The Physiological Costs of Reproduction in a Capital Breeding Fish

Kim Birnie-Gauvin, Carsten Berthelsen, Torben Larsen, Kim Aarestrup

Research output: Contribution to journalJournal articleResearchpeer-review


Reproduction represents the most energetically demanding period of life for many organisms. Capital breeders, such as anad-romous sea trout (Salmo trutta), provide a particularly interesting group of organisms to study within the context of reproduction because they rely on energy stores accrued before breeding to reproduce and sustain all phenotypic and behavioral changes related to reproduction. Energy allocation into current reproduction therefore cannot be mitigated via food intake, resulting in an important life history trade-off. For this reason, exploring indexes related to energetics in salmonids can provide powerful insights into the physiological costs of reproduction. In this study, we sampled blood from and PIT tagged 232 fish captured in the wild before the spawning season. We recaptured and resampled 74 individuals (53 females and 21 males) at the end of the spawning season. Females were further divided into spawning phases (non-spawned, partially spawned, and spawned individuals), though males could not be classified as such. We compared nutritional correlates (triglycerides, cholesterol, calcium, inorganic phosphorus, and total protein), stress correlates (cortisol, sodium, potassium, chloride, and glucose), and indexes of tissue damage (aspartate aminotransferase) between initial capture and recapture as well as among spawning phases in females. We found that nutritional status decreased in all fish throughout the spawning season but that it was substantially lower in females that had spawned. We further found that spawning itself appears stressful, with elevated glucose in partially spawned females and elevated cortisol in male sea trout at recapture. Our findings thus support the idea that the cost of reproduction is energetically high and that incurred stress and a decrease in nutritional status are important physiological costs.
Original languageEnglish
JournalPhysiological and Biochemical Zoology
Issue number1
Pages (from-to)40-52
Number of pages13
Publication statusPublished - 2023


  • Anadromy
  • Energetics
  • Migration
  • Spawning
  • Salmo trutta
  • Stress
  • Tissue damage


Dive into the research topics of 'The Physiological Costs of Reproduction in a Capital Breeding Fish'. Together they form a unique fingerprint.

Cite this