scholarly journals Does Long-distance Downstream Migration Influence the Survival of Chum Salmon? Comparison of Adult Returns between the Upper and Lower Reaches Release Sites

2021 ◽  
Author(s):  
Kiyoshi Kasugai ◽  
Mitsuru Torao ◽  
Mitsuhiro Nagata
Keyword(s):  
Chum Salmon ◽  
Downstream Migration ◽  
Long Distance

scholarly journals Comparison of the swimming ability and upstream-migration behavior between chum salmon and masu salmon

2014 ◽  
Vol 71 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Koji Miyoshi ◽  
Kazufumi Hayashida ◽  
Taku Sakashita ◽  
Makoto Fujii ◽  
Hisaya Nii ◽  
...  
Keyword(s):  
Swimming Speed ◽  
Chum Salmon ◽  
Swimming Performance ◽  
High Water ◽  
Masu Salmon ◽  
Oncorhynchus Keta ◽  
Upstream Migration ◽  
Migration Behavior ◽  
Spawning Ground ◽  
Long Distance

The spawning ground of chum salmon (Oncorhynchus keta) is usually located farther downriver than that of masu salmon (Oncorhynchus masou) in Hokkaido, Japan. To compare the swimming abilities of these two species, the relationship between swimming speed and oxygen consumption was compared using a swim tunnel in the laboratory. Then, the upstream-migration behaviors of chum salmon and masu salmon were compared using electromyogram telemetry at fish passages in the Toyohira River, Hokkaido. In the laboratory study, the standard metabolic rate of masu salmon was lower and the critical swimming speed (Ucrit) was faster than those of chum salmon. In the field study, the holding time needed to recover the swimming performance exceeding Ucrit at the fish passages and the trial number needed to pass the fish passages were significantly lower for masu salmon than chum salmon. These results revealed that masu salmon are more adaptable to extended swimming in high water velocity conditions than chum salmon and that masu salmon are better equipped for a long distance upstream migration to their spawning ground than chum salmon.

Characterization of feeding and downstream migration of juvenile chum salmon in the Kichiga river (north-eastern kamchatka)

2021 ◽  
pp. 39-50
Author(s):  
E. S. Voronova ◽  
T. N. Travina ◽  
A. M. Biryukov
Keyword(s):  
Chum Salmon ◽  
Hydrological Regime ◽  
Downstream Migration ◽  
Juvenile Survival ◽  
Salmon Juvenile ◽  
North Eastern ◽  
Juvenile Chum Salmon ◽  
First Time ◽  
Qualitative Characteristics

Analysis of the data of fish biology spring-summer researches in the Kichiga river basin in the period 2017–2019 for the first time brought results as next: characterized dynamics of chum salmon juvenile downstrean migration, including daily dynamics, revealed qualitative characteristics of the underyearlings, described diet of the juvenile migrants, demonstrated effects of the spring-summer hydrological regime on the intensity of the underyearling feeding. Also noted, that the conditions for the downstream migration of chum salmon in 2018 were maximum favouravle, and most likely that could enhance later juvenile survival.

Phenotypic Differentiation in Seasonal Ecotypes of Chum Salmon, Oncorhynchus keta

1991 ◽  
Vol 48 (4) ◽  
pp. 661-671 ◽  
Author(s):  
Ross F. Tallman ◽  
Michael C. Healey
Keyword(s):  
Egg Size ◽  
Chum Salmon ◽  
Downstream Migration ◽  
Oncorhynchus Keta ◽  
Age At Maturity ◽  
Similar Time ◽  
Phenotypic Differentiation ◽  
Chum Salmon Oncorhynchus Keta ◽  
Spawning Stock ◽  
Autumn And Winter

We compared the reproductive environments and phenotypes of early and late season breeding stocks of chum salmon, Oncorhynchus keta, to test the hypothesis that seasonal separation has resulted in phenotypically distinct forms. These were autumn- and winter-spawning populations from Bush Creek (Vancouver Island, B.C.) and a winter-spawning stock from nearby Walker Creek. All stocks had a similar time of downstream migration of the fry. No differences were found among the Walker Creek and the autumn-spawning stock of Bush Creek in age at maturity, length composition of spawners, egg size, vertebral counts of adults and fry, and time of fry migration. The winter-spawning stock of Bush Creek differed from the other stocks in egg size and vertebral counts. Discriminant analysis of 10 morphological features of the fry revealed considerable overlap in body form among the stocks. These results do not support the hypothesis that distinct life history morphs are associated with the season of reproduction. We propose that the large amount of similarity in terms of morphology and seasonality among the populations may be the product of selection. Genetic divergence may have occurred to compensate for the environmental differences experienced during embryonic development.

scholarly journals Involvement of hormones in olfactory imprinting and homing in chum salmon

