Proximate composition of the river lamprey, Lampetra fluviatilis , during the spawning run

• Published in: Canadian Journal of Zoology
• Main Authors: Heikkala, R. M., Laukkanen, A. T., Mikkonen, A. V.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1984
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Northern Finland
• Online Access: http://dx.doi.org/10.1139/z84-330; http://www.nrcresearchpress.com/doi/pdf/10.1139/z84-330

The composition of the muscle, liver, and gonads of adult river lampreys (Lampetra fluviatilis L.) was studied in northern Finland from the beginning of the spawning run in August–September until the end of the spawning season in late May or early June of the following spring. During the spawning run period, which may last for9–10 months, lampreys spend 6 months in water with a temperature around 0 °C. These harsh physical circumstances only have remarkable delaying or economizing effects on the results when compared with findings on lampreys with a shorter spawning run. The locomotor activity of the lamprey was very minor during the winter, and so it did not need greater than 10–15% wet weight (w.w.) muscular lipid reserves as an energy source for swimming. The gonads were well developed; i.e., the gonadosomic index was 5% in males and 11% in females at the beginning of the spawning run (9 and 26%, respectively, during the spawning time) and, as a result, the lipid concentration of liver, where vitellogenesis takes place, was not greater than 15% w.w. in males and 5% w.w. in females. Our results suggested that after wintering in the northernmost parts of the species' range, river lampreys were prepared for the rapid start of spawning in the spring, as soon as the water temperature was appropriate.