A record of the archerfish (Toxotes jaculator) from Iriomote Island, the Ryukyu Islands

1987 ◽  
Vol 34 (2) ◽  
pp. 231-232
Author(s):  
Hiroshi Senou ◽  
Tetsuo Yoshino ◽  
Korechika Yano
Keyword(s):  
Ryukyu Islands ◽  
Iriomote Island ◽  
The Ryukyu Islands

scholarly journals Ocean Bottom Electromagnetometer Carried From Bonin to Ryukyu Islands by Sea Currents

2021 ◽  
Author(s):  
Noriko Tada ◽  
Haruka Nishikawa ◽  
Hiroshi Ichihara ◽  
Hiromi Kayama Watanabe ◽  
Tatsu Kuwatani
Keyword(s):  
Eddy Diffusion ◽  
Ryukyu Islands ◽  
Ocean Bottom ◽  
Rare Occurrence ◽  
Submarine Volcano ◽  
Bonin Islands ◽  
Iriomote Island ◽  
The Ryukyu Islands ◽  
Sea Currents ◽  
Drift Path

Abstract Ocean bottom electromagnetometers (OBEMs) installed on the seafloor around Nishinoshima Island (Bonin Islands) were missing after a December volcanic eruption. In February 2021, one was found on a beach on Iriomote Island (Ryukyu Islands), implying that it drifted westward for 1,700 km. The reason(s) for the disappearance of the OBEMs and the path followed by the recovered OBEM while drifting are important information for future ocean bottom observations and seafloor volcanology in general. We conducted particle drifting simulations with and without horizonal eddy diffusion to estimate the possible drift path and duration of the recovered OBEM. Our simulations show that particles transported from Nishinoshima have a 7-10 % probability of arriving at Iriomote Island, which is thus not a rare occurrence. Transport durations in our simulations varied widely between 140 and 602 days depending on the drift paths. The most likely drift duration in our simulation was 150 – 180 days, with or without eddy diffusion, corresponding to the release from the seafloor of the OBEM between 22 August and 21 September 2020. These dates follow shortly after intensifying eruptions at Nishinoshima, which may have affected the seafloor around the island. A similar drift duration and path was reported for pumices that erupted from Fukutoku-Oka-no-Ba submarine volcano (northern Bonin Islands) during 18-21 January 1986 and arrived in the Ryukyu Islands in late May 1986. Such drifting simulations may prove useful for identifying the sources of drift pumices, and thus otherwise undetectable eruptions. Finally, the Fukutoku-Oka-no-Ba submarine volcano erupted on 13 August 2021, producing abundant pumice rafts that, based on our results, will likely arrive in the Ryukyu Islands in the coming months.

A new species of alpheid shrimp tentatively assigned to Salmoneus Holthuis, 1955 (Decapoda: Caridea) from the Ryukyu Islands, Japan

Zootaxa ◽  
2021 ◽  
Vol 4920 (2) ◽  
pp. 287-296
Author(s):  
TOMOYUKI KOMAI ◽  
TADAFUMI MAENOSONO ◽  
TOHRU NARUSE
Keyword(s):  
New Species ◽  
Dorsal Spine ◽  
Ryukyu Islands ◽  
Seagrass Beds ◽  
Shrimp Species ◽  
Soft Sediments ◽  
Iriomote Island ◽  
The Ryukyu Islands ◽  
A New Species ◽  
Alpheid Shrimp

A new alpheid shrimp species, provisionally assigned to the genus Salmoneus Holthuis, 1955, is described and illustrated on the basis of three specimens extracted from intertidal soft sediments on seagrass beds at Iriomote Island, southern Ryukyu Islands, Japan. Salmoneus singularis n. sp. is highly distinctive within the genus in having a pair of postorbital spines on the carapace, otherwise showing some affinities to the species of the S. gracilipes Miya, 1972 group. The possession of paired spines on the dorsolateral surface of the carapace is shared with several members of Triacanthoneus Anker, 2010, which is undoubtedly closely related to Salmoneus. However, the new species cannot be placed in Triacanthoneus because of the absence of a mid-dorsal spine on the carapace. 