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Hiroshi Ueda ◽  
Shingo Nakamura ◽  
Taro Nakamura ◽  
Kaoru Inada ◽  
Takashi Okubo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chum Salmon ◽  
Gene Activation ◽  
Memory Formation ◽  
Downstream Migration ◽  
Hormonal Control ◽  
Oncorhynchus Keta ◽  
Control Mechanisms ◽  
Olfactory Memory ◽  
Releasing Hormone

Abstract The olfactory hypothesis for salmon imprinting and homing to their natal stream is well known, but the endocrine hormonal control mechanisms of olfactory memory formation in juveniles and retrieval in adults remain unclear. In brains of hatchery-reared underyearling juvenile chum salmon (Oncorhynchus keta), thyrotropin-releasing hormone gene expression increased immediately after release from a hatchery into the natal stream, and the expression of the essential NR1 subunit of the N-methyl-D-aspartate receptor increased during downstream migration. Gene expression of salmon gonadotropin-releasing hormone (sGnRH) and NR1 increased in the adult chum salmon brain during homing from the Bering Sea to the natal hatchery. Thyroid hormone treatment in juveniles enhanced NR1 gene activation, and GnRHa treatment in adults improved stream odour discrimination. Olfactory memory formation during juvenile downstream migration and retrieval during adult homing migration of chum salmon might be controlled by endocrine hormones and could be clarified using NR1 as a molecular marker.

The Behaviour of Pacific Salmon Fry During Their Downstream Migration to Freshwater and Saltwater Nursery Areas

1960 ◽  
Vol 17 (5) ◽  
pp. 655-676 ◽  
Author(s):  
J. McDonald
Keyword(s):  
Light Intensity ◽  
Chum Salmon ◽  
Pacific Salmon ◽  
Downstream Migration ◽  
Current Speed ◽  
Migration Route ◽  
Visual Contact ◽  
Nursery Areas ◽  
Salmon Fry ◽  
Downstream Movement

The downstream migration of sockeye, coho, pink and chum salmon fry is initially nocturnal and appears to be regulated quite precisely by changes in light intensity. Downstream movement is seen to arise from a displacement by the current when firm visual contact with fixed objects in the stream is lost. Once the migration is under way the distribution of the fry varies. The lateral distribution of pink and sockeye, but not chum and coho, was closely and positively related to current speed, above a threshold of 1.3 ft/sec (0.4 m/sec). Pink fry were found to be distributed throughout the total depth of water but greatest catches were made at intermediate depths. The negative response of fry to light appears to change after exposure to it, and pink and chum fry were found to extend their movements into and throughout the daylight hours where the migration route was lengthy. Feeding and schooling activity is probably associated with this change in response to light. Both pink and chum fry were observed to school only near the end of their seaward movement. Pink fry were found to feed to some extent in the natal areas but to a greater extent as the sea was approached.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

Popliteal entrapment syndrome and age

VASA ◽  
2012 ◽  
Vol 41 (4) ◽  
pp. 262-268 ◽  
Author(s):  
Schweizer ◽  
Hügli ◽  
Koella ◽  
Jeanneret
Keyword(s):  
Risk Factors ◽  
Leg Pain ◽  
Walking Distance ◽  
Therapeutic Approaches ◽  
Long Distance ◽  
Entrapment Syndrome ◽  
Long Distance Running ◽  
Popliteal Entrapment ◽  
Popliteal Entrapment Syndrome ◽  
Atherosclerotic Risk Factors

On the occasion of diagnosing a popliteal entrapment syndrome in a 59-year old man with no cardiovascular risk factors, who developed acute ischemic leg pain during long distance running, we give an overview on this entity with emphasis on patients’age. The different types of the popliteal artery compression syndrome are summarized. The diagnostic and therapeutic approaches are discussed. The most important clinical sign of a popliteal entrapment syndrome is the lack of atherosclerotic risk factors in patients with limited walking distance. Not only in young athletes but also in patients more than 50 years old the popliteal entrapment syndrome has to be taken into account.

Attachment Styles, Physical Proximity, and Relational Satisfaction

2014 ◽  
Vol 4 (2) ◽  
pp. 106-112
Author(s):  
Anita Shrivastava ◽  
Andrea Burianova
Keyword(s):  
Attachment Styles ◽  
Romantic Relationship ◽  
Distinct Type ◽  
Relational Satisfaction ◽  
Long Distance ◽  
Avoidant Attachment ◽  
Geographic Separation ◽  
Relationship Of ◽  
Attachment Dimensions

This study aimed to explore the relationships between attachment styles, proximity, and relational satisfaction. This was achieved by assessing a distinct type of long distance romantic relationship of flying crews, compared with proximal (non-flying crew) romantic relationships. The responses of 139 expatriate professionals revealed significant associations between proximity and anxious and avoidant attachment dimensions. The role of the avoidant dimension in comparison with that of the anxious dimension was found to be a significant predictor of relational satisfaction. This study contributes significantly toward addressing the role of proximity and attachment in relational satisfaction in a new context of geographic separation.

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