United States-Japan Natural Resources (UJNR)
Panel on Aquaculture
41st Scientific Symposium“Advanced Aquaculture Technologies”
October 9-10, 2013
Sapporo, Hokkaido

Program and Abstracts

Photo: Spawning sea cucumbers (Apostichopus japonicus) induced with “cubifrin” pictured by Dr. K.
Yamano (FRA)

Program
The 41st Scientific Symposium of the UJNR Aquaculture Panel

Advanced Aquaculture Technologies

Wednesday, October 9th, 2013
Registration 13:00-17:00
Welcome and opening remarks (Masaaki Fukuda, Director, Hokkaido National Fisheries
Research Institute, FRA) ・・・・・・・・・・・・・・・・・・・ 13:30-13:45
Aim of the Symposium (Katsuma Hanafusa, Japan Panel Chair) ・・・・・・・13:45-14:00
Session Ⅰ. Overview of Aquaculture in the US and Japan(Moderators: P. Olin & Y. Machiguchi)
1. The Fisheries Agency’s policy directions for aquaculture
Kazumasa Ikuta (Counselor, Resource Enhancement Promotion Department
Japan Fisheries Agency, Ministry of Agriculture Forestry and Fisheries)
・・・・・・・・・・・・・・・・・・・・・・・・・・・・・14:00-14:20
2. Aquaculture in the US: The First Annual National Report on Aquaculture
Marie Fujitani (NOAA Office of Aquaculture)・・・・・・・・・・・14:20-14:40
3. The Challenge of Reconstructing Coho Salmon Aquaculture after the Great East Japan
Earthquake and Tsunami in 2011
Ikutaro Shimizu (National Research Institute of Fisheries Science, FRA)
・・・・・・・・・・・・・・・・・・・・・・・・・14:40-15:00
Discussion・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・15:00-15:10
Break・・・・・・・・・・・・・・・・・・・・・・・・・・・・・15:10-15:20
Session Ⅱ. Fish Diet and Nutrition(Moderators: K. Webb & K. Murashita)
4. Development of a new type of fish diet, non-fish meal extruded-pellet
Noriko Ishida (National Research Institute of Fisheries Science, FRA)
・・・・・・・・・・・・・・・・・・・・・・・・・・15:20-15:40
5. The importance of taurine and n-3 fatty acids in cobia nutrition

Aaron Watson (University of Maryland)
・・・・・・・・・・・・・・・・・・・・・・・15:40-16:00
1

6. Availability of fisheries by-product materials with cadmium removal treatment as a feed
ingredient for fingerling black rockfish Sebastes schlegeli
Nobukazu Satoh (Fisheries Research Department Mariculture Fisheries ResearchInstitute, Hokkaido Research Organization) ・・・・・・・・・・16:00-16:20
7. Development and characterization of several open formula reference diets for marine
fish larvae
Ken Webb (NOAA, Northwest Fisheries Science Center)・・・・・・・・・・・・・・・・・・・・・・・・・・・16:20-16:40
8. Effects of diets supplemented with herb essential oils on ectoparasitic protozoan
infections on chum salmon (Oncorhynchus keta) fry
Shinya Mizuno (Salmon and Freshwater Fisheries Research Institute,
Hokkaido Research Organization) ・・・・・・・・・・・・・・・・・・16:40-17:00
Discussion・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・17:00-17:20
Thursday, October 10th, 2013

Registration

9:00-9:20

Session Ⅱ. Fish Diet and Nutrition; continued(Moderators: A. Watson & N. Satoh)
9. Effect of feed ingredients on digestive enzyme secretion in fish
Koji Murashita (National Research Institute of Aquaculture, FRA)
・・・・・・・・・・・・・・・・・・・・・・・・9:20-9:40
10. Cholecystokinin and trypsin responses of larval red drum (Sciaenops ocellatus) in
response to algae, live prey, and inert particles
Michael B. Rust (NOAA) (Presented by Ken Webb)・・・・・・・・・・・9:40-10:00
Discussion・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・10:00-10:10
Session Ⅲ. Management, Social and Economic Issues of the Aquaculture Industry(Moderators: M. Fujitani & I. Shimizu)
11. An analysis of the causality between the market price of imported fishmeal and market
price of marine farmed fish
Yoshifumi Takahashi (Tohoku National Fisheries Research Institute, FRA)
・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・10:10-10:30
12. Good Aquaculture Practices to Reduce the Use of Chemotherapeutic Agents,
Minimize Bacterial Resistance, and Control Product Quality
Stanley Serfling (Food and Drug Administration Office of Food Safety)(Presented by M. Fujitani)・・・・・・・・・・・・・・・・・・・・・・10:30-10:50
13. Modeling intraspecific genetic effects for Management of Aquaculture Programs
Jason Volk (ICF International) ・・・・・・・・・・・・・・・・・10:50-11:10
2

Discussion・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・11:10-11:20
Group Photo Session・・・・・・・・・・・・・・・・・・・・・・・・11:20-11:40
Lunch Break・・・・・・・・・・・・・・・・・・・・・・・・・・・・11:40-13:00
Session Ⅳ. Techniques of Aquaculture Production(Moderators: J. Volk & K. Okuzawa)14. Specific monovalent and divalent ion supplementation for culture of marine species
Chris Green (Louisiana State University Agricultural Center) ・・・・・13:00-13:20
15. Genetically modified salmon in aquaculture: well regulated and safe
Paul G. Olin (UC SD/ Scripps Institution of Oceanography) ・・・・・13:20-13:40
16. Reproductive dysfunction in cultured sablefish (Anoplopoma fimbria)
Jose Guzman (NOAA) ・・・・・・・・・・・・・・・・・・・13:40-14:00
Discussion・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・14:00-14:10
Session Ⅴ. Invertebrate Aquaculture I: Echinoderm(Moderators: S. Eddy & T. Unuma)
17. Induced spawning in the sea cucumber Apostichopus japonicus by neuropeptide,cubifrin
Keisuke Yamano (National Research Institute of Aquaculture, FRA)
・・・・・・・・・・・・・・・・・・・・・・・・・・・・・14:10-14:30
18. Mass production of artificial seed of the Japanese common sea cucumber(Apostichopus japonicus) in Hokkaido, Japan
Yuichi Sakai (Fisheries Research Department Mariculture Fisheries ResearchInstitute, Hokkaido Research Organization) ・・・・・・・・・・・・14:30-14:50
Break・・・・・・・・・・・・・・・・・・・・・・・・・・・・・14:50-15:00(Moderators: D. Morse & K. Yamano)
19. Fluorochrome marking of out-planted green sea urchins, Strongylocentrotus
droebachiensis, for sea ranching and restocking programs in the Gulf of Maine, USA
Stephen Eddy (University of Maine, Center for Cooperative Aquaculture
Research) ・・・・・・・・・・・・・・・・・・・・・・・・・・15:00-15:20
20. Improving the food quality of sea urchin gonads by suppressing gametogenesis
Tatsuya Unuma (Hokkaido National Fisheries Research Institute, FRA)
・・・・・・・・・・・・・・・・・・・・・・・・・15:20-15:40

3

21. Maturation control of the short-spined sea urchin, Strongylocentrotus intermedius, by
low temperature rearing using deep-sea water, with the aim of extending the market
seasonTakaaki Kayaba (Kushiro Fisheries Research Institute, Hokkaido Research
Organization)・・・・・・・・・・・・・・・・・・・・・・・・・・15:40-16:00
Session Ⅵ. Invertebrate Aquaculture II: Mollusc(Moderators: C. Green & Y. Sakai)
22. Long-term outcomes in the tech transfer of scallop spat collection techniques, from
Aomori Prefecture, Japan to Maine, USA
Dana Morse (Maine Sea Grant)・・・・・・・・・・・・・・・・・・16:00-16:20
23. Relationship between spat density and environmental factors in cultured Japanese
Scallop, Mizuhopecten yessoensis in Funka Bay, Japan.
Katsuhisa Baba (Hakodate Fisheries Research Institute, Hokkaido Research
Organization) ・・・・・・・・・・・・・・・・・・・・・・・・・16:20-16:40
24. Oyster culture in Hokkaido, Japan
Natsuki Hasegawa (National Research Institute of Aquaculture, FRA)
・ ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・16:40-17:00
Discussion・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・17:00-17:10
Closing remarks (Paul Olin, U.S.A. Panel Chair)・・・・・・・・・・17:10-17:20

4

Abstracts

THE FISHERIES AGENCY’S POLICY DIRECTIONS FOR
AQUACULTURE
Kazumasa Ikuta
Counselor, Resource Enhancement Promotion Department
Japan Fisheries Agency, Ministry of Agriculture Forestry and Fisheries
Aquaculture is an important industry in Japan, and production levels occupy
approximately 20% in terms of yield, and 30% in terms of market value, of the country’s
total fisheries production. However, the economic aspects of aquaculture have been
precarious due to the low price of certain products and increasing costs of production. In
addition, the guarantee of food safety, minimization of environmental impact, andmanagement of natural stock populations are highly necessitated in order to achieve thesustainability of the industry.
In order to address these problems, the Fisheries Agency held a series of committee
meetings during 2013 in order to develop ideal projections for the aquaculture industry.
Thereafter, policy directions for aquaculture were put forth as follows:
1) Measures to improve unstable business practices of aquaculture should be
implemented; this includes the expansion of mutual-aid systems, conversion of
feed resources to alternative usages of protein, maintenance of carrying capacity,
improvement of systems to compensate for increases in feed costs, and thepromotion of planned production including the enhanced exportation of products.
2) Measures to improve production techniques should be implemented; this includes
achieving improved food safety based on production systems that have hightraceability, risk management and the usage of vaccines, conservation of theenvironment in and around aquaculture grounds, a shift from the use of wild fish
seedlings and natural feed resources to the use of artificially-produced seedlings
and feeds, the development of enclosed recirculating aquaculture systems, andR&D for advanced aquaculture technologies that will reduce costs and enhance
productivity such as offshore aquaculture systems, enhanced breeding
methodologies, and raft aquaculture systems for new bivalve species.

