Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Most canopy-forming macroalgae have disappeared from temperate reefs in southern Japan, one of the ocean warming hotspots, but Sargassum nipponicum is surviving in this region. As this species’ annual shoots emerge from holdfasts during summer, both plant components may be highly tolerant to warm and nutrient-poor conditions in this season. The present study examined the effects of temperature and nutrient conditions on holdfast growth, shoot emergence from holdfasts, and shoot growth in S. nipponicum samples collected in Tanegashima Island, southern Japan. The summer temperature in this region (30 °C) allowed holdfast growth and shoot emergence but inhibited shoot growth. Nutrient-poor conditions had limited effects on the first two parameters but suppressed shoot growth. These results suggested that during warm summers and under nutrient-poor conditions in southern Japan, shoots can emerge from S. nipponicum holdfasts but cannot further grow. Additionally, nutrient loading from a nearby river was higher at the only site dominated by S. nipponicum, than at the other sites where this species was absent on Tanegashima Island. This was observed especially between autumn and winter, implying that such a nutrient-rich environment may contribute to shoot growth in S. nipponicum and to the persistence of its population in the area.

DOI： 10.3390/plants13121689

Scopus

PubMed

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Magnolia Press  

Three species of the aorid amphipod were collected from remote islands in southern Japan. Protolembos ryukyuensis sp. nov. was collected from Ishigaki Island in Okinawa Prefecture and Tanegashima Island in Kagoshima Prefecture, and characterized by the dense plumose setae on the male gnathopods 1 and 2. Tethylembos cavatus sp. nov. and T. japonicus Ariyama, 2004 were collected from Miyake Island and the Ogasawara Islands in Tokyo Prefecture, respectively. Both species share the male gnathopod 1 propodus heavily setose medially; however, Tethylembos cavatus can be distinguished from T. japonicus in the excavated basis of the male pereopod 5. Keys to species of Protolembos Myers, 1988 and Tethylembos Myers, 1988 in the world and a key to all Japanese species of the family Aoridae are provided. Number of aorid species in Japan stands at 34.

DOI： 10.11646/zootaxa.5433.4.2

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Plankton Society of Japan/The Japanese Association of Benthology  

<p>The Tsushima Strait and the neighboring waters has been known as major spawning and nursery grounds for migratory fishes due to the high standing stocks of the plankton community in spring to summer. In the present study, spatial and temporal variations in taxonomic composition, standing stocks and productivity of the mesozooplankton community were investigated in the southwestern Japan Sea to explore their variations during the productive seasons. Both spatial and temporal fluctuations were significant for mesozooplankton standing stocks while only temporal variability affected their productivity. The mesozooplankton community was split into one coastal group, represented by cladocerans and noctilucids throughout the seasons, and five pelagic groups, predominated by calanoids, cyclopoids and copepod nauplii, with temporal replacement during spring to summer. The coastal community group contained the additional standing stocks of cladocerans and noctilucids along with the predominant copepods from the other groups and thus resulted in the spatial difference in mesozooplankton standing stocks between coastal and pelagic sites. Three pelagic community groups were characterized by the abundant appearance of noctilucids and clustered toward the pelagic stations neighboring the coastal community group. Generalized linear models demonstrated that salinity was a significant explanatory variable for standing stocks of mesozooplankton and coastal taxonomic groups (i.e., cladocerans and noctilucids). These findings suggest that the spatial and temporal variations in mesozooplankton standing stocks are a mixture of the pelagic community groups with the coastal community group advected toward the pelagic sites.</p>

DOI： 10.3800/pbr.19.26

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Society of Fisheries Oceanography  

<p>Juvenile yellowtail <i>Seriola quinqueradiata</i> follow floating algae in the East China Sea and have been caught for natural nursery stocks of mariculture in Japan. However, we have still limited knowledge of prey sources supporting their early growth. Here, we clarify prey organisms and sources of the juvenile fishes that appeared in the Satsunan area, southern Japan based on stable isotope ratios and metabarcoding analysis. Stable isotope ratios of carbon and nitrogen for yellowtail juveniles were equivalent to those for zooplankton and fish larvae that appeared in the Kuroshio and its neighboring waters. The most predominant and frequently appearing prey revealed by metabarcoding analysis was calanoid copepods. The next in importance was poecilostomatoid copepods for smaller juveniles and appendicularians and chaetognaths for larger juveniles. A positive correlation was found for the juvenile growth index to the contribution of calanoid copepods of their gut-content DNA. These results suggest that juvenile growth of yellowtail that appeared in the Satsunan area is supported by not benthic animals on floating seaweeds but by zooplankton in the water column.</p>

