This just in! The last of the migrants are on their way back, as evidenced by this announcement by JN Ding Darling National Wildlife Refuge.
If people think ecology is simple, this story would explain otherwise. Beside this study, Yellowstone has been a laboratory for many wildlife biologists as they sort out which species to introduce, conserve or eliminate. One example is the reintroduction of the gray wolf whose unintentional effects rippled throughout the park. Biologists were startled to find that wolves scared the elks up into the hills, thus freeing aspen trees to mature free from the elks’ gnawing teeth. Allowed to grow tall, they provide habitat for songbirds, materials for beavers to build their dams, and aquatic organisms to find a home in the newly created ponds. All because of the wolf. This is why ecology is rarely simple.
Often the news with the fishing industry and its effect on aquatic organisms is unsettling. Now, some good news. The commercial fishing industry might come to the rescue of penguins.