Reproductive ability of triploid ornamental (koi) carp ( Cyprinus carpio L.) × goldfish ( Carassius auratus L.) hybrids and characteristics of their offspring

Abstract

The purpose of this study was to investigate reproductive ability of backcross triploid koi (Cyprinus carpio L.) × goldfish (Carassius auratus L.) hybrids. These triploids have been obtained by crossing of F 1 hybrid females producing diploid eggs with males of parental species. Triploid hybrid females, when crossed with goldfish or koi males, produced mostly aneuploid fish with ploidy range from approximately 2.2n-3.2n with a mean value 2.5n; some fish in crosses of triploid females with koi males were tetraploid (4.0n). Since analysed fish had in their genomes one haploid set from parental males, the data indicate that triploid hybrid females mostly produced aneuploid eggs with ploidy range from approximately 1.2n-2.2n and a mean ploidy around 1.5n while some eggs were triploid. Triploid hybrid males were completely sterile and have not released any sperm after hormonal injection. Despite their low viability, some aneuploid fish obtained from triploid hybrid females were raised in indoor recirculating systems until the age of 2 years and their reproductive ability has been evaluated. One aneuploid female with ploidy 2.1n produced larvae with ploidy range from 2.9n to 3.4n with a mean ploidy of 3.1n when crossed with a koi male; about 60% of obtained larvae had ploidy from 3.0n to 3.2n. These data indicate that this female produced mostly eggs with unreduced ploidy level. K E Y W O R D S common carp, goldfish, hybrids, koi, ploidy, reproductive ability How to cite this article: Kramer AG, Gomelsky B, Warner JL, Novelo ND, Thomas BL. Reproductive ability of triploid ornamental (koi) carp (Cyprinus carpio L.) × goldfish (Carassius auratus L.) hybrids and characteristics of their offspring. Aquac

Inheritance and Expression of Koi Color Dominant Mutations in Koi × Goldfish Hybrids

“…Earlier, it was reported (Durborow et al 2008;Durborow 2014) that stocking koi (variant of Common Carp Cyprinus carpio) in ponds and recreational water bodies reduces the occurrence of vexatious submersed aquatic weeds and filamentous algae by keeping the water turbid. Using koi × Goldfish hybrids (koi × Goldfish Carassius auratus) for this purpose should have some advantage compared with using pure Common Carp due to the reduced fertility of hybrids (Gomelsky et al 2012;Kramer et al 2020). Previously, Gomelsky et al (2012) reported that koi × Goldfish hybrids had a dark, wild-type color.…”