scholarly journals Predation of stocked salmon by riparian wildlife in semi-natural stream

2017 ◽  
Author(s):  
Kouta Miyamoto ◽  
Theodore E. Squires ◽  
Hitoshi Araki
Keyword(s):  
Camera Trap ◽  
Masu Salmon ◽  
Time Of Day ◽  
Natural Environments ◽  
Oncorhynchus Masou ◽  
Predator Species ◽  
Hatchery Fish ◽  
Natural Stream ◽  
Ardea Cinerea ◽  
The Relationship

AbstractPredation after release is one of the major concerns of hatchery fish conservation and propagation. However, the relationship among the size of hatchery fish, the predator species, and their behaviors in natural environments is largely unknown. To understand the relationship, we conducted predation experiments in outdoor tanks and a semi-natural stream with exposure to local predators. Two different ranges of fork lengths of masu salmon (Oncorhynchus masou) were examined as prey sizes. Camera trap data showed that grey herons (Ardea cinerea) were the primary predator animal in the system, and that most herons utilized shallow areas in the morning or evening. Increasing the density of stocked salmon brought in more grey herons. More importantly, predation by grey herons resulted in the survival rate of larger salmon being significantly lower than that of the smaller salmon. Our results suggest that it is important to understand local predators, adjust the optimum body size of hatchery fish at release, and choose the appropriate stocking site and time of day for maximizing the effectiveness of fish stocking.

Experimental evaluation of predation of stocked salmon by riparian wildlife: effects of prey size and predator behaviours

2018 ◽  
Vol 69 (3) ◽  
pp. 446 ◽  
Author(s):  
Kouta Miyamoto ◽  
Theodore E. Squires ◽  
Hitoshi Araki
Keyword(s):  
Experimental System ◽  
Masu Salmon ◽  
Time Of Day ◽  
Natural Environments ◽  
Grey Heron ◽  
Predator Species ◽  
Lower Survival Rate ◽  
Hatchery Fish ◽  
Ardea Cinerea ◽  
Masu Salmon Oncorhynchus Masou

Predation after release is one of the major concerns of hatchery fish conservation and propagation. However, the relationships between the size of hatchery fish, the predator species and their behaviours in natural environments are largely unknown. To understand these relationships, we conducted predation experiments in outdoor tanks and a seminatural stream with exposure to local predators. Masu salmon (Oncorhynchus masou) of two different size classes were used as experimental prey fish in the present study. Camera trap data showed that grey herons (Ardea cinerea) were the primary predator in the experimental system, and that most herons used shallow areas in the morning or evening while feeding. Increasing the density of stocked salmon led to increases in the number of occurrences of grey heron. More importantly, predation by grey herons resulted in a significantly lower survival rate of larger salmon compared with smaller salmon. The results indicate that it is important to understand local predators, adjust the optimum body size of hatchery fish at release and choose the appropriate stocking site and time of day for maximising the effectiveness of fish stocking.

scholarly journals Feeding of young masu salmon Oncorhynchus masou in the base river of the Aniva hatchery (southern Sakhalin) after release of the hatchery juveniles

2017 ◽  
Vol 188 (1) ◽  
pp. 212-223
Author(s):  
Lyubov A. Zhivoglyadova ◽  
Sergey S. Makeev
Keyword(s):  
Masu Salmon ◽  
Empty Stomach ◽  
Natural Environments ◽  
Oncorhynchus Masou ◽  
Species Protection ◽  
Successful Transition ◽  
River Habitat ◽  
Southern Sakhalin ◽  
River Bottom

Feeding of masu parr in the natural river habitat on 8-9 days after their release from hatchery is considered on the data obtained in the Lyutoga River tributaries in 2014-2015. No fish with empty stomach were found that indicated successful transition of artificially hatched fish to feeding in the natural environments. More than 40 species of prey were found in their stomachs, mostly terrestrial and aerial invertebrates and the river bottom dwellers as mayflies and chironomids. The diet corresponded to biotopes features. For better feeding (higher stomach filling) gradual releasing is recommended over wide areas by the parties no more than 4,000 ind. The juveniles should be transported in isothermic boxes to the lower or middle parts of streams and in packages with oxygen (for 600-1000 ind. each) to the upper streams. Involving of volunteers from fishermen to the releasing is desirable that attracts additional attention to the species protection.

