15 research outputs found

    Can fisheries-induced evolution shift reference points for fisheries management?

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    Biological reference points are important tools for fisheries management. Reference points are not static, butmay change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to "shifting" reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in "true" reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in more perilous directions, such that actual risks are greater than anticipated. Our qualitative analysis suggests that all commonly used reference points are susceptible to shifting through fisheries-induced evolution, including the limit and "precautionary" reference points for spawning-stock biomass, B-lim and B-pa, and the target reference point for fishing mortality, F-0.1. Our findings call for increased awareness of fisheries-induced changes and highlight the value of always basing reference points on adequately updated information, to capture all changes in the biological processes that drive fish population dynamics

    Cheetahs modify their prey handling behavior depending on risks from top predators

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    While handling large kills, mesocarnivores are particularly vulnerable to kleptoparasitism and predation from larger predators. We used 35 years of observational data on cheetah (Acinonyx jubatus) hunts in Serengeti National Park to investigate whether cheetahs’ prey handling behavior varied in response to threats from lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Male cheetahs and single females, whose main threat was kleptoparasitism, minimized time on the kill by being less vigilant and eating quickly, thereby shortening their handling times. Mothers with cubs showed a different strategy that prioritized vigilance over speed of eating, which increased time spent handling prey. Vigilance allowed them to minimize the risk of their cubs being killed while giving cubs the time they need to eat at the carcass. Flexible behavioral strategies that minimize individual risk while handling prey likely allow mesocarnivores to coexist with numerous and widespread apex predators
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