Researcher Database
Last Updated :2024/07/25
Researcher Profile and Settings
Master
Affiliation (Master)
- Faculty of Fisheries Sciences Marine Bioresource and Environmental Science Interdisciplinary Sustainability Studies
Affiliation (Master)
researchmap
Profile and Settings
Degree
- Doctor of Science（Hokkaido University）
- Master of Science（University of Hawai'i at Manoa）
- Bachelor of Science（University of California, Santa Barbara）
Profile and Settings
Name (Japanese)
BOWERName (Kana)
JohnName
200901067008346734
Achievement
Research Interests
Research Areas
Research Experience
- 2009 - Today Hokkaido University Faculty of Fisheries Sciences Associate Professor
- 2008 - 2009 United States Agency for International Development (USAID) AAAS Science & Technology Policy Fellow
- 2006 - 2008 Hokkaido University Faculty of Fisheries Sciences Associate Professor
- 1999 - 2006 Hokkaido University Assistant Professor
- 1997 - 1999 Hokkaido University School of Fisheries Sciences
- 1997 - 1999 Hokkaido University Graduate School of Fisheries Sciences JSPS Postdoctoral Fellow
Education
- 1994 - 1997 Hokkaido University Graduate School of Fisheries Sciences Doctor of Fisheries Sciences
- 1990 - 1994 University of Hawai'i at Manoa Oceanography Master of Science
- 1982 - 1986 University of California at Santa Barbara Aquatic Biology Bachelor of Arts
- - 1986 カリフォルニア大学
Awards
- 2017 Hokkaido University Commendation for Excellent Teaching
受賞者: John BOWER - 2016 Hokkaido University Commendation for Excellent Teaching
受賞者: John BOWER - 2015 Hokkaido University Commendation for Excellent Teaching
受賞者: John BOWER - 2015 Hokkaido University President's Award for Excellence in Education
受賞者: John BOWER - 2012 Hokkaido University Commendation for Excellent Teaching
受賞者: John BOWER
Published Papers
- Ryusei Ohtani, Jun Yamamoto, Takashi Yanagimoto, Kohsuke Adachi, John R Bower, Hidefumi A Fujioka, Miyuki Hirose, Mitsuhiro Nakaya, Satoshi Suzuki, Shun TokiokaJournal of Molluscan Studies 88 (3) 0260-1230 2022/09/19ABSTRACT The genetic diversity of sperm and spermatangia stored by mated Japanese flying squid (Todarodes pacificus) was examined to better understand how this ommastrephid squid mates and stores sperm. Analyses were conducted using spermatangia implanted in the lips of immature squid collected in Tsugaru Strait, northern Japan, in July–August 2019, spermatangia implanted in the lips of mature squid collected in the East China Sea in April 2019, and sperm stored in the seminal receptacles of squid collected off Tosashimizu, Kochi Prefecture, Japan, in February 2019. DNA was extracted, microsatellite loci were amplified using five PCR primers, and allele peaks were analysed. Analysis of the spermatangia confirmed that females in the field mate with multiple males, suggesting that males transfer from 1 to at least 14 spermatangia in each mating. Analysis of the seminal receptacles showed that sperm from multiple males are mixed within individual sperm chambers. Spermatangia were also found implanted in the lips of males, providing evidence of same-sex sexual behaviour. To date, studies of cephalopod mating systems have focused on coastal species, and the results of this study add to our growing knowledge of more oceanic species.
