Get access

Rainbow trout (Oncorhynchus mykiss, Walbaum ) develop a more robust body shape under organic rearing

Authors

  • Domitilla Pulcini,

    Corresponding author
    1. Laboratory of Experimental Ecology and Aquaculture, Department of Biology, University of Rome ‘Tor Vergata’, Rome, Italy
    • Correspondence: D Pulcini, Laboratory of Experimental Ecology and Aquaculture, Department of Biology, University of Rome ‘Tor Vergata’, via della Ricerca Scientifica s.n.c., 00133 Rome, Italy. E-mail: domitillapulcini@fastwebnet.it

    Search for more papers by this author
  • Tommaso Russo,

    1. Laboratory of Experimental Ecology and Aquaculture, Department of Biology, University of Rome ‘Tor Vergata’, Rome, Italy
    Search for more papers by this author
  • Paola Reale,

    1. Laboratory of Experimental Ecology and Aquaculture, Department of Biology, University of Rome ‘Tor Vergata’, Rome, Italy
    Search for more papers by this author
  • Alexia Massa-Gallucci,

    1. UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
    Search for more papers by this author
  • Grace Brennan,

    1. UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
    Search for more papers by this author
  • Stefano Cataudella

    1. Laboratory of Experimental Ecology and Aquaculture, Department of Biology, University of Rome ‘Tor Vergata’, Rome, Italy
    Search for more papers by this author

Abstract

Prolonged exposure to captive conditions has led to the development of a rainbow trout ‘farmed’ phenotype, which is different from that of wild trout. Selection for desirable productive traits in hatcheries has resulted in the development of some morphological traits that are maladaptive in nature. The recent development of organic aquaculture, guided by the well-being of the fish, could potentially produce a new farmed phenotype that would be more adaptive in nature. In this study, rainbow trout reared in intensive and organic farms were compared by means of shape analysis, to detect patterns of shape variation associated with rearing environment. The results of this study highlight a significant effect of the rearing method on rainbow trout shape: organically reared trout showed a higher body profile, in particular in the head and trunk regions, shorter median fins and a deeper caudal peduncle. A combined effect of density and habitat complexity could have contributed to the observed shape differences: in organic rearing systems, lower densities and steady water could increase territoriality and aggressive interactions, promoting body designs more functional in rapid attacks and escapes.

Ancillary