Influence of temperature on number of circuli of first year scales of brown trout, Salmo trutta L.
Article first published online: 24 JAN 2006
Journal of Fish Biology
Volume 26, Issue 3, pages 363–366, March 1985
How to Cite
Skurdal, J. and Andersen, R. (1985), Influence of temperature on number of circuli of first year scales of brown trout, Salmo trutta L. Journal of Fish Biology, 26: 363–366. doi: 10.1111/j.1095-8649.1985.tb04275.x
- Issue published online: 24 JAN 2006
- Article first published online: 24 JAN 2006
- (Received 30 March 1984, Accepted4 July 1984)
We studied the number of circuli of first year scales in brown trout fry originating from eggs and alevins incubated at 2 °C and 7 °C. During the first 31/2 months the 7 °C fry were reared at a lower temperature than the 2 °C fry whereas temperature was identical during subsequent months. The numbers of circuli increased with body length in both groups. However, both the number of circuli and the rate of circuli formation were higher in the group incubated at 7 °C and varied between 2 and 9 in the 2 °C–group and 5 to 14 in the 7 °C group. Differences among natural populations in the number of first year circuli may therefore be due to differences in incubation temperature. Experimental manipulation with incubation temperature can be used to mark large numbers offish permanently at low cost with a minimum of handling and hatchery stress.