記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Marine Biology  

The Japanese eel, Anguilla japonica, is a commercially important fish species. Most eels intended for consumption are currently produced in aquaculture systems that rely exclusively on wild-caught glass eels. Studies on the diet of glass eels and elvers have been limited in the wild populations. In the present study, we evaluated the feeding habits of Japanese glass eels and elvers in the Sendai River estuary of southern Japan using morphological and DNA metabarcoding analyses of the gut contents as well as stable isotope analyses of glass eels and elvers. Among 80 glass eels, amorphous materials were observed in the guts of 11 glass eels using stereomicroscopy. The feeding intensity of glass eels increased with increasing water temperature. Various eukaryotes were detected by DNA metabarcoding analysis of the gut contents of glass eels. Planktonic and benthic organisms were identified in the guts of six of the 10 elvers. The carbon and nitrogen stable isotope values were significantly different between glass eels and elvers. Our results suggest that Japanese glass eels resume feeding mainly on detrital particulate organic matter after metamorphosis and start actively feeding on planktonic and benthic organisms after the elver stage.

DOI： 10.1007/s00227-025-04699-0

Scopus

その他リンク： https://link.springer.com/article/10.1007/s00227-025-04699-0/fulltext.html

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thalassas  

This study reports Eurythenes aequilatus Narahara-Nakano, Nakano & Tomikawa, 2017 with confirmation by DNA barcoding using COI mtDNA. The species has not been recorded after the original description; only its type specimens have been known to date, and thus our specimens represent the second discovery of the species. Our specimens showed coloration quite different from that of the type specimens. The species has been observed by fishermen to feed on bycatch giant grenadier, Albatrossia pectoralis (Gilbert, 1892) in the field. Some individuals were reared in an aquarium. They were fed several different types of food but observed feeding only on the soft-fleshed Okhotsk atka mackerel, Pleurogrammus azonus Jordan & Metz, 1913. One of the reared individuals survived for more than 60 days without eating.

DOI： 10.1007/s41208-025-00868-6

Scopus

その他リンク： https://link.springer.com/article/10.1007/s41208-025-00868-6/fulltext.html

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thalassas  

The blacktip grouper (Epinephelus fasciatus) is commercially important and serves as the top predator in reef ecosystems. Understanding its dietary habits is crucial for understanding its ecological role and informing conservation strategies. In this study, we investigated the dietary composition and feeding ecology of E. fasciatus to assess potential variation by size and season. From May 2022 to January 2024, 171 specimens were collected via line fishing around Koshikishima Island, Japan. We determined the key prey items through stomach content analysis and dietary contributions through stable isotope (δ¹⁵N and δ¹³C) analysis combined with a Bayesian mixing model (MixSIAR). Crabs, shrimp, and fish were the primary prey groups, with less contributions from polychaetes, starfish, and slipper lobsters. Shrimp was the primary food source for the latter and start of the year (October–December and January–March). Peak crab consumption occurred in the second (April–June) and third (July–September) quarters. The diet of the smaller class (≤ 300 mm) primarily comprised of crabs and shrimp, whereas that of the larger class (≥ 301 mm) was more diverse. However, permutational multivariate analysis of variance indicated no significant dietary variation by size or season. Stable isotopes indicated an increase in trophic levels with body size. Notably, crabs contributed approximately 95% of the diet in smaller individuals, whereas the contribution of shrimp and fish was slightly higher in larger individuals. These findings provide critical insights into the feeding ecology and role of E. fasciatus in reef ecosystems.

