Study Shows Human Impacts on Disease Transmission in the Ocean

Recent studies have linked anthropogenic stressors to disease occurrence in marine species. In a 2019 study published in Proceedings of the Royal Society B, Allison Tracy and others examined relevant studies published between 1970 and 2013 in order to analyze disease outbreaks within nine marine taxonomic groups, from sea grasses to marine mammals. They found evidence of a significant increase in disease reports for coral and urchins but a significant decrease in disease reports for bony fish and elasmobranchs (cartilaginous fish such as sharks, rays, and skates). 

Evidence of increased disease outbreaks in corals and urchins were linked to warming oceans due to climate change. The decrease in disease reports for fish may be because overfishing has reduced population numbers and densities, and this in turn could limit disease transmission opportunities. The study authors caution, however, that even though a decrease in fish diseases may at first glance seem beneficial, the loss of parasites could alter food webs and ecosystem function in unknown ways.

The study is further evidence that human impacts on the environment have far-reaching consequences for all animals, their habitats, and ecosystem functioning.