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Energy allocation among developmental stages, age groups, and types of Atlantic salmon ( Salmo salar ) spawners

2003; Canadian Science Publishing; Volume: 60; Issue: 5 Linguagem: Inglês

10.1139/f03-042

1205-7533

Nina Jönsson, Bror Jönsson,

Marine and fisheries research

Relationships between energy density (kJ·100 g –1 ) and body length (mm), which varied between life-history stages of Atlantic salmon (Salmo salar), were described by power functions. The variation was chiefly caused by differences in lipid concentrations. Energy densities of maturing and rematuring parr were higher than those of similarly aged smolts. Monthly specific growth rate was higher in maturing parr than in salmon at sea. Mature parr males allocated relatively more energy to gonadal development and less to soma development than anadromous males. Spawning expenditure increased from 34 to 53% for 55- to 72-cm-long females. In males, similar losses were from 47 to 49% of their total energy content at river entry. More energy was used in reproduction in a long river than in a short one. Male allocation to gonads relative to soma was highest in the shorter river. Energy allocation pattern varied among developmental stages. Very energy-rich male parr rematured in subsequent years without going to sea; less energy-rich ones smolted and migrated to sea.