4U.S. FIRST ANNUAL REPORT ON AQUACULTURE FOR THE
U.S.-JAPAN NATURAL RESOURCES PANEL ON AQUACULTURE
Marie Fujitani
Office of Aquaculture NOAA National Marine Fisheries Service 1315 East-West Highway
Silver Spring, MD 20910*E-mail: Marie.fujitani @ noaa.gov
The first U.S. National Report on Aquaculture for the 41st U.S. Japan Natural Resources
Panel on Aquaculture will overview major policy items, current trends in aquaculture
production, and other important developments affecting contemporary U.S. aquaculture.
Policy- April 2013 saw the release of the National Ocean Policy Implementation Plan
(NOP-IP), a document to translate President Obama’s 2010 National Ocean Policy(Executive Order 13547 --Stewardship of the Ocean, Our Coasts, and the Great Lakes) to
specific federal actions. Aquaculture featured prominently in the Implementation Plan. The
Joint Sub-committee on Aquaculture (JSA) was re-named the Interagency Working Groupon Aquaculture (IWG-A), and was tasked with identifying and supporting milestones in the
NOP-IP. The NOP-IP also supported the National Shellfish Initiative to increase shellfish
production and restoration in U.S. waters. NOAA is currently reviewing the proposed
regulations that would implement the Gulf Council's Fishery Management Plan forRegulating Offshore Marine Aquaculture in the Gulf of Mexico. This would permit
aquaculture in federal waters in the Gulf of Mexico, and would be a first for the U.S. as
there is currently no framework for permitting aquaculture anywhere in our Exclusive
Economic Zone. We expect final regulations to be effective sometime in 2014.
Developments- For the first time in some years, in 2013 many new sites for shellfish
aquaculture have been permitted. This is attributed to increased interest in shellfish
aquaculture, particularly in the northwest and northeast, federal interagency and state efforts
on behalf of the Washington Shellfish Initiative, and state-level successes at streamlining
permitting. In September 2013, the California Shellfish Initiative was launched. A programis underway to permit and restore Hawaiian fishponds, a form of traditional Hawaiian
aquaculture, for cultural heritage, subsistence, and possibly commercial production.
Production Trends- Aquaculture production in the U.S. consists of trout, tilapia, catfish,
crawfish, shrimp, salmon, oysters, mussels, and clams. For the period from 2005-2010, thevalue of U.S. aquaculture showed 3% average year-over-year growth, though total volume
fell by an average of 1.8%. Marine aquaculture (salmon and shellfish), on the other hand,showed robust 14.6% year-over- year average (by volume) growth in the same period. 2010is the last year published aquaculture statistics are available. From 2009 to 2010, total U.S.
aquaculture grew 4% by volume (to 341,568 metric tons) and 10% by value (to 1.28 billion
dollars). Marine aquaculture grew 22% by volume (to 40,823 metric tons) and 28% byvalue (to 312 million dollars). Most of the growth in value for marine aquaculture is from
salmon (Salmo salar) and oyster (mainly Crassostrea gigas and Crassotrea virginica)
production.
5

THE CHALLENGE OF RECONSTRUCTING COHO SALMONAQUACULTURE AFTER THE GREAT EAST JAPAN EARTHQUAKEAND TSUNAMI IN 2011
Ikutaro Shimizu1*, Tsuyoshi Tanaka2, Hideki Miura 3 and Kohichi Saotome 41

National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4
Fukuura, Kanazawa-ku, Yokohama, 236-8648 Japan
2
Fishing Industry and Communities Promotion Organization, 1-27 Kaisei, Ishinomaki,
Miyagi, 986-0032 Japan
3
Japan Fisheries Cooperatives, 1-1-12 Uchikanda, Chiyoda-ku, Tokyo, 101-8503 Japan
4
Tohoku National Fisheries Research Institute, Fisheries Research Agency, 3-27-5
Shinhamacho, Shiogama, Miyagi, 985-0001 Japan*
E-mail: ikutaro@affrc.go.jp
Aquaculture of coho salmon (Oncorhynchus Kisutsh) is one of the most importantfisheries in Miyagi prefecture, Tohoku, where they had annually produced more than
10,000 tons until 2010. However, the Great East Japan Earthquake hit the Pacific coast areaof eastern Japan on March 11 in 2011. The tsunami destroyed nearly all the farming
facilities, local fish markets, and processing firms in the Sanriku region, and suspended
coho salmon farming since then. One year later, farmed coho salmon started being landed
again by the support of national funding. Fortunately, the tsunami did not affect thejuveniles of inland coho salmon. While the wholesale prices of the farmed salmon in local
fish markets showed higher prices (more than 400 yen/kg) before the tsunami, the price ofthe farmed salmon slumped in 2012 (less than 200 yen/kg). The higher price (beyond
370-380 yen/kg) is necessary to maintain the farming facilities for management. It isnecessary for stakeholders to clarify the causes of the slump to make a reconstruction planfor Sanriku salmon aquaculture. This paper aims to clarify the issues in the reconstruction
process of coho salmon aquaculture.
We conducted interviews at fisheries cooperatives, farming facilities, local fish markets,
seafood processing firms, and wholesale markets in Miyagi prefecture in September andOctober 2012, and general merchandising stores in the Tokyo area in November.
Based on the interviews, the causes of the price drop in domestic farmed coho salmon(Sanriku coho salmon) can be as follows: (1) The mass imports of Chilean farmed coho
salmon since the autumn in 2011 reduced the domestic wholesale price, (2) Low sea watertemperature in the winter 2012 suppressed the growth of Sanriku coho salmon, (3) Latelanding of Sanriku coho salmon in the spring 2012 affected centralized supply in June, (4)The spread of rumors about radiation caused by the accident at Fukushima nuclear power
plant decreased the demand for Sanriku coho salmon, (5) Avoiding prolonged cold storageand increase in fresh supply of Sanriku coho salmon reduced the farmed coho salmon price,and (6) The discontinuation of the supply of Sanriku coho salmon in 2011 changed
consumers’ purchasing pattern from Sanriku to imported salmon.
The price of Sanriku coho salmon has synchronized with the price of Chilean frozen
6farmed coho salmon, and has decreased since the 1980s. One of the most importantcharacteristics of Sanriku coho salmon aquaculture is differentiation by fresh products. In
addition, the spring supply of fresh seafood has been less than other seasons in the Sanriku
region. It is important to supply fresh salmon for consumer markets by the Golden Week
holidays (from late April to early May). It is necessary to improve the traditional
aquaculture system to consolidate a new brand value for Sanriku coho salmon. Sales
promotion has been expected to drive the fresh coho salmon price up to a fair level. We
believe that the development of Sanriku coho salmon aquaculture contributes to thereconstruction of regional industries in Miyagi prefecture.
Key words:
Sanriku coho salmon aquaculture, Great East Japan Earthquake, Reconstruction, Wholesale
price, Chilean coho salmon

7

DEVELOPMENT OF A NEW TYPE OF FISH DIET, NON-FISH MEAL
EXTRUDED-PELLET
Noriko Ishida1*, Tomohiko Koshiishi2, Tatsuo Tsusaki3, Koji Maeno4, Satoshi
Katayama5, Minoru Sato5, and Shuichi Sato6
1

National Research Institute of Fisheries Science, FRA, Yokohama 236-8648, Japan
Marubeni Nisshin Feed Co., LTD., Aichi 441-3605, Japan
3
National Research Institute of Fisheries and Environment of Inland Sea, FRA, Ehime794-2305, Japan
4
Kagoshima Prefectural Fisheries Technology and Development Center, Kagoshima
891-0315, Japan
5
Tohoku University, Sendai 981-8555, Japan
6
Tokyo University of Marine Science and Technology, Tokyo 108-8477, Japan*Email: larry@affrc.go.jp
2

Globally the price of fish meal has increased dramatically in recent years due toreduced production caused by fishery regulation in South America and the increased
worldwide demand for aquacultured fish. The increasing fish meal price threatens businessconditions of Japanese aquaculture farmers because fish meal for Japanese aquaculture feed
is dependent on imports. Therefore, in Japan a new type of diet that is independent of fishmeal is strongly desired. Low or non-fish meal extruded-pellets have been developed. Firstof all, 10% fish meal containing diets were prepared, and fed to cultured yellowtail, and thefish growth performances were compared to those of 50% fish meal containing diet. It wasobserved that fish growth was similar in both diet groups. Then, three experimental
non-fish meal extruded-pellets were designed, and were fed to one-year-old yellowtail(immature, rapidly growing fish).
The control diet contained 50% fish meal and the fish growth was compared withyellowtail reared on three kinds of non-fish meal diets that replaced the fish meal withcommercially available plant and animal ingredients. Soy protein concentrate, defatted soybean meal, and corn gluten meal for plant material and pork meal, feather meal, and blood
meal for animal material were employed in this study.
It is known that yellowtail become less responsive to a diet as the amount of fish meal
included is reduced. Therefore, two commercially available materials, a skipjack peptide
and a fish sauce were supplemented to maintain the palatability of the non-fish meal diet.
The skipjack peptide is concentrated from the cooking water of skipjack and tuna. The fishsauce is made from mackerel gut using a patent-pending method of rapid production.
Non-fish meal diet No.1 contains plant meals and the skipjack peptide.
Non-fish meal diet No.2 contains animal meals and the skipjack peptide.
Non-fish meal diet No.3 contains plant meals and the fish sauce.
One-year-old yellowtail that originated from seeding production in Goto Island,
Nagasaki Prefecture were used. 55 fish with an average body weight of 753g. were8

transported to 4 m x 4 m net cages on the sea surface, and fed the trial diets from July till
March for 8 months.
Five months later, fork length and body weight were measured and compared. Average
fork length and body weight were 476 mm and 2068 g in the control diet, 474 mm and2131 g in the No. 1 diet, 476 mm and 2233 g in the No.2 diet, and 480 mm and 2152 g in
the No.3 diet. Differences between control and non-fish meal diets were not observed andthe growth was almost the same. There was no difference between daily weight gain(%/day), daily feeding rate (%/day), and weight gain ratio (%), 0.58 %, 2.24 %/day, 2.83 in
the control, 0.58 - 0.59 %, 2.21 - 2.26 %/day, 2.76 - 2.83 in the non-fish meal diet groups.
These results demonstrate that non-fish meal diets have the potential to support thegrowth of one-year-old yellowtail. Now, the effect of these diets on fish meat quality as amethod of enhancing the meat quality control is being determined.
This work was supported by Research and Development Projects for application inpromoting new policy of agriculture, forestry and fisheries from the Ministry of Agriculture,
Forestry and Fisheries of Japan.
Key words
yellowtail (Seriola quinqueradiata), non-fish meal extruded pellet.

