The relationship between migration speed and release date for chum salmon Oncorhynchus keta fry exiting a 110-km northern Japanese river     

Kiyoshi Kasugai  Mitsuru Torao  Mitsuhiro Nagata  James R. Irvine 《Fisheries Science》2013,79(4):569-577

The relationship between release date and migration speed was examined for hatchery chum salmon Oncorhynchus keta fry exiting the Nishibetsu River in eastern Hokkaido, northern Japan so that future releases might be scheduled so that fry arrive at the ocean during periods favoring high survival. Separate marked groups of chum salmon released in early April, mid-April, and early May in 2008, late March and mid-April in 2009, and mid-April in 2010 were recaptured with a rotary screw trap 12 km above the river mouth. Chum salmon in later release groups tended to migrate downstream faster than fish in earlier release groups. Those released after mid-April arrived in the lower river on average 9 days after release, while those released before mid-April arrived on average 26–28 days after release. Most marked fish arrived in the lower river during late April to mid-May. These results suggest that chum salmon are adapted to adjust their migratory speed so as to arrive at the ocean during a relatively discrete period, presumably during a time of high productivity favoring good survival.  相似文献   

A Leafhopper (Hishimonus sellatus) Transmits Phylogenetically Distant Phytoplasmas: Rhus Yellows and Hovenia Witches' Broom Phytoplasma     

Manabu KUSUNOKI  Toshiki SHIOMI  Motowo KOBAYASHI  Torao OKUDAIRA  Akihiro OHASHI  Teruo NOHIRA 《Journal of General Plant Pathology》2002,68(2):147-154

Phytoplasmas causing a severe decline of three tree species, i.e., Rhus javanica, Hovenia tomentella and Zizyphus jujuba, in Japan were examined for their transmissibility by a leafhopper species Hishimonus sellatus, and for their phylogenetic relatedness. By H. sellatus, Rhus yellows (RhY) phytoplasma was transmissible to white clover and periwinkle seedlings, causing typical symptoms in these plants. Jujube witches' broom (JWB) phytoplasma was also transferred to the host plant, Z. jujuba, by the leafhopper. Because JWB phytoplasma was transmitted to Hovenia tomentella and caused the same symptoms as Hovenia witches' broom (HWB), JWB phytoplasma may be very closely related to HWB phytoplasma. RFLP analysis of the PCR products of 16S rDNA revealed that RhY phytoplasma belongs to the Aster yellows (AY) group, and JWB and HWB phytoplasmas belong to a different group (possibly Elm yellows group). Thus, we found that one species of leafhopper can carry phylogenetically distant phytoplasmas. Received 23 April 2001/ Accepted in revised form 29 October 2001  相似文献   

Circulating insulin-like growth factor I in juvenile chum salmon: relationship with growth rate and changes during downstream and coastal migration in northeastern Hokkaido,Japan     

Nobuto Kaneko  Natsumi Taniyama  Yu Inatani  Yuta Nagano  Makoto Fujiwara  Mitsuru Torao  Yasuyuki Miyakoshi  Munetaka Shimizu 《Fish physiology and biochemistry》2015,41(4):991-1003

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Early developmental phase of wakasagi, Hypomesus nipponensis, in Lake Abashiri     

Mitsuru Torao 《Fisheries Science》2000,66(3):605-607

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