The European purple sea urchin (Paracentrotus lividus) is considered to be a key herbivore throughout its distribution range--North-East Atlantic and Mediterranean Sea. It was also abundant in its eastern distributional edge, on rocky habitats of the coastline of Israel, but its populations have recently collapsed, and today it is an extremely rare species in the region. Field and laboratory experiments, that were carried out in order to examine the impact of the recent sea surface temperature rise in the Eastern Mediterranean, showed massive urchin mortality when temperatures crossed 30.5 °C before reaching peak summer values. These results suggest that elevated seawater temperatures in recent years may be a main cause for the disappearance of P. lividus from the southeast Mediterranean Sea, which may indicate distributional range contraction in this region.