9THE IMPORTANCE OF TAURINE AND N-3 FATTY ACIDS IN
COBIA NUTRITION
Aaron Watson1*, Allen R. Place1
1

Institute of Marine and Environmental Technology, Baltimore, USA*E-mail: watsona@umces.edu
In the wild, fish evolve to their diet by down regulating or eliminating biosynthetic
pathways for nutrients found in abundance in their diets. Upon domestication these fish may
now have unique dietary requirements which must be met through supplementation. To
examine this hypothesis and aid in determining potential minimum requirement levels foraquaculture production, we have examined the synthetic capacity for taurine andpolyunsatured fatty acids in cobia, Rachycentron canadum, through molecular methods andgrowth trials, respectively.
Taurine, a non-protein amino acid, is found in high concentrations in the natural diet ofcobia and plays a variety of physiological roles. These roles include photoreceptor protection,
osmolyte, antioxidant, feed attractant, and as a bile salt conjugate. The taurine biosynthesis
pathway in vertebrates is well known; however it appears to be nonfunctional in someterrestrial (Felidae) and marine (Rachycentridae) carnivores, thereby necessitating dietary
supplementation. Taurine is not found in plant protein sources used for fishmeal
replacement.
We examined the effects of graded levels of taurine addition (0%, 0.5%, 1.5%, 5.0%) toboth a fishmeal based diet and a plant protein based diet with complete fishmeal replacement
formulated and manufactured by the USDA-ARS. At the conclusion of a growth trial, RNA
was extracted from liver, muscle, and brain tissue for quantitative-RT-PCR analysis of thegenes involved in taurine synthesis. Cysteine sulfinate decarboxylase (CSD), cysteine
dioxygenase (CDO), cysteamine dioxygenase (ADO), and taurine transporter (TauT)
activity and expression levels were examined and no differences in transcript abundance was
detected within the tissues between the dietary taurine levels. Increasing dietary taurine
resulted in increased growth rates.
To examine the effects of alternative sources completely replacing fish oil, tworeplacements were examined as the lipid sources in a fishmeal free, plant based feed
(USDA-ARS) and compared to a fish oil version of the diet. A thraustochytrid meal plus
soybean oil (TM+SOY) and a canola oil with exogenous docosahexaenoic (DHA) andarachidonic (ARA) acids (CO+EFA) were utilized. At the conclusion of an eight week
growth trial, whole body and fillet fatty acid profiles were examined.
The TM+SOY diet worked equivalently to the USDA-ARS control diet, however the
CO+EFA diet resulted in significantly lower growth and survival as well as an increased feed
conversion ratio. Whole body fatty acid profiles revealed a significant reduction in total
essential fatty acid (EFA) concentration in the CO+EFA fed fish, indicating the
supplemented levels of DHA and ARA were insufficient to meet requirements. Although all
three diets were sufficient in the precursors for EFA synthesis, this reduction in growth,survival, and whole body EFA concentration suggests cobia have limited synthetic capacity
for DHA and ARA. Both alternative lipid diets were devoid of eicosapentanoic acid (EPA)
supplementation, which does not appear to be essential for cobia as the TM+SOY dietperformed equivalently to the fish oil control.

10

AVAILABILITY OF FISHERIES BY-PRODUCT MATERIALS WITHCADMIUM REMOVAL TREATMENT AS A FEED INGREDIENT FOR
FINGERLING BLACK ROCKFISH SEBASTES SCHLEGELI
Nobukazu Satoh1*, Motoomi Wakasugi2, Shigeharu Nobuta3
1

Fisheries Research Department Mariculture Fisheries Reseach Institute, Hokkaido
Research Organization, 1-156-3, Funami-cho, Muroran, Hokkaido, 051-0013, Japan
2
Industrial Research Institute, Hokkaido Research Organization, Kita 19-jo Nishi
11-chome, Kita-ku, Sapporo, Hokkaido, 060-0819, Japan
3
Fisheries Research Department Kushiro Fisheries Reseach Institute, Hokkaido Research
Organization, 4-25, Nakahama-cho, Kushiro, Hokkaido, 085-0027, Japan*E-mail: sato-nobukazu@hro.or.jp
The price of fish meal, a major ingredient for fish feed, has been at high levels since2006 due to the increasing demand worldwide. Moreover, fish meal production in Chileand Peru has gradually declined because of fishery regulations for the purpose of sustaining
the fishery for anchovy (Engraulidae). These difficulties have affected the increase of feed
cost, which is predominant cost in aquaculture production. Therefore, the importance ofstudies on alternative protein sources for fish meal in diets has been increasingly realized.
However, it is widely recognized that high inclusion of alternative protein source in diets
results in poor palatability, particularly at low temperatures.
Squid liver and scallop mid-gut glands, which are generated and discarded as wastefrom the Japanese common squid Todarodes pacificus and Japanese scallop Mizuhopecten
yessoensis, are rich in amino acids and lipids. However, the squid liver and scallop mid-gut
glands contain cadmium (Cd) at 34 and 39 mg per kg wet weight on average, respectively.
Cd is generally known as a harmful heavy metal for human health. Wakasugi et al. recently
studied a technique for removal of Cd from squid viscera and scallop mid-gut glands andconfirmed the efficacy of the acid leaching and electrolysis method to produce the fisheries
by-product materials (meal and extract) with Cd removal treatment as a feed ingredient for
cultured fish.
So far we have evaluated the nutritional value of squid viscera meal with Cd removal
treatment (dCSVM), which contained 1.5-2.0 mg/kg Cd, as an alternative protein source tosardine meal in diets for fingerling black rockfish Sebastes schlegeli. In our study, it was
clearly demonstrated that dCSVM with good protein digestibility can be substituted for
60% of sardine meal in diets for juvenile black rockfish without growth retardation, poor
palatability and the problem of Cd accumulation. We suggested that dCSVM was superior
to commercial squid viscera meal without Cd removal treatment (CSVM) as a high-quality
feed ingredient for black rockfish based on the heavy metal accumulation in fish tissues.
Moreover, based on the merit that supplementation of methionine and lysine is notnecessary with the inclusion of dCSVM, we concluded that dCSVM can be used as analternative protein source in diets for fingerling black rockfish.
Recently, we are investigating availability of scallop mid-gut gland extract with Cd
11removal treatment (dCSMGE) as a feed ingredient for fingerling black rockfish. In the
recent study, we found that weight gain, specific growth rate, and feed efficiency of fish fed
the diet containing dCSMGE at 2% were significantly higher than those of the control.
Moreover, we confirmed that the Cd concentrations in fish muscle of all treatment groups
were below the detection limit (<0.01 mg/ kg dry matter).
Our results demonstrate that proper inclusion of dCSVM and dCSMGE is effective forthe improvement of feed quality in practical diets for fingerling black rockfish. Future
research is needed to clarify the nutritional value of dCSVM and dCSMGE as a feed
ingredient for aquaculture fish species other than black rockfish.
The research was financially supported by a Research Project for Utilizing Advanced
Technologies in Agriculture, Forestry, and Fisheries (grant no. 18031), Ministry ofAgriculture, Forestry, and Fisheries, Government of Japan and partly by Hokkaido
Government.
Key words
Black rockfish (Sebastes schlegeli), Squid viscera meal, Cadmium, Growth performance,
Alternative protein, Scallop mid-gut gland,

12

DEVELOPMENT AND CHARACTERIZATION OF SEVERAL OPEN
FORMULA REFERENCE DIETS FOR MARINE FISH LARVAE
Michael B. Rust1*, Frederic T. Barrows2, Mark Drawbridge3, Emily R. Hart 1, Kevin Stuart3,
Ken Webb1, Harold J. Barnett 1, Peter M. Nicklason1, and Ronald B. Johnson1.
1

NOAA, Northwest Fisheries Science Center, 2725 Montlake Blvd. E. Seattle, WA 98121
USDA/ARS-Fish Technology Center, 4050 Bridger Canyon Rd, Bozeman, Montana
59715
3
Hubbs-SeaWorld Research Institute, 2595 Ingraham Street, San Diego, CA 92109*E-mail: Mike.rust@noaa.gov
2

A limiting constraint in the development and growth of marine aquaculture is
successful hatchery production. Presently, larval finfish are raised using live feeds such as
copepods, rotifers and Artemia. Live feeds are expensive, time-consuming, labor intensive,
unreliable and nutritionally imperfect. An alternative to live feeds is microparticulate feeds,
however, high performance microparticulate diets for larval finfish are typically closed
formula commercial diets that make scientific inference difficult or impossible. We
describe a series of open formula microparticulate reference diets that have beenformulated and produced to facilitate comparisons across species and systems for use by
the scientific community. Open formula diets can produce consistent results among trials
and species, they can be simply formulated with well-defined ingredients and provide a
basic platform for improvement. The reference diets were processed by three methods:
flaking (F), microextrusion followed by marumerization (MEM) and particle-assisted
rotational agglomeration (PARA). An additional two diets were made by using the flake
diet and further processing it using the MEM (F-MEM) or PARA (F-PARA) methods.
The F, F-PARA and F-MEM diets had the same formulation and only differed byprocessing method. PARA and MEM had unique formulations. Each diet was screened
to the 400-700 m range. All microparticulate diets were compared to enriched Artemia
and rotifers (Brachionus plicatilis) for chemical analysis. Scanning electron microscopy(SEM) was used to visualize the microparticles between 22x and 4000x magnification. It
was clear that micropellet structure, sinking rate and leaching was influenced by bothformulation and manufacture method. Basic structure remained largely intact for all but
the F-PARA particles even after being immersed in fresh water for 15 minutes.
Compositional data, leaching half-life and sinking rates are given in the table below (values
in a column with differences at P<0.05 are denoted by superscripts). Data on feeding trials
with larval fish indicate that two of the open formula diets performed as well as, or almost
as well as, a popular commercial diet (Otohime, Marubeni Nisshin Feed, Tokyo, Japan)
with larval yellowtail (Seriola lalandi), white sea bass (Atractoscion nobilis) Pompano(Trachinotus carolinus) and red drum (Sciaenops ocellatus). This performance illustrates
that these diets provides a good base on which to make improvements.