- Close-up observations on the spawning behavior of a captive Japanese flying squid (Todarodes pacificus)Jun Yamamoto, Kohsuke Adachi, John R. Bower, Hajime Matsui, Mitsuhiro Nakaya, Ryusei Ohtani, Pandey Puneeta, Satoshi Suzuki, Shun Tokioka, Dharmamony Vijai, Takashi Yanagimoto, Hae-Kyun YooScientific reports 9 19739 2019/12 [Refereed][Not invited]
- J.R. Bower, W. Gallardo, S. JumnongsongBulletin of Fisheries Sciences., Hokkaido University 北海道大学大学院水産科学研究院 65 (2) 117 - 124 1346-1842 2015 [Not refereed][Not invited]
This study presents and discusses the results of a survey of internationalization of higher education in fisheries science at four universities in Vietnam, Thailand and the Philippines. Faculty members were asked about the importance, rationales, benefits and risks of internationalization at their universities. Information was also collected on the importance of foreign-language training, geographic priorities, and obstacles. More than 90% of respondents ranked internationalization either a high or medium priority. At every university, the most important reason to internationalize was to strengthen research and knowledge capacity and production. Key benefits included improved academic quality, and strengthened research and knowledge production. Nearly two-thirds of respondents noted internationalization also has associated risks; the most important were loss of cultural or national identity, and brain drain. The foreign language ranked most important was English. Japan and the ASEAN region ranked consistently high in importance for international collaboration, indicating the importance of intra-Asia collaboration, but efforts should be made to prevent less-developed countries and institutions from being left behind. The most important obstacle to internationalization at all universities was lack of financial support. - Alexander I. Arkhipkin, Paul G. K. Rodhouse, Graham J. Pierce, Warwick Sauer, Mitsuo Sakai, Louise Allcock, Juan Arguelles, John R. Bower, Gladis Castillo, Luca Ceriola, Chih-Shin Chen, Xinjun Chen, Mariana Diaz-Santana, Nicola Downey, Angel F. Gonzalez, Jasmin Granados Amores, Corey P. Green, Angel Guerra, Lisa C. Hendrickson, Christian Ibanez, Kingo Ito, Patrizia Jereb, Yoshiki Kato, Oleg N. Katugin, Mitsuhisa Kawano, Hideaki Kidokoro, Vladimir V. Kulik, Vladimir V. Laptikhovsky, Marek R. Lipinski, Bilin Liu, Luis Mariategui, Wilbert Marin, Ana Medina, Katsuhiro Miki, Kazutaka Miyahara, Natalie Moltschaniwskyj, Hassan Moustahfid, Jaruwat Nabhitabhata, Nobuaki Nanjo, Chingis M. Nigmatullin, Tetsuya Ohtani, Gretta Pecl, J. Angel A. Perez, Uwe Piatkowski, Pirochana Saikliang, Cesar A. Salinas-Zavala, Michael Steer, Yongjun Tian, Yukio Ueta, Dharmamony Vijai, Toshie Wakabayashi, Tadanori Yamaguchi, Carmen Yamashiro, Norio Yamashita, Louis D. ZeidbergREVIEWS IN FISHERIES SCIENCE & AQUACULTURE 23 (2) 92 - 252 2330-8249 2015 [Refereed][Not invited]
Some 290 species of squids comprise the order Teuthida that belongs to the molluscan Class Cephalopoda. Of these, about 30-40 squid species have substantial commercial importance around the world. Squid fisheries make a rather small contribution to world landings from capture fisheries relative to that of fish, but the proportion has increased steadily over the last decade, with some signs of recent leveling off. The present overview describes all substantial squid fisheries around the globe. The main ecological and biological features of exploited stocks, and key aspects of fisheries management are presented for each commercial species of squid worldwide. The history and fishing methods used in squid fisheries are also described. Special attention has been paid to interactions between squid fisheries and marine ecosystems including the effects of fishing gear, the role of squid in ecosystem change induced by overfishing on groundfish, and ecosystem-based fishery management. - John R. Bower, Katsunori Seki, Tsunemi Kubodera, Jun Yamamoto, Takahiro NobetsuBIOLOGICAL BULLETIN 223 (3) 259 - 262 0006-3185 2012/12 [Refereed][Not invited]
