- Cetacean biology, Management of whale stock, Systematics of marine mammalsedit
Relationship between body size, maturity, and feeding habit of common
Research Interests: Japan and North Pacific
This study analysed post-1900 published and unpublished records of gray whales in the western North Pacific. Modern whaling recorded a peak annual catch of 100-200 whales in the 1910s, followed by a rapid decline in the 1920s and 1930s... more
This study analysed post-1900 published and unpublished records of gray whales in the western North Pacific. Modern whaling recorded a peak annual catch of 100-200 whales in the 1910s, followed by a rapid decline in the 1920s and 1930s and a continued low level (perhaps 10-20 whales/year) for over 40 years to the l960s. Catches made during the last phase could have been the major factor suppressing recovery until recently. There are reasons to believe that this gray whale stock breeds in Hainan waters.
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Ocean ambient noises against seismic signals are well studied using archived waveforms recorded on three-component seismometers and hydrophones connected to a seafloor cabled seismic network off Kushiro, Hokkaido, Japan basically facing... more
Ocean ambient noises against seismic signals are well studied using archived waveforms recorded on three-component seismometers and hydrophones connected to a seafloor cabled seismic network off Kushiro, Hokkaido, Japan basically facing the Pacific Ocean. The system was deployed to install in late July 1999 by Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Outstanding “noises” at frequency bands of 15-30 Hz are recorded on all components of both seismometers and hydrophones, which are directly recognized as fin whale calls in comparison with in-situ visual surveys carried in September to October 2009. It is extremely conspicuous that a seasonal variation of the fin whale calls has been revealed in ambient noise spectrograms of continuous longterm waveform records from 2009 to 2013. High-intensity signals associated with the fin whale calls appear commonly in the periods from September to February over cold winter at high latitudes. The remarkable seasonal pattern should be corresponded to their annual living behavior and might be related to climate changes in the Pacific Ocean.
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origin, objectives and research progress made in the period 2002-2007, including scientific considerations for the next research period
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In order to avoid collisions between the hydrofoil (HF) and cetaceans, the Under Water Speaker (UWS) has been installed on the HF. Because of its potential in utility, the authors tried to improve the UWS to minimize the risk of the... more
In order to avoid collisions between the hydrofoil (HF) and cetaceans, the Under Water Speaker (UWS) has been installed on the HF. Because of its potential in utility, the authors tried to improve the UWS to minimize the risk of the collisions. Under the project, they examined three subprojects; 1) Analyzing the characteristics of the HF underwater noise; 2) Assessing audibility of major large cetaceans by measuring their vocalizations and 3) An anatomical prediction of the audible range by examining the cochlear basal membrane. Through the analyses, it was identified that the noise produced by the HF was a broad-band noise with approximately 150dB re 1μPa-m. That noise level was lower than those of larger boats suggesting difficulties for cetaceans in sensing approach of the vessels. In addition, analysis of their vocalizations and anatomical observation indicated that dominant frequency of their audible range was lower than signals produced by the existing UWS.
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... Coastal component. TOSHIYA KISHIRO 1, HIDEHIRO KATO 1, HIDEYOSHI YOSHIDA 1, TOMIO MIYASHITA 1, TAMEO RYONO 2, SHIGEO TABATA 2, RYOSUKE OKAMOTO 2, KUNIHIRO YASUI 2, HITOMI SATO 2, YUKA MORITA 2, ...
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Yearly trend in the age at sexual maturity of Antarctic
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We analyzed the seismic data from 2009 to 2013 obtained from seafloor cable seismic network off Kushiro, Hokkaido, Japan, which was deployed by Japan Agency for Marine Earth Science and Technology in 1999. Two kinds of calls were... more
We analyzed the seismic data from 2009 to 2013 obtained from seafloor cable seismic network off Kushiro, Hokkaido, Japan, which was deployed by Japan Agency for Marine Earth Science and Technology in 1999. Two kinds of calls were recorded, one is “Single” which is not related to the preceding and following intervals, and the other is “Doublet” which alternates short intervals and long intervals. Especially the interval of “Doublet” shows a seasonal change, it is characterized as a long interval in January and February, while becomes shorter interval in October and November. It is quite unlikely that the same group of fin whales are calling while the call is appearing off Kushiro. The seasonal change of “Doublet” might be a change of the group appearing off Kushiro.