13

Feed

Moisture(%as fed)

Protein

Proximate

Fatty Acid

Composition

Concentrations

Leaching t1/2/% lostSinkingRate(mg fatty acid/100mg(% dry weight)

total fatty acids)

Protein

Lipid

Ash

ARA

EPA

DHA

(n-6)

(n-3)

(n-3)

(sec)/(%)(cm/sec)
a

MEM

5.7

53.8

30.5

8.4

0.4

7.5

5.7

98/23.0

0.84±0.010

PARA

5.3

54.2

29.7

8.9

0.4

7.4

5.6

94/30.2

0.34±0.001

F

9.0

75.9

10.9

7.3

1.0

6.0

15.2

20/44.3

0.33±0.001c

F-MEM

13.3

75.6

13.4

7.5

1.0

5.3

13.0

50/41.8

0.78±0.060

F-PARA

11.0

75.6

12.6

7.3

1.0

6.0

15.2

33/47.2

0.61±0.001b

Artemia

91.3

NA

15.3

13.7

5.6

12.1

7.1

NA/0.1

NA

Rotifers

90.1

49.6

15.5

17.7

1.5

5.7

23.3

NA

NA

14

c

a

EFFECTS OF DIETS SUPPLEMENTED WITH HERB ESSENTIALOILS ON
ECTOPARASITIC PROTOZOAN INFECTIONS ON CHUM SALMON(ONCORHYNCHUS KETA) FRY
Shinya Mizuno1*, Makoto Hatakeyama1, Mahito Miyamoto1, Miki Kobayashi1, Nobuhisa
Koide1, Shigehiko Urawa2
1

Salmon and Freshwater Fisheries Research Institute, Hokkaido Research Organization,
3-373 Kitakashiwagi, Eniwa, Hokkaido, 061-1433, Japan
2
Hokkaido National Fisheries Research Institute, Fisheries Research Agency, 2-2
Nakanoshima, Toyohira, Sapporo, 062-0922, Japan*E-mail: mizuno-shinya@hro.or.jp
Chum salmon Oncorhynchus keta are artificially propagated to enhance their stock forthe coastal fishery in Hokkaido, northern Japan. Ectoparasitic infection of ciliates,
Trichodina sp. and flagellates, Ichthyobodo sp. causes a high mortality in chum salmon fry
cultured at salmon hatcheries for release into the river as artificial seed in the propagation.
These ectoparasitic protozoans are exterminated by soaking the infected fry into diluted
vinegar or salt solution. However, the treatments debilitate the fry physiologically andincrease cost for required effort. As a breakthrough of this problem, we need to develop
techniques to prevent the protozoan infections. It is reported that essential oil of herbs
including mint and lavender have an effect of insect proofing. The present study was aimed
to examine suppressive effects of dietary supplement with herb essential oils on infections
with two ectoparasitic protozoans by two experiments.
In the first experiment, hatchery-reared chum salmon fry infected with noectoparasitic protozoan were separated into 5 groups on May 21, 2010. Each group (n=200
fish) was stocked in a 60 l -acrylic tank and cultured using running spring water for 35 days.
Each of the five groups were fed either commercial trout crumble diet (control) or diets
supplemented with essential oils of original Japanese (OJ-) mint, breeding Japanese (BJ-)
mint, peppermint or lavender, respectively. Herb oil was added to respective diets at 500
ppm. Total amount of the supplied diets were equalized among the 5 groups. Fry wererandomly sampled from each group during the experiment and examined for the total
parasite number of Trichodina and for quantitative analysis of small subunit ribosomal
RNA gene of Ichthyobodo by real-time PCR. In the second experiment, uninfectedhatchery-reared chum salmon fry were divided into 2 groups: control and 500 ppm OJ-mintgroups on February 21, 2013. Each group (n=85,000 fish) was taken in a hatchery pond andreared for 64 days. Methods of fry culture, fry sampling and protozoan analysis followed
those of the first experiment.
In the first experiment, dietary supplement with all herb oils significantly restrained
Trichodina infection up to 21 and 35 days and Ichthyobodo infection up to 35 days.
Especially, Trichodina infection was not completely found in the OJ-mint group for 35
days. Effects of herb oils on suppression of protozoan infections were high in the following
order: OJ-mint>lavender=BJ-mint>peppermint. In the second experiment, the OJ-mint
15

dietary supplement significantly suppressed Trichodina infection up to 15 and 40 days andIchthyobodo infection up to 40 and 55 days, whereas it was not able to prevent protozoan
infections perfectly. In consequence, the present study suggested that dietary supplement ofmint and lavender oils suppressed protozoan infections on chum salmon fry and thoseeffects depend on variation of herb species.
Key words
chum salmon (Oncorhynchus keta), Trichodina, Ichthyobodo, herb essential oil, mint,lavender16EFFECT OF FEED INGREDIENTS ON DIGESTIVE ENZYMESSECRETION IN FISH
Koji Murashita1*, Haruhisa Fukada2, Noriyuki Takahashi2, Noriko Hosomi2, Hiroyuki
Matsunari1, Hirofumi Furuita1, Hiromi Oku1, Takeshi Yamamoto1
1

National Research Institute of Aquaculture, Fisheries Research Agency, Tamaki, Mie
519-0423, Japan.
2
Faculty of Agriculture, Kochi University, 200 Monobe, Nankoku, Kochi 783-8502, Japan.
*E-mail: kojim@affrc.go.jp
In response to limitations in the global supply of fish meal, the traditional protein
source used in aquaculture feed, efforts have increasingly been focused on the use ofalternative protein sources of plant origin. However, plant ingredients cause growth
retardation in most aquacultured fish species. Feed must be digested for their utilization,and pancreatic digestive enzymes have essential roles for the digestion. Also,cholecystokinin (CCK) is known to be a hormone that stimulates the secretion of digestive
enzymes in vertebrates. To improve the utilization of plant based diets in fish, weinvestigated the effects of various feed ingredients on secretion of digestive enzymes in red
seabream (Pagrus major) and yellowtail (Seriola quinqueradiata) which are commercially
important species in Japan.
We first investigated the effect of soybean meal on digestive enzyme secretion in red
seabream. Activities of pancreatic digestive enzymes (trypsin, chymotrypsin, lipase,amylase) in the intestinal content of soybean meal based diet (SBM) fed fish were lower
than those of fish meal based diet (FM) fed fish. Also, lower gene expression levels of thedigestive enzymes in hepatopancreas were observed in SBM fed fish compared with FM
fed fish. These data indicate that SBM does not fully stimulate the secretion/synthesis of
the pancreatic digestive enzymes. In other words, FM strongly stimulates the digestive
enzymes secretion/synthesis. Then, we tried to identify the stimulation factor in fish meal.
Administration of a FM water-soluble fraction increased the gene expression of pancreatic
digestive enzymes, CCK and CCK receptor (CCK-1R) in yellowtail, suggesting the
enzyme stimulation factor may exist in the water-soluble fraction of FM. Supplementationof the enzyme stimulation factor will improve the utilization of plant based diets inaquacultured fish species.
This work was partly supported by JSPS Grant-in-Aid for Scientific Research (B) (Grant Number:
24380117) to H. Fukada and K. Murashtia.

Key words
red seabream (Pagrus major), yellowtail (Seriola quinqueradiata), pancreatic digestive
enzymes, cholecystokinin, fish meal, soybean meal

17

CHOLECYSTOKININ AND TRYPSIN RESPONSES OF LARVAL RED
DRUM (SCIAENOPS OCELLATUS) IN RESPONSE TO ALGAE, LIVE
PREY, AND INERT PARTICLES
Ken Webb
Environmental and Fisheries Sciences, National Marine Fisheries Service
Northwest Fisheries Science Center 2725 Montlake Boulevard East Seattle, WA 98112*E-mail: Ken.Webb@NOAA.gov
In an attempt to better understand the problems in weaning larval fish to artificial diets,
our lab has begun to investigate the role of the digestive hormone cholecystokinin(CCK). While there are a number of other labs also investigating CCK and other digestive
hormones such as bombesin, PPY, and gastrin; research into the roles of these hormones infish is still in its infancy. Previous research with red drum larvae suggests that somecomponent of rotifers and algae enable red drum larvae to more efficiently utilize
microparticulate diets than when these are not included in the culture system. The current
work investigated the impact of soluble components of rotifers and algae on the CCK andtrypsin responses of larval red drum at 6 and 10 days post hatch (DPH) as well as the
response of red drum larvae to ingestion of inert polystyrene particles at 10
DPH. Introduction of homogenized rotifers was shown to significantly increase whole body
CCK levels, CCK mRNA, and trypsin activity in 6 DPH red drum larvae, but not in 10 DPH
larvae. Homogenates of Isochrysis galbana did not significantly affect CCK or trypsin ateither age. Ingestion of the polystyrene particles was increased in response to the presenceof rotifer homogenate and both CCK mRNA and trypsin activity was increased aswell. This research suggests that there is a soluble component of rotifers that can upregulate
digestive function in larval red drum, at least in 6 DPH larvae, as well as influence
consumption.

