Abstract
We present a genome assembly from an individual male Clangula hyemalis (the Long-tailed duck; Chordata; Aves; Anseriformes; Anatidae). The genome sequence spans 1,206.10 megabases. Most of the assembly is scaffolded into 41 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled and is 16.63 kilobases in length.