DOI： 10.1007/s41208-025-00866-8

Scopus

その他リンク： https://link.springer.com/article/10.1007/s41208-025-00866-8/fulltext.html

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ICES Journal of Marine Science  

Unlike most fish larvae that prey exclusively on mesozooplankton, such as copepods, leptocephali feed on a type of particulate organic matter (POM) known as marine snow. However, the components of POM consumed and assimilated by leptocephali have not been clarified to date. To characterize POM components ingested in the form of marine snow by leptocephali found in the waters around Satsunan, southern Japan, we performed morphological and DNA metabarcoding analyses of their gut contents and stable carbon and nitrogen isotope analyses for leptocephali and their potential food items. The analyses were carried out on the Dysomma, Gnathophis, and Muraenosox leptocephali, which occur abundantly in this area. Our data supported that leptocephali feed on marine snow particles, which can contain faecal pellets of copepods. The gut contents varied greatly among taxonomic groups of leptocephali. Differences in feeding depth and the transport of larvae from other regions may lead to differences in the leptocephali gut contents. Our results showed that the leptocephali of the Satsunan area did not actively use gelatinous zooplankton (i.e. cnidarians) and appendicularian houses, whose presence was frequently confirmed in leptocephali guts by former studies, as nutrient sources or as substrates to aggregate small particles such as bacteria, protozoans, and zooplankton faecal pellets. These results suggest that leptocephali feed non-selectively on marine snow in the ambient water column.

DOI： 10.1093/icesjms/fsaf065

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Crustacean Biology  

A new species of Sicafodiidae (Amphipoda) and a new associated copepod parasite of the family Nicothoidae are described from bathyal (200–3,500 m) depths in the Northwest Pacific Ocean. The sicafodiid can be distinguished by several features, including left and right mandibles respectively having a bi-dentate and tri-dentate incisor and an acute lacinia mobilis; the inner palp of maxilla 1 having two slender setae; coxa 4 being slightly longer than wide with a subacute ventral margin; and the telson having three slender setae and a deep notch. The associated parasite, Rhizorhina sicafodiaesp. nov., is the tenth known species of Rhizorhina Hansen, 1892 and the third to parasitise amphipods. Only a single female of the parasite was recovered, and it can be distinguished from all congeners by its pyriform shape, body size, length to width ratio, and geographical location. The mitochondrial cytochrome c oxidase subunit I (COI) and 16S rRNA genes were sequenced for Sicafodia pentagonumsp. nov. The Kimura 2 parameter distances of 0.267–0.271 for COI were calculated between S. pentagonumsp. nov. and S. iceage Campean & Coleman, 2018. The 18S rRNA gene of R. sicafodiaesp. nov. and a phylogenetical analysis performed with existing sequences formed a robust clade with the other known species of Nicothoidae, Diexanthema hakuhomaruae Kakui, Fukuchi & Ohta, 2023, Rhizorhina soyoae Kakui, 2016, and R. ohtsukai. Kakui, 2016.

DOI： 10.1093/jcbiol/ruaf027

Scopus

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Zootaxa  

A new species of lepechinellid amphipod, Lepechinella macrospinosa sp. nov., is described from off Yakushima Island, Japan. The present new species closely resembles Lepechinella curvispinosa Pirlot, 1933 sharing strongly enlarged and backward-curved posterodorsal tooth on the pleonites 1–3. However, the present new species can be distinguished from L. curvispinosa by the longer pereopod 5 carpus, different shape of the posterodorsal tooth on pleonite 3 and urosomite 1, presence of the posteroventral tooth on the epimeral plates 1–3, and longer uropod 3 of which outer and inner rami are subequal in length. In addition, a partial DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) of this species was determined for future studies.