18

AN ANALYSIS OF THE CAUSALITY BETWEEN THE MARKET
PRICE OF IMPORTED FISHMEAL AND MARKET PRICE OF
MARINE FARMED FISH
Yoshifumi Takahashi1*
1

Tohoku National Fisheries Research Institute, Fisheries Research Agency,
3-27-5, Shinhama, Shiogama, Miyagi, 985-0001, Japan*E-mail: gibun@affrc.go.jp
In Japan, many piscicultural famers are facing difficulties due to the impact of fallingfish prices and the rising cost of feed. These are serious problems because they cause agreat reduction in profits for many piscicultural farmers. According to statistics producedby the Japanese Corporation of Feed for Pisciculture (Nihon Yougyo Shiryou Kyoukai), theproduction of feed reached 360 thousand tons in 2011, the majority of which was foryellowtail and sea bream. Moreover, this feed was made from raw ingredients such as
fishmeal and starchy food. Fishmeal was especially important, making up 50% or more of
the feed content. Therefore, piscicultural farmers who farm yellowtail and sea breamalways worry about a rising market in imported fishmeal.
The market price of imported fishmeal is determined by a number of factors, such as
global competition among importing countries, and the gap between internal and external
prices. The three main exporting countries are in South America - Peru, Ecuador and Chile– and account for 65-80 percent of the domestic market share. The market price ofimported fishmeal has been rising lately because many importing countries are struggling
to obtain larger amounts of fishmeal to maintain their piscicultural industries. In this case,South American countries have stronger price leadership than importing countries.
Importing countries (including Japan) have to accept the market price determined by thecountries with price leadership. A rise in the price of imported fishmeal affects the cost of
pisciculture, and ultimately the “cost-push inflation” phenomenon may affect theequilibrium price of farmed fish.
This research investigates the extent of influence on the market price of pisciculture
when the imported fishmeal price changes, because there has been no research about that inJapan. The purposes of this paper are as follows: 1) to reveal the causality among prices in
the imported fishmeal market, yellowtail market and sea bream market, and 2) to calculate
the impact on market prices of those fish products in landing area when the price ofimported fishmeal is increasing. I used the Granger causality test and impulse response
functions to conduct my analysis.
The results of the Granger causality test and impulse response functions are as
follows: 1) there is causality between the price of imported fish meal and the market priceof sea bream in landing area, but no causality linked to the market price of yellowtail. 2)
When the price of imported fishmeal changes it has a positive impact on the market priceof sea bream in landing area, and this positive impact is decreasing. Finally, the positive
impact converges to zero at around the sixth month
Key words
Granger causality test, Impulse response functions, Cointegration test, market price ofimported fishmeal, market price of yellowtail and sea bream in landing area

19

GOOD AQUACULTURE PRACTICES TO REDUCE THE USE OF
CHEMOTHERAPEUTIC AGENTS, MINIMIZE BACTERIALRESISTANCE, AND CONTROL PRODUCT QUALITY
Stanley G. Serfling, M.S.
Consumer Safety Officer, US Food and Drug Administration
Office of Food Safety, College Park, MD 20740*E-mail: stanley.serfling@fda.hhs.gov
The need to minimize antimicrobial use in aquaculture is widely understood byacademia as well as the aquaculture industry. Many fish and shrimp farmers, particularly in
Asian countries, face production problems due to disease and may use chemotherapeutic
agents in an effort to save stock. These agents also may pose food safety risks and have thepotential for immediate and long-range human health consequences that may include
carcinogenic and mutagenic effects, and increasing prevalence of antibiotic-resistantmicroorganisms.
In all aspects of health care for food producing animals the first step towards
minimizing risk of disease is prevention. In aquaculture, the preventive measures intended
to reduce the risk of disease occurring can be called many things one being good aquaculture
practices. They all have the intent of preventing disease from occurring and then having touse a chemotherapeutic agent to treat the animals. Therefore, developing and implementing
a preventive measures program is the first step in prudent and responsible use of veterinary
medicines (antimicrobials) in aquatic food production.
It is generally understood that a disease in aquaculture is a combination of the health of
the animal, the condition of the environment and the presence of a pathogen. Therefore, if
infectious agents are reduced along with stress, disease outbreaks are less likely tooccur. From this concept there are a number of physical, chemical, and biologicalprecautionary measures that fish and shrimp farmers may practice to minimize disease
outbreaks.
Biosecurity plans for aquaculture should include the following: Hazard and risk analysis (identify the hazard associated with the product) Identify Critical Control Points (a step at which controls can be applied to prevent ofeliminate a hazard or reduce it to an acceptable level)
 Establish Critical Limits (a maximum and/or minimum value to which a biological orchemical hazard must be controlled to an acceptable level) Monitor each critical control point (accurate monitoring indicates when there is a lack ofcontrol at a Critical Control Point) Establish corrective actions (identify corrective action, implement and document)
 Establish verification procedures (the system is operating according to the plan) Record keeping (establish record keeping and documentation procedures)Good aquaculture practices are an essential component of sustainable aquaculture.
These practices can improve the quality and safety of aquaculture products by reducing
bacteria and filth and the use of chemotherapeutic agents. Ensuring the safety of the foodsupply is a priority for the United States Food and Drug Administration.

20

MODELING INTRASPECIFIC GENETIC EFFECTS FORMANAGEMENT OF AQUACULTURE PROGRAMSJason D. Volk1*, Michael B. Rust 2, Gregory R. Blair1, Lars E. Mobrand1, Conrad V.W.
Mahnken3, and Walton W. Dickhoff2.
1

ICF International, 710 Second Avenue Suite 550, Seattle, WA 98104
NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Blvd. East, Seattle
WA 98112
3
Aquatic Resource Consultants, 9933 NE Lafayette, Bainbridge Island WA 98110*E-mail: Jason.Volk@ icfi.com
2

Rapid worldwide development of marine finfish cage farming has raised awarenessover the possible genetic and ecological effects of escaped fish on wild populations. With
increased interest in implementation of marine aquaculture in the United States, NOAA
Fisheries and other regulators charged with stewardship of marine ecosystems need tools tounderstand and mitigate risks presented by aquaculture escapees. To develop anunderstanding of genetic and ecological effects of escapes and design management strategies
to address potential risks to marine resources, NOAA Fisheries has developed a numericaldecision-support tool: the Off-shore Mariculture Escapes Genetics/Ecological Assessment(OMEGA) model. The OMEGA model is an extension of concepts from another model, the
All-H Analyzer (AHA) that is used successfully in the U.S. Pacific Northwest to evaluate
genetic and ecological interactions between hatchery and wild salmon and trout.
OMEGA model input parameters include size and growth characteristics of cultured
fish, frequency and magnitude of escape events, survival of escapees in the wild, probabilityof escapees encountering a conspecific natural population and interbreeding, and population
dynamics of the natural population. Model results describe the influence of aquaculture
escapees on spawning biomass, juvenile production, and genetic fitness of the composite
population. Effects of interactions on fitness and abundance are based on the frequency andrelative abundance of cultured fish that escape and survive to encounter a natural population,
the difference in survival characteristics between the artificial and the natural environments,
and the genetic legacy of the cultured and natural populations.
NOAA Fisheries is using the OMEGA model to identify and evaluate risks of marine
aquaculture operations, design sustainable aquaculture programs, explore the effects ofregulation, and identify research priorities for areas of uncertainty.
This talk will describe the model and present results for a hypothetical sablefish(Anoplopoma fimbria) culture program along the U.S. West Coast. We are interested in
speaking with any and all individuals interested in collaborating on the further developmentof the model, applying the model to other species of interest such as rockfish (Sebastes spp.),yellowtail (Seriola quinqueradiata), salmon (Oncorhynchus spp.), or any other aquaculture
candidate species, and to identify opportunities to validate model results.

21

SPECIFIC MONOVALENT AND DIVALENT ION
SUPPLEMENTATION FOR CULTURE OF MARINE SPECIESCalvin Fisher1, C. Bodinier1, Adam Kuhl1, and Christopher C. Green1*
1

