They are members of the cod family, with a mild taste and few bones.
There are at least a dozen species of fish called “hake” belonging to the family Merlucciidae (both subfamilies Merlucciinae and Steindachneriinae) or the or family Gadidae (subfamily Phycinae.) They live in both the Pacific and Atlantic.
Some Hake are considered very high end, with sweet, flaky flesh: among these are European hake (M. merluccius), South African hake (M. capensis) and a big hake from southern Chile (M. australis.)
At the low end, Argentine hake (Merluccius hubbsi), Chilean hake (M. gayii) and Pacific whiting (M. productus) have greyish flesh, and are fatty, with a taste that people don’t like that puts people off all Hake.
South African is being sold as “Cape capensis” and southern Chilean M. australis as “Antarctic queen” to distinguish them from the pack.
Sosebee, Kathy. White hake (Urophycis tenuis). NEFSC – Resource Evaluation and Assessment Division. December 2006.