Domestication and feralization influence the distribution and phenotypes of escaped ornamental fish

Abstract

Domestication has a dominant and increasing influence on the evolutionary trajectory of species, the extent of which may be influenced by advertent selection used to meet consumer demands of the ornamental trade. Ornamental species can have multiple varieties in trade, including those produced without advertent selection for color (i.e., inadvertent selection). Consumer demand for colorful varieties can have invasion consequences because demand is related to propagule pressure and color can exhibit fitness costs. However, domesticated varieties can also adapt to wild conditions through feralization, changing the phenotypes of feral populations. Our objective was to examine how domestication and feralization together influence the feral distribution and phenotypes of two highly domesticated, ornamental poeciliids. We first determined that colorful varieties exhibited higher trade availability and local production than the wild-type variety. Using a multi-year landscape-scale survey, we then determined that colorful varieties are common near sources of production but attenuated at increasing distance, replaced by the wild-type form. Wild-type varieties exhibited trait differences from ornamental varieties, which may affect fitness and result from feralization. Domestication to meet consumer demand influences feral distributions and phenotypes of escaped fish, but only in proximity to sources of production. Feralization influences relative capture rate of ornamental versus wild-type varieties, as well as the traits of captured fish. Thus, there may be a balance between propagule pressure, thought to increase with trade volume, and the pattern of domestication and feralization selection, which affects feral distribution and phenotypes.