Spawning behaviour of Sakhalin taimen, Parahucho perryi, from northern Hokkaido, Japan

Abstract

A video camera mounted in an underwater housing and remotely operated was used to monitor the behaviour of five different Sakhalin taimen (Parahucho perryi), females and attendant males spawning in three coastal tributary streams in Northern Hokkaido, Japan. Based on three complete and two incomplete spawnings, we describe in detail for the first time the complete spawning behavioural repertoire of this species. The Sakhalin taimen was originally placed within Hucho, then removed from that genus based on morphological, life history and molecular data. Our study supports that removal-none of the behavioural traits we recorded clustered Parahucho with Hucho uniquely. Similarities between the two genera were all plesiomorphic traits that are widespread throughout the salmonines. The immediate behaviour right after spawning was found to be a major difference between Hucho and Parahucho. Like female Oncorhynchus and Salmo, Sakhalin taimen females cover their eggs by beats of their tails immediately after spawning. This is different from the "rest, then cover" behaviour shown by Siberian taimen (Hucho taimen) as well as lenok (Brachymystax lenok), supporting again that the Sakhalin taimen be removed from Hucho and placed in its own genus.

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).…”

Spawning behaviour of amemasu charr, Salvelinus leucomaenis leucomaenis, with a discussion of the macroevolutionary patterns of postspawning behaviour in the Salmoninae

“…During the undulating process, very often the tail, anal and ventral fins are pressed against the gravel, effectively moving loose pebbles inward towards the centre of the pit (Greeley 1932; observations in this study). For example, Salvelinus species very often breed in lakes, but for Parahucho, Salmo or Oncorhynchus species, still-water spawning is exceptional (Watson 1999;Esteve et al 2009b). Even if undulating does function to cover the eggs quickly after oviposition, why undulating in Salvelinus, and not an advance of cover digging as in Parahucho + Salmo + Oncorhynchus?…”

“…This behaviour, called undulating (cf. Undulating separates Salvelinus from salmonines that either immediately cover their eggs by beats of their tail (cover digging: Salmo, Oncorhynchus and Parahucho) or rest for a variable number of minutes before covering the eggs (resting: Hucho and Brachymystax; Esteve et al 2009b). After a few minutes of undulating, females switch to normal tail diggings that are invariably performed a few centimetres upstream from the nest (Greeley 1932;Frost 1965).…”