scholarly journals Spawning Environment of Chum Salmon in the Coastal Rivers on the Pacific Side of Northern Japan

2021 ◽  
Author(s):  
Satoki Oba ◽  
Tatsuya Kawakami ◽  
Yuki Minegishi ◽  
Jun Aoyama
Keyword(s):  
Chum Salmon ◽  
The Pacific ◽  
Pacific Side ◽  
Coastal Rivers ◽  
Northern Japan

Deepwater Migrations of Chum Salmon (Oncorhynchus keta) along the Pacific Coast of Northern Japan

1992 ◽  
Vol 49 (11) ◽  
pp. 2307-2312 ◽  
Author(s):  
Yasuhiro Ueno
Keyword(s):  
Surface Waters ◽  
Chum Salmon ◽  
Pacific Coast ◽  
Depth Distribution ◽  
Stomach Contents ◽  
Oncorhynchus Keta ◽  
Southern Limit ◽  
Chum Salmon Oncorhynchus Keta ◽  
The Pacific ◽  
Northern Japan

Mature chum salmon (Oncorhynchus keta) were caught in bottom trawls off lwate Prefecture, northern Japan, in autumn. To document the incidence and depth distribution of these catches, records were kept of salmon caught by five trawlers that fished along the Pacific coast of northern Honshu during September–December 1986. During this period, 4337 chum salmon were caught at bottom depths ranging from 150 to 460 m with most taken from 200 to 350 m. Gonads and stomach contents were examined for 100 of these salmon. All were mature and close to spawning. Thirty-nine of the 100 stomachs examined were empty and the remaining 61 contained only a small quantity of food, averaging 2.4 g. Chum salmon may move at these depths to avoid the high temperatures of surface waters (12–20 °C) found in this area and to follow temperatures close to their thermal preferendum (3–11 °C) which are found near bottom. This phenomenon appears to be an adaptation of chum salmon near the southern limit of their range.

Water quality assessment of six rivers of the Pacific side of Guatemala

2021 ◽  
Vol 80 (5) ◽  
Author(s):  
Norma Gil-Rodas ◽  
Guillermo Calvo-Brenes ◽  
Alex Guerra ◽  
Alejandra Perdomo
Keyword(s):  
Water Quality ◽  
Quality Assessment ◽  
Water Quality Assessment ◽  
The Pacific ◽  
Pacific Side

The utilization of cold-water zooplankton as prey for chum salmon fry (Oncorhynchus keta) in Yamada Bay, Iwate, Pacific coast of northern Japan

2019 ◽  
Vol 29 ◽  
pp. 100633
Author(s):  
Yuichiro Yamada ◽  
Kei Sasaki ◽  
Kodai Yamane ◽  
Miwa Yatsuya ◽  
Yuichi Shimizu ◽  
...  
Keyword(s):  
Chum Salmon ◽  
Pacific Coast ◽  
Cold Water ◽  
Oncorhynchus Keta ◽  
Salmon Fry ◽  
Northern Japan

scholarly journals Sedimentary dynamics and structural control of Neogene tropical biofacies during the formation of the Central American Isthmus

1992 ◽  
Vol 6 ◽  
pp. 62-62 ◽  
Author(s):  
Anthony Coates ◽  
Jorge Obando ◽  
Herman Gonzalez
Keyword(s):  
Structural Control ◽  
Sedimentary Basins ◽  
Conclusive Evidence ◽  
Central American ◽  
The Pacific ◽  
Pacific Side ◽  
Late Neogene ◽  
The Caribbean ◽  
Final Closure ◽  
Central American Isthmus

The central evolutionary, ecological and paleoceanographic questions of the American tropical Neogene relate to how and during what time the Central American Isthmus formed. Geographically, closure was located between the southern edge of the Chortis Block in southern Nicaragua and the Atrato Valley in Colombia. In this region we describe, on the Caribbean side, five Neogene sedimentary basins. They are the Atrato, Chucunaque, Gatun, Bocas del Toro, and Limon Basins. On the Pacific side the Neogene sediments formed as part of the Central American Trench and are well exposed in a series of uplifted blocks on the Nicoya, Osa and Burica Peninsulas. Our analysis allows 1) a construction of the sequence of contrasting sedimentary environments which characterize the different basins, giving a composite geological history of the isthmus for the Late Neogene and 2) identifies the comparable biofacies from the different basins which allow and constrain the evolutionary and ecological questions to be posed concerning the effect of the isthmus as a biogeographic barrier. Temporally, from it's partial emergence in the Middle Miocene, the isthmus shallows by the Early Pliocene (3.5–3.4 Ma) to less than 50 m (Duque-Caro, 1990) when there is a marked differentiation of shelf marine macrobenthic species between the Caribbean and the Pacific. The evidence from reliably dated, large, diverse exchanges of North and South American vertebrates on land constrains the final closure date to not later than 2.8–2.5 Ma (Marshall, 1988). Given that no conclusive evidence for final closure can come exclusively from a study of sedimentary facies, when depths of less than 50 m are involved, the present window of almost 1 Ma, during which final closure must have occurred, will only be narrowed further by the detailed study of very shallow-water fossil clades and complementary molecular data. Present studies indicate that such clades are abundantly preserved.

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