ABC News recently posted an article on the threats jellyfish are posing to the ocean. These abundant cnidarians are becoming a problem in many areas because of their impact on swimmers and beaches, and threats to fish and fishermen. They are thriving due to a decrease in predators (i.e., fish), their willingness to eat a variety of prey, and their tendency to increase in numbers as the climate gets warmer, and survive even in polluted, oxygen-depleted water.
Because they are difficult to raise in aquariums and study in the wild, there aren't very many jellyfish researchers, according to the article. But these researchers are doing the best they can to learn more about jellyfish. One technique is working with fishermen, and arming them with a smartphone app to report jellyfish sightings to give scientists a better idea of where jellyfish are most common.