DOI： 10.34423/jsfo.87.4_209

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Plankton Society of Japan/The Japanese Association of Benthology  

<p>The northern Satsunan area, comprising the mouth of Kagoshima Bay and Osumi Strait, is an important spawning and nursery ground for Japanese jack mackerel <i>Trachurus japonicus</i> in Japan. Upwellings frequently occur at the mouth of the bay during winter and spring, and the consequent nutrient supply promotes phytoplankton blooms. This study examined how <i>T. japonicus</i> utilizes upwelling (Kagoshima Bay) and non-upwelling areas (Osumi Strait) as larval nursery grounds. Densities and growth rates (measured as the average width of the last three otolith increments) of <i>T. japonicus</i> larvae in both areas were compared to determine the upwelling influence on nursery ground formation. The mouth of the bay had lower temperature and salinity but higher chlorophyll-<i>a</i> concentrations and prey density than that of the strait. Densities of larvae were consistently higher in the bay than in the strait, indicating that the main nursery of <i>T. japonicus</i> is formed in Kagoshima Bay. No significant differences were observed in the growth rates of larvae among areas, suggesting that lower temperatures and prey availability are growth limiting factors in the mouth of the bay and the strait, respectively, and the Osumi Strait could also provide a favorable nursery area.</p>

DOI： 10.3800/pbr.18.148

Scopus

DOI： 10.21203/rs.3.rs-2655652/v1

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s12526-022-01333-w

Scopus

Other Link： https://link.springer.com/article/10.1007/s12526-022-01333-w/fulltext.html

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Informa UK Limited  

DOI： 10.1080/14772000.2022.2118389

Scopus

Other Link： https://www.tandfonline.com/eprint/M7MV99WCNNQDCKUE4XJW/full?target=10.1080/14772000.2022.2118389

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：INTER-RESEARCH  

Epibenthic invertebrate assemblages in macroalgal beds generally show remarkable seasonal fluctuations in abundance and species composition, reflecting macroalgal host growth and defoliation. Notably, they often drastically decrease during macroalgal host defoliation. Though this reduction has been explained in terms of dispersal away from the macroalgal bed in relation to macroalgal host defoliation, this hypothesis has not previously been experimentally detailed. We conducted a field experiment using an imitation of Sargassum that was set 1 m away from a Sargassum yezoense bed to examine whether the epibenthic gammarids disperse away from the Sargassum bed as a result of Sargassum defoliation. The imitations were replaced monthly throughout the Sargassum defoliation season; subsequently, gammarids associated with the imitation (assumed as migrants from the Sargassum beds) as well as the gammarids that occurred in the Sargassum bed were investigated. Seasonal patterns of gammarid abundance in the Sargassum bed and their dispersal to the imitations were found to be quite different among gammarid species. In particular, 2 dominant gammarids, the suspension-feeding Jassa morinoi and Podocerus sp., drastically decreased in the Sargassum bed and coincidently increased in the imitations during the Sargassum defoliation season, indicating their defoliation-associated dispersal from the Sargassum bed. This is the first field experimental study demonstrating the defoliation-associated dispersal of epibenthic invertebrates in macroalgal beds. The dispersal is likely caused by a reduction of habitat space and quality due to thalli defoliation. Since many macroalgae show seasonal growth and defoliation, the concept of defoliation-associated dispersal is potentially applicable to various macroalgal species.

DOI： 10.3354/meps13903

Web of Science

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Inter-Research Science Center  

Clarification of the biological and/or physical factors determining the location requirements for spawning aggregations is necessary for understanding the population dynamics of freespawning marine animals. We monitored the density of adult abalone Haliotis discus hannai on 2 types of artificial reefs with different heights (tall and short blocks) and the surrounding seabed area in Otsuchi Bay, northeast Japan, from February 2016 to December 2019. In addition, the number of neighboring adults located within a 50 cm radius from each individual was counted from March 2017 to December 2019. Algal succession in the 3 types of location (tall and small blocks, seabed) was monitored and compared with temporal fluctuations in adult abalone density. Our results show that the fluctuations in density were different among the 3 locations, especially during the spawning season (August-October). Ontall blocks, clear increases in adult abalone density and number of neighboring adults were confirmed during the spawning seasons in 2016 and 2019. In contrast, there was no clear increase in the adult density on small blocks and surrounding bottom areas. Aggregations on the tall blocks clearly differed among the 4 years, and the difference was considered to be influenced by differences in the macroalgal species and coverage during the spawning season. This is the first study to report that a difference in phenology among algal species is a key factor in the formation of spawning aggregations of a free-spawning marine animal.

