Sea Otters Background
Sea otters, once nearly eliminated by fur hunters, have made a spectacular comeback throughout the North Pacific following protection in 1911 and reintroductions about 30 years ago. But until recently, otters had not found their way into Glacier Bay. Now that has changed - presenting the National Park Service with a unique opportunity to understand more about the effect of the otters' return on the ecosystem.
Glacier Bay Sea Otters
Since 1995 when the first five otters were observed in Glacier Bay, the population has grown to an estimated 3,000 individuals. Most of these animals are concentrated in lower reaches of the Bay, leaving large areas of potential sea otter habitat as yet unoccupied, hence serving as controls.
Sea otters consume large quantities of clams, mussels, crabs and other invertebrates, some of which are commercially, culturally or ecologically important. Scientists have long known that increased predation on these species can cause long-term changes that ripple through the ecosystem.
What are the Breeding Habits of Sea Otters?
What Poses a Threat to an Otter's Existence?
The greatest threat to the sea otter remains humans. It has been estimated that the 1989 Exxon Valdez oil spill caused the deaths of more than 2500 sea otters. Otters are also caught in fishing nets, and hunted for subsistence by Alaskan Natives.
What Impact Might an Otter Have on Glacier Bay?
Since sea otters were not seen here before 1995, Glacier Bay provides the perfect opportunity to study an area before and after their introduction and learn exactly how these changes occur. In order to accurately describe and understand the magnitude of the otters' likely effect on the region's ecosystem, researchers are currently studying:
These studies will enable park managers to differentiate naturally occurring changes from those that are human-induced.
Source: Principle Investigator: Jim Bodkin, Resarch Wildlife Biologist, USGS/BRD and Mike Donnellan, Research Biologist, NPS
Did You Know?
Dense schools of forage fish, like herring and sand lance, are an abundant food source for many creatures, from the massive Humpback Whale to the diminutive Marbled Murrelet. Schools of forage fish can be literally miles long and hundreds of feet thick.