Environmental Biology of Fishes

, Volume 58, Issue 1, pp 61–73

Evidence for Morphometric Differentiation of Wild and Captively Reared Adult Coho Salmon: A Geometric Analysis

  • Jeffrey J. Hard
  • Barry A. Berejikian
  • Eugene P. Tezak
  • Steven L. Schroder
  • Curtis M. Knudsen
  • L. Ted Parker
Article

DOI: 10.1023/A:1007646332666

Cite this article as:
Hard, J.J., Berejikian, B.A., Tezak, E.P. et al. Environmental Biology of Fishes (2000) 58: 61. doi:10.1023/A:1007646332666

Abstract

As part of a comprehensive genetic evaluation of reproduction in naturally spawning coho salmon, Oncorhynchus kisutch, we examined morphometric variation in captively reared and wild adults from Hood Canal, Washington (U.S.A.) for evidence of differentiation between these groups. We collected captively reared fish as parr from two stocks and reared to adulthood at a freshwater hatchery, maturing in 1995 and 1996; we sampled closely size-matched wild fish as they returned to a neighboring stream in both years. Multivariate analysis of shape variation by Procrustes coordinates, visualized by thin-plate splines, indicated that the captively reared adults were differentiated from the wild fish by sharply reduced sexual dimorphism as well as smaller heads and less hooked snouts, increased trunk depth, larger caudal peduncles, shorter dorsal fins, larger hindbodies and a reduction in body streamlining. The differences between the captively reared and wild fish were similar to but more pronounced than some differences previously reported between hatchery and wild coho salmon. The magnitude and pattern of differences suggested that at least some of them were environmentally induced. Shape variation showed an allometric relationship with variation in body (measured as centroid) size. Morphometric variation was a poor correlate of most spawning behaviors. Nevertheless, our results suggest that the morphometric consequences of captive rearing for mate selection and reproductive activity of spawning fish may limit its effectiveness as a restorative tool.

relative warpsthin-plate splinedomesticationreproductive behaviorsalmonid fish

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • Jeffrey J. Hard
    • 1
  • Barry A. Berejikian
    • 2
  • Eugene P. Tezak
    • 2
  • Steven L. Schroder
    • 3
  • Curtis M. Knudsen
    • 3
  • L. Ted Parker
    • 4
  1. 1.National Marine Fisheries ServiceNorthwest Fisheries Science CenterSeattleU.S.A.
  2. 2.National Marine Fisheries ServiceManchester Marine Experimental StationManchesterU.S.A.
  3. 3.Washington Department of Fish and WildlifeOlympiaU.S.A.
  4. 4.Frank Orth and Associates, Inc.BellevueU.S.A.