Brooding of egg masses by a squid in Japan is described. Brooding females were photographed in situ, and the females, their eggs, and their hatchlings were collected. The squid had all undergone gelatinous degeneration and swam slowly and continuously by undulating the fins and expelling water sporadically through the funnel. Eggs were held together by a dark, viscous material that formed a single-layer, sheet-like mass, from which hatchlings were seen to emerge. The annual appearance of brooding females in surface waters during spring suggests that they transport their egg masses from deep water to the surface before the eggs hatch. Genetic analyses identified the squid as Gonatus madokai (family Gonatidae), now the second gonatid and third squid known to brood. - J.R. Bower, C. NgugiJ. Higher Education and Lifelong Learning 北海道大学高等教育推進機構 19 (19) 9 - 16 1341-9374 2012 [Not refereed][Not invited]
- J. R. Bower, G. IshimuraAFRICAN JOURNAL OF AQUATIC SCIENCE 37 (2) 225 - 227 1608-5914 2012 [Refereed][Not invited]
- John R. BowerFISHERIES OCEANOGRAPHY 20 (1) 89 - 91 1054-6006 2011 [Refereed][Not invited]
The goal of scientific writing is clear communication of facts and ideas. Many books are available that explain the myriad of English grammar rules but clear communication requires more than just correct grammar; it also requires an understanding of how people read English. This paper briefly describes the structure of English prose and lists four principles to help non-native speakers improve their writing. The first two deal with individual sentences, focusing on the importance of the stress position and the subject-verb link. The final two deal with series of sentences, focusing on the importance of cohesion and coherence. - John R. Bower, Tsunemi Kubodera, Dhugal J. Lindsay, Naonobu Shiga, Saya Shimura, Fumikazu Sano, Naoto Horii, Tamio Kamiya, Mio TateyamaFISHERIES SCIENCE 72 (2) 446 - 448 0919-9268 2006/04 [Refereed][Not invited]
- Bower, JR, T IchiiFISHERIES RESEARCH 76 (1) 39 - 55 0165-7836 2005/10 [Refereed][Not invited]
We review the biology, ecology, fisheries, and resource status of the red flying squid (Ommastrephes bartramii) in the North Pacific focusing on recent literature published in Japan. The North Pacific population of O. bartramii comprises two seasonal cohorts (fall and winter-spring) and four stocks: (1) central stock of the fall cohort, (2) east stock of the fall cohort, (3) west stock of the winter-spring cohort, and (4) central-east stock of the winter-spring cohort. The population makes an annual round-trip migration between its subtropical spawning grounds where the sea surface temperature ranges from 21 to 25 degrees C and its northern feeding grounds near the Subarctic Boundary. O. bartramii matures at 7-10 months and has an estimated 1-year life span. Near the Subarctic Frontal Zone, adult squid commonly occupy 0-40 m depths at night and 150-350 m depths during the day. They prey primarily on fishes, squids and crustaceans. Predators include marine mammals and swordfish (Xiphias gladius). The North Pacific population of O. bartramii was targeted by an international driftnet fishery during 1978-1992, and annual catches reached more than 350,000 t during the 1980s. It is now targeted by jigging vessels from Japan, China, South Korea and Taiwan. Annual catches in the Japanese jigging fishery ranged from 49,000 to 71,000 t during the mid- 1990s, but dropped to below 25,000 t in 2000 and 2001. (c) 2005 Elsevier B.V. All rights reserved. - Bower, JR, K MiyaharaFISHERIES RESEARCH 73 (1-2) 1 - 11 0165-7836 2005/06 [Refereed][Not invited]