scholarly journals Drift of an ocean bottom electromagnetometer from the Bonin to Ryukyu Islands: estimation of the path and travel time by numerical tracking experiments

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Noriko Tada ◽  
Haruka Nishikawa ◽  
Hiroshi Ichihara ◽  
Hiromi Kayama Watanabe ◽  
Tatsu Kuwatani
Keyword(s):  
Eddy Diffusion ◽  
Ryukyu Islands ◽  
Ocean Bottom ◽  
Rare Occurrence ◽  
Submarine Volcano ◽  
Bonin Islands ◽  
Iriomote Island ◽  
The Ryukyu Islands ◽  
Drift Path ◽  
Insight Into

AbstractOcean bottom electromagnetometers (OBEMs) installed on the seafloor around Nishinoshima Island (Bonin Islands) were missing after a December volcanic eruption. In February 2021, one was found on a beach on Iriomote Island (Ryukyu Islands), implying that it drifted westward for 1700 km. The reason(s) for the disappearance of the OBEMs and the path followed by the recovered OBEM while drifting are important information for future ocean bottom observations and seafloor volcanology in general. We conducted particle drifting simulations with and without horizonal eddy diffusion to estimate the possible drift path and duration of the recovered OBEM. Our simulations show that particles arriving at Iriomote Island have a 7–10% probability of having been transported from Nishinoshima; thus, such transport is not a rare occurrence. Transport durations in our simulations varied widely between 140 and 602 days depending on the drift paths. More detailed insight into the path and duration of drift of the OBEM will require further comparison between drifting simulations and growth histories of barnacles attached on the OBEM. A similar drift duration and path was reported for pumices that erupted from Fukutoku-Oka-no-Ba submarine volcano (southern Bonin Islands) during 18–21 January 1986 and arrived in the Ryukyu Islands in late May 1986. Such drifting simulations may prove useful for identifying the sources of drift pumices, and thus otherwise undetectable eruptions. Finally, the Fukutoku-Oka-no-Ba submarine volcano erupted on 13 August 2021, producing abundant pumice rafts that, based on our results, would likely arrive in the Ryukyu Islands. In fact, the beginning of October 2021, they began to arrive in the Ryukyu Islands. Graphical Abstract

Monthly Water Exchange through the Ryukyu Islands Revealed by Salinity Structural Changes

2013 ◽  
Vol 864-867 ◽  
pp. 2335-2339
Author(s):  
Ya Pan Liu ◽  
Jian Cheng Kang ◽  
Jiong Zhu ◽  
Qin Chen Han
Keyword(s):  
Structural Changes ◽  
Water Exchange ◽  
High Salinity ◽  
World Ocean ◽  
Core Layer ◽  
Ryukyu Islands ◽  
High Salinity Water ◽  
The Ryukyu Islands ◽  
Salinity Water ◽  
World Ocean Atlas

Using salinity database of World Ocean Atlas 2009 (WOA09) issued by NOAA in 2010, refer the range of high-salinity tongue to indicate the strength about high-salinity water, from the perspective of structural changes of salinity; the water exchange through Ryukyu Islands upper 500 m have been analyzed, the results show that: due to Ryukyu Trough, currents on both sides of Ryukyu Islands occur exchange, for upper 500 m, high-salinity water in east of the Ryukyu Islands mainly invade the west waterthe Kuroshio in East China Sea; the intrusion strength is powerful from the depth of 100 m to 200 m, and the 150 m layer is the core layer of high-salinity water intrusion; the high-salinity water at the east of Ryukyu Islands invades the Kuroshio are stronger in March, May, June, September, October and November, are weaker in April and December.

The comparative yields of two types of leucaena (Peruvian v. Hawaiian) grown for forage production in Ryukyu Islands

1986 ◽  
Vol 106 (3) ◽  
pp. 623-624 ◽  
Author(s):  
Y. Kitamura
Keyword(s):  
Leucaena Leucocephala ◽  
Ryukyu Islands ◽  
Forage Production ◽  
High Quality ◽  
The Ryukyu Islands

Leucaena leucocephala (Lam.) de Wit, a leguminous shrub, has come into use as a fodder plant for animals in the Ryukyu Islands as it provides highly palatable, high quality feed (Kitamura, 1985). It is superior to other feeds available in this regard (Higashiohmine, Aramoto & Yamashiro, 1971; Isa et al. 1982).