Aquaculture Research Station, Louisiana State University Agricultural Center,
Baton Rouge, LA, USA 70820*E-mail: Cgreen@agcenter.lsu.edu
The culture of marine and euryhaline fishes in low salinity or ion deficient waters has
been an area of interest for many aquaculturists due to the expense of marine salt mixes. The
Gulf killifish (Fundulus grandis) is a euryhaline teleost found abundantly in coastal marshes
along the Gulf of Mexico. The ability to investigate the molecular underpinnings of specificions in this model species could have a number of implications for other commercially
important marine finfish species. Although studies have examined the influence of salinity
on adults and juveniles, few have investigated the role of salinity or specific ion
concentrations in larvae. These investigations utilize a model teleost to determine the role ofspecific monovalent and divalent ions at production relevant, biochemical, and molecularlevels.
Separate four week trials were conducted exposing newly hatched Gulf killifish toconcentration gradients of potassium (K+), calcium (Ca2+), and magnesium (Mg2+). The K+
supplementation consisted of 0.3, 1.3, and 2.9 mM. Treatment groups for Ca 2+ consisted of
0.2, 1.1, 1.5, and 2.1 mM Ca2+, while trials using Mg2+ consisted of 0.1, 2.7, 5.1, and 10.4
mM Mg2+. All treatments were maintained at a salinity of 9.5-10‰ using crystal salt (99.6%
NaCl). Each investigation consisted of four 50-L aquariums stocked at 7 larvae per liter foreach concentration. Fish were sampled at 0, 1, 3, 7, 10, 14, and 28 d post hatch (dph). Upon
each sampling the standpipe was adjusted to maintain a constant density for eachtreatment. Collected samples were analyzed for whole body ion concentrations (K+, Na+,
Mg2+, Cl-), Na+/K+-ATPase (NKA) activity, dry weight, and expression/localization ofosmoregulatory proteins (NKA, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis
transmembrane conductance regulator (CFTR)).
Mortality and growth was significantly influenced by K+ concentration (p < 0.05). No
differences were observed among treatment groups for NKA enzyme activity, however at
28-d post hatch (dph) there were significant differences in dry weight among K+ treatment.
At 7 dph, differences in intestinal NKA and CFTR staining were observed and NKA mRNA
expression was found to be higher in the 0.3 mM [K+] group than in other treatment groups.
Survival was significantly influenced by both Mg2+ and Ca2+ concentration (p ≤0.05). Highest survival (71.1%) in the Ca2+ trial was noted in the 0.2 mM [Ca2+]
treatment. In the Mg2+ trial, highest survival was noted in the 2.7 mM [Mg 2+] treatment(82.9%). NKA enzyme activity was reduced and delayed peaks were observed in wholebody ion composition in the Mg2+ treatments. In addition, decreased CFTR intensity wasobserved at the gill and intestinal epithelium for the 0.05 mM [Mg 2+] treatment at 1 dph,
indicating that Mg2+ deficiency has a possible effect on larval ormoregulatory
capability. The role of intestinal epithelium in ion uptake not only allows the potential for
uptake and maintenance of ion balance from dietary sources, but also demonstrates thepotential to modulate concentrations of specific ions in prepared waters for euryhaline andmarine teleosts.

22

GENETICALLY MODIFIED SALMON IN AQUACULTURE: WELLREGULATED AND SAFE
Paul G. Olin1
1

UC San Diego, Scripps Institution of Oceanography, La Jolla, CA 92093-0232
polin “at” ucsd.edu

A Massachusetts company, Aquabounty Technologies, submitted an application to the
U.S. Food and Drug Administration (FDA) in 1995 to grow a genetically modified
AquAdvantage® Atlantic salmon to be marketed as a food product. Aquabounty proposed
to raise the broodstock fish on Prince Edward Island, ship their eggs to a contained inland
recirculating production system in Panama to grow, harvest and process the fish, and thenship food grade product back to the United States for sale. The fish for this physicallysecure production system would be at least 99 percent triploid and all-female, as anadditional reproductive-containment measure.
The AquAdvantage®
Atlantic salmon carries a
Chinook salmon growth
hormone gene that results in
production of growth hormonesthat enable the fish to grow tomarket weight in half the time it
normally takes (Fig. 1.). This
gene is regulated by a segment
of DNA from the ocean pout, aFigure 1. AquAdvantage® and non-GM Atlantic salmon of similar age
blenny-like fish found in frigid
waters of the Northwest
Atlantic.
The review process used by FDA on the AquAdvantage® salmon involved a team ofscientists and subject-matter experts on the Veterinary Medicine Advisory Committee who
advise the FDA and the general public on scientific issues as they relate to ensuring public
and animal health. The FDA released a 172 page briefing packet and an 84 pageenvironmental assessment containing information relevant to the application in advance ofa public advisory committee meeting held in September 2010. This briefing packet
summarized their scientific review, and the basic conclusions were that the
AquAdvantage® salmon are safe, nutritionally comparable to other Atlantic salmon, andwhen produced as described in the application do not pose a threat to the environment. The
review process used by FDA on the AquAdvantage® salmon was rigorous, detailed andextensive, spanning more than 15 years. Specific conclusions from the report stated that“Food from AquAdvantage® Salmon is the same and as safe to eat as food from otherAtlantic salmon.”23

In reference to concerns about adverse environmental impacts the report states “Thereis substantial, reliable information available in the environmental assessment document toconclude that AquAdvantage® Atlantic salmon are not expected to have a significant
impact on the environment when raised and reared under the current conditions of physical,
biological and geographical/geophysical confinement present at hatchery and grow-out
facilities in Canada and Panama. We have a high degree of certainty in our conclusions
regarding AquAdvantage® Salmon.”
Despite this rigorous scientific review, there remains considerable public controversy
regarding the potential for FDA approval of this Aquabounty application to produce andmarket a genetically modified salmon. As a result, 11 senators signed a request that FDA
stop the process for approving genetically modified AquAdvantage® Atlantic salmon. The
manner in which this review for approval of a transgenic animal for agricultural production
and marketing in the United States has progressed has stymied American research in thispromising sector of animal biotechnology.
New technologies to genetically improve food and animal crops are one tool to supply
the additional food people will need in the future, improving human health, reducing theuse of pesticides and fertilizers, and lessening the carbon footprint of animal and plant
agriculture. A 2008 scientific review published in the Journal of the Royal Society of
Medicine noted that genetically modified foods had been eaten by millions of people
worldwide for 15 years, with no reports of ill effects.

24

REPRODUCTIVE DYSFUNCTION IN CULTURED SABLEFISH(ANOPLOPOMA FIMBRIA)
Jose M. Guzmán *, J. Adam Luckenbach, Frederick W. Goetz, William T. Fairgrieve,
Mollie A. Middleton and Penny Swanson
National Marine Fisheries Service, Northwest Fisheries Science Center,2725 Montlake Boulevard East, Seattle, WA 98112*E-mail: jose.guzman-jimenez@noaa.gov
Sablefish (Anoplopoma fimbria), known as gindara in Japan, is a groundfish native to
the North Pacific Ocean ranging from Baja California to Alaska’s Bering Sea and Japan. The
primary market for sablefish is in Japan, where demand and prices are high, but an increasing
amount of the wild catch is staying in the US market over the past few years. Due to its highmarket value and growth rate, sablefish has been identified as an excellent candidate formarine aquaculture in the US. However, efforts to establish sustainable and efficient
production of sablefish have been constrained by reproductive problems in F1 females (i.e.,
those produced in captivity), which fail to mature in captivity even when they reach a similar
body size and age as wild, reproductively mature females. This situation hampers thecreation of captive broodstock for a selective-breeding program.
Current research at the Northwest Fisheries Science Center (NOAA, Seattle, US) is
integrating basic and applied biology to gain knowledge on the reproductive endocrine
system of sablefish and processes underlying the reproductive dysfunction of F1 female
sablefish. As part of our basic line of research, we are characterizing the reproductive cyclein wild females caught off the Washington coast (US). Cortical alveolus stage ovarianfollicles (i.e., developmental stage that precedes the onset of vitellogenesis) were firstobserved in May, whereas the first vitellogenic ovarian follicles were found during latesummer, concomitant with increases in plasma sex steroids and gonadosomatic index. These
data suggest that late spring-summer is a critical period of time for the initiation of ovarian
vitellogenic grown, and therefore, key to the onset of puberty (i.e., first sexual maturation) in
cultured broodstock. Also in support of this idea, wild females captured in the fall
successfully completed gametogenesis in captivity, whereas females captured three months
earlier, during summer, failed to mature. Interestingly, these wild non-maturing females
exhibited similar reproductive features as prepubertal F1 females, including low levels of
pituitary gonadotropin subunit and ovarian receptor mRNAs and plasma sex steroids, andovarian follicles arrested at the perinucleolus stage (i.e., primary oocyte growth). These datasuggest that rearing conditions impair vitellogenic growth of ovarian follicles in sablefish,compromising the reproductive success of broodstock. Using an in vitro ovarian tissue
culture system, we demonstrated that fragments of prepubertal F1 sablefish ovaries
incubated with either human-chorionic gonadotropin or testosterone increased the
production of estradiol, the main regulator of vitellogenin production and ovarian growth, ina dose-dependent manner. This indicates that ovaries of F1 females are equipped tosynthesize and release sex steroids critical for vitellogenesis under the appropriate hormone
25

stimulation, and that the failure to initiate vitellogenesis, and thus undergo puberty is likely alack of adequate gonadotropin signaling. Finally, we found that F1 female sablefish express
higher levels of dopamine receptor in the brain and pituitary than wild-caught maturing
females. These data provided the foundation for the development of an initial phase ofhormone treatments aimed at inducing puberty for the first time in F1 female sablefish. This
experiment is currently underway.

26

INDUCED SPAWNING IN THE SEA CUCUMBER APOSTICHOPUS
JAPONICUS BY NEUROPEPTIDE, CUBIFRIN
Keisuke Yamano1*, Atushi Fujiwara2, Michiyasu Yoshikuni3
1

National Research Institute of Aquaculture, Fisheries Research Agency, Minamiise,
Watarai, Mie 516-0193, Japan
2
National Research Institute of Fisheries Science, Fisheries Research Agency, Fukuura,
Kanazawa, Yokohama, Kanagawa 236-8648, Japan
3
Fishery Research Laboratory, Kyushu University, Fukutsu, Fukuoka 811-3304, Japan*E-mail: yamano@fra.affrc.go.jp
In hatcheries, the induction of spawning in sea cucumbers has been typically carriedout by the regulation of rearing conditions such as temperature and light intensity. However,this method is relatively ineffective and the rate of spawning is unpredictable. In this study,
we established an efficient method for inducing spawning in the Japanese sea cucumber
Apostichopus japonicus by injecting a neuropeptide, cubifrin.
We purified peptides that can induce oocyte maturation in in vitro assay with ovarianfragments, from the buccal tissues containing the nerve ring. The effective dose of each
peptide was evaluated with chemically synthesized peptides. Consequently, the most potent
peptide was identified as NGIWY-amide. We also found that synthetic derivatives that
replaced the third amino acid, isoleucine, with a different basic amino acid could be 10-100
times more potent than the natural hormone.
When injected into the body cavity of sexually matured individuals, NGIWY-amide,or its derivative, induced spawning in both males and females. NGIWY-amide was thennamed cubifrin after the Japanese word "kubifuri" meaning waving head, which is a
reproductive behavior of sea cucumbers. Gamete shedding started about 60 min and 80 min
after the injection in males and females, respectively, and was completed almost
simultaneously in the two sexes about 2 hours after the administration. The in vitro
responsiveness of biopsied ovarian fragments was well correlated with the spawningsuccess induced by an injection. Therefore, cubifrin can be used as an excellent detector of
maturity as well as an inducer of spawning in A. japonicus in a hatchery setting.
Key words
reproduction, hormone, oocyte maturation