We review the fishery for the diamond squid (Thysanoteuthis rhombus) in Japan and recent Japanese research conducted on this species. T rhombus occurs worldwide in tropical and subtropical waters, including near southern and central Japan, where it is targeted by a growing fishery. The annual catch in Japan increased from 339 t in 1989 to almost 6000 t in 2001, and during 1998-2003, averaged close to 4900 t. The main fishing grounds are located in the Sea of Japan, Okinawa Prefecture, and Kagoshima Prefecture, and 90% of the total catch is made in the Sea of Japan and Okinawa. In the Sea of Japan, it is caught with free-floating angling gear called "taru-nagashi" and inshore trap nets; the fishery there usually runs from July to February, with highest catches occurring in September-December. The annual catch in the Sea of Japan during 1998-2003 ranged between 1600 and 3700t. In Okinawa, it is fished primarily in the daytime with free-floating angling gear called "hata-nagashi"; the fishery there runs mainly from November to April, with highest catches occurring in February-April. The annual catch in Okinawa increased from 15 t in 1989 to 2300 t in 2003. The free-floating egg masses of T rhombus occur widely in surface waters near southern and central Japan, and paralarval distribution patterns suggest that it spawns over a wide area almost year-round. Part of the population is transported by the Tsushima Current into the Sea of Japan, but little is known about this migration. The vertical distribution of T rhombus varies regionally; in Okinawa, it occurs mainly at 300-650 m depth during the day and 0-150 m depth at night, while in the Sea of Japan, it occurs mainly at 75-100 m depth during the day and 0-50 m depth at night. Its life span is thought to be about I year, and squid larger than 30 cm, mantle length grow about 7-10 cm mo(-1). © 2005 Elsevier B.V. All rights reserved. - K Miyahara, T Ota, N Kohno, Y Ueta, Bower, JRFISHERIES RESEARCH 72 (1) 71 - 79 0165-7836 2005/04 [Refereed][Not invited]
This paper describes recent catch fluctuations of the diamond squid Thysanoteuthis rhombus in the Sea of Japan and the development of models used to forecast catch per unit effort (CPUE) off Hyogo Prefecture based on statistical analyses of environmental indices measured 600 km upstream in the Tsushima Current. Annual catches during 1989-2002 fluctuated widely, and prefectural annual catches were closely related to each other, especially among the western prefectures. Four indices in June were closely related with CPUE during the fishing season (September-November) off Hyogo: (1) water temperature in the Tsushima Strait, (2) salinity in the Tsushima Strait, (3) sea level at Izuhara (Tsushima Island) and (4) sea level difference between Izuhara and Hakata (Kyushu Island). Using these indices as independent variables, simple and multiple regression analyses were conducted, and CPUE was accurately estimated by both regression and extrapolation, indicating that the CPUE off Hyogo can be forecasted 2 months before the fishery starts using the described models. The strong correlation among catches in different prefectures suggests the indices discussed here affect the catches over a large area. (c) 2004 Elsevier B.V. All rights reserved. - K Uchikawa, Bower, JR, Y Sato, Y SakuraiFISHERY BULLETIN 102 (4) 733 - 739 0090-0656 2004/10 [Refereed][Not invited]
The stomach contents of the minimal armhook squid (Berryteuthis anonychus) were examined for 338 specimens captured in the northeast Pacific during May 1999. The specimens were collected at seven stations between 145-165degreesW and 39-49degreesN and ranged in mantle length from 10.3 to 102.2 mm. Their diet comprised seven major prey groups (copepods, chaetognaths, amphipods, euphausiids, ostracods, unidentified fish, and unidentified gelatinous prey) and was dominated by copepods and chaetognaths. Copepod prey comprised four genera, and 86% by number of the copepods were from the genus Neocalanus. Neocalonus cristatus was the most abundant prey taxa, composing 50% by mass and 35% by number of the total diet. Parasagitta elegans (Chaetognatha) occurred in more stomachs (47%) than any other prey taxon. Amphipods occurred in 19% of the stomachs but composed only 5% by number and 3% by mass of the total prey consumed. The four remaining prey groups (euphausiids, ostracods, unidentified fish, and unidentified gelatinous prey) together composed <2% by mass and <1% by number of the diet. There was no major change in the diet through the size range of squid examined and no evidence of cannibalism or predation on other cephalopod species. - Bower, JR, S TakagiJOURNAL OF PLANKTON RESEARCH 26 (8) 851 - 857 0142-7873 2004/08 [Refereed][Not invited]