DOI： 10.11646/zootaxa.5601.1.6

Scopus

PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Continental Shelf Research  

In the northern Satsunan area, southern Japan, upwellings generated by the intrusion of the Kuroshio branch current into Kagoshima Bay are observed at the bay's mouth once every two weeks in winter and spring, and the resulting nutrient supply promotes phytoplankton blooms. Currently, this is a key spawning and nursery habitat for chub mackerel Scomber japonicus in Japan. This study examined how water temperature and prey density influenced the growth, mortality, and predatory effects of S. japonicus larvae in the northern Satsunan area. Recent growth (measured as the average width of the last three otolith increments) of S. japonicus larvae was positively correlated with water temperature but not with prey density, indicating that prey abundance was adequate for larvae and that water temperature controlled their growth rate in the study area. The instantaneous daily mortality rate of S. japonicus larvae was 0.322 in 2021 and 0.252 in 2022 (equivalent to 27.5% mortality d−1 in 2021 and 22.3% in 2022). The food requirements of S. japonicus larvae and mesozooplankton production were 0.00427 ± 0.00334 and 6.37 ± 3.04 mg DW m−3 d−1, respectively. S. japonicus larvae had no significant predatory impact on mesozooplankton (0.0869 ± 0.0796%). The present study suggests that none of the plankton feeders have a significant top-down regulating effect on mesozooplankton biomass in the northern Satsunan area, which provides a good food environment for S. japonicus larvae.

DOI： 10.1016/j.csr.2024.105399

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Progress in Oceanography  

The Kuroshio has been long thought to be disadvantageous as nursery grounds for larval fishes due to the low plankton standing stocks under the oligotrophic conditions. Despite of the potential risk for survival and growth, early life stages of various fishes appear abundantly in the Kuroshio and its neighboring waters. Here, we report what kind of taxonomic groups establish community structure of larval fishes in the Continental shelf waters (CW) and the Kuroshio (KW). 16 orders and 78 families were classified in the present study. Mesopelagic fishes more abundantly appeared in the KW than in the CW, while larval fish abundance was not different between the two areas. Multivariate analysis demonstrated the regional difference of the taxonomic compositions, represented by Callionymidae, Bothidae, Labridae and Bregmacerotidae for the CW and Gonostomatidae, Myctophidae and Notosudidae for the KW. Abundance of fish larvae to ambient salinity exhibited significantly positive correlations for Gonostomatidae, Sigmops gracilis and Myctophum orientale predominated in the KW and negative correlations for Labridae appeared abundantly in the CW. These results suggest that mixture of advected specimens from the coastal and Kuroshio waters also contribute to larval fish community with high biodiversity and comparable abundance between the Kuroshio and its neighboring waters.

DOI： 10.1016/j.pocean.2024.103386

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Zootaxa  

The ampithoid amphipod Cymadusa imbroglio Rabindranath, 1972 was collected from Ishigaki Island, southwest Japan, as the first Japanese record of the genus. The specimens collected from Ishigaki Island also represent the northernmost record of the species. We herein provide a detailed description and illustration of the specimens from Ishigaki Island. Sequences of COI were determined from two specimens for DNA barcoding and future taxonomic studies.

DOI： 10.11646/zootaxa.5551.3.6

Scopus

PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Marine Pollution Bulletin  

Although pesticides are a cornerstone of modern agriculture, they are also known to be a major factor in the decline of biodiversity. Even pesticides applied in inland agricultural areas can be transported via rivers and have often been detected in marine environments. Pesticides would disturb not only the ecosystems around agricultural areas but also marine ecosystems, and there is a growing need for research on how pesticides affect marine environments. Recently, several pesticides have been detected at high concentrations in the coastal areas of Ishigaki Island, Japan, where seagrasses and seaweeds form important macrophyte bed ecosystems. To elucidate the effects of pesticides on the macrophyte bed epifauna, a field survey was conducted in the intertidal seaweed-seagrass mixed beds in Ishigaki Island. As a result of the survey, several pesticides were detected, including the highly toxic insecticide fipronil. The epifaunal abundance, taxon richness and Shannon's diversity index (H′) were all negatively and significantly correlated with fipronil concentration. Crustaceans were found to be more affected by fipronil than molluscs. Abundance, taxon richness and H′ of crustaceans were negatively correlated with fipronil concentration, whereas those of molluscs were not. The alteration and decline of epifaunal assemblages by pesticides may lead to a loss of the ecological functions and resilience of macrophyte bed ecosystems. This study demonstrates the disturbance of epifauna by discharged pesticides in in situ coastal macrophyte bed ecosystems. Pesticides appear to disturb a much wider range of ecosystems than previously considered, and accordingly may require a reconsideration of pesticide use and discharge in the future.

