Size change in male sealions suggest that the predatory pressure over seals was alleviated. This is bad news. It means that Killer whales and white sharks are

Size change in male sealions suggest that the predatory pressure over seals was alleviated. This is bad news. It means that Killer whales and white sharks are silently [1] vanishing. Either they are being hunted by us (or killed by our machines), and/or their preys disappeared by a climatic event, and/or we can suspect a major disease. If this disease extends to the functional category "predator" instead to the taxonomic category "Dolphinidae" the problem lies most probably in the trophic chain, and we can suspect bioaccumulation also. If the big predators that eat fish are going locally extinct, we have a problem, because we are big predators that eat fish. If predators are not anymore to do their jobs, we can safely predict that next-in-list group of preys will start suffering from major epidemics... that lead us directly to summer 2022: "More than 150 sea lions have been found sick or dead along Oregon’s coast due to a bacterial outbreak of Leptospirosis this summer" [2]. "Hundreds of dead or dying sea lions have washed up on the beaches of Peru since January 2023 affected by bird flu" [3] So it seems that what we have here is an ecosystem eroding and collapsing over the next lower level like a house of cards. Probably because there is a serious problem with the trophic chain that lead animals unable to trigger a good immune response. The wave will travel slowly toward the basis until eventually losing momentum and stopping. If the most affected seals were the older ones and the sample was focused in stranded animals, we would have a direct alternative explanation for the bigger skulls: Bad sampling. [1] As they are pelagic and just sink on open sea most of the effect was silent and missed. [2] https://www.opb.org/article/2022/11/04/disease-outbreak-leaves-sea-lions-stranded-on-oregon-coast/ https://www.opb.org/article/2022/11/04/disease-outbreak-leav... [3] https://english.elpais.com/science-tech/2023-02-15/mass-death-of-sea-lions-from-bird-flu-suggests-virus-may-be-spreading-between-mammals-in-the-wild.html https://english.elpais.com/science-tech/2023-02-15/mass-deat...