TILLAMOOK - Oregon Department of Fish and Wildlife employees will be rousting double-crested cormorants from the Nehalem and Tillamook estuaries for two months this year to protect juvenile salmon and steelhead during their peak migration out to sea.
The hazing operation - which takes place from dawn to dusk on jet skis and, if needed, using firecrackers launched from a handheld pistol - disturbs and scares the birds without harming them. It started Thursday and might eventually expand to other coastal rivers, though not the Columbia.
The state is beefing up its avian predation management program this year. In January, ODFW hired Michelle Schuiteman to work out of the Tillamook field office as the avian predation?coordinator.
"Our main focus so far has been getting the hazing programs up and running," Schuiteman said.
Avian predation on fragile salmon and steelhead runs has long been a concern, she said, but it has become a higher priority as bird populations keep increasing. The Pacific population of double-crested cormorants is growing by 3 percent a year.
ODFW recently started working with U.S. Fish and Wildlife Service on a new, long-term plan for managing avian predators to protect vulnerable fish runs.
Low chinook returns to the Nehalem River last year prompted a basin-wide chinook angling closure. While better returns are anticipated in 2010, some restrictions in the basin will be necessary this year to reduce harvest and increase spawning escapement.
A study in the Nehalem River using accoustic tags on juvenile fish headed to sea showed birds ate 60 percent of hatchery coho smolts one year and 9 percent of wild steelhead.
Research from the?National Oceanic and Atmospheric Administration's Point Adams lab track similar data on the Columbia River by scanning bird droppings for fish tags on East Sand Island and other nesting sites in the estuary. Their research shows the birds - namely colonies of around 20,000 Caspian terns and 22,000 double-crested cormorants - consume up to 4 percent of the Columbia River's 1.5 to 2.5 million tagged juvenile salmonids. They estimate the birds on East Sand Island consume at least 25 to 45 percent of the lower Columbia tule fall chinook.
Double-crested cormorants tend to focus on large groups of outmigrating salmonids. In the Nehalem and Tillamook estuaries they prey on a number of threatened and sensitive fish species, including coastal coho, chinook, steelhead and chum. Hazing can interrupt individual predation events, according to Schuiteman. However, on the Columbia River, the area is too large for hazing methods to be effective.
"We have historical data from the Nehalem and the Tillamook that show us where the hot spots of avian predation occur," said Schuiteman. "Hazing has been taking place off and on for quite some time. ... Using a jet ski they drive toward the flock and they scatter before the jet ski gets there. We keep on the birds until they have left the area."
Management of avian predators on fish populations is complex and requires balancing the needs of competing species within federal laws, including the Endangered Species and the Migratory Bird Treaty acts. Cormorants are protected by international treaty and federal law.