DOI： 10.1016/j.marpolbul.2024.117123

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PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Marine Biology  

The nature of symbiotic relationships between organisms can be difficult to assess and may range from commensalism, to mutualism, and parasitism. Trophic linkage and feeding ecology are essential to disentangle symbiont-host relationships/interactions. Amphipods of the genus Dactylopleustes are known as urchin symbionts. Though their ecology remains largely unknown, Dactylopleustes was recently reported to aggregate on diseased hosts, suggesting that Dactylopleustes feeds on diseased urchins’ tissues and uses urchins as both a habitat and prey. We investigated by DNA metabarcoding analyses, the feeding ecology of Dactylopleustes yoshimurai in relation to growth and disease status of the host (Strongylocentrotus intermedius). Contrary to our hypothesis, sequence reads from the gut contents were dominated by planktonic copepods regardless of body size or host disease status. These results suggest that they mainly feed on copepod fecal pellets deposited on sediments, and do not have a strong trophic linkage with their host. Large individuals on diseased urchins feed more on urchins than those on healthy urchins. However, their main prey still remains copepods, implying that host disease has a limited effect on the feeding behavior. In conclusion, our study indicates that this species is mainly commensal, but also may parasitize its host depending on the situation.

DOI： 10.1007/s00227-024-04507-1

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Progress in Oceanography  

Commercially important fish spend their vulnerable early life stages in the Kuroshio Current, resulting in high fishery production even in the vicinity of poor prey availability under oligotrophic conditions. Nevertheless, little information is available on how ichthyoplankton are supported by trophodynamics in complicated food webs. Here, we have explored trophic sources and pathways toward ichthyoplankton in the Kuroshio and its neighboring waters based on metabarcoding analysis of gut DNA content for major taxonomic groups of mesozooplankton and ichthyoplankton. Calanoids were found to be the most predominant and frequently appearing prey, whereas non-crustaceans were the secondary prey for most mesozooplankton and ichthyoplankton groups. Trophic networks based on gut DNA content demonstrated that calanoids were the most important sector with multiple linkages among their prey and predators, and gelatinous and non-crustacean mesozooplankton were the secondary sectors. These findings suggest that calanoids are important hubs of trophic pathways toward ichthyoplankton, and that gelatinous and non-crustacean mesozooplankton groups strengthen trophic relationships with multiple components. Contrary to general thought, our metabarcoding analysis has revealed that trophodynamics toward ichthyoplankton are not strongly dependent on the grazing food chain, but are supported by multiple trophic pathways in the Kuroshio and its neighboring waters.

DOI： 10.1016/j.pocean.2024.103356

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本プランクトン学会、日本ベントス学会  

A new species of photid amphipod, Podoceropsis nanseiae, is described from Kagoshima Bay, Japan. The present new species can be distinguished from all the congeners in having clusters of robust setae on the male gnathopod 2 basis. This species resembles Gammaropsis laevipalmata Ren, 1992, however can be distinguished from G. laevipalmata by the presence of small accessory flagellum in antenna 1, the size of eyes, the shape of palmer margin of male gnathopod 2, and the clusters of robust setae on the male gnathopod 2 basis. The closely related species G. laevipalmata should be transferred to the genus Podoceropsis. Additionally, a partial DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) was determined from the type specimens of P. nanseiae sp. nov. for future taxonomic studies.

