[music and rushing water] [music] Narrator: The killer whale, a majestic creature, revered by Native tribes in the Pacific Northwest, and by locals and tourists alike. The animals most often found here are the Southern Resident killer whales, a population defined by its summer range in the inland waters of Washington state, extending north into Canada, and they are strictly fish eaters. Unfortunately, this Southern Resident population is a far cry from historical estimates that may have reached 200. In the 1960s, numbers plummeted, mainly from a live-capture fishery that removed approximately 47 whales for display at marine parks. By the early 1990s, the population made a slight recovery to around 100, but was followed by a 20% drop. This decline was a mystery, and in 2005, the Southern Residents were listed as endangered under the Endangered Species Act. Anticipating this, NOAA Fisheries jump-started a research program in 2003, and together with many partners, developed a recovery plan guiding research and management of three main risk factors, the first being prey availability. Brad Hanson: So, for identifying prey availability, we had to address prey selection first because very little was known prior to the early 2000s as to what the primary prey of Southern Resident killer whales were. So to address this question, we collect tissue and scales from the predation events by the whales. “Stop!” You can actually take fish scales and identify the species and the age of those. Narrator: What Brad and his team have found is that over 70% of their diet is Chinook, also known as king salmon. And in 2006, advances in genetics enabled researchers to pinpoint what river systems these fish were from. It turns out that about 90% of the Chinook salmon these killer whales eat in the summer come from one watershed in Canada, the Fraser River. Lynne Barre: From a management perspective, knowing which rivers the preferred salmon prey of the whales comes from is extremely important. NOAA manages both recovery of killer whales and restoration of salmon, that are also depleted, and if we can focus our salmon recovery efforts in a way that also benefits the whales, we get the best bang for the buck. Narrator: With these animals spending so much time near urban areas, scientists and managers are also worried about the level of toxic contaminants in the whales. To measure this, scientists collect tissue samples using a projected dart, that to us, would feel like getting a pin-prick. Samples are sent back to the lab for processing and analysis. Results show it’s likely that contaminants are affecting the whale’s health, including their ability to reproduce successfully or fight off disease. The third risk factor is the effect of noise and boat traffic. These animals inhabit busy shipping lanes and often come into contact with recreational boaters and whale watching tours. Scientists monitor their behavior, and deploy a specialized tag called a DTAG, to record noise levels detected at the whale. Lynne Barre: The data show that the whales change their behavior. They call louder in response to the vessel sound around them. They also spend less time foraging and more time traveling, and do things like breaching and tail slapping. So with all that information, we developed a 200-yard vessel regulation to keep the boats a little bit further from the whales, so that there’s some more protection, but it’s also a distance that allows for an educational and economically viable whale watch industry. Narrator: As winter approaches, these whales head out the open ocean, and until recently, nobody knew where they went. But with the development of satellite tags, a large male known as K25 was tagged in December of 2012, and everything changed. “I’m on target.” Brad Hanson: We were able to get a 94-day track from the animal, in which he made three trips to California with his pod mates. And we were able to catch up with those animals off the southern coast of Oregon in March on one of the large NOAA vessels and follow them for 10 days. Narrator: Since 2012, researchers have tagged and tracked several other animals in the winter, yielding information never previously known about this population, including feeding hotspots. Prey samples confirm that Chinook salmon remain a dominant prey item, with other species mixed in, like halibut and lingcod. The new data is exciting and informative, but there is still more to learn. Lynne Barre: These whales are still a mystery to us. There’s still a lot we don’t know. But we do know that these whales live a long time and are slow to reproduce, like humans, and so recovery is really going to take a long-term effort. But, major breakthroughs, like learning about where the whales go in the winter, really can help us identify what the health needs are for the whales, to improve their survival, and enables us to focus on the right tools for recovery.