Photothermal control of the reproductive cycle in temperate fishes

Abstract

Temperate fish species are annual spawners and mainly rely on annually cycling cues (temperature and photoperiod) to synchronise the three main phases of their reproductive cycle, that is, induction (initiation of oogenesis), vitellogenesis and the final stages (including maturation, ovulation and oviposition). This review synthesises how these three phases are controlled by specific temperature and photoperiod variations. The direction of the changes (i.e. decrease or increase) is the most important factor, although the amplitude, rates and timing of variations should also be considered to improve/optimise the quality of reproduction in aquaculture. In addition, we tentatively classified temperate fish species sharing similar temperature and/or photoperiod variation requirements for reproduction into three general functional groups. The first group (salmonids) is induced by increasing photoperiod. Vitellogenesis and the final stages are synchronised by decreasing photoperiod. The second group (percids, moronids and gadids) is induced by decreasing both temperature and photoperiod. A chilling period allows vitellogenesis. Increasing temperatures synchronise the final stages. The third group (cyprinids) is induced by decreasing either photoperiod or temperature. Vitellogenesis is faster at warm temperatures. The final stages require an increase in either photoperiod or temperature. This classification may help future research on the control of reproduction in newly cultured fish species.

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“…Two long keeping the spawners in too low temperature (control groups) did not caused ovulation. From environmental factors, the most important of fish reproduction are environmental conditions and their changes (Brooks et al, 1997;Bromage et al, 2001;Angius and Canavate, 2005;Wang et al, 2010;Nowosad et al, 2014a,b), feeding brooders before the reproduction period (Król et al, 2014;Kucharczyk et al, 2014), applying the right hormonal stimulation in order to induce final gamete maturation (Podhorec and Kouril, 2009), origin of fish or a combination of these factors (Nowosad et al, 2014a(Nowosad et al, , 2015. Depending on the species, the most important conditions include temperature and its regime or the photoperiod and its regime.…”

“…The thermal conditions play a crucial role during the initial phase of stimulation of fish maturing under controlled conditions. Improperly chosen thermal conditions as well as their fluctuations either delay spawning or cause gametes to mature with defects (Wang et al, 2010;Targońska et al, 2010Targońska et al, , 2012Nowosad et al, 2014a). Final gamete maturation, especially in cyprinids, is induced by hormonal stimulation (Yaron, 1995;Policar et al, 2007; (Kahkesh et al,2010;Targońska et al, 2011b).…”

Annual variations in hepatic antioxidant defenses and lipid peroxidation in a temperate fish, common bream Abramis brama (L.)

“…In the obvious absence of temperature compensation on the enzymatic activities, one might consider a cueing role of photoperiod. Temperate fish's fundamental metabolic processes are driven to maintain seasonality in reproduction; photoperiod is an important synchronizing factor inducing changes in trends and rates of metabolism (Shulman and Love 1999; Wang et al 2010). The second possible explanation of the observed elevation of the antioxidant levels might be the fish's response to hypoxia termed ''preparation to oxidative stress'' (HermesLima et al 1998).…”

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“…The environmental control of reproduction in fish has great interest for the development of aquaculture industry (Wang et al, 2010). Photoperiod and water temperature show theirs effect on gonadal development through endocrine system that controls reproduction.…”

“…In fish farms, photothermal programs are commonly used to control reproductive cycle and to obtain larvae all year round (Wang et al, 2010). The ability to control spawning has enabled supplies of seed for fish farms during the year (Bromage and Roberts, 1995).…”