The vertical distribution patterns of paralarvae from several abundant cephalopod taxa were examined from depth-stratified tows in the northeast Pacific (44-56degreesN, 145-165degreesW) during three summer surveys in 1999-2001. A total of 309 cephalopods representing 10 taxa in three families were collected. Gonatid squids composed 97% of the total catch, and the most numerous taxa were Berryteuthis anonychus (59% of the total catch), Gonatus spp. (21%) and Gonatopsis borealis (17%). B. anonychus and Gonatus spp. were both most abundant in the upper 20 m; catches of both taxa varied significantly with depth and were significantly higher above the thermocline than in and below the thermocline. Gonatopsis borealis was collected mostly between 20 and 50 m, and catches were significantly higher in the thermocline than above and below the thermocline. Paralarvae of the three major taxa showed no evidence of diel vertical migration. Mantle lengths of Gonatus spp. and G. borealis each varied significantly with depth, and Gonatus spp. showed a strong positive correlation between mantle length and depth. - M Kaeriyama, M Nakamura, R Edpalina, Bower, JR, H Yamaguchi, RV Walker, KW MyersFISHERIES OCEANOGRAPHY 13 (3) 197 - 207 1054-6006 2004/05 [Refereed][Not invited]
The effects of climate events on the feeding ecology and trophic dynamics of Pacific salmon (Oncorhynchus spp.) in offshore waters of the central Gulf of Alaska were investigated during early summers (1994-2000), based on analyses of stomach contents, and carbon and nitrogen stable isotopes (delta(13)C and delta(15)N). Gonatid squids (mainly Berryteuthis anonychus) were the dominant prey of all salmon species except for chum salmon (O. keta). During the 1997 El Nino event and the 1999 La Nina event, squids decreased sharply in the diets of all Pacific salmon except coho salmon (O. kisutch) in the Subarctic Current, and chum salmon diets changed from gelatinous zooplankton (1995-97) to a more diverse array of zooplankton species. A delta(13)C and delta(15)N analysis indicated that all salmon species occupied the same branch of the food web in 1999-2000. We hypothesize that high-seas salmon adapt to climate-induced changes in their prey resources by switching their diets either within or between trophic levels. To understand the effects of climate change on Pacific salmon in the Gulf of Alaska, biological oceanographic research on B. anonychus and other important prey resources is needed. - Kenji Hayashi, John R. BowerJournal of Oleo Science 53 (1) 1 - 8 1347-3352 2004 [Refereed][Not invited]
The lipid content and class composition of the digestive gland, mantle and stomach fluid of the gonatid squid Berryteuthis anonychus collected in the North Pacific are described. The digestive glands contained large amounts of lipids (20.0 — 35.6%), which comprised mainly triacylglycerols (TAG: 57.1 — 77.3%) and diacyl glyceryl ethers (DAGE: 12.9 — 14.6%). The mantles contained the least amounts of lipids (1.3 — 1.4%), which comprised phospholipids (76.2 — 79.4%), TAG (0.1%) and trace amounts of DAGE. The stomach fluids contained low amounts of lipids (4.5%), which comprised wax esters (75.2%), TAG (4.7%) and DAGE (0.9%). The main components of the alkyl chains in DAGE from the digestive glands were 16:0 (50.7 — 57.3%), 20:1n-11 (6.2 — 8.0%), 16:1n-7 (3.7 — 7.1%) and 18:0 (2.8 — 7.9%) alcohols. Component fatty alcohols originating in wax esters from the stomach fluids were rich in monoenes (90.9%), including 22:1n-11 (45.3%) and 20:1n-11 (15.3%) alcohols. The fatty acid compositions of DAGE and TAG in the digestive glands, of phospholipids in the mantles, and of wax esters and TAG in the stomach fluids are also discussed. © 2004, Japan Oil Chemists' Society. All rights reserved. - Bower, JR, JM Murphy, Y SatoVELIGER 45 (4) 309 - 315 0042-3211 2002/10 [Refereed][Not invited]
