Swirling in a translucent mass, a bloom of jellyfish like salps pulsates through the waters off the coast of New Zealand. Some reports have suggestedthat blooms like this are on the increase, choking fishermen s nets and power plant intake pipes. But while these striking consequences do happen, a recent study published in the journal Proceedings of the National Academy of Science finds no strong evidence for a global jelly rise over the past 200 years. In fact, jellyfish numbers oscillate from high to low over decade long periods but remain stable over time, researchers reported online Dec. 31. Some areas, such as Japan and the Mediterranean have seen regional increases in these gelatinous creatures, however.