Salmon is one of my favorite fish to eat. I like it grilled on the barbecue and smoked.
Lots of other animals rely on salmon for food, like Alaskan brown bears and sea lions. But the biggest of the bunch are killer whales, or orcas, that live and hunt in the ocean waters off the coast of the Pacific Northwest.
Studying what fish a killer whale eats is not an easy job. You can’t ask them to fill out a survey or swim alongside them for a day to record what they eat. So scientists collected their poop. Yech! What a smelly job.
Scientists use this same method to study other animals, like grizzly bears and wolves in Yellowstone National Park, to see what they are eating. But finding whale poo in the ocean has to be a lot harder; that’s probably why no one had tried it with killer whales before.
Once the poo was collected, the scientists analyzed it and found that out of 175 samples collected over six summers, 98 percent of what the whales ate was some kind of salmon. Chinook salmon were 80 percent of the orcas’ diet, followed by coho (15 percent). Fish that weren’t salmon were rarely found in the killer whale poo.
Understanding what the whales eat, especially when it’s a species like salmon that has seen its population decline dramatically with the building of dams on the rivers where they spawn, is important for scientists so they can see the big picture of what’s important in the ecosystem.
But it’s kind of funny that they get a better understanding of that system by looking at whale poop, don’t you think?
— Brett French
Gazette Outdoors editor