Reproductive sensitivity to elevated water temperatures in female Atlantic salmon is heightened at certain stages of vitellogenesis

Abstract

In order to compare the effects on reproductive performance of short-term or prolonged exposure to elevated temperatures during vitellogenesis, female Atlantic salmon Salmo salar were held at a water temperature of 22°C for periods of 4 or 6 weeks during the austral summer and autumn. Plasma levels of 17b-oestradiol (E 2 ), testosterone (T) and vitellogenin (Vtg) were monitored and reproductive success was compared to that in groups of fish maintained at 14 or 22°C for 12 weeks from mid-January. Significant endocrine effects were observed within as few as 3 days of the commencement of exposure to 22°C, when plasma levels of E 2 (c. 0Á5 ng ml ÿ1 ) and Vtg (c. 1Á4 mg ml ÿ1 ) were approximately half those observed in fish maintained at 14°C (c. 1Á0 ng ml ÿ1 and 2Á7 mg ml ÿ1 respectively). The fertility and survival to the eyed stage of ova from fish held at 14°C exceeded 85 and 70% respectively, whereas ova from fish held at 22°C for 6 or 12 weeks exhibited significantly reduced fertility (<70 and <45% respectively) and survival (c. 40 and 13% respectively). In spite of significant endocrine effects at all stages, a 4 week exposure to 22°C only generated significant reductions in egg fertility (<65%) and survival (c. 30%) when it occurred between mid-February and mid-March. Together, these data confirm that high temperature spikes can affect reproductive success as strongly as more prolonged exposures, and indicate that there is a critical period of reproductive sensitivity to elevated temperature in late February and early March in this stock of Atlantic salmon.

Effects of elevated water temperature and food availability on the reproductive performance of a coral reef fish

“…This was associated with reductions in plasma E 2 levels, and levels of the yolk precursor vitellogenin (in turn synthesized by the liver in response to stimulation by E 2 ) in Atlantic salmon, but no change in plasma E 2 in rainbow trout (Pankhurst et al 1996, Pankhurst & Thomas 1998. Later studies on Atlantic salmon showed that depression of E 2 levels for only part of the period of vitellogenesis could generate reductions in plasma vitellogenin, egg size and subsequent fertility and survival (King et al 2007). It is possible that the same effect has occurred here but has not been detected using only single time point sampling.…”

The importance of parentage in assessing temperature effects on fish early life history: a review of the experimental literature

“…Elevated temperatures can alter the circulating levels of reproductive hormones, which can have downstream effects on ovarian and testicular steroid production (Manning and Kime 1985;King et al 2007). Disrupted steroid synthesis and subsequent alterations in hepatic vitellogenesis can result in reduced maternal investment and gamete viability (Tveiten and Johnsen 1999;King et al 2003).…”

Quality of pejerrey (Odontesthes bonariensis) eggs and larvae in captivity throughout spawning season

“…In this sense, it is known that vitellogenin plasma levels, the precursor of egg yolk, decreased in fish kept at high water temperatures impairing its reproductive activity (King et al, 2007;Pankhurst & King, 2010;Miranda et al, 2013).…”