DOI： 10.3354/meps13753

Web of Science

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Cambridge University Press (CUP)  

<title>Abstract</title>The amathillopsid subfamily Cleonardopsinae Lowry, 2006 is reviewed. The only species of the subfamily, <italic>Cleonardopsis carinata</italic> K.H. Barnard, 1916, should be regarded as a species-complex. A new genus and species of the subfamily, <italic>Carinocleonardopsis seisuiae</italic> gen. et sp. nov., is described from the Sea of Kumano, Japan as the second species of the subfamily Cleonardopsinae as well as the first record of the subfamily from the North Pacific. This new genus can be easily distinguished from <italic>Cleonardopsis</italic> by the presence of distinct large eyes and the dorsal carination on head, pereonites and pleonites.

DOI： 10.1017/S0025315421000357

Scopus

Authorship：Last author   Language：Japanese  

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE ASSOCIATION OF BENTHOLOGY  

<p>The anisogammarid amphipod <i>Jesogammarus</i>(<i>Jesogammarus</i>)<i>hinumensis</i> Morino, 1993 has been reported from south of Iwate Prefecture in Japan and Jeju Island in Korea. In this study, one male and one female of <i>J.</i>(<i>J.</i>)<i>hinumensis</i> were collected from the Imaizumi River flowing into the Lake Jusan, in the Tsugaru Peninsula of Aomori Prefecture in northern Honshu, Japan. This is the first record of <i>J.</i>(<i>J.</i>)<i>hinumensis</i> from the prefecture, representing the northernmost record. At the site, <i>J.</i>(<i>J.</i>)<i>hinumensis</i> was found under fallen leaves deposited at the roots of <i>Phragmites australis</i></p>

DOI： 10.5179/benthos.76.13

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Magnolia Press  

Two new species of Maera Leach, 1814 and Quadrimaera Krapp-Schickel &amp; Ruffo, 2000 included in the Maera-clade are described from Japan. Maera denticoxa sp. nov. was collected from Iwate and Hokkaido Prefectures and can be distinguished from its congeners by the small notches on the posteroventral margins of coxae 1–6. Quadrimaera angulata sp. nov. from north of Tanegashima Island in Kagoshima Prefecture is characterized by the distal tooth on the mandibular palp article 1, the rounded palm of the female gnathopod 2, and the angular posterodistal margin of the pereopod 7 basis. Keys to Japanese species of the Maera-clade are provided. In total, seventeen species included in the clade occur in Japan.

DOI： 10.11646/zootaxa.4885.3.2

PubMed

Other Link： https://www.biotaxa.org/Zootaxa/article/viewFile/65760/64202

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s12526-020-01100-9

Scopus

Other Link： http://link.springer.com/content/pdf/10.1007/s12526-020-01100-9.pdf

Language：Japanese   Publisher：Carcinological Society of Japan  

DOI： 10.18988/cancer.29.0_e136

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

A pair of a gravid female and a male of Ceratothoa oxyrrhynchaena Koelbel, 1878 (Isopoda: Cymothoidae) were collected from the buccal cavity of a blackthroat seaperch, Doederleinia berycoides (Hilgendorf, 1879) (Perciformes: Acropomatidae), in the western North Pacific Ocean off Kinkasan Island, Miyagi Prefecture, northeastern Japan. This expands the geographical distribution range of C. oxyrrhynchaena from off Onahama (ca. 37°N), Fukushima Prefecture, northward to off Kinkasan Island (38°17′N) and represents the first record of the species from the southern subarctic waters. Based on the previous and present records of C. oxyrrhynchaena from Japan, the species is suggested to occur in a wide area ranging from the subtropical through temperate to southern subarctic waters.

