Mathematicians propose new hunting model to save rhinos and whales from extinction

Mathematicians have created a new model - of a variety commonly found in the world of finance - to show how to harvest a species at an optimal rate, while making sure that the animals do not get wiped out by chance. According to the theoretical study, hunting thresholds can be calculated for individual populations and species. The key to this is how quickly a population grows naturally, and how much it competes for resources.

The researchers say they conducted the study because many wild species are at risk of being harvested to both local and global extinction, including whales, elephant seals, bison, rhinos, endangered birds, mammals and many species of fish.

They conclude that a "bang-bang" approach is the most effective strategy. This is where hunting is done at one of two fixed rates, like an on-off switch. It is argued that if humans can control animal populations better, harvesting can be more efficient and the risk of the population going extinct is lower. According to the study, populations that grow faster should be left to grow to a larger size, before hunting starting again at the pre-designated hunting rate.

The researchers explain this risk of extinction is increased because animal populations fluctuate randomly in time, due to environmental factors that cannot be predicted. The issue of chance is not taken into account in previous studies and it can lead to an overestimation of the ability of species to recover, potentially leading to extinction. However, the authors say a rate of harvesting that is too low also causes problems for a species as higher numbers will lead to higher competition for limited resources, which could also have a negative effect on their habitat.