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Large predator attacks on humans often provoke calls for animal population reduction, assuming it will reduce such incidents. Whilst this seems logical, there is currently little evidence supporting a consistent link between large predator density and attacks on humans.Here, we assessed whether large predator density is linked to the frequency of attacks on humans using estuarine crocodile (Crocodylus porosus) data in the Northern Territory (NT), Australia. Over the past 50 years, the estuarine crocodile population in the NT has grown from a few thousand to over 100,000 non‐hatchling individuals. Crocodile and human population densities have been closely monitored throughout this period, allowing the frequency of attacks on humans to be assessed over a wide range of densities for both populations.Our analysis showed an increase in the frequency of attacks on humans as the crocodile population recovered from very low levels in the 1970s. However, the attack rates stabilised around 2009, despite crocodile density and the human population continuing to increase. Based on the relationship between crocodile density and human‐attack frequency, scenario modelling suggested that the crocodile population would need to be culled to a critically endangered level (e.g. 90% population reduction) to reduce attacks on humans from 2.16 to 1.16 attacks per year.We conclude that whilst crocodile density significantly influences crocodile attack rates at low crocodile population sizes, this relationship becomes weaker as the density increases. For estuarine crocodiles in the NT, a plateauing of attack risk occurred once crocodile density attained ~2 crocodiles per km of river, and we argue that this was because high crocodile densities instigated management (e.g. removal of bold animals, exclusion zones) and education initiates by the government (e.g. 'Be crocwise' campaign) that subsequently evoked a change in human behaviour around waterways and stabilised the attack rate. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Abstract: The localization, distribution and orientation of O2 chemoreceptors associated with the control of cardio-respiratory responses were investigated in the neotropical, Hoplias lacerdae. Selective denervation of the cranial nerves (IX and X) was combined with chemical stimulation (NaCN) to characterize the gill O2 chemoreceptors, and the fish were then exposed to gradual hypoxia to examine the extent of each cardio-respiratory response. Changes in heart rate (f H) and ventilation amplitude (V amp) were allied with chemoreceptors distributed on both internal and external surfaces of all gill arches, while ventilation rate (f R) was allied to the O2 chemoreceptors located only in the internal surface of the first gill arch. H. lacerdae exposed to gradual hypoxia produced a marked bradycardia (45%) and 50% increase in V amp, but only a relatively small change in f R (32%). Thus, the low f R response yet high V amp were in accord with the characterization of the O2 chemoreceptors. Comparing these results from H. lacerdae with hypoxia-tolerant species revealed a relationship existent between general oxygenation of the individual species environment, its cardio-respiratory response to hypoxia and the characterization of O2 chemoreceptors. [Copyright &y& Elsevier]