Patterns of Downstream Migration of Pink Salmon Oncorhynchus gorbuscha in the Malaya Khusi River (Sakhalin Oblast)

Journal of Fish Biology

Urabe

Nakamura

2022

Downstream migration is a critical stage in the anadromous salmonid life cycle, but previous studies have shown different results between rivers or surveys for the diel downstream migration pattern of the fry of the pink salmon Oncorhynchus gorbuscha. We investigated the diel migration pattern of pink salmon fry in three small streams. Our results showed that pink salmon fry migrate mainly within a few hours after sunset; 89.9% of migration occurred between 18:00 and 23:00. Therefore, the results indicated that sunset time influences the diel migration pattern of pink salmon fry in small streams. This pattern could be a predator‐avoidance behaviour.

mentioning

confidence: 63%

Section: Metric Chienbetsu Stream Funbe Stream Syoji Streammentioning

confidence: 99%

Section: Metric Chienbetsu Stream Funbe Stream Syoji Streammentioning

confidence: 99%

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Diel migration pattern of pink salmon fry in small streams

Journal of Fish Biology

Urabe

Nakamura

2022

“…In addition, dippers sometimes prey on salmon fry (Obermeyer et al, 2006; Ormerod, 1985; Ormerod & Tyler, 1986, 1991). Since most salmon fry mainly emerge during spring and summer (Kirillov et al, 2018; Pavlov et al, 2008; Yamada et al, 2022), salmon fry may be used as a food resource by dippers during this period. Therefore, spawning by anadromous salmonids may compensate for declines in the abundance of aquatic invertebrates during various seasons.…”

Section: Discussionmentioning

confidence: 99%

Relationship between salmon egg subsidy and the distribution of an avian predator

Katahira

Miura

et al. 2022

Ecology and Evolution

As a spatial subsidy, which is the phenomenon of transferring resources from a donor system to a recipient system, anadromous salmonids contribute to the supply of marine‐derived nutrients to freshwater and terrestrial systems. Live salmon and salmon carcasses and eggs are utilized by various organisms and affect their abundance and distribution. However, the evaluation of the effect of salmon subsidies on the abundance and distribution of terrestrial animals is biased toward predators or scavengers that utilize spawning adults and carcasses, and few studies have focused on the effect of salmon eggs as a subsidy. To avoid underestimating the function of salmon subsidies, the response to the availability of salmon eggs in various systems should be investigated. Here, we investigated the abundance and feeding behavior of the brown dipper Cinclus pallasii, as a consumer of salmon eggs, based on the hypothesis that the availability of salmon eggs affects the diet composition and stream distribution of this small predator. In addition, to test whether changes in the abundance of brown dippers are determined by salmon spawning, their abundance was compared upstream and downstream of the check dams in three streams during the peak spawning period. Brown dippers used salmon eggs during the spawning season (53.7% of diet composition), and their abundance increased as the number of spawning redds increased. In contrast, this pattern was not observed upstream of the check dam. These results suggested that the abundance and stream distribution of brown dippers vary according to the variation in the spatiotemporal availability of salmon eggs.

Section: Discussionmentioning

confidence: 99%

Relationship between salmon egg subsidy and the distribution of an avian predator

Katahira

Miura

et al. 2022

Preprint

As a spatial subsidy, which is the phenomenon of transferring resources from a donor system to a recipient system, anadromous salmonids contribute to the supply of marine-derived nutrients to freshwater and terrestrial systems. Live salmon and salmon carcasses and eggs are utilized by various organisms and affect their abundance and distribution. However, the evaluation of the effect of salmon subsidies on the abundance and distribution of terrestrial animals is biased towards predators or scavengers that utilize spawning adults and carcasses, and few studies have focused on the effect of salmon eggs as a subsidy. To avoid underestimating the function of salmon subsidies, the response to the availability of salmon eggs in various systems should be investigated. Here, we investigated the abundance and feeding behaviour of the brown dipper Cinclus pallasii, as salmon egg a consumer, based on the hypothesis that the availability of salmon eggs affects the diet composition and stream distribution of this small predator. In addition, to test whether changes in the abundance of brown dippers are determined by salmon spawning or by other factors, their abundance was compared upstream and downstream of the dam. Brown dippers used salmon eggs during the spawning season (63% of diet composition), and their abundance increased as the number of spawning redds increased. In contrast, this pattern was not observed upstream of the dam. These results suggested that the abundance and stream distribution of brown dippers vary according to the variation in the spatiotemporal availability of salmon eggs.