Trends in body size and maturation with latitude of the gonatid squid Berryteuthis anonychus in the northeast Pacific are described. Squid were collected during May 1999 at seven stations along 145degrees and 165degreesW between 39degrees and 49degreesN. Mantle lengths ranged from 10.3 to 102.2 mm and increased significantly in both sexes from south to north. Females were both larger and more numerous than males at the northern stations. Both sexes showed a clear pattern of increasing maturity from south to north, and at each station, males were generally in a more advanced stage of maturity than females. Most mature males occurred at the northernmost stations. No mature females were collected. Our data suggest that B. anonychus migrates northward in the northeast Pacific during spring, with males maturing at a smaller size than females. - J Yamamoto, T Miyoi, Bower, JR, T Goto, Y Nakamura, S Masuda, Y SakuraiNIPPON SUISAN GAKKAISHI 67 (3) 497 - 499 0021-5392 2001/05 [Refereed][Not invited]
- John R. Bower, Michael P. Seki, Richard E. Young, Keith A. Bigelow, Jed Hirota, Pierre FlamentMarine Ecology Progress Series 185 203 - 212 0171-8630 1999/08/20 [Refereed][Not invited]
The distribution and abundance of cephalopod paralarvae near the Hawaiian Islands are described. Paralarvae were collected during 5 plankton surveys in 1991 to 1993. The 404 tows at 59 stations collected 10375 paralarvae from 21 families and 57 species. The most numerous families were the Ommastrephidae (23% of total catch), Pyroteuthididae (17%), Enoploteuthididae (16%), Onychoteuthididae (14%), and Chtenopterygidae (8%). The most numerous species were Ommastrephes bartramii (18%), Pterygioteuthis microlampas (15%), Chtenopteryx sicula (8%), and Onychoteuthis campacta (6%). Analysis of paralarval distribution patterns identified 2 paralarval assemblages: 'island associated' and 'oceanic'. The 15 'island-associated' species showed increased paralarval abundance near the islands, suggesting preferential spawning in this area. Epipelagic nearshore spawners included Onychoteuthis sp. C. Sthenoteuthis oualaniensis, and Nototodarus hawaiiensis. Mesopelagic nearshore spawners included 3 reported members of the Hawaiian Mesopelagic Boundary Community (Abralia trigonura, Liocranchia reinhardti, and Chiroteuthis picteti) and 3 probable flew members (Liocranchia valdiviae, Histioteuthis hoylei and Enoploteuthis jonesi). - Bower J, Nakamura Y, Mori K, Yamamoto J, Isoda Y, Sakurai YMar Biol. 135 99 - 106 1999 [Not refereed][Not invited]
- Bower, JRFISHERY BULLETIN 94 (3) 398 - 411 0090-0656 1996/07 [Refereed][Not invited]
Research was conducted to test the hypothesis that spawning of the oceanic squid Ommastrephes bartramii in the central North Pacific is related to the proximity of the Hawaiian Archipelago. Paralarvae were collected during five plankton surveys near the Hawaiian Island chain during the 1991-93 spawning seasons. In total, 1,720 O. bartramii paralarvae were collected from 406 tows. Estimation of ages and hatch dates of all squid was inferred from analysis of statolith microstructures from 85 specimens. A well-defined relationship existed between the number of statolith growth increments and the dorsal mantle length of the paralarvae. Estimated hatch dates of individuals collected during the three years surveyed ranged between mid-January and early April. Spawning sites were then estimated from hatch dates by backcalculating with physical data on the speed of ocean currents near the archipelago. Although estimated spawning of O. bartramii did often occur along the island chain, spawning was not limited to nearshore waters. Some animals hatched, on the basis of estimated current speeds, at least 646 kilometers away from the archipelago. Projected hatching locations of more than 72% of all collected paralarvae were at least 10 kilometers from shore. Data do not support the hypothesis that the location of the spawning grounds in this region is solely related to the position of the Hawaiian Archipelago.
