Growth of different year classes of smelt Osmerus eperlanus L. in Lake Tyrifjorden, Norway
Main Article Content
Abstract
Smelt Osmerus eperlanus L. were collected during spawning run in May in Lake Tyrifjorden in southern Norway. Age determination was carried out by otoliths. Fish length (Y) and otolith radius (X) were correlated (r = 0.954). Calculation of growth was carried out for 610 mature smelt of age 1 + to age 6+, by using the regression model Y = 81.39 X + 17.95. Females were significantly longer than males, except those of age 4 + and 5 +. The smelt grew about 60 mm in first year and from 20-30 mm in second and third year of growth. Then the growth decreased gradually. The eldest smelt caught were five smelt of age 7 +. Back-calculation of growth indicated differences in growth rates between the year classes, with an apparent steady decrease in yearly growth rate of younger year classes. Natural mortality caused by strong size selective predation from other fish species, is considered to be the cause for this growth pattern.
Downloads
Article Details
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).