27

MASS PRODUCTION OF ARTIFICIAL SEED OF JAPANESECOMMON SEA CUCUMBER (APOSTICHOPUS JAPONICUS) IN
HOKKAIDO, JAPANYuichi Sakai
Fisheries Research Department Mariculture Fisheries Research Institute, Hokkaido
Research Organization, 1-156-3, Funami-cho, Muroran, Hokkaido, 051-0013, Japan*E-mail: sakai-yuichi@hro.or.jp
Seed production and releasing of Apostichopus japonicus is one of the major projects
to increase and maintain their natural stocks in Japan.
Nevertheless, in many trials conducted mainly in Honshu and Kyushu by the end of
the 1990’s, the amount of seed production fluctuated annually, and the survival rate ofreleased artificial juveniles was uncertain because of the difficulty of distinguishingreleased juveniles from natural ones. Due to this, some hatcheries discontinued A.
japonicus enhancement projects.
On the other hand, due to the increase in Chinese demand, the price of A. japonicus
dramatically increased after 2003 in Hokkaido. Facing the decline in the price of sea urchin
and abalone, which are major high-value catches in the coastal areas, fishermen werestrongly interested in A. japonicus stock enhancement by releasing artificial seeds.
Thereafter sea urchin and abalone hatcheries began to produce A. japonicus seed after
2006.
This paper will introduce the recent mass production techniques developing in
Hokkaido.
Key word
Apostichopus japonicus, artificial seed production, larval rearing, post-larval rearing,
control of predation,

28

FLUOROCHROME MARKING OF OUT-PLANTED GREEN SEAURCHINS, STRONGYLOCENTROTUS DROEBACHIENSIS, FOR SEA
RANCHING AND RESTOCKING PROGRAMS IN THE GULF OF
MAINE, USA
Pamelia Fraungruber1, Stephen D. Eddy1*, Nicholas P. Brown1, Larry Harris2
1

University of Maine, Center for Cooperative Aquaculture Research, Franklin, Maine,USA
2
University of New Hampshire, Durham, NH, USA*E-mail: stephen.eddy@ umit.maine.edu
Fluorescent batch tagging by immersion can be used to identify sea urchins released
onto the ocean bottom for sea ranching aquaculture and stock enhancement. Here, we
present information on the use of fluorochrome tagging to estimate returns of green sea
urchins, Strongylocentrotus droebachiensis, out-planted onto two sea ranching lease sites in
the Gulf of Maine, USA. We tagged a hatchery cohort of 31,000 green sea urchinjuveniles (≈5 mm test diameter) with the fluorochrome marker tetracycline prior toout-planting onto 400m2 study areas located at each lease. The release areas were surveyed
seven times by SCUBA divers at 3-5 month intervals for up to 27 months post-release tomeasure growth and recovery rates of out-planted juveniles. The growth and recovery data
was used to extrapolate returns to the lease holder from out-planting the entire lease area(.80937 ha) with hatchery seed urchin numbers proportional to those used for the study
area Juveniles from the same hatchery cohort were simultaneously reared in a land-based
recirculating aquaculture system as a benchmark to assess sea ranching returns.
Our results show that the fluorochrome tetracycline can be detected for at least 27
months in sea urchins released into the field. Tagged urchins were consistently found at
both sites and at every dive survey, showing that there is potential for out-planting programsin the Gulf of Maine to succeed. A disproportionate number of urchins recovered from thetwo out-planting areas were smaller than the average release size, suggesting that size
dependant mortality or dispersal of out-planted urchins had occurred. There weresignificant differences in growth and recovery rates between the two sites, but recovery rates
were sufficiently high at one of the sites to indicate that sea ranching could be economically
viable under certain conditions. Growth and recovery rates in the land-based recirculating
aquaculture system were significantly higher than those seen at either ocean lease site, andprovided a benchmark against which future out-planting efforts could be compared.
The results presented here offer a case study of how fluorochrome marking can be usedin sea ranching and out-planting studies to compare different sites and estimate returns. This
study also illustrates some of the limitations of this approach, but recent advances in tagging
methods and visualization offer promise that these limitations can be overcome. In all
likelihood, fluorochrome marking will be a requirement for sea ranching urchins in the Gulfof Maine, as it is presently the only practical means of differentiating between hatchery andwild stocks.
29

IMPROVING THE FOOD QUALITY OF SEA URCHIN GONADS BY
SUPPRESSING GAMETOGENESIS
Tatsuya Unuma1*, Yuko Murata2, Natsuki Hasegawa1, Sayumi Sawaguchi1, Kazuhiro
Takahashi31

Hokkaido National Fisheries Research Institute, Fisheries Research Agency, Kushiro,
Hokkaido 085-0802, Japan.
2
National Research Institute of Fisheries Science, Fisheries Research Agency, Fukuura,
Yokohama 236-8648, Japan.
3
Mariculture Fisheries Research Institute, Hokkaido Research Organization, Muroran,
Hokkaido 051-0013, Japan.
* Email: unuma@fra.affrc.go.jp
The quality of sea urchin gonads as food products gradually decreases as
gametogenesis progresses. Mature ovaries and testes are not suitable as food products,
because of the unpleasant taste caused by gamete content and the melting appearance
caused by gamete flow via breakage of the gonoduct. Immature to pre-mature gonads that
contain predominantly nutritive phagocytes (somatic nutrient storage cells) and without
copious gametes have a higher commercial value. Thus, suppressing gametogenesis bycontrolling environmental conditions is advantageous for sea urchin aquaculture. In thepresent study, we investigated the effect of water temperature on the size and quality of the
gonads of Strongylocentrotus nudus. Rearing S. nudus under a low temperature between
summer and autumn suppressed the progress of gametogenesis and alleviated the quality
deterioration caused by maturation, without sacrificing the gonad size.
Key Words
gametogenesis, ovary, quality, sea urchin, temperature, testis

30

MATURATION CONTROL OF THE SHORT-SPINED SEA URCHIN,STRONGYLOCENTROTUS INTERMEDIUS, BY LOWTEMPERATURE REARING USING DEEP-SEA WATER,WITH THE AIM OF EXTENDING THE MARKET SEASON
Takaaki Kayaba1*, Kohji Tsuji2, Hiroshi Hoshikawa3, Yaoki Kikuchi4, Kazuhiro
Kawabata4, Isao Otaki4, Toru Watanabe5
1

Kushiro Fisheries Research Institute, Hokkaido Research Organization, Kushiro,
Hokkaido 085-0024, Japan
2
Abashiri Fisheries Research Institute, Hokkaido Research Organization, Monbetsu,
Hokkaido 094-0011, Japan
3
Central Fisheries Research Institute, Hokkaido Research Organization, Yoichi, Hokkaido
046-8555, Japan
4
Department of Mariculture, Rausu Fishery Cooperative, Rausu, Hokkaido 086-1893,
Japan
5Hachinohe Scientific Museum MARIENT, Hachinohe, Aomori, 031-0841, Japan*E-mail: kayaba-takaaki@hro.or.jp
The short-spined sea urchin Strongylocentrotus intermedius, which is distributed on
the northern coast of Japan, is a valuable commercial species and one of the most popularand expensive seafoods in Japan. The edible part of the sea urchin is the gonads, and its
quality as food varies dramatically with gonadal growth and maturation. In general, thesuperior quality of gonads, defined by attractive taste and shape, is only present during theterm of the unripe phase when gametogenesis is limited. The mature gonad has an
unpleasant taste due to the gamete contents and a melting appearance caused by the flow ofgametes. Therefore, the best season for harvesting S. intermedius is very short (less than
three months per fishery region) in spite of continuous annual market demand. There would
be considerable commercial value in developing an aquaculture technique to control thetiming of gonadal maturity so as to ensure a supply of high quality sea urchins over alonger period.
Serving local S. intermedius to visitors during the summer tourist season in Rausu,
located in a world natural heritage site “Shiretoko,” has long been hoped. However, it has
not been feasible during the sea urchin spawning season (July to September), resulting inquality degradation in gonads due to maturation. In several echinoderms, water temperature
has been shown to have a strong effect on the progress of gametogenesis. Fortunately, afacility for collecting deep-sea water, which has properties for stable low temperature, isavailable in Rausu. Therefore, taking advantage of the available facility, we examined thepossibility of suppressing gonadal maturation and maintaining high quality sea urchin
gonads by low temperature rearing using deep-sea water. Unripe sea urchins captured
before the spawning season were reared under two temperature conditions from June to
September. In groups reared at ambient temperatures (2.8–19.6°C), gametogenesis in both31

sexes progressed rapidly with increased temperature, and almost all sea urchins reached fullmaturity by late July. Whereas in groups reared at low temperatures (2.1–5.1°C),
gametogenesis progressed slowly and over 60% of the sea urchins had not reached maturity
even by early September. This result suggests that the progress of gametogenesis in S.
intermedius is effectively suppressed by rearing sea urchins under low temperature
conditions. Additionally, we also investigated the effects of feeding on gonadal
development in sea urchins reared under low temperature conditions, and revealed thatfeeding with live Saccharina diabolica, which were cultured as food in Rausu, could
increase the gonadal volume efficiently to commercially preferable size under low
temperature, while suppressing the progress of gametogenesis. Moreover, the results ofchemical analysis (free amino acids) and tasting test proved that the quality of gonads werevery excellent in sea urchin fed with live Saccharina diabolica. Consequently, wedemonstrate that low temperature rearing, supplemented with feeding live Saccharina
diabolica, is effective in suppressing gametogenesis to allow for the harvesting of highquality sea urchins during the summer tourist season. At present, this aquaculture method isbeing put to practical use by the Rausu Fishery Cooperative.
This study was conducted as part of a research project, “Research and Development
Projects for Application in the New Policy of Agriculture, Forestry and Fisheries,” fundedby the Ministry of Agriculture, Forestry and Fisheries, Japan.