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1017/S002531541900105X

Other Link： https://doi.org/10.1017/S002531541900105X

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Inter-Research Science Center  

Macroalgal beds can be vertically differentiated into canopy and understory strata, and each can exhibit different phenology in algal biomass and morphology. Thus, for epibenthic invertebrates, macroalgal beds provide both vertically and seasonally heterogenous habitats, and epibenthic assemblages can be predicted to show different patterns of seasonal dynamics reflecting the different effects of algal phenology between the canopy and understory. We described and compared the seasonal dynamics of gammarid assemblages and algal phenology in the canopy and understory of a Sargassum bed in Otsuchi Bay, Japan. Gammarid assemblages showed distinctly different seasonal dynamics in abundance and species composition between the 2 habitats. In the canopy, gammarid abundance peaked in July, which was mainly explained by fluctuations in abundance of the dominant tube-dwelling filter-feeder Jassa morinoi. In the understory, gammarid abundance peaked in August-September, clearly later than in the canopy, and was also dominated by tube-dwelling filter-feeders, but different species such as Monocorophium uenoi and Gammaropsis japonicus. These differences in assemblage dynamics of gammarids can be explained by the Sargassum defoliation in late summer, resulting in decreased habitat space and complexity for gammarids in the canopy. In the understory, however, Sargassum defoliation increased the amount of detrital deposition, providing food sources and additional habitat for gammarids. This study demonstrates that algal phenology can have strong but different effects on epibenthic invertebrates inhabiting canopy and understory strata.

DOI： 10.3354/meps13194

Web of Science

Other Link： https://doi.org/10.3354/meps13194

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Brill  

<title>Abstract</title>
The ischyrocerid amphipod <italic>Ventojassa dentipalma</italic> Kim &amp; Kim, 1991 was recently collected from Otsuchi Bay, northeast Japan. The present specimens represent the second record of the species as well as the first Japanese record of the genus. Brief morphological descriptions and line drawings of diagnostic characters are provided. Details of the characters distinguishing the species from <italic>V. ventosa</italic> (Barnard, 1962) are discussed.

DOI： 10.1163/15685403-00003923

Other Link： https://brill.com/view/journals/cr/92/8/article-p1007_8.xml

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jcbiol/ruy098

Other Link： https://academic.oup.com/jcb/advance-article/doi/10.1093/jcbiol/ruy098/5280210?guestAccessKey=6eeb0893-ef19-46fd-9d07-d33425911483

Language：English   Publishing type：Research paper (scientific journal)  

Other Link： http://w3.u-ryukyu.ac.jp/naruse/lab/Contents_J_files/45-3_Kodama_Kawamura.pdf

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.dib.2018.07.031

Other Link： https://www.sciencedirect.com/science/article/pii/S2352340918308047

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Estuarine, Coastal and Shelf Science  

Various aspects of plant diversity such as species diversity and phylogenetic diversity enhance the species diversity of associated animals in terrestrial systems. In marine systems, however, the effects of macrophyte diversity on the species diversity of associated animals have received little attention. Here, we sampled in a subtropical seagrass-seaweed mixed bed to elucidate the effect of the macrophyte phylogenetic diversity based on the taxonomic relatedness as well as the macrophyte species diversity on species diversity of mobile epi-benthic invertebrates. Using regression analyses for each macrophyte parameter as well as multiple regression analyses, we found that the macrophyte phylogenetic diversity (taxonomic diversity index: Delta) positively influenced the invertebrate species richness and diversity index (H′). Although the macrophyte species richness and H′ also positively influenced the invertebrate species richness, the best fit model for invertebrate species richness did not include them, suggesting that the macrophyte species diversity indirectly influenced invertebrate species diversity. Possible explanations of the effects of macrophyte Delta on the invertebrate species diversity were the niche complementarity effect and the selection effect. This is the first study which demonstrates that macrophyte phylogenetic diversity has a strong effect on the species diversity of mobile epi-benthic invertebrates.

DOI： 10.1016/j.ecss.2018.03.020

Scopus

Other Link： https://www.sciencedirect.com/science/article/pii/S0272771417308946

Language：English   Publishing type：Research paper (international conference proceedings)  

Other Link： http://www.biodiversityjournal.com/pdf/8(2)_391-688.pdf#page=81

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1163/15685403-00003676

Other Link： https://brill.com/view/journals/cr/90/5/article-p639_10.xml

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.11646/zootaxa.4169.1.6

PubMed

Other Link： https://www.mapress.com/j/zt/article/view/zootaxa.4169.1.6

Country：Japan

Country：Japan

Country：Japan

Country：Japan

Country：Japan