Inverse Correlation between Ovarian Development of Atlantic Salmon (Salmo salar) Smolts and Sea Age

Abstract

In order to understand the factors which determine sea age of Atlantic salmon (Salmo salar), ovarian development of smolts was examined in 14 groups which varied in parental sea age, smolt age, and size. Parental sea age of smolts explained most of the variation in ovarian development. Smolts from one-sea-winter parents had a higher percentage of the more advanced oocyte stages in their ovaries, while smolts from two-sea-winter parents had a low percentage, and those from three-sea-winter parents had none. Annual within-stock variation and covariance with freshwater age were not significant. Hatchery-reared smolts had similar ovarian development to their wild counterparts. There was also a significant, positive correlation between fork length of smolts and ovarian development within groups.

Gonadal development and associated changes in gonadosomatic index and sex steroids during the reproductive cycle of cultured male and female Caspian brown trout,Salmo trutta caspius(Kessler, 1877)

“…In fish life cycle, the age at first maturity is in relation to genetic properties (Glebe and Saunders 1986;Ritter et al 1988) and biological and environmental factors (Chadwick et al 1986). A negative linear relationship between growth rate and age at first maturation was reported in rainbow trout, Oncorhynchus mykis (Sylven and Elvingson 1991) and Atlantic salmon, Salmo salar (Duncan et al 2002).…”

Identification of follicular vitellogenesis stage by monitoring of plasma calcium and estradiol-17β concentrations in the cultured Caspian brown trout, Salmo trutta caspius Kessler, 1877

“…In fish life cycle, the age at first maturity is in relation to genetic properties (Glebe & Saunders 1986;Ritter et al 1988) and biological and environmental factors (Chadwick et al 1986). A negative linear correlation between growth rate and age at first maturation was reported in rainbow trout, Oncorhynchus mykis (Walbaum, 1792) (Sylven & Elvigson 1991) and Atlantic salmon, Salmo salar (Duncan et al 2002).…”

Relationships between smolt size, postsmolt growth and sea age at maturity in Atlantic salmon ranched in the Baltic Sea

“…To analyse the relationships between growth and maturity, the ratio of grilse (1SW salmon) and multi-sea-winter salmon Sea age in Atlantic salmon 198019811982198319841987198819891990Bothnian Sea 198019811982198319841987198819891990 '1st sea year = time from release to the end of April next year; 2nd year = next 12 months (May-April), and so on. 'Coastal gear or near-shore location.…”

“…Present knowledge of thcse crucial relationships is, however, too vague to be applied to the management of smolt production. A number of authors have found an inverse relationship bctween sea age at first maturity and absolute smolt size (Ritter et al 1986;Hansen and Jonsson 1991;Nicieza and Braiia 1993), whereas others, stressing the significance of genetic factors, have related this age to relative smolt size within a family (Chadwick et al 1987;Skilbrei 1989). Others have emphasized the role of marine conditions in deciding maturation trends (Saunders et al 1983;Friedland and Haas 1996).…”