DOI： 10.3800/pbr.19.141

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CiNii Research

記述言語：日本語   出版者・発行元：日本甲殻類学会  

DOI： 10.18988/cancer.33.0_e28

CiNii Research

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plants  

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

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PubMed

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Zootaxa  

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

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本プランクトン学会、日本ベントス学会  

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 mesozooplank-ton community were investigated in the southwestern Japan Sea to explore their variations during the productive sea-sons. 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.

DOI： 10.3800/pbr.19.26

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CiNii Research

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 水産海洋学会  

<p>ブリ稚魚は海面養殖の天然種苗として利用されてきたが，初期成長を支える餌料源に関する情報は少ない．本研究では，安定同位体比およびメタバーコーディング解析により，薩南海域に来遊するブリ稚魚の初期成長を支える餌生物および餌料源を明らかにした．ブリ稚魚の筋肉組織の炭素・窒素安定同位体比は，黒潮域の水柱内に分布する動物プランクトンおよびブリ稚魚以外の仔稚魚と近似した．ブリ稚魚の消化管内容物から検出された遺伝子では，カラヌス目カイアシ類が最も優占し頻出する餌生物であった．小型稚魚ではポエキロストム目カイアシ類，大型稚魚では尾虫類・毛顎類がこれに次ぐ餌生物であった．また，消化管内のカラヌス目カイアシ類が増加すると，ブリ稚魚の成長指数も増加する傾向を示した．これらの結果は，流れ藻に随伴して薩南海域に来遊するブリ稚魚が，流れ藻の葉上動物ではなく水柱内の動物プランクトンを餌料源として成長することを示唆する．</p>

DOI： 10.34423/jsfo.87.4_209

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本プランクトン学会、日本ベントス学会  

The northern Satsunan area, comprising the mouth of Kagoshima Bay and Osumi Strait, is an important spawning and nursery ground for Japanese jack mackerel Trachurus japonicus 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 T. japonicus 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 T. japonicus 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-a 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 T. japonicus 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.

DOI： 10.3800/pbr.18.148

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CiNii Research

DOI： 10.21203/rs.3.rs-2655652/v1

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Marine Biodiversity  

The eusirid amphipod Rhachotropis aculeata (Lepechin, 1780) is a boreal species distributed around the Arctic Ocean as well as in high-latitude areas of the North Atlantic and North Pacific Oceans. This is a considerably wide distribution for an amphipod species with no larval stage, implying the possibility that genetic divergence may occur among each population of the species. However, this has not been detailed since there has been no genetic data obtained from Pacific populations. Recently, R. aculeata was collected from the north of Wakasa Bay, Sea of Japan, representing the first specimen-based Japanese record of this species, as well as the southernmost record in the Pacific Ocean. We obtained genetic data from the R. aculeata specimens and subsequently constructed a phylogenetic tree and haplotype network. This included samples from Arctic, Atlantic, and Pacific populations, in order to study the phylogeography of the species. Our analyses indicate a relatively strong genetic divergence of the species between the Pacific and the other populations.

DOI： 10.1007/s12526-022-01333-w

Scopus

その他リンク： https://link.springer.com/article/10.1007/s12526-022-01333-w/fulltext.html

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Systematics and Biodiversity  

The order Amphipoda is one of the largest orders in the Crustacea, many species of which are involved in symbiotic relations with other animals. Despite the considerable diversity of the Amphipoda both in number of species and ecology, polychaete-commensalism has been poorly known and described from few species. In particular, there has been little discussion of the evolutionary origins of polychaete-commensalism relationships. Amphipods in the family Leucothoidae are known as commensal inhabitants of filter-feeding invertebrates, where they utilize the feeding current produced by their hosts. Leucothoids are typically found from three types of filter-feeding hosts: sponges, ascidians, and bivalve molluscs. Relatively little is known about leucothoids that associate with other types of hosts. An undescribed species of the genus Leucothoe associated with burrows of terebellid polychaetes from Japan has been found. We herein describe this species as Leucothoe vermicola sp. nov., providing COI mtDNA and 18S rDNA sequences for DNA barcoding. This is the first record of a symbiotic association between Leucothoidae and Terebellidae. We also provide a hypothesis of the phylogenetic position of L. vermicola sp. nov. and evolution of the polychaete-commensalism in this species. The polychaete-commensalism in the present new species may have resulted from the entry of generalist species into polychaete hosts, rather than from host-conversion from a specialist species. http://zoobank.org/urn:lsid:zoobank.org:pub:4EBA42DD-EC19-4278-B712-8BEFBC519F8F.

