Thermolabile Sex Determination in honmoroko

Abstract

In six pairings (one female three males and vice versa) of honmoroko Gnathopogon caerulescens, although in one pairing the sex ratio of the offspring did not deviate significantly from 1 : 1, in four pairings the proportion of females decreased significantly with an increase in temperature. Heavy mortality due to disease was observed in the remaining pair. There were highly significant differences in sex ratios among the broods produced by different mothers with the same father and vice versa, and the response of sex ratio to temperature treatments differed considerably within pairings. The progeny of five out of 20 males produced at 34 C were almost all females, two were male-biased, and the remaining had balanced (1 : 1) sex ratios. These results suggest that the sex determination system in honmoroko is close to female homogamety but is influenced by temperature, genetic factors and genotype-temperature interactions. 2001 The Fisheries Society of the British Isles

Evolutionary Diversity and Turn-Over of Sex Determination in Teleost Fishes

“…For example, several cichlids integrate genetic, environmental, and demographic cues into sex determination [Oldfield, 2005]. Some cyprinids [Fujioka, 2001] as well as the sockeye salmon, Oncorhynchus nerka [Craig et al, 1996], have both sex chromosomes and thermal contributors. Such combination strategies may occur as ephemeral transitional states between the different mechanisms, persisting only as long as it takes a newly emergent sex determining mechanism to replace a more ancient form.…”

Effect of temperature on sex ratio in guppy Poecilia reticulata (Peters 1860)

“…Recently, thermolability of sex differentiation has been established under controlled thermal conditions using normal and putative monosex progeny of various fish species (Strüssman & Patiño 1995). The effect of temperature on sex ratio was also reported by Strüssmann, Saito, Usui, Yamada and Takashima (1997) in two other atherinid fish Odontesthes bonariensis (Valenciennes 1835) and Patagonina hatchery (Eigenmann (1909)); Patiño, Davis, Schoore, Uguz, Strüssmann, Parker, Simco and Goudie (1996) in channel catfish Ictalurus punctatus (Rafinesque); Goto, Mori, Kawamata, Matsubara, Mizuno, Adachi and Yamauchi (1999) in barfin flounder Verasper moseri (Jordan 6 Gilbert); Goto, Kayaba, Adachi and Yamauchi (2000) in marbled sole Limanda yokohamae Günther; Fujioko (2001) in honmoroko Gnathopogon caerulescens Sauvage; Desprez and Mélard (1998) and Mair, Beardmore and Skibinski (1990) in Oreochromis aureus Steindachner and O. mossambicus Peters; Baroiller, Chourrout, Fostier and Jalabert (1995); Baroiller, Fostier, Cauty, Rognon and Jalabert (1996); Abucay, Mair, Skibinski and Beardmore (1999); Baras, Jacobs and Charles (2001) and Karayücel, Penman, Karayücel and McAndrew (2003) in O. niloticus Linneus.…”