Time filter

Source Type

Okamoto M.,Shimane Prefectural Fisheries Technology Center | Saito H.,Shimane PrefecturalMatsue Regional office of Fisheries Affairs
Nippon Suisan Gakkaishi (Japanese Edition) | Year: 2011

We examined the best procedure for the handling of Japanese Spanish mackerel caught by shipboard angling. The mackerel were killed using four different procedures: stabbing the spinal bulb, bleeding out, killing by iceseawater, and struggled suffocation. Breaking strengths of stabbed spinal bulb samples were greater than those of the other groups, while the extent of muscle tearing was less than those of the other groups. Muscle tearingin the struggled suffocation group was greatest among all groups. However, K values and lactic acid concentrations were independent of the killing method. These results indicatedthat stabbing the spinal bulb can delay the loss of breaking strength of muscle and prevent muscle tearing.


Yokoo T.,The University of Shimane | Mito T.,Farming Fisheries Center | Iwasaki T.,The University of Shimane | Sasaki T.,Shimane Prefectural Fisheries Technology Center | And 2 more authors.
Japanese Journal of Limnology | Year: 2010

Spatial and temporal variability of fish assemblages in Nakaumi Lagoon along the Sea of Japan were studied using the seasonal catch data acquired by small set-net sampling from February to December 2008. We compared species composition and assemblage structures among different seasons and areas such as the sub-enclosed Honjo District and the outer Honjo District in the lagoon. A total of 10649 individuals representing 39 species were recorded, with Engraulis japonicus, Sardinella zunasi, Nuchequula nuchalis, Lateolabrax japonicus, Plecoglossus altivelis altivelis, Trachurus japonicas, Plotosus japonicus, and Konosirus punctatus being numerically dominant in the Lagoon. Species richness was greatest in summer due to the seasonal occurrence of temporary resident species including Sardinops melanostictus and Acanthopagrus schlegelii. In addition, the fact that the number of benthic species in summer was higher in the Honjo District than in the outer Honjo District, may have been a response to the relatively low level of hypoxia in the former.


Onitsuka G.,Japan National Research Institute of Fisheries Science | Miyahara K.,Hyogo Prefectural Institute of Technology | Hirose N.,Kyushu University | Watanabe S.,Tottori Prefectural Fisheries Experimental Station | And 5 more authors.
Harmful Algae | Year: 2010

Since 2002, blooms of the harmful dinoflagellate Cochlodinium polykrikoides Margalef have occurred in the eastern San-in area, the Japanese coastal area fronting the southwest Sea of Japan. To investigate the occurrence mechanisms of the blooms, numerical experiments were conducted using a Lagrangian particle-tracking model, under different hydrographic conditions in 2002-2008. The results of Lagrangian simulations revealed that the source region of the blooms was located in the southeast Korean coastal area, >500 km away from the eastern San-in area. They were transported by the Tsushima Warm Current over about two weeks to one month. The blooms in the eastern San-in area were thought to occur only when a series of sequential conditions were met, which included preceding outbreaks in Korean waters, southwesterly winds in the Tsushima Strait, and the nearshore position of the Tsushima Warm Current off the San-in coast, veering eastward from the Korean peninsula. © 2010 Elsevier B.V. All rights reserved.


Abe N.,Japan Institute for Environmental Sciences | Okamoto M.,Shimane Prefectural Fisheries Technology Center | Maehara T.,Food Sanitation Inspection Laboratory of Osaka Municipal Central Wholesale Market
Acta Parasitologica | Year: 2014

Classification and identification of muscle-parasitizing didymozoids found in marine fish is difficult because of their novel parasitism and morphology. Recent sequence analysis has helped, but only seven sequences are available. Therefore, the usefulness of molecular methods for differentiation of muscle-parasitizing didymozoids, as well as genetic differences between the muscle and the other site-parasitizing didymozoids are quite unclear. In the present study, six unidentified didymozoid isolates from the trunk muscles of four marine fish species (Diagramma pictum, Plectorhinchus cinctus, Pagrus major and Cypselurus heterurus) were examined genetically using sequence analysis (18S rDNA, 28S rDNA, ITS-2 and coxI). All isolates were placed phylogenetically as a lineage independent of other site-parasitizing didymozoids at 18S rDNA, ITS-2 and coxI. They were grouped into three distinct lineages. The present and the previous unidentified or identified didymozoids from trunk muscles were found to differ clearly for every host species by sequence analysis, suggesting that muscle-parasitizing didymozoids are host-specific. This report is the first describing the molecular characteristics of muscle-parasitizing didymozoids by sequence analysis targeting the nuclear and mitochondrial DNA loci, which is proposed as a superior method for didymozoid differentiation. © 2014 Versita Warsaw and Springer-Verlag Wien.


Kamaishi T.,National Research Institute of Aquaculture | Miwa S.,Japan National Research Institute of Fisheries And Environment of Inland Sea | Goto E.,Shimane Prefectural Fisheries Technology Center | Matsuyama T.,National Research Institute of Aquaculture | And 2 more authors.
Diseases of Aquatic Organisms | Year: 2010

In February 2005, a mass mortality of giant abalone Haliotis (Nordotis) gigantea Gmelin, 1791 occurred on a private abalone farm in Shimane Prefecture, Japan. The cumulative mortality rate reached about 84%. In histological observations, bacteria-like spherical particles were found in affected animals, suggesting a bacterial infection. Many of the bacteria-like particles were found in the cells that were presumably host phagocytes. DNA was extracted from the hemolymph of a diseased abalone and a bacterial 16S rRNA gene was amplified by PCR. The bacterium was classified within the genus Francisella by gene sequence analysis. A bacterial isolate was obtained by spreading hemolymph of a diseased abalone on modified Eugon agar dissolved in 70% seawater containing 1% (w/v) hemoglobin. A gene fragment of the expected size was amplified from the bacterial isolate by PCR using specific primers for the 16S rRNA gene obtained from the diseased abalone. Experimental infections were carried out by intramuscular injection with the bacterial isolate or by immersion in the bacterial suspension using 2 species of abalone, the giant abalone and the Japanese black abalone Haliotis (Nordotis) discus discus Reeve, 1846. Most (98.6%) of the abalone challenged with the bacterial isolate died in experimental infections. These results suggest that the Francisella sp. isolate was the causative agent for the mass mortality of giant abalone. This is the first report of a pathogenic Francisella sp. isolate for mollusks. © Inter-Research 2010.

Loading Shimane Prefectural Fisheries Technology Center collaborators
Loading Shimane Prefectural Fisheries Technology Center collaborators