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コククジラEschrichtius robustus は北太平洋に分布し， 日本を含むアジア周辺海域に生息する西部系群と北米側 に生息する東部系群の二系群に分けられている．しかし 近年，衛星標識を用いた研究などから夏季に西部系群の 摂餌海域と考えられているサハリン沖に出現した個体 が，冬期に東部系群の繁殖海域と考えられているオレゴ ン近海に回遊した例などから，従来の系群構造について 再考が迫られている．本研究は1990–2005 年にかけて，... more
コククジラEschrichtius robustus は北太平洋に分布し， 日本を含むアジア周辺海域に生息する西部系群と北米側 に生息する東部系群の二系群に分けられている．しかし 近年，衛星標識を用いた研究などから夏季に西部系群の 摂餌海域と考えられているサハリン沖に出現した個体 が，冬期に東部系群の繁殖海域と考えられているオレゴ ン近海に回遊した例などから，従来の系群構造について 再考が迫られている．本研究は1990–2005 年にかけて， ストランディングや混獲などにより日本の太平洋沿岸域 から得られたコククジラ5 個体を対象に，頭骨を中心と した全身骨格の計測値および骨学的特徴の記載をおこな うとともに，既報データをもとに蔚山（n＝1），中国 （n＝2），カリフォルニア産（n＝1）の個体との骨格形態 を比較した．頭頂部を中心に各海域に特徴的な形質が認 められ，日本産個体では前上顎骨が鼻骨を包むように緩 やかにカーブしており，前上顎骨後端が尖っておらず， 上顎骨の後端より後方に位置していた．また，鼻骨の前 縁部が央付近でやや前方に突出し，性成熟個体では左右 の鼻骨が後方で癒合していた．頭頂部に加え，胸骨と骨 盤痕跡の形状においても海域間に明瞭な違いが認めら れ，いずれの形質も日本産個体はカリフォルニア産の個 体に類似した形状を示していた．本研究結果は東部系群 が近年，日本沿岸域へ分布域を拡張している可能性を示 唆している．
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To improve the age readability for common minke whales, Balaenoptera acutorostrata, we tried to minimize damaged earplugs using newly developed techniques. Because of its soft constitution of the earplug tissue, we examined the... more
To improve the age readability for common minke whales, Balaenoptera acutorostrata, we tried to minimize damaged earplugs using newly developed techniques. Because of its soft constitution of the earplug tissue, we examined the feasibility of three different types of treatment to collect the earplugs safely from the external auditory meatus （EAM） as follows: type A treatment, impregnate EAM with g elatin stuff through needle but without opening its corium of the dermis （CD） subsequently cooling them with shaved ice to solidify gelatin stuff; type B, impregnate EAM with gelatin stuff after opening CD then cooling with the ice; type C, impregnate EAM with gelatin stuff after opening CD then cooling with coolant gas. Through a total of 214 trials on the minke whales at the platform of JARPN II p rograms （coastal components） in 2007 to 2009, proportions of embedding earplugs with gelatin were 50%, 71% and 80% in type A, B and C treatments, respectively. From these experiments, the gelat...
Summary Bryde’s whales were long confused with sei whales. Further, as known they included a later-described separate species, Omura’s whale (Balaenoptera omurai). Large pelagic and smaller coastal forms are recognized as subspecies B.... more
Summary Bryde’s whales were long confused with sei whales. Further, as known they included a later-described separate species, Omura’s whale (Balaenoptera omurai). Large pelagic and smaller coastal forms are recognized as subspecies B. edeni brydei and B. edeni edeni, respectively. Bryde’s whales can be recognized at sea by the three distinct ridges on the top of the head. They are seen throughout tropical and warm temperate waters of 16.3°C or warmer year round. They not only feed mainly on pelagic schooling fishes such as pilchard, anchovy, sardine, mackerel, herring, and others but also on crustaceans. Little is known about the breeding grounds, even for inshore or coastal stocks, although it is generally believed that they must be somewhere in lower latitudes. Bryde’s whales have a 2-year reproductive cycle composed of 11–12 months’ gestation, 6 months of lactation, and 6 months resting. Because Bryde’s whales have been mainly exploited after substantial improvement of IWC stock management procedures adopted in 1975, stocks have been kept relatively stable.