Key words
short-spined sea urchin Strongylocentrotus intermedius, gametogenesis, deep-sea water, lowtemperature rearing, sea urchin aquaculture32

LONG-TERM OUTCOMES IN THE TECH TRANSFER OF SCALLOPSPAT COLLECTION TECHNIQUES, FROM AOMORI PREFECTURE,
JAPAN TO MAINE, USA
Dana Morse
Maine Sea Grant College Program and UMaine Cooperative Extension,
193 Clark's Cove, Darling Marine Center Walpole, ME 04573*E-mail: dana.morse @maine.edu
In 1999, a delegation from Maine traveled to their sister-state of Aomori Prefecture in
Japan, to gain a better firsthand view of the world-famous scallop industry there. The
delegation included representatives from the fishing sector, processing, management,
aquaculture, science and outreach, and the hopes were to learn from the Japanese experiencesuch that the scallop industry in Maine could be strengthened. While the trip was
tremendously informative from many angles, the detail that had most immediate andbroadest application was the use of so-called ‘spat bags’ to capture competent larvae, andretain them for later stock enhancement and intensive aquaculture. Over the next years
following the delegation, over 100 fishermen in Maine used spat bags to capture juveniles of
our local scallop species, the Giant Scallop (Placopecten magellanicus). The practiceallowed us to build relationships with counterparts in Atlantic Canada and through southern
New England as well, as we sought expertise in the technique, and in determining theeffectiveness in augmenting wild populations of scallops.
Although we have not been successful in documenting strong stock enhancement
success (it is suspected, but not verified), there are several other areas in which the use of spatcollection has proven to be extraordinarily valuable. For example, the current progress
made in the aquaculture sector of sea scallops is largely due to the excellent success incollecting spat as a reliable seed supply. There is activity and great interest in linking source
populations for settled juveniles, spat collectors provide excellent access to juveniles forshell composition analysis, and are a component in understanding the oceanographic andbehavioral components of larval dispersal. Area closures - sometimes at the request of thefishermen - also involve discussions of spat collection for the purposes of stockenhancement. In addition, spat collectors have provided an invaluable window forfishermen to observe details of this early life stage, observations that they would nototherwise make. Overall, spat bags have been useful both directly and indirectly, and havebeen so for well over a decade.
Many of these outcomes were not foreseen during the visit of 1999. Technology
transfer often aims for immediate impact, but it seems likely that the normal case is that
impacts and benefits may take many years to be observed. It is important to keep this inmind both in reporting to funders of various tech transfer efforts, but to appropriately gauge
the long-term value of contemporary efforts.

33

RELATIONSHIP BETWEEN SPAT DENSITY, FOOD AVAILABILITY,
AND GROWTH OF SPAWNERS IN CULTURED JAPANESESCALLOP (MIZUHOPECTEN YESSOENSIS) IN FUNKA BAY:
CONCURRENCE WITH ENSO
Katsuhisa Baba1*, Rieko Sugawara1, Nao Nitta2, Kiyoshi Endou3, Akira Miyazono4
1

Hakodate Fisheries Research Institute, Fisheries Research Department, Hokkaido
Research Organization, Local Independent Administrative Agency, 1–2–66 Yunokawa,
Hakodate, Hokkaido 042–0932, Japan
2
South–Rumoi District Fisheries Training Center, 2 Suminoe, Rumoi, Hokkaido 077–8585,
Japan
3
Central–Oshima District Fisheries Training Center, 4–6–16 Mihara, Hakodate, Hokkaido
041–8558, Japan
4
Abashiri Fisheries Research Institute, Fisheries Research Department, Hokkaido Research
Organization, Local Independent Administrative Agency, 1–1–1 Masuura, Abashiri,
Hokkaido 099–3119, Japan*E-mail: baba–katuhisa@hro.or.jp
To elucidate the factors that influence the interannual variation in the density ofcultured Japanese scallop (Mizuhopecten yessoensis) spat, we analyzed the relationshipbetween spat density (Ds), monthly Chl-a concentration, water temperature, and adductor
muscle weight of spawners over 15 years (1992–2006) in Funka Bay on the western North
Pacific Ocean. The interannual variation of spat density was best explained by acampaniform model that used chlorophyll a concentration in February (ChlFeb) and a
categorical variable, which indicates whether growth of spawners in a year is low or not, as
independent variable (R2 = 0.91). The gonad-somatic index increased fastest in February.
Low growth years were detected as outliers in the Ds– ChlFeb relationship, and werecharacterized by an average weight of adductor muscles in February of < 12 g. Therefore,food availability during gonadal development and growth conditions of spawners were themain factors determining spat density. The proportion of ovary necrosis was high in theyears of low ChlFeb and low growth. Those years corresponded with El Niño and La Niña
years, respectively. Thus, global climatic anomalies apparently affect reproduction of thescallop in Funka Bay.
Key words
scallop, spat, food availability, ovary necrosis, ENSO.

34

OYSTER CULTURE IN HOKKAIDO, JAPANNatsuki Hasegawa1*, Toshihiro Onitsuka2, Satoru Takeyama 3, Kimihiko Maekawa4
1

National Research Institute of Aquaculture, Fisheries Research Agency, 422-1,
Nakatsuhamaura, Minamiise, Watarai, Mie, 516-0193, Japan
2
Hokkaido National Fisheries Research Institute, Fisheries Research Agency (Kushiro
Laboratory), 116 Katsurakoi, Kushiro, Hokkaido, 085-0802, Japan3
Akkeshi Oyster Hatchery, 1-1, Wakatake, Akkeshi, Hokkaido, 088-1118, Japan
4
Aquaculture Cooperative of Saroma Lake, Sakaeura, Tokoro, Hokkaido, 093-0156, Japan*E-mail: hasena@fra.affrc.go.jp
The Pacific oyster, Crassostrea gigas is the one of the most commercially importantaquaculture species in the Japanese fisheries industry with around 200, 000 metric tons ayear, the same as Japanese scallop Mizuhopecten yessoensis. The Oyster is cultured using
hanging method in various Japanese coastal areas including Hokkaido. The Saroma Lakeand the Akkeshi Bay with estuary, which face Ohotsuku Sea and Pacific Ocean,respectively are both major oyster production areas in Hokkaido with total annual
production of about 700 tons a year. In the early days Hokkaido, then popularly called Yezo
(pre-1869), natural oyster beds were grown in these areas and the oysters were harvested.
However, after loss of natural oyster resources in these areas, the aquaculture of oysters has
depended on seedling spat supplied from Miyagi, Japan. Miyagi seedlings are widely usedin Japanese oyster production areas, not only Hokkaido. Therefore, when the catastrophic
tsunami on March 11, 2011 damaged the Miyagi fisheries, many oyster culturing areas
were heavily affected.
Most Miyagi seedlings are naturally collected using scallop shells and reared by the
specialized fishermen. The seedlings have fast growth potential as reported by several
studies, and thus are preferred by many oyster farmers. However, the hardship caused by
the tsunami exposed the risks of excessive dependence on the Miyagi seedlings. Moreover,introduction of seedlings from distant areas have risks of invasion of diseases and alienorganisms as hitchhiking species. For example, the paramyxean parasite, Marteilioideschungmuensis, has had negative impacts on the oyster industry in some Japanese
production areas, and invasive ascidian such as Molgula manhattensis and Ascidiellaaspersa were also recorded in some bivalve culturing areas. Moreover, the potential
transport of harmful algae via relocation of bivalve molluscs has been reported. Therefore,
the techniques to reduce these risks have to be applied with efforts for maintaining local
populations of oysters when the seedlings grown in different locations are relocated. In
addition, using seedlings that originated from local populations in each area is also one of
the approaches for decreasing some risks. In the Akkeshi area, the artificial seedlings spatscollected from the locally survived adults are also used for aquaculture, although there islittle genetic variation. Akkeshi Bay faces the Pacific Ocean where a cold subarctic ocean
current “Oyashio” flows, but Akkeshi-ko estuary connected to the bay is shallow and its
water temperature increases during summer enough to enhance oyster growth and35maturation. Culture of single-seed oysters in hanging baskets is more suitable in this kindof shallow area than seedlings attached to scallop shell. This is because more oysters can becultured by basket hanging than scallop shell hanging in a shallow area, and the amounts ofoysters and extraneous organisms falling to the sea bottom is smaller in cage culturing thanin culturing with seedlings on scallop shell. Moreover, single-seed oysters have deep shell
breadth, which are marketed as value-added oysters with shell and are popular among
consumers as the local special products. However, the yield of single-seed oysters was
lower than that of Miyagi-seedling oysters at the beginning of this culturing, because theculturing methods for Miyagi seedlings were not suitable for single-seed oysters. After thecrisis of Miyagi seedlings, the preliminary use of local populations is beginning in someproduction areas. In these attempts, it is important that the existing culturing management
is suitable for culturing of local population, which might have original characteristics.
This research was partly supported by annual research grants “ Study of coastal
shellfish fisheries for supports the recovery from tsunami damage in eastern Hokkaido” andgrants-in-aid for Scientific Research “ Analysis and future prediction of coastal ecosystem”
provided by the Hokkaido National Fisheries Research Institute, Fisheries Research Agencyof Japan.
Key words
Pacific oyster (Crassostrea gigas), Miyagi seedlings, Saroma Lake, Akkeshi Bay,
single-seed36