This question comes up all the time. What actually happened around 40,000 years ago. The old chestnust that Neanderthals were conservative in their diet no longer holds true – from a variety of evidence from different sites (but see http://phys.org/print298626001.html). A cave in the Caucasus mountains suggests Neanderthals were eating fish – or so it is theorised. It is assumed the fish were brought to the cave by humans for consumption – how else might they have got there. How else indeed. In this case they were salmon – and these were big salmon in the process of migrating up river to spawn. Bones of cave bears and cave lions were found in the same layer and an isotopic analysis has shown these had not eaten the fish. The bears had a vegetarian diet and the lions preyed on herbivores. Hence, it has been assumed humans must have ate the salmon (and left the bones behind). As modern humans had not at that time reached the Caucasus, or so it is thought, the culprits must have been the earlier Neanderthals. The idea the salmon remains, along with the bears and lions, were killed during a catastrophic event, does not appear to have been considered. Therefore the claim Neanderthals relished eating salmon will enter the literature with hardly a ripple – but did they? There is no reason to say they did not eat a varied diet – this is in fact suggested at other sites, so in the grand scheme of things it matters little how the bones are interpreted. However, if the deposit has a catastrophic origin of some kind, a major storm event for example, that link is lost if it is allowed to be brushed aside so easily.
I have only seen the abstract. Perhaps actual Neanderthal remains have been found in proximity to the other bones – but this is not how it is presented to the public.