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The differences in rorqual feeding ecology have been linked to the presence of different morphological markers. The Antarctic minke whale (Balaenoptera bonaerensis Burmeister, 1867) and common minke whale (Balaenoptera acutorostrata... more
The differences in rorqual feeding ecology have been linked to the presence of different morphological markers. The Antarctic minke whale (Balaenoptera bonaerensis Burmeister, 1867) and common minke whale (Balaenoptera acutorostrata Lacépède, 1804) are closely related species, but their morphological differences have not been fully investigated. In this study, we compared 21 skull and 11 feeding apparatuses (baleen and mouth-related parts) measurement points between these two species using hundreds of individuals covering a wide range of body lengths in both sexes. Their engulfment capacities were estimated using these measurements. Our results show that Antarctic minke whales have (1) proportionally larger skulls to the body length, (2) more dorsoventrally and laterally curved rostra, (3) proportionally larger feeding apparatuses to the condylobasal length, and (4) significantly larger engulfment capacity than common minke whales. These differences could indicate that Antarctic min...
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Publisher Summary This chapter describes the Bryde's whale, least known of the large baleen whales. Bryde's whales are medium-sized balaenopterids. They were long confused with sei whales ( Balaenoptera borealis ) because of... more
Publisher Summary This chapter describes the Bryde's whale, least known of the large baleen whales. Bryde's whales are medium-sized balaenopterids. They were long confused with sei whales ( Balaenoptera borealis ) because of morphological similarities; this confusion lasted into the 1970s. Bryde's whales were first described based on examination of a stranded balaenopterid on Thaybyoo Creek beach, Gulf of Marataban, Burma. Females are larger than males throughout life, by about 2 ft (0.5–0.6 m) at full maturity. It is believed they reach 15.5 m, but most are much smaller. As demonstrated for South African Bryde's whales, animals from coastal stocks or stocks inhabiting rather areas are generally smaller than those from migratory pelagic stocks . Southern Hemisphere animals are also larger than Northern Hemisphere animals. In the South Africa and western North Pacific stocks, body length increases rapidly until 4–5 years, reaches about 90% of asymptotic length for both sexes at about 10 years, and ceases to increase at about 20–25 years. If mean lengths at physical maturity in the western North Pacific stock are substituted into the equation, weight estimates are 15.0 (at 13.0 m) and 16.6 (at 13.5 m) tons for males and females, respectively. Bryde's whales do not gather into large groups. They are usually seen singly or in groups of 2–3 in the North Pacific, with a maximum group size of 12. Although Bryde's whales have a life history similar to that of other balaenopterids, there are species-specific aspects due to the fact that they remain in tropical and temperate waters throughout the year.
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... SHANNON RANKIN', DON LJUNGBLAD+, CHRIS CLARK# AND HIDEHIRO KATO++ Contact e-mail: Shannon.Rankin@noaa.gov ... in the presence of blue whales can be divided into two categories: short-duration or long-duration (Thompson... more
... SHANNON RANKIN', DON LJUNGBLAD+, CHRIS CLARK# AND HIDEHIRO KATO++ Contact e-mail: Shannon.Rankin@noaa.gov ... in the presence of blue whales can be divided into two categories: short-duration or long-duration (Thompson and Cummings, 1996; Norris and ...
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An in-depth assessment of an eastern Indian stock (I-stock) and a western South Pacific stock (P-stock) of Antarctic minke whales distributed between 35°E and 145°W was carried out by the Scientific Committee of the International Whaling... more
An in-depth assessment of an eastern Indian stock (I-stock) and a western South Pacific stock (P-stock) of Antarctic minke whales distributed between 35°E and 145°W was carried out by the Scientific Committee of the International Whaling Commission (IWC/SC) from 2001 to 2014 using data mainly collected from 1985 to 2004. This paper is a synthesis and summary of the outcomes of that assessment, although research on this species has been ongoing since 2014. The assessment integrates information from a wide range of topics including systematics, survey methods, direct catches, population structure, abundance, spatial distribution, biological information, population dynamics, species interactions, pollutants and interactions with marine debris. At least two stocks (I-stock and P-stock) are found between 35°E–145°W, with a soft boundary between 100°E and 165°E. Two sets of agreed circumpolar estimates of abundance from IWC assessment cruises (termed ‘CPII’ – 1985/86–1990/91, and ‘CPIII’ ...
