Orcas Dying from Starvation

The orca whale population in Puget Sound is declining alarmingly. The Southern Resident population is at its lowest level in thirty years of 78 individuals. No new calves have been born to the three pods since 2012, and two new deaths in pod L (Lulu and Indigo) were confirmed. It seems their social structure is also splitering from the stress of what appears to be starvation due to a decline in chinook salmon, their preferred food. Historically all three pods, J,K and L came together in the San Juan Islands to feed and socialize, but for the past few years the pods have divided up into small groups, often staying far apart. Orca society is strongly matrilineal. So far martrilines of grandmothers, mothers and offspring have stayed together. Transient orcas seem to be faring better. They travel in small groups feeding on marine mammals, and their groups are growing larger. The coastal orcas of Puget Sound carry a heavy load of toxins in their bodies, but observers say its not toxins that are responsible for the population decline. Researchers have developed a computer model based on the diet of fish-eating orcas with a seawater contamination level of less than 0.5 becquerels/m³. Based on the model orcas will carry Cesium 137 levels exceeding the Canadian guideline of 1,000 becquerels/kg for seafood consumption within thirty years, the isotope's halflife.