Salty Snackers

 The number of saltwater crocodiles in Australia's Northern Territory has surged from less than 3000 in 1971 to more than 100,000. These cold-blooded apex predators each consume fewer prey than warm-blooded  equivalent (e.g. lions). Their numbers, however, mean that, whereas they consumed less then 20 kg of prey per square kilometre in 1979, in 2019 that figure rose to 180 kg. Crocs are now largely taking land animals, including feral pigs, cattle and Asian water buffalo, rather than feeding on fish. This has led, over a 50 year period, to massive increases in nitrogen and phosphorus (186 and 50 fold, respectively) released into Northern Territory waterways. There's consequently a much increased probability of eutrophication. This substantial algal growth, removes oxygen from the water, killing many organisms including fish  (https://www.theguardian.com/environment/2025/mar/12/northern-territory-growing-saltwater-crocodile-population-gorging-on-nine-times-more-prey-than-50-years-ago). It's, of course, very difficult to determine an appropriate density of saltwater crocodiles in this area. Too few apex predators can also be problematic. Feral pigs, cattle and Asian water buffalo are all relatively recent alien introductions to this Australian location. Their numbers need to be controlled.