May the fishing bears have been all killed by humans? Have you looked on the N status on upper part of rivers? in North America, the bears faeces bring a lot of suppiles to the plants left and right to the remote rivers.

https://www.spiegel.de/wissenschaft/natur/wildlachs-elternkadaver-duengen-kinderbiotop-a-442802.html

The story is in German, but you may translate via google and search for the sources. Maybe the fishing bears could not give their traditions to the youngsters anymore? Maybe there a historically still a ot of N and other materials on the shores? This is just a guess.

Hello Axel,

Thank you for the reference. Yes, Pacific salmon add a huge amount of Nitrogen to ecosystems where they spawn and die, so long as bears and other predators/scavengers eat them, then poop on shore. Atlantic salmon, by contrast, often survive spawning, then return to the sea. So much less salmon flesh to scavenge. So far, no record of bears or wolves preying on Atlantic salmon. Even if people killed off all bears that had the tradition of preying on salmon, new bears would soon figure out that this was a food source. In some streams with shallow water, bears can learn quickly to catch salmon. But in other streams it takes years to develop sufficient skill.

Steve

Hi Steve,

It's nice to read from you! The following answer is not directly to your question, but it is closely related. I know of a lake in Slovenia which dries up completely every year over most of its surface area, leaving parts of the fish populations trapped in enclosed shalow lagoons where they eventually die. There can be very large numbers of them at scecific years. Both wild boar and bears are known to feast on these fish. In the past, they were also fed to domestic pigs. The lake itself and its phenomenon (a carst lake, operating as sinkhole, and as a spring) was first described centuries ago. It was described by Baron Janez Vajkard Valvazor, member of the Royal Society in London. The lake is certainly worth a visit. Although the case of fish feeding/scavenging by bears is well known, it has not been described in an article that I am aware of.

Best regards, K

Hello Stephen,

I've never heard and don't know any literature describing a bear preying/preyed on Atlantic salmon for the European part of Russia. I think that the critical biomass of Atlantic salmon going to spawn is not enough to form this habit in bears, well, as mentioned above, this fish does not die after spawning. But an even more interesting situation for me was introduced and finally, after decades, naturalized humpback salmon. For many years, the low temperature in the rivers of the Kola Peninsula (and not only) did not allow the formation of a stable reproducing humpback salmon population, but since the 2000s the rivers have warmed up. Since that time, the peaks in the number of pink salmon have been getting higher and higher. Ten years ago for two years we checked rivers to watch fishing bears but nothing. We checked ca. 500 feces to find fish remains and nothing. But 10 years ago the number of humpbacks were much less. Till nowadays I don't get any real evidence of fishing bears. But I know that they feast on fish carcasses. Humpback salmon has a 2-years life cycle, so maybe even one year lapse is the key factor to block the new habit arise.

Best wishes,

Hello Konstatin,

Thanks for your insights. Quite valuable for understanding bear ecology and the role of tradition.

Steve