MISC
- Japan launches a new, state-of-the-art training ship – the Oshoro Maru VJ.R. Bower PICES Press 23- (1) 21 -23 2015 [Not refereed][Not invited]
- JSPS Asia-Africa Science Platform Program: Brief summaryu of first year activitiesKatsutoshi Arai, Junichiro Okamoto, Nobuo Kimura, Yasuaki Takagi, Kunihiko Konno, John Bower, Virgilia Sulit Fish for the People 10- (2) 42 -47 2012 [Not refereed][Not invited]
- S Kimura, Y Higuchi, M Aminaka, Bower, JR, Y Sakurai JOURNAL OF MOLLUSCAN STUDIES 70- 117 -121 2004/05 [Refereed][Not invited]
This paper describes the properties of egg-mass glycoproteins from the Japanese common squid Todarodes pacificus (Steenstrup, 1880) and provides chemical evidence for the role of a nidamental mucosubstance in the formation of egg masses. Samples were collected from the surface layer and the interior jelly of an egg mass spawned in captivity, and the interior jelly was separated into fibrils and the liquid portion of the jelly. Mucosubstances in the nidamental and oviducal glands of maturing squid were then isolated and compared with those of each part of the egg mass. The surface layer and the interior fibrils were found to be composed of distinct types of mucin complexes and to have originated from the water-soluble and insoluble fractions of nidamental mucosubstance, respectively. Oviducal mucosubstance, however, appeared to play no role in the formation of the fibrils. These results suggest the egg-mass surface layer is derived from the water-soluble fraction of the nidamental mucosubstance, and the fibrils within the mass are derived from the insoluble fraction of the mucosubstance. - The Oshoro Maru: a short history of Hokkaido University's workhorse in the North PacificJ.R. Bower PICES Press 9- (1) 25 -28 2002 [Not refereed][Not invited]
- The Hokusei Maru: 53 years of research in the North PacificJ.R. Bower PICES Press 10- (2) 25 -28 2002 [Not refereed][Not invited]
- Jun Yamamoto, Takako Miyoi, John R. Bower, Tsuneo Goto, Yoshikazu Nakamura, Shinya Masuda, Yasunori Sakurai Nippon Suisan Gakkaishi (Japanese Edition) 67- (3) 497 -499 2001 [Not refereed][Not invited]
- Bower, JR, Y Sakurai, J Yamamoto, H Ishii AQUACULTURE 170- (2) 127 -130 1999/01 [Refereed][Not invited]
We describe a method for transporting live squid, Todarodes pacificus (Cephalopoda: Ommastrephidae), using cold-water anesthesia. Squid were placed individually in 30-l plastic bags with 5 1 of 0-1 degrees C seawater and 10-15 l of oxygen gas. Thirteen of 14 anesthetized squid survived 6.5 h transport by car and airplane with no signs of distress or shock. The longest survival under anesthesia was 10 h. (C) 1999 Elsevier Science B,V. All rights reserved. - Y Sakurai, Bower, JR, Y Nakamura, S Yamamoto, K Watanabe AMERICAN MALACOLOGICAL BULLETIN 13- (1-2) 89 -95 1996 [Refereed][Not invited]
Embryonic development and survival of paralarvae of the Japanese common squid Todarodes pacificus (Steenstrup, 1880), were examined at 16 temperatures (3-39 degrees C) to determine the optimum temperature range for development and survival. Normal embryonic development occurred at temperatures between 14.0 degrees and 26.0 degrees C, with highest embryonic survival rates occurring between 14.7 degrees and 22.2 degrees C. The relationship between temperature (T) and the number of days from artificial fertilization to hatching (D) is expressed by a polynomial function: ln(D) = 4.73 - 0.227(T) + 0.00304(T-2). A modified formula, based on observations of two egg masses spawned in captivity, was used to estimate the development rate of eggs within naturally spawned egg masses. It is suggested that T. pacificus spawns in waters wanner than 12.1 degrees C, and egg masses maintain their structure for 4.0 - 9.5 days before disintegrating at temperatures between 14.7 degrees and 22.2 degrees C. Paralarvae survived up to 13 days after hatching, with the highest survival rates occurring at 15 degrees C. - Bower, JR, Y Sakurai AMERICAN MALACOLOGICAL BULLETIN 13- (1-2) 65 -71 1996 [Refereed][Not invited]
Two egg masses of the ommastrephid squid Todarodes pacificus (Steenstrup, 1880) are described. Immature squid were collected from inshore waters of southern Hokkaido, Japan, and maintained in a raceway tank where they matured, mated, and spawned. Both gelatinous masses were spherical and nearly neutrally buoyant. The larger mass measured 80 cm in diameter and contained approximately 200,000 eggs. The egg-mass surface layer effectively prevented crustaceans, protozoans, and bacteria from infesting the masses. Paralarvae hatched after 4-6 days at 18-19 degrees C and actively swam at once, with many individuals swimming at the surface. Both masses disintegrated soon after hatching. Paralarvae died approximately 6-7 days after hatching, presumably due to starvation.