Trade-offs in the adaptation towards hatchery and natural conditions drive survival, migration, and angling vulnerability in a territorial fish in the wild

2019 ◽  
Vol 76 (10) ◽  
pp. 1757-1767 ◽  
Author(s):  
Jun-ichi Tsuboi ◽  
Kohichi Kaji ◽  
Shinya Baba ◽  
Robert Arlinghaus
Keyword(s):  
High Growth ◽  
Natural Environments ◽  
Recreational Fisheries ◽  
Plecoglossus Altivelis ◽  
Poor Growth ◽  
Hatchery Fish ◽  
Natural Stream ◽  
Trade Offs ◽  
In Captivity ◽  
In The Wild

Hatchery fish that support capture fisheries need to thrive in both hatchery and natural environments. We conducted joint experiments in both environments with individuals stemming from multiple generations held in captivity to test the performance of hatchery-reared ayu (Plecoglossus altivelis). Ayu is an annual, herbivorous, territorial, and amphidromous riverine fish native to Japan of high importance to recreational fisheries. Hatchery fish of the first hatchery generation exhibited poor growth and highest malformation rates relative to the second and following hatchery generations. The first generation offspring stocked into a natural stream also showed low survival and poor vulnerability to angling, suggesting that maladaptation to the hatchery environment explained the performance in the wild. By contrast, offspring of the seventh to ninth generations exhibited high growth in the hatchery environment, but when stocked into the wild they also exhibited low survival, maladapted migratory behaviour, and again poor vulnerability to angling. Consequently, intermediate generations held in captivity were found to offer the best fisheries performance and can thus be recommended for enhancements to support recreational fisheries.

Spaces of Consumption in American Literary Realism

2019 ◽  
pp. 391-410
Author(s):  
Gary Totten
Keyword(s):  
Consumer Culture ◽  
Social Space ◽  
Natural World ◽  
Power Dynamics ◽  
Literary Realism ◽  
Natural Environments ◽  
Production And Consumption ◽  
The Social ◽  
The Relationship ◽  
New Strategies

This chapter discusses how consumer culture affects the depiction and meaning of the natural world in the work of American realist writers. These writers illuminate the relationship between natural environments and the social expectations of consumer culture and reveal how such expectations transform natural space into what Henri Lefebvre terms “social space” implicated in the processes and power dynamics of production and consumption. The representation of nature as social space in realist works demonstrates the range of consequences such space holds for characters. Such space can both empower and oppress individuals, and rejecting or embracing it can deepen moral resolve, prompt a crisis of self, or result in one’s death. Characters’ attempts to escape social space and consumer culture also provide readers with new strategies for coping with their effects.

Changes of serum growth hormone and vitellogenin levels during vitellogenesis in female masu salmon Oncorhynchus masou

2000 ◽  
Vol 66 (4) ◽  
pp. 789-791 ◽  
Author(s):  
Haruhisa Fukada ◽  
Naoshi Hiramatsu ◽  
Makiko Kitamura ◽  
Munetaka Shimizu ◽  
Akihiko Hara
Keyword(s):  
Growth Hormone ◽  
Masu Salmon ◽  
Oncorhynchus Masou ◽  
Serum Growth Hormone ◽  
Masu Salmon Oncorhynchus Masou

Development and Testing of an Unmanned Aerial Vehicle for Large Scale Particle Image Velocimetry

2014 ◽  
Author(s):  
Christopher Pagano ◽  
Flavia Tauro ◽  
Salvatore Grimaldi ◽  
Maurizio Porfiri
Keyword(s):  
Particle Image Velocimetry ◽  
Large Scale ◽  
Field Experiments ◽  
Particle Image ◽  
Low Cost ◽  
Surface Flow ◽  
Natural Environments ◽  
Natural Stream ◽  
Image Velocimetry ◽  
Scale Particle

Large scale particle image velocimetry (LSPIV) is a nonintrusive environmental monitoring methodology that allows for continuous characterization of surface flows in natural catchments. Despite its promise, the implementation of LSPIV in natural environments is limited to areas accessible to human operators. In this work, we propose a novel experimental configuration that allows for unsupervised LSPIV over large water bodies. Specifically, we design, develop, and characterize a lightweight, low cost, and stable quadricopter hosting a digital acquisition system. An active gimbal maintains the camera lens orthogonal to the water surface, thus preventing severe image distortions. Field experiments are performed to characterize the vehicle and assess the feasibility of the approach. We demonstrate that the quadricopter can hover above an area of 1×1m2 for 4–5 minutes with a payload of 500g. Further, LSPIV measurements on a natural stream confirm that the methodology can be reliably used for surface flow studies.

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