The structure and dimensions of redds and egg pockets of the endangered salmonid, Sakhalin taimen

Abstract

Each redd of the Sakhalin taimen Hucho perryi had a V-shaped pot that is specific to this species. The shape of each multiple-egg-pocket redd was a combination of one-egg-pocket redds, and the number of egg pockets in the redd could be estimated from the shape. False redds were small and did not have any V-shaped pots. The factors affecting redd size were examined numerically; consequently, numbers of egg pockets and eggs and female fork length were correlated significantly with tail length. Each egg pocket contained 11-920 eggs (mean: 546·7 95% CL 81·9) and the egg pocket depth was correlated significantly with female fork length. Mean number of redds per female was three, and the number of females could be estimated as one third of the redds. 2000 The Fisheries Society of the British Isles

Observations of Spawning Behaviour in Salmoninae: Salmo, Oncorhynchus and Salvelinus

“…As a result a depression enclosed in elevated rims is formed approximately in the middle of the cleared elliptical area. This depression constitutes the pit where eggs will be laid (Burner, 1951;Crisp and Carling, 1989;Edo et al, 2000;Quinn, 2005). Detailed descriptions of digging behaviour for particular species can be found throughout the literature (Needham and Taft, 1934;Jones and King, 1950;Fabricius and Gustafson, 1954;McCart, 1969;Hartman, 1970;Legget, 1980).…”

Migration history of Sakhalin taimen Hucho perryi captured in the Sea of Okhotsk, northern Japan, using otolith Sr:Ca ratios

“…However, information about the life history of anadromous Sakhalin taimen is still limited with only a few studies being done on ecological aspects of their freshwater phases [8][9][10][11], the morphology of anadromous Sakhalin taimen [12], or on the microchemistry of the otoliths and scales [13][14][15]. Fish otoliths are metabolically inert with the aragonite mineralogy remaining unaltered after deposition [16], so the elemental composition of the otolith reflects to some degree the environment of the water in which the fish lives [17].…”

Life history and migration of Sakhalin taimen, Hucho perryi, caught from Lake Akkeshi in eastern Hokkaido, Japan, as revealed by Sr:Ca ratios of otoliths

“…Hucho perryi is the largest freshwater fish in Japan and is the only Hucho species with an anadromous form (Gritsenko et al 1974;Holčík et al 1988). In addition, this species is an iteroparous salmonid that spawns primarily from March to June in far upstream regions in Hokkaido Island (Fukushima 1994(Fukushima , 2001Edo et al 2000;Esteve et al 2009). Not only adult H. perryi but also juveniles utilize a wide range of habitats, from upstream to coastal waters (Yamashiro 1965;Kimura 1966;Gritsenko et al 1974;Kawamula et al 1983;Sagawa et al 2002Sagawa et al , 2003Edo et al 2005;Honda et al 2009).…”