Induction and viability of tetraploids in brook trout (Salvelinus fontinalis).

Brook trout (Salvelinus fontinalis) populations are threatened by introduction of invasive species, habitat loss, and habitat degradation in their native range; and are a problem invasive species in western Unites States and Canada, and in Europe. Stocking sterile triploids has been promoted as an approach to reduce negative effects of stocking of brook trout for recreational fishing on native fish populations. Crossing a tetraploid with a diploid is a method of triploid production that may help hatcheries meet demand. We induced tetraploidy in brook trout by application of 633 kg∙cm-2 of hydrostatic pressure for 8 minutes at 70-72.5% of the first cleavage interval. Yields of above 50% tetraploid progeny at hatching were readily achieved although few animals reached one year of age. We crossed a male tetraploid with female diploid fish and produced interploid-triploids with eyeing rates in excess of 50%, demonstrating male tetraploids are fertile and capable of siring triploid progeny. Female tetraploid fish were reared to 16 months post-hatching and possessed follicles in secondary vitellogenesis, suggesting tetraploid females are also fertile. Tetraploid induction rates in excess of 96% were achieved applying the same hydrostatic pressure treatment to zygotes of tetraploid x diploid crosses at 30 minutes post-fertilization.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author