News Letter Vol.11
Kinki University 21st Century COE Program English Site > News Letter Vol.11
21st Century COE Program 'Center for Aquaculture Science and Technology for Bluefin Tuna and Other Cultivated Fish'
A detailed introduction to and the current status of the research activities of the cross-group project

Shigeru Miyashita (Cross-group project member, Fisheries Laboratory)

At this research site, we launched two projects, 'Research on the development of a bluefin culture manual' and 'Research on the development of environmentally friendly seedling production technology', in 2004 to systematically coordinate the activities of the research groups and contribute directly to the development of the culture industry. In 2005, we started an 'Experiment for the practical application of artificial formula feed for bluefin tuna' and initiated 'Research on the aptitude of crossbred red sea bream (female) × black sea bream (male) for cultivation in South Korea' in accordance with the academic agreement with and at the strong request of Chonnam National University in South Korea.

In this year or the COE Program's final year, we suspended the 'Research on the development of a bluefin culture manual' as it requires more than one year's experiment and it is not difficult to start a new experiment. In this volume, we would like to depict the current status of the other three projects.

1. Research on the development of environmentally friendly seedling production technology (Seedling Production and Environmental Groups)

Launched by the Environmental Group and the Seedling Production Group in 2007, this project has been pursued as part of the effort to develop microbe-controlled seedling production technology in cooperation with University Malaysia Sabah, with which we concluded an overseas academic agreement. At the same time, we have studied initial feed for fish species which are very difficult to breed. Presented below are the achievements attained so far and the research activities being conducted now.

Development of microbe-controlled seedling production technology (Gentoku Nakase and Yoshizumi Nakagawa, CEO Doctorate Researchers)

Blubberlip snapper
Grey large-eye bream
Experiment at the University Malaysia Sabah Borneo Marine Research Institute
Bacteria communities existing in larva breeding water affect the survival of the larvae, and successful breeding requires skillful control of these communities. In order to conduct an ecological study of the relationship between the microbial communities and the larvae in larva breeding water, we analyzed the composition of bacteria communities in a culture solution of Nannochloropsis sp., phytoplankton added to larva breeding water and breeding water, at the University Malaysia Sabah Borneo Marine Research Institute. And we studied the impact of the feeding of Nannochloropsis by Protozoa in the breeding tank.

We found that specific bacteria communities are predominant in the culture solution of Nannochloropsis, which was added to the breeding water, and this suggested that Nannochloropsis is controlling surrounding bacteria communities. We also found that the addition of Nannochloropsis to larva breeding water resulted in smaller variance in the composition of bacteria communities the breeding water, contributing to the increase of the larva survival rate. Based on the results of these studies, we found that we would be able to use Nannochloropsis as a 'Tool' for controlling bacteria communities in breeding water. We are now trying to understand how Nannochloropsis controls surrounding bacteria communities. It was also found that Protozoa in the breeding tank eat up to approximately 80% of Nannochloropsis in a day. We are now studying the relationship between the amount of Nannochloropsis added and the effect of such addition.

Research on initial feed for fish species which are highly difficult to breed (Yoshizumi Nakagawa, COE Doctoral Researcher)

The mouth of grey large-eye bream, and blubberlip snapper in Malaysia, is so small at the first breeding time that they cannot eat rotifer and thus cannot be bred with it at the initial stage. It is necessary to develop feed other than rotifer. Thus, we conducted research on the feeding ecological characteristics of these two fishes at the larval stage.

As a result, it was suggested that the size of feed that can be eaten by grey large-eye bream at the first feeding time is around 50µm. When we investigated the larval selectivity of feed and size at the first feed time, using natural plankton, the larval blubberlip snapper and grey large-eye bream ate plankton larger than approximately 10µm and selectively took in flagellate, ciliate and diatom greater than 20µm. Diatom and Protozoa can be cultivated and are prospective initial feed for these fishes.

