Spring is here and along with it comes a parade of events along the coast of Southeast Alaska that prepares many species for the months to come.
One of those events is the annual spring spawning run of eulachon that occurs in numerous rivers throughout the region.
Eulachon is a member of the smelt family and ranges from Northern California to the Bering Sea. Eulachon are known by many names, including hooligan, oolichan, saak, ooligan and candlefish. Like salmon, eulachon spend most of their lives at sea and return to spawn in rivers.
Although eulachon are small in size - about 8 inches - they are very high in fat and energy content and densely aggregated, thus making them a very important seasonal resource to many consumers throughout the region.
In Southeast Alaska, eulachon spawn in many river systems such as the Taku, Stikine, Chilkat, Chilkoot, Unuk, Alsek, Berners Bay and numerous others.
In Berners Bay, about 40 miles north of downtown Juneau, eulachon return to spawn in the Antler and Berners/Lace River systems in April and early May. Prior to ascending the lower reaches of the rivers to spawn, eulachon aggregate in Berners Bay along the bottom near the mouths of the rivers.
These densely aggregated high-energy fish provide a seasonal pulse of energy for marine mammal species that visit the bay, including humpback whales, harbor seals and Steller sea lions. When eulachon are in the bay, it is not uncommon to see humpback whales cruising the bay, harbor seals staging in the mouths of the rivers, and sea lions floating about in large groups.
In fact, large groups of several hundred sea lions have been observed cooperatively hunting in Berners Bay when eulachon are present. The large groups of sea lions move across the bay diving and surfacing synchronously, emerging in a different area of the bay each time.
Eulachon may be critical prior to the energetically demanding breeding season of Steller sea lions. Male sea lions depart the inside waters and travel to breeding sites along the outer coast in early May to establish territories. Once males establish their territories they may fast for 20 to 68 days without feeding in order to successfully defend their territories from intruding males. Female Steller sea lions also travel to breeding sites along the outer coast and will give birth to a pup in early June and fast for five to 13 days before going to sea to feed.
In addition, females must provide milk for their pups for up to one year, which is energetically costly. Therefore, spawning aggregations of eulachon may be of substantial seasonal significance to the nutrition and energy budgets of sea lions during a critical part of their reproductive cycle, when energy demands are at a peak.
Once eulachon enter the rivers to spawn in Berners Bay, they are exploited by numerous bird species. Hundreds of bald eagles sit atop trees along the shorelines of the Berners/Lace and the Antler Rivers, while thousands of gulls cloud the sky and make repetitive dives into the milky glacial water to capture the small silvery fish. There are also numerous shorebirds, waterfowl and seabird species present on the river flats and in the bay during the eulachon run. It is likely that spring-spawning runs of eulachon are important stopover areas for numerous bird species migrating north for the breeding season.
To the Tlingit, the spring-spawning runs of eulachon have been an important cultural and subsistence event for thousands of years. Eulachon are harvested using dip nets, wooden rakes, basket traps, nets and fishhooks. Once harvested, they can be eaten fresh, smoked, dried, canned and processed for oil. Making eulachon oil, also known as "grease," for trade and consumption is a very important and intricate process.
Historically, Natives traveled along trading routes or "grease trails" into the Interior. The Tsimshian of the Nass River in British Columbia refer to eulachon as "salvation" fish because they are one of the first fish to return to spawn after winter when most food supplies have been depleted. The Gitksan people of the Skeena River in British Columbia refer to eulachon oil as "ha la mootxw" or "for curing humanity."
Eulachon spawning runs are an important link between coastal, estuary and riverine systems during spring, which is a critical time for numerous mammalian and avian predators. Eulachon, which return year after year to spawn in the rivers of Berners Bay, provide an energy-rich feast and wildlife spectacle for all who attend.
Jamie N. Womble is a graduate student the School of Fisheries and Ocean Sciences at the University of Alaska Fairbanks in Juneau. Her research focuses on Steller sea lions and high-quality prey species in Southeast Alaska.
The Juneau Audubon Society is hosting cruises to Berners Bay on April 19 and May 3 to observe spring wildlife activity. Contact members at email@example.com.
Juneau Empire ©2014. All Rights Reserved.