to the Suwa Hydrobiological Station, Shinshu University, located by the Suwa lake. Very surprisingly, the station has its own hot spring, which is so amazing!

Asst. Prof. Shumpei Morita was in Tateyama Marine Station of Ochanomizu University for a week for his collaborative research with Prof. Kiyomoto there on germ cell regeneration in sea urchin embryos. Labeled green in the left image are primordial germ cells in a Hemicentrotus gastrula embryo.

We are now recruiting students for April 2026 admission to the Master degree program of our Graduate School. If you are interested in studying with us in Asamushi, please visit the website below and contact us for more information and a lab tour. www.lifesci.tohoku.ac.jp/en/admission...

We got some adults of the ascidian Ciona savignyi with full of eggs and sperm for our research from a fisheries facility of Aomori city. While they are a useful animal for us to study biology with, they are very disliked by local fishermen as being damaging to the scallop farming in the Mutsu bay.

A PhD student Mako Takahashi found a fused medusa of C. pacificum in one of her culturing dishes. It has two manubria (and mouths) and twelve main tentacles. It was produced in fusion during its budding off the side of a polyp, unlike a recent report on fused comb jellies by Dr. Jokura in Curr Biol.

The manuscript entitled “Diversification of cnidarian mechanosensory neurons across life cycle phases: evidence from Hydrozoa”, which describes research done by Prof. Nakanishi from U. of Arkansas during his sabbatical stay in the station, has been accepted in Integrative and Comparative Biology.

The ascidian Halocynthia roretzi fertilized in February in the lab has grown into a juvenile about 1 mm in its size in the station’s aquarium tank.