2. Experiment for the practical application of artificial formula feed for bluefin tuna (Feed, Nutrition, and Culture Group)
In this experiment started in fiscal 2006, it was difficult to breed bluefin tuna in a test small preserve (12m) and we had to breed them separately at each stage of growth, but there is a good prospect of the practical application of the feed to artificially incubated larvae.

Thus, this year, we are conducting an experiment to breed larvae for a long time to evaluate the effectiveness of the feed and elucidate feed digestion and swimming behavior.

1,700 of 35-day-old artificially incubated larval bluefin tuna (7cm in length and 3kg in weight) were contained in a 12m-square preserve at the Tanabe Bay test fishery of the Fisheries Laboratory Shirahama test site, and a breeding experiment is being conducted there under the leadership of Professor Osamu Murata. The test feed is Single Moist developed by Professor Takii etc. based on enzyme-processed fish meal. In 40 days after the start of the experiment, the test fish grew to approximately 23cm in length and approximately 200g in weight. Although the survival rate was as low as around 24%, we assume that this formula feed is highly effective for long-term breeding, taking the fact into account that this species is difficult to breed in a (small) test preserve.

3. Research on the aptitude of crossbred red sea bream (female) × black sea bream (male) for cultivation in South Korea (Seedling Production, Culture, Feed, and Nutrition Groups)
It is difficult to cultivate red sea bream in waters around the Korean Peninsula in winter, so Chonnam National University has been searching for other fish species for cultivation. Finding crossbred red sea bream (female) × black sea bream (male), a species which has been developed at the Kinki University Fisheries Laboratory since 1966 and is resistant against low temperatures, to be prospective, the university strongly called for our cooperation in their introductory experiments. Thus, in fiscal 2006, we launched this research to examine the species' aptitude for cultivation in South Korea, transporting ova and larvae to the country. The experiment is now under way and the results will be reported in the next volume.

Selection of graduate students receiving tuition reduction/exemption and scholarship in 2007

Hiromi Ota (COE Special Director, Graduate School of Agriculture)

Kinki University grants a tuition reduction/exemption and a scholarship to graduate school doctoral and masters course students (MC, DC) at the bluefin tuna COE so that they can devote themselves to the studies and researches without having to worry about money. The COE Promotion Committee reviewed and screened applicants for this year on the basis of their research plans and TOEIC certificates, the recommendation letters written by their tutors (responsible for business promotion), and the President finally approved tuition exemption for eight DC students, a 50% tuition cut for 19 MC students, and a scholarship for five DC students.

We hope that the graduate students in such a good environment will become researchers or engineers who can provide plenty of information to the world.

Report on the Fiscal 2007 COE Young Researchers' Symposium 'Kindai Cultured Fish Festival — Come and touch and do science!'

Yoshizumi Nakagawa, COE Doctoral Researcher (Seedling Production and Culture Group, Fisheries Laboratory)

We held 'Kindai Cultured Fish Festival — Come and touch and do science!' on August 25 (Saturday), 2007 at the Fisheries Laboratory Shirahama test site. This symposium was planned and administered by young COE Program researchers (doctoral researchers and graduate school doctoral course students). The young researchers have held a symposium every year since 2005, and the symposium for this year, or the final year of the COE Program, is the third one.

At the previous symposiums, the young researchers tried to have laypeople understand the results of COE Program researches and the studies related to fish culture. Last year, the symposium was held in the form of Science Cafe so that the participants could talk about science at the front, especially themes related to the studies conducted under the COE Program, in a relaxing atmosphere. We conducted a few sessions and received the largest audience at the last session, seeing the symposium end with great success.

This year, we developed a plan very deliberately through several face-to-face meetings and email discussions. The objective of this year's symposium is to have general participants understand the results of COE Program researches as well as how it is exciting, difficult, and important to study fish cultivation. For this end, we thought it is necessary not only for us to give presentations and show video images, but also for the participants to see, touch, and feel closer to the subjects of research. Thus we decided to offer the participants an opportunity to see a marine culture preserve, feed the fish, and conduct a fundamental fish culture experiment indoors at the Fisheries Laboratory Shirahama test site.

