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Ecology and salmon related articles

Sudden Large Smelt Run Likely Reason for
High Numbers of Sea Lions Plying Lower Columbia River

by Staff
Columbia Basin Bulletin, March 29, 2013

Visiting pinnipeds, led by California sea lions, are present in what many believe are record numbers this year at a usual resting place at the Astoria, Ore., East Mooring Basin, and up the Columbia River, with relatively high concentrations as far upstream as St. Helens, Ore., located at river mile 86.

The speculation is that sea lions, traveling north along the Pacific coast, as they do each year, had their heads turned by a sudden and large flood of euchalon, commonly called smelt, into the system.

The fat-rich little fish have been a no-show for the most part in recent years -- so much so that they were listed by NOAA Fisheries Service in 2010 for protection under the Endangered Species Act.

Once so abundant they were caught by the bucket load with dip nets, eulachon return numbers have dropped dramatically since the early 1990s when they regularly entered the Columbia River tributaries.

But this year, over the past couple weeks, the small fish have been seen washed up on the Columbia's shore, and shores of Oregon and Washington tributaries. They have been pulled from the stomachs of salmon.

And large schools of smelt have been seen coursing up the Columbia and those tributary streams.

The Sandy River just upstream of Portland was an occasional host even in the good times. And no smelt had been reported in the Sandy for at least 10 years -- until this year.

"And it's been 20 years or so since runs like this were the standard," said NOAA Fisheries Robert Anderson, euchalon recovery coordinator for NOAA Fisheries' Northwest Division.

He and state officials warn that, while this year's smelt run appears to be good-sized, the longer term trend has not been good.

"Eulachon are typically boom or bust," a good year or years balanced by years with low returns, Anderson said. In the past couple of decades, the lows have gotten lower, and the highs are not so high as they were in days when commercial fishers often harvested more than a million pounds of the species per year in the Columbia.

The southern "distinct population segment" of eulachon ranges from northern California to southeast Alaska and into the southeastern Bering Sea. Strongholds historically included the Fraser River in British Columbia, the Klamath River in northern California and the "epicenter of the DPS - the Columbia," Anderson said. The smelt flush out of the river systems as newly hatched larvae, and return as adults to spawn, and die.

And it is unclear whether the protected species has shown an uptick across that range this year, or just in the Columbia.

"It's just one year," Anderson said of the apparent Columbia surge. "And we don't know what's going on across the stock's range."

Regardless, the species remain federally protected in U.S. waters from humans, though not from sea lions. Oregon and Washington have since the listing declared smelt off limits for sport and commercial fishers. The closure applies to the Columbia River and all other inland waters.

"We want to make sure people remember that eulachon smelt are now protected and need to be left alone," said Todd Alsbury, district fish biologist for the Oregon Department of Fish and Wildlife. "Smelt arrive in waves, and in the past when one was seen in the Sandy River within hours lots of people were fishing for them. We want to make sure that doesn't happen this year."

The NOAA Fisheries, the states and the Cowlitz Tribe are working together in research looking into what caused the declining smelt runs and how to restore them.

Meanwhile, the sea lions are enjoying this one year's bounty.

A tandem boat survey conducted by the Columbia River Inter-Tribal Fish Commission March 19 from Bonneville Dam (located at river mile 146) to the East Mooring Basin in Astoria resulted in 62 Steller sea lions being observed, as well as 198 California sea lions, and at least 30 harbor seals.

CRITFC senior scientist Doug Hatch stressed that those tallies are preliminary, and are mostly certainly bare minimums. The survey involved CRITFC crews in two boats, one following the other downstream by about 15 minutes. The idea is to cross-check the counts from the two crews.

"I think it's incredibly high," Hatch said of the lower river sea lion counts. The animals seem bunched up near the mouths of rivers that have historically been unknown as smelt spawning sites.

"We saw a lot of sea lions upstream in the Cowlitz," Hatch said of the southwest Washington river that has historically been the largest tributary smelt producer in the Columbia.

Witnesses there confirm that yes, a big slug of eulachon has arrived, and maybe a little behind what used to be the normal schedule. A small run - sometimes called pilot fish - started to appear in late November and stretched to mid-December.

"Then it stopped," said Taylor Aalvik, the Cowlitz Indian Tribe's Natural Resources director.

When the normal return time - late February into early March - had passed, hopes were dashed.

"And then they all decided to come in" to the Cowlitz, Kalama and Lewis rivers and elsewhere in Washington, and to the Sandy. Eulachon typically spawn annually in the Cowlitz River, with inconsistent runs and spawning events occurring in the Grays, Elochoman, Lewis, Kalama, and Sandy rivers, according to the states' Jan. 14 "2013 Joint Staff Report Concerning Stock Staus and Fisheries for Sturgeon and Smelt."

"The river's full of smelt," said Aalvik early this week. "It's really late."

But better late than never, though the tribe is not allowed to harvest smelt either. The little fish hold a special place in tribal history and culture, providing food in late winter.

"It was a time period when there aren't any salmon in the river," and stores of smoked fish were getting low, Aalvik said.

The smelt presence has likely occupied some sea lions that typically would have a main course of salmon as more and spring chinook spawners begin to show up in the river. That run too appears to be at least somewhat behind schedule. Only 168 adult spring chinook had been counted passing through Bonneville Dam's fish ladders through Wednesday. That's higher than last year's count of 33 through March 27, but well below the recent 10-year average of 1,214 through that date.

The majority of the spring chinook are upriver fish bound for spawning areas and hatcheries upstream of Bonneville in Idaho, Oregon and Washington tributaries. The preseason forecast is for a return of 141,400 adult upriver spring chinook to the mouth of the Columbia, as well as 83,600 lower river spring chinook headed for the Willamette river and other tributaries. Such an upriver run would fall shy of the recent 10-year average of 188,000.

With few fish passing by, and plenty to eat downriver, the annual gathering of California sea lions in the waters just below Bonneville has been slow to assemble. Historically only a handful visited the dam during the spring chinook run, but with the turn of the century the number of California sea lions feeding at the dam spiked, with the total number of individual animals annually ranging from 30 to 104. A total of 39 were counted last year, marking the third year in a row that number has declined.

California sea lions, which seem to prey primarily on salmon and steelhead, have not had much of a presence so far this year with a daily high count of 12 on one day last week. Their witnessed toll this season through Thursday is a single salmon, though Steller sea lions at the dam have been observed taking 34 salmon, 39 steelhead and 288 white sturgeon.

On most days this early spring no California sea lion sightings have been reported at the dam. Observations of sea lion activity at Bonneville are recording as part of ongoing research led by