Association Memberships
- American Association for the Advancement of Science 日本水産学会 The Japanese Society of Fisheries Science
Research Projects
- Japan Society for the Promotion of Science：Grants-in-Aid for Scientific ResearchDate (from‐to) : 2004 -2006Author : J.R. BowerThis study describes the paralarvae of five gonatid squids from the North Pacific identified based on analyses of the mitochondrial DNA cytochrome oxidase subunit (COI) gene. A total of 281 paralarvae ranging in size from 2.76 to 13.50 mm ML were collected from surface waters in the North Pacific. The morphology of each was examined in detail, and the base sequence of the mtDNA COI gene area was determined. The base sequence data from adults of three species (Gonatopsis borealis, Berryteuthis anonychus, and Gonatus kamtchaticus) were also determined, and base-sequence data from the paralarvae were compared to those from the adults and from previously published studies. Based on this analysis, we positively identified the paralarvae of six paralarval morphotypes : 1) Gonatopsis sp. (slender), 2) Gonatopsis borealis (small), 3) Berryteuthis anonychus, 4) Gonatus pyros, 5) Gonatus onyx, and 6) Gonatus madokai. The results of this research were presented at four international symposia: 1) the 2004 PICES annual meeting in Honolulu (poster), 2) the 2005 PICES annual meeting in Vladivostok (oral), 3) the 2006 PICES annual meeting in Yokohama (poster), and 4) the 2007 AAAS (American Association for the Advancement of Science meeting in San Francisco (poster). Data collected in this research were also analyzed by a graduate student at Hokkaido University (Ms. Saya Shimura) and used to complete her master's thesis in 2006 (title: "DNA analysis and morphology of difficult-to-identify gonatid squid paralarvae"). Two manuscripts based on the results of this study are now being prepared-one that describes the morphology of the paralarvae, and one that describes their distribution patterns. In addition, one paper describing a paralarva of the vampire squid (Vampyroteuthis infernalis) collected during this study was published last year (Bower et al. 2006).
- 日本学術振興会：科学研究費助成事業Date (from‐to) : 2000 -2002Author : BOWER John R.本研究では、スルメイカ幼生の初期餌料について解明することを目的に以下の事項について調査を行った。(1)フィールドで採集した幼生の消化腺内容物の調査。(2)人口授精にて得たふ化幼生に、初期餌料となりうるプランクトン与え、その摂餌の可能性を調べる。(3)人口授精にて得られたふ化幼生に有機懸濁物(DOM)を与え、その吸収の可能性の有無を調べる。以下にそれぞれの部分の結果について報告する。 (1)フィールドで採集した幼生の消化腺内容物の調査。 日本海で採取したスルメイカ幼生を顕微鏡下で解剖し、その消化腺内容物ついて調べた。外套長1.2-3.3mmのスルメイカ幼生の顎片のみに、ノコギリ状の細かな歯の発達が観察され、初期餌料の索餌と密接に関連している可能性が示された。3.5mm未満の幼生の胃中には、植物プランクトンが認められず、液状物質のみが出現したことから、海中の有機物を摂餌している可能性が高い。一方外套長3.5mm以上のスルメイカの幼生のには、カイアシ類が認められたことから、このサイズから他生物を捕食する行動が始まると推察された。 (2)人口授精にて得たふ化幼生の初期餌料の摂餌実験。 道南(南茅部町)の定置網で採集したスルメイカ成体を水槽内で飼育し、成熟後、人口授精を実施して3000個体以上のふ化幼生を得た。初期餌料として可能性のある数種類の植物・動物プランクトンをふ化幼生に与えたが、それらの摂餌は認められなかった。 (3)人口授精にて得られたふ化幼生の有機懸濁物(DOM)実験。 有機懸濁物を調べるためには、ふ化幼生の無菌培養が必要条件である。そのため、人口授精には、交尾したスルメイカメスの受精のうから精子を抽出し、精子の殺菌を試みた。しかしこの実験は、バクテリアが無い状態(無菌培養)が維持できなかっため、困難であった。
- イカ類の生態学的研究