19 Result(s)

Chapter

Partial Migration in Salmonids: Focusing on Asian Endemic Masu Salmon (Oncorhynchus masou) and White-Spotted Charr (Salvelinus leucomaenis)

Partial migration is perhaps one of the most striking features of life-history polymorphism, in which a population displays both migratory and resident behavior. Not surprisingly, both plasticity and genetics ...

Genki Sahashi, Kentaro Morita in Advances in the Ecology of Stream-Dwelling Salmonids (2024)

Article

Size-dependent growth tactics of a partially migratory fish before migration

In many migratory species, smaller migrants suffer higher mortality rates during the risky migration. To minimize the size-selective mortality, migrants with smaller body sizes would need to accelerate growth ...

Ryo Futamura, Kentaro Morita, Yoichiro Kanno, Shoji Kumikawa, Yuichi Matsuoka… in Oecologia (2022)

Article

Occurrence of mature male white-spotted charr (Salvelinus leucomaenis) in spring, an unusual season

Ryo Futamura, Kentaro Morita, Koume Araki, Masato Ayumi… in Ichthyological Research (2022)

Article

Japanese eel at the northern edge: glass eel migration into a river on Hokkaido, Japan

Kentaro Morita, Mari Kuroki in Ichthyological Research (2021)

Article

Ongoing localized extinctions of stream-dwelling white-spotted charr populations in small dammed-off habitats of Hokkaido Island, Japan

Habitat fragmentation caused by damming can greatly reduce the population viability of aquatic organisms, with smaller fragmented populations at higher risk of extinction due to increased demographic, genetic,...

Kentaro Morita, Genki Sahashi, Masaki Miya, Shouko Kamada, Takashi Kanbe… in Hydrobiologia (2019)

Article

Spatial and temporal changes in genetic structure and diversity of isolated white-spotted charr (Salvelinus leucomaenis) populations

In Japan, numerous artificial dams constructed for erosion control or hydroelectric power generation have affected almost all rivers and resulted in isolation and fragmentation of many freshwater fish populati...

Shoichiro Yamamoto, Kentaro Morita, Genki Sahashi in Hydrobiologia (2019)

Article

Spatial expansion and increased population density of masu salmon parr independent of river restoration

Spatial expansion and increased population abundance of masu salmon Oncorhynchus masou have been recently reported following habitat restoration in some rivers, but no studies have examined these types of changes...

Genki Sahashi, Kentaro Morita, Daisuke Kishi in Ichthyological Research (2018)

Article

Sexual size dimorphism in a landlocked Pacific salmon in relation to breeding habitat features

Many animal species exhibit size dimorphism between sexes. Sexual selection, whereby male–male competition favors larger body sizes, has been considered a likely cause of sexual size dimorphism. Habitat featur...

Kentaro Morita, Jun-ichi Tsuboi in Evolutionary Ecology (2017)

Article

Altitudinal niche partitioning between white-spotted charr (Salvelinus leucomaenis) and masu salmon (Oncorhynchus masou) in a Japanese river

White-spotted charr (Salvelinus leucomaenis) typically occupy the upstream reaches of Japanese streams, whereas masu salmon (Oncorhynchus masou) are generally found downstream. Temperature varies predictably with...

Kentaro Morita, Genki Sahashi, Jun-ichi Tsuboi in Hydrobiologia (2016)

Article

Potential threat of introduced rainbow trout Oncorhynchus mykiss to native salmonids in the western part of Hokkaido, Japan

We obtained the following five results in 10 rivers while elucidating the potential threat of introduced rainbow trout to native salmonids. First, native salmonid density decreased with increasing trout densit...

Genki Sahashi, Kentaro Morita in Ichthyological Research (2016)

Article

Fall–winter collection of two salmonid species: seasonal changes in population densities in four tributaries of the Kushiro river system

Genki Sahashi, Kentaro Morita in Ichthyological Research (2014)

Article

Seasonal changes in stream salmonid population densities in two tributaries of a boreal river in northern Japan

We examined seasonal changes in population densities of stream salmonids (masu salmon Oncorhynchus masou, white-spotted charr Salvelinus leucomaenis, and rainbow trout O. mykiss) in two tributaries of the Shoro R...

Kentaro Morita, Shoko H. Morita, Toru Nagasawa in Ichthyological Research (2011)

Article

Habitat fragmentation by damming threatens coexistence of stream-dwelling charr and salmon in the Fuji River, Japan

Habitat fragmentation by damming can affect the persistence of single species population and also coexistence of two or more species through intensified competition. This study examined the effects of habitat ...

Jun-ichi Tsuboi, Shinsuke Endou, Kentaro Morita in Hydrobiologia (2010)

Article

Effects of habitat fragmentation by damming on salmonid fishes: lessons from white-spotted charr in Japan

Dam construction has serious consequences, and one of the most serious concerns is the fragmentation of riverine ecosystems. We reviewed the influence of habitat fragmentation on white-spotted charr Salvelinus le...

Kentaro Morita, Shoko H. Morita, Shoichiro Yamamoto in Ecological Research (2009)

Article

Evidence of downstream migration of Sakhalin taimen, Hucho perryi, as revealed by Sr : Ca ratios of otolith

The migratory history of Sakhalin taimen, Hucho perryi, was examined in terms of strontium (Sr) and calcium (Ca) uptake in the otolith by using wavelength dispersive X-ray spectrometry on an electron microprobe. ...

Takaomi Arai, Aya Kotake, Kentaro Morita in Ichthyological Research (2004)

Article

Marine growth and survival of white-spotted charr,Salvelinus leucomaenis, in relation to smolt size

The relationships between marine growth and survival, and smolt sizes were examined for white-spotted charr (Salvelinus leucomaenis) populations in the Nairo River, Rebun Island, off northern Hokkaido Island, and...

Shoichiro Yamamoto, Kentaro Morita, Akira Goto in Ichthyological Research (1999)