Carbon and Oxygen Isotope Records of Tridacna squamosa Shells from two Different Latitudes in the Ryukyu Islands

2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Satoshi Kodama ◽  
Hideko Takayanagi ◽  
Kosuke Yoshii ◽  
Thuy Thi Nhu Ha ◽  
Ryuji Asami ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Ryukyu Islands ◽  
Carbon And Oxygen Isotope ◽  
The Ryukyu Islands ◽  
Tridacna Squamosa

A taxonomic review of the genus Physopelta (Hemiptera: Heteroptera: Largidae) from Japan, Korea, and Taiwan, with a new record of Ph. parviceps from China

Zootaxa ◽  
2021 ◽  
Vol 4951 (3) ◽  
pp. 461-491
Author(s):  
JUN SOUMA ◽  
TADASHI ISHIKAWA
Keyword(s):  
New Species ◽  
New Record ◽  
Guangdong Province ◽  
Zhejiang Province ◽  
Ryukyu Islands ◽  
Taxonomic Review ◽  
The Ryukyu Islands ◽  
Two New Species ◽  
Central Taiwan ◽  
First Time

In this paper, we revised the physopeltine genus Physopelta Amyot & Serville, 1843 (Hemiptera: Heteroptera: Largidae) from Japan, Korea, and Taiwan. Five species were recognized and diagnosed, including two new species, Ph. (Neophysopelta) lutaspidata sp. nov. from northern and central Taiwan and Ph. (N.) fusciscutellata sp. nov. from the Ryukyu Islands, Japan and Taiwan, and three known species, Ph. (N.) gutta gutta (Burmeister, 1834), Ph. (N.) parviceps Blöte, 1931, and Ph. (N.) quadriguttata Bergroth, 1894. Physopelta (Neophysopelta) fusciscutellata sp. nov., was previously regarded as either of the two species, Ph. (N.) cincticollis Stål, 1863 and Ph. (N.) parviceps, for populations from Taiwan. Previous records of Ph. (N.) cincticollis from Japan proper and Korea, and Ph. (N.) slanbuschii (Fabricius, 1787) from the Ryukyu Islands were considered as misidentifications of Ph. parviceps. A key to facilitate the identification of the five species known in Japan, Korea, and Taiwan is provided. Additionally, Ph. (N.) parviceps is recorded from China (Guangdong Province and Zhejiang Province) for the first time. 

Long-chain n-3 polyunsaturated fatty acids contained in liver and muscle tissues of Okinawan long-spine porcupinefish (Diodon holocanthus Linnaeus 1758)

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yutaka Tashiro
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Ryukyu Islands ◽  
Okinawa Island ◽  
Content Type ◽  
Muscle Tissues ◽  
The Ryukyu Islands ◽  
Total Fatty Acids ◽  
Long Chain

Purpose This study aimed to analyze the lipid content and fatty acid composition in the liver and muscle of a porcupinefish species inhabiting waters around the Ryukyu Islands to investigate their potential as a source of long-chain n-3 polyunsaturated fatty acids (LC-PUFAs). Design/methodology/approach Porcupinefish were collected along the Okinawa Island coast. The composition of fatty acids and cholesterol in both liver and muscle were analyzed using a gas chromatograph mass spectrometer. Findings The liver of Okinawan long-spine porcupinefish was rich in lipids whose content correlated to the proportion of liver/body weight. Fatty acid compositions in their liver and muscles were similar to each other. LC-PUFAs occupied 44% of total fatty acids, with docosahexaenoic acid (DHA) being the dominant (42%), whereas eicosapentaenoic acid occupied 2.4%. The liver contained 1,690 mg of cholesterol and 14.8 g of DHA per 100 g, whose proportion decreased in summer compared to other seasons (p = 0.036). Originality/value The liver of Okinawan long-spine porcupinefish, which has not yet been commercially used although its non-toxicity is claimed, can be an excellent source of LC-PUFAs, especially DHA, accentuating its potential in food supplements’ production.

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