DOI： 10.1080/14772000.2022.2118389

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CiNii Research

その他リンク： https://www.tandfonline.com/eprint/M7MV99WCNNQDCKUE4XJW/full?target=10.1080/14772000.2022.2118389

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Marine Ecology Progress Series  

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 dis - persal 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

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Marine Ecology Progress Series  

Clarification of the biological and/or physical factors determining the location requirements for spawning aggregations is necessary for understanding the population dynamics of free-spawning 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). On tall 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

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Marine Biological Association of the United Kingdom  

The amathillopsid subfamily Cleonardopsinae Lowry, 2006 is reviewed. The only species of the subfamily, Cleonardopsis carinata K.H. Barnard, 1916, should be regarded as a species-complex. A new genus and species of the subfamily, Carinocleonardopsis seisuiae 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 Cleonardopsis by the presence of distinct large eyes and the dorsal carination on head, pereonites and pleonites.

DOI： 10.1017/S0025315421000357

Scopus

担当区分：最終著者   記述言語：日本語  

担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本ベントス学会  

<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

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.11646/zootaxa.4885.3.2

PubMed

その他リンク： https://www.biotaxa.org/Zootaxa/article/viewFile/65760/64202

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Marine Biodiversity  

DOI： 10.1007/s12526-020-01100-9

Scopus

その他リンク： http://link.springer.com/content/pdf/10.1007/s12526-020-01100-9.pdf

記述言語：日本語   出版者・発行元：日本甲殻類学会  

DOI： 10.18988/cancer.29.0_e136

CiNii Research

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1017/S002531541900105X

その他リンク： https://doi.org/10.1017/S002531541900105X

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3354/meps13194

Web of Science

その他リンク： https://doi.org/10.3354/meps13194

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Brill  

<jats:title>Abstract</jats:title>
<jats:p>The ischyrocerid amphipod <jats:italic>Ventojassa dentipalma</jats:italic> Kim & 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 <jats:italic>V. ventosa</jats:italic> (Barnard, 1962) are discussed.</jats:p>

DOI： 10.1163/15685403-00003923

CiNii Research

その他リンク： https://brill.com/view/journals/cr/92/8/article-p1007_8.xml

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/jcbiol/ruy098

その他リンク： https://academic.oup.com/jcb/advance-article/doi/10.1093/jcbiol/ruy098/5280210?guestAccessKey=6eeb0893-ef19-46fd-9d07-d33425911483

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://w3.u-ryukyu.ac.jp/naruse/lab/Contents_J_files/45-3_Kodama_Kawamura.pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.dib.2018.07.031

その他リンク： https://www.sciencedirect.com/science/article/pii/S2352340918308047

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：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

その他リンク： https://www.sciencedirect.com/science/article/pii/S0272771417308946

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

その他リンク： http://www.biodiversityjournal.com/pdf/8(2)_391-688.pdf#page=81

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1163/15685403-00003676

その他リンク： https://brill.com/view/journals/cr/90/5/article-p639_10.xml

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.11646/zootaxa.4169.1.6

PubMed

その他リンク： https://www.mapress.com/j/zt/article/view/zootaxa.4169.1.6

研究科代表の東京大学総長賞の候補。全学生のうち候補29名、そのうち受賞8名。大学本部の最終選考にて落選。

受賞国：日本国

受賞国：日本国

受賞国：日本国

受賞国：日本国

受賞国：日本国