As our readers know, I disagree with the rabbinical ban on sturgeon, shrimp, and oysters. Sturgeon, like every other fish up to eel, has rudimentary scales; only sea mammals are truly non-kosher. Shrimp have both scales and fin-like tentacles, and are thus also kosher. Oysters lack heads, blood, or hearts, and thus are not living creatures by the Torah’s definition.

But in another area kosher laws are insufficiently strict: salmon roe. Salmon roe is traditionally permitted for food, but it must be forbidden beyond doubt. The Torah famously prohibits us from killing a bird to take eggs from its nest. This hint is bolstered by yet another prohibition, to cook a young goat in its mother’s milk.

Is salmon roe kosher?

Merely killing a pregnant animal is not prohibited: honest mistakes would be unavoidable, and if one is hunting gazelles there is simply no way to tell reliably from a distance whether they are pregnant. Rather, the Torah prohibits the killing of a mother to make use of its eggs or offspring.

This difference allows us to eat pike or carp roe. These are fished in bulk mainly for meat, and generally it is not feasible to single out and release the pregnant fish. If one is fishing with a rod and skilled enough to distinguish a fatty male carp from a pregnant female, releasing such females is obligatory because their roe is more valuable and tasty than their meat and they are going to be killed primarily for the roe.

It is different with salmon, whose meat is worthless at the time of spawning, which means that they are deliberately killed for their roe. There is no logical difference between killing a bird to get its eggs and killing a salmon to get its roe. Indeed, the bird would at least be eaten, which could provide some excuse for killing it, while in the case of salmon the fish is being killed solely for its roe.

Whether the spawning fish is utilized after it is emptied of its roe is irrelevant. The only test is whether roe-harvesting is the primary objective in fishing in the same way that taking eggs from a nest is the primary objective when killing a mother bird.

On other hand, if you want the roe badly, you may note that the spawning fish is going to die anyway, and fishing just brings this inevitable outcome a few days closer. This logic, reportedly, is applicable to the Pacific, but not Atlantic salmon which often survives the spawning.

Fine roe seems to be kosher: the salmon is fished out in the early stages of spawning, still in the sea, when its roe is small and flesh is good. At that time, salmon is fished mainly for its flesh, with roe being acquired as useful byproduct. Some species of salmon have fine roe even at late stages of spawning, so in practice small roe is not necessarily kosher. Marking the salmon species on cans may establish whether the particular fine roe is kosher. Large roe is always non-kosher.