Junya Hirai 교수

Marine planktonic copepods are an ecologically important group with high species richness and abundance. Here, we propose a new metagenetic approach for revealing the community structure of marine planktonic copepods using 454 pyrosequencing of nuclear large subunit ribosomal DNA. We determined an appropriate similarity threshold for clustering pyrosequencing data into molecular operational taxonomic units (MOTUs) using an artificial community containing 33 morphologically identified species. Th

We evaluated the internal transcribed spacer 2 and large subunit ribosomal DNA (ITS2-28S) region as a molecular marker for identifying calanoid copepods in the subtropical western North Pacific. The ITS2-28S sequence was successfully amplified in 232/244 individuals, a much higher rate of success than for cytochrome oxidase I amplification (77/244 individuals). A total of 194 sequences of ITS2-28S were obtained using a single primer pair. A high degree of genetic variability in ITS2-28S was obse

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 564:99-113 (2017) - DOI: https://doi.org/10.3354/meps12008 Molecular-based diet analysis of the early post‑larvae of Japanese sardine Sardinops melanostictus and Pacific round herring Etrumeus teres Junya Hirai1,3,*, Kiyotaka Hidaka1, Satoshi Nagai1, Tadafumi Ichikawa2 1National Research Institute of Fis

Monitoring zooplankton communities is important to understand dynamics in marine ecosystems. However, it is difficult to identify cryptic species and immature stages of zooplankton using morphological classification, which is time-consuming and requires high skill levels. Here, we conducted a metagenetic analysis of the 18S region in 101 zooplankton samples collected weekly throughout 2014 and 2015 at the Okhotsk Tower in Mombetsu, Hokkaido, Japan, and compared the results of this analysis with

A clear insight into the large-scale community structure of planktonic copepods is critical to understanding the mechanisms controlling diversity and biogeography of marine taxa in terms of their high abundance, ubiquity, and sensitivity to environmental changes. Here, we applied a 28S metabarcoding approach to large-scale communities of epipelagic and mesopelagic copepods at 70 stations across the Pacific Ocean and three stations in the Arctic Ocean. Major patterns of community structure and di

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 534:65-78 (2015) - DOI: https://doi.org/10.3354/meps11404 Metagenetic community analysis of epipelagic planktonic copepods in the tropical and subtropical Pacific Junya Hirai1,*, Atsushi Tsuda2 1National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa, Yokoham

Metagenetics is a rapid and taxonomically comprehensive method for revealing community structures within environmental samples, based on large amounts of sequence data produced by high-throughput sequencers. Because community structures of planktonic copepods are important in the ocean owing to their high diversity and abundance, a metagenetic analysis of the 28S D2 region using Roche 454 was previously developed. However, the Illumina MiSeq platform with a high sequence output is being used mor

Metagenetic diet analyses of the 18S V9 region were conducted in 40 adult female Calanus sinicus during winter in Tosa Bay (Japan). The majority of prey items were small crustaceans (of Copepoda and Cirripedia) and diatoms, taxa that are dominant in the environment and have been previously reported as important prey items of Calanus. The abundance of sequences attributable to Dinophyta and Chlorophyta was significantly lower in C. sinicus gut contents than in environmental plankton communities,

Abstract The temporal and spatial distribution of Meganyctiphanes norvegica near the seabed (<5 m above the seafloor) was investigated using remotely operated vehicle (ROV) video footage from eight sites in the Faroe–Shetland Channel. Meganyctiphanes norvegica was most abundant near the seabed at 400–600 m depth, which corresponds to a temperature transitional region between shallower warmer water and deeper cold water. Densities of M. norvegica were significantly lower in the warm water, and no

Abstract The Izu Ridge off the southern coast of Japan is composed of many seamounts and knolls and is an important fishery ground and hatchery for commercially important fish. As pelagic copepods link lower and higher trophic levels, we investigated the epipelagic copepods in the Izu Ridge using 28S DNA/RNA metabarcoding and microscopic approaches. In comparison with off-ridge regions, a low water temperature and high chlorophyll a concentration were observed in the Izu Ridge, possibly attribut

Small copepods are important prey for fish larvae in the Kuroshio region off southern Japan. However, revealing entire community structures of small copepods is difficult using conventional methods. We applied a metabarcoding method to size-fractionated community samples of epipelagic copepods (small: 0.1-0.5 mm, medium: 0.5-1.0 mm, and large: 1.0-2.0 mm). Samples were collected from 2013 to 2016 from the shoreward (Kuroshio Slope, KS) and oceanic (Kuroshio Gyre, KG) sides of the Kuroshio Curren

Abstract A clear insight into large-scale community structure of planktonic copepods is critical to understanding mechanisms controlling diversity and biogeography of marine taxa, owing to their high abundance, ubiquity, and sensitivity to environmental changes. Here, we applied a 28S metabarcoding approach to large-scale communities of epipelagic and mesopelagic copepods at 70 stations across the Pacific Ocean and three stations in the Arctic Ocean. Major patterns of community structure and div