'Kindai Cultured Fish Festival — Come and touch and do science!' consisted of two parts. At Part 1 'Let's see an actual culture site', the participants saw an actual marine preserve, fed the fish, inspected fish bathing in freshwater for parasite extermination at a wharf, watched water quality analysis and sampling, and visited the Samusaura Breeding Building. At Part 2 'Touch cultured fish and enter into the world of science', the participants observed cultured larvae, collected and observed fish otolith, observed the maturity, ovum collection and fertilization of cultured fish, made and observed qualitative measurements of the water of a culture preserve, and watched a video film about the distribution of tuna.

Major advertisements included a new website, a link to the websites of the Graduate School of Agriculture and the Fisheries Laboratory, invitations to the participants of the last year's Science Cafe, posters put up in Nara, and Tanabe in Shirahama, and newspaper and TV advertisements. While we were ready to provide up to 50 seats, we received previous application from almost 60 persons. Since some canceled their applications, the actual number of participants was 53. The audience was so diverse as to include a three-year-old kid and a retiree aged over 60. The participants also included several families as the symposium was held during the summer vacation. We recognized the effect of the advertisements when we received applications not only from the venue, Shirahama Town, and areas around it, but also from other prefectures. Two news reporters also came. Later, the Kindai Cultured Fish Festival was covered in a newspaper.

'The 'Kindai Cultured Fish Festival' began at 13:00, when the reporter gave an opening speech and explained the objective of the festival. At an actual marine preserve, the participants fed the cultured fish, cheering to see them eating the feed. The responses to the questionnaire also showed that feeding at the preserve was the most exciting event. We are sure that it was a very impressive experience. The participants also enjoyed fish bathing in freshwater in a preserve at a wharf and the tour of the Samusaura Breeding Building. We were impressed to see them staring at freshwater bathing in the strong sunlight. At Part 2, we conducted five experiments and showed a film at the main and new buildings, respectively. We were impressed to see the participants, from young to old, dissect fish and listen carefully to the young researchers' explanations about the fish in a tank and the plankton observed under the microscope. Many participants watched a video film about the distribution of tuna. During the tours and experiments, the participants asked many questions. We are sure that it was also a wonderful experience for the high school students who were excited with the smell of fish left on their palms after the experiments. The 'Kindai Cultured Fish Festival' ended with success at 16:45, when the reporter gave a closing speech.

Discovery and problem
When we asked the participants in a questionnaire whether they would like to come if similar events are held, 78% replied positively. When asked whether their image of cultured fish has changed, 76% answered that their image of cultured fish improved during the symposium. About one half of these respondents said their image of cultured fish improved considerably. We think that this festival was a success, just because the questionnaire survey showed it and there was no injury, accident, or trouble. Later, we received a letter of gratitude from a three-year-old participant, on which a picture of cultured fish was drawn. He came to the Shirahama test site just because he wanted to hand the letter in person. We are very happy that the festival ended successfully. This success should be attributed to COE Leader Kumai, Professor Murata, Instructor Kato, the staff at the marine culture preserve, the administrative office of the Shirahama test site and all the other members of the Fisheries Laboratory, Professor Takii, Associate Professor Tsukamasa, and other COE symposium committee members, all of whom understood and supported the symposium. We sincerely appreciate for their warmth combined with strictness.

Lastly, I would like to thank the young researchers, who worked with great patience with the person who doesn't have what it takes to be a chairperson, and sometimes gave me severe advice, all the way from the planning stage, though they were busy with their experiments and theses. This symposium would not have ended with success without their cooperation and patience. I will never forget my collaboration with them. I would also like to thank the pleasant friends at the Shirahama test site who pleasantly helped me in the preparations, including the cleaning of the breeding building, the making of billboards, the putting up of posters, and the transportation of sweetfish.