Effect of elevated summer temperatures on gonadal steroid production, vitellogenesis and egg quality in female Atlantic salmon
✍ Scribed by H. R. King; N. W. Pankhurst; M. Watts; P. M. Pankhurst
- Book ID
- 104455648
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 858 KB
- Volume
- 63
- Category
- Article
- ISSN
- 0022-1112
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✦ Synopsis
Groups of Tasmanian female Atlantic salmon Salmo salar L. were maintained at 14, 18 and 22° C for 3 months from mid‐summer (January). Blood plasma levels of 17β‐oestradiol (E~2~), testosterone (T), cortisol and vitellogenin (Vtg) were measured at regular intervals, and in autumn (April) temperatures were reduced to 8° C to facilitate spawning and egg incubation. Maintenance at 22° C during vitellogenesis was associated with a general reduction in plasma E~2~ levels and an early reduction in plasma Vtg levels relative to those observed in fish held at 14 and 18° C. Significantly reduced oocyte diameters in ova from fish held at 22° C (5·4 mm cf. 5·7 mm) confirmed reduced maternal investment, and an increase in the incidence of previously undescribed chorion damage suggested that zonagenesis may also have been impaired. As a result, the fertility and survival of ova from fish exposed to 22° C (69 and 42%, respectively) were significantly reduced relative to those of ova from fish maintained at 14° C (93 and 86%) and 18° C (86 and 84%).