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This study examined the morphology, growth and life history of dwarf minke whales to identify and confirm any differences from other minke whale species and subspecies. The study was based on biological samples and data obtained from 16... more
This study examined the morphology, growth and life history of dwarf minke whales to identify and confirm any differences from other minke whale species and subspecies. The study was based on biological samples and data obtained from 16 whales (3 males and 13 females) collected through the 1987/88 to 1992/93 austral summer seasons by the Japanese Whale Research Program under Special Permit in the Antarctic (JARPA). The whales were collected between latitudes 58°23′S and 65°04′S in the Antarctic area between 90°E and 180°. Mean body length at physical maturity was estimated to be 7.16 m for females, approximately 1.5 m to 2.0 m smaller than equivalent values of Antarctic minke whales and North Pacific common minke whales. The characteristic feature of a white shoulder/flipper patch was confirmed and some variations in the overall color pattern was found. Skeletal observations confirmed the previously reported characteristic features on the vertex of the skull. In addition, this study found a longer rostrum, deeply curved mandible, and narrower nasal bone in dwarf minke whales in comparison with other minke whales. All pregnant females had conceived in mid-austral winter (middle of June to early August). Females are likely to attain sexual maturation at 6-6.5 m and at around 7-10 years of age. Stomach contents indicated that dwarf minke whales mainly fed on lantern fishes around the Antarctic Convergence in summer. Analyses by ANCOV revealed significant differences in both external body and skull morphology among different species and subspecies. Furthermore, cluster analyses on the skull morphology revealed differentiation between dwarf minke whales and other common minke whales but they are more closely related to North Atlantic common minke whales. These analyses concurred with previous genetic analyses results. The results of this study provided support for the proposed subspecific status of dwarf minke whales.
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This study examined the morphology, growth and life history of dwarf minke whales to identify and confirm any differences from other minke whale species and subspecies. The study was based on biological samples and data obtained from 16... more
This study examined the morphology, growth and life history of dwarf minke whales to identify and confirm any differences from other minke whale species and subspecies. The study was based on biological samples and data obtained from 16 whales (3 males and 13 females) collected through the 1987/88 to 1992/93 austral summer seasons by the Japanese Whale Research Program under Special Permit in the Antarctic (JARPA). The whales were collected between latitudes 58°23′S and 65°04′S in the Antarctic area between 90°E and 180°. Mean body length at physical maturity was estimated to be 7.16 m for females, approximately 1.5 m to 2.0 m smaller than equivalent values of Antarctic minke whales and North Pacific common minke whales. The characteristic feature of a white shoulder/flipper patch was confirmed and some variations in the overall color pattern was found. Skeletal observations confirmed the previously reported characteristic features on the vertex of the skull. In addition, this study found a longer rostrum, deeply curved mandible, and narrower nasal bone in dwarf minke whales in comparison with other minke whales. All pregnant females had conceived in mid-austral winter (middle of June to early August). Females are likely to attain sexual maturation at 6-6.5 m and at around 7-10 years of age. Stomach contents indicated that dwarf minke whales mainly fed on lantern fishes around the Antarctic Convergence in summer. Analyses by ANCOV revealed significant differences in both external body and skull morphology among different species and subspecies. Furthermore, cluster analyses on the skull morphology revealed differentiation between dwarf minke whales and other common minke whales but they are more closely related to North Atlantic common minke whales. These analyses concurred with previous genetic analyses results. The results of this study provided support for the proposed subspecific status of dwarf minke whales.
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Study on the interactions between marine mammals or marine birds and fisheries in the PICES region of interest. (PDF contains 168 pages)
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Although it has long been assumed that modern cetaceans lack nervous system structures that mediate olfaction, recent studies suggest that mysticetes still maintain olfactory nerves. We collected samples of the mucous membrane covering... more
Although it has long been assumed that modern cetaceans lack nervous system structures that mediate olfaction, recent studies suggest that mysticetes still maintain olfactory nerves. We collected samples of the mucous membrane covering the cribriform plate at the bottom of the dorsal nasal meatus from a mature female common minke whale. The samples were then thinsectioned and stained with hematoxylin and eosin. Microscopic observations revealed that the mucosa was covered with a pseudostratified columnar epithelium with vessels, glands, and nerve plexuses in its lamina propria. These histological characteristics resembled those of the olfactory epithelium in terrestrial mammals, suggesting that mysticetes do indeed possess a
The origin of whales and their transition from terrestrial life to a fully aquatic existence has been studied in depth. Palaeontological,, morphological and molecular studies suggest that the order Cetacea (whales, dolphins and porpoises)... more
The origin of whales and their transition from terrestrial life to a fully aquatic existence has been studied in depth. Palaeontological,, morphological and molecular studies suggest that the order Cetacea (whales, dolphins and porpoises) is more closely related to the order Artiodactyla (even-toed ungulates, including cows, camels and pigs) than to other ungulate orders. The traditional view that the order Artiodactyla is monophyletic has been challenged by molecular analyses of variations in mitochondrial and nuclear DNA. We have characterized two families of short interspersed elements (SINEs) that were present exclusively in the genomes of whales, ruminants and hippopotamuses, but not in those of camels and pigs. We made an extensive survey of retropositional events that might have occurred during the divergence of whales and even-toed ungulates. We have characterized nine retropositional events of a SINE unit, each of which provides phylogenetic resolution of the relationships ...
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The distribution and local movement patterns of humpback whales in waters off the west coast of Okinawa Island, southwest Japan, were investigated using line transect and photo-identification methodologies. Line transect surveys were... more
The distribution and local movement patterns of humpback whales in waters off the west coast of Okinawa Island, southwest Japan, were investigated using line transect and photo-identification methodologies. Line transect surveys were conducted from 2011 to 2014 and photo-identification survey from 2006 to 2012. During the surveys, humpback whales aggregated in the areas around Ie and Kerama Islands, and tended to travel along the inshore coast of Okinawa Island when they move locally between those two sites. A total of 496 humpback whales of the known sex were photo-identified (322 males, 75 females and 99 females with a calf). Of these, 24.8% were confirmed moving locally between the sites of Ie and Kerama Islands within the same season. Frequency rates of the local movement for males, females and females with a calf were 41.9, 25.0, and 15.1%, respectively; the frequency of local movement for males was significantly higher than that for females and females with a calf. These resul...
Research Interests: Zoology, Aging, Female, Animals, Male, and 6 moreAnimal migration, Ecosystem, Time Factors, Pacific ocean, Humpback whale, and Seasons
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Relationship between body size, maturity and feeding habit of common minke whales in coastal waters off Sanriku, northeast Japan, in spring season, was studied from animals collected during the whale sampling surveys under the JARPN II... more
Relationship between body size, maturity and feeding habit of common minke whales in coastal waters off Sanriku, northeast Japan, in spring season, was studied from animals collected during the whale sampling surveys under the JARPN II coastal component off Sanriku conducted in 2003 to 2007. From these surveys, a total of 227 common minke whales (91 males and 136 females)
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The stomach contents of common minke whales Balaenoptera acutorostrata sampled off Sanriku from April to May and Kushiro region from September to October in 2002-2007 JARPN II were analyzed. In Sanriku region, the dominant prey species... more
The stomach contents of common minke whales Balaenoptera acutorostrata sampled off Sanriku from April to May and Kushiro region from September to October in 2002-2007 JARPN II were analyzed. In Sanriku region, the dominant prey species consisted of one krill (Euphausia pacifica) and two fishes (Japanese sand lance Ammodytes personatus and Japanese anchovy Engraulis japonicus). On the other hand, in
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... killer whale Feresa attenuata, melon-headed whale Peponocephala electra, Risso's dolphinGrampus griseus, long-finned ... gathered by other researchers working in the Philippines and Taiwan showing there ... totals of 1,403... more
... killer whale Feresa attenuata, melon-headed whale Peponocephala electra, Risso's dolphinGrampus griseus, long-finned ... gathered by other researchers working in the Philippines and Taiwan showing there ... totals of 1,403 and 1,212 respirations of two dolphins were recorded ...
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... Studies concerning accumulations of heavy metals in marine mammals have been reported in relation to heavy metal pollution in the marine environment and their bioaccumulation processes (Koeman et al. 1972, 1975; Jones et al. 1976;... more
... Studies concerning accumulations of heavy metals in marine mammals have been reported in relation to heavy metal pollution in the marine environment and their bioaccumulation processes (Koeman et al. 1972, 1975; Jones et al. 1976; Drescher et al. ...
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Research Interests: Zoology and Minke whale
SC/62/O7; Status report of conservation and researches on the western gray whales in Japan, May 2009 – April 2010. by Kato, H, Miyashita, T. Kanda, N., Ishikawa, H., Furukawa, H. and Uoya, T. ... Status Report of Conservation and... more
SC/62/O7; Status report of conservation and researches on the western gray whales in Japan, May 2009 – April 2010. by Kato, H, Miyashita, T. Kanda, N., Ishikawa, H., Furukawa, H. and Uoya, T. ... Status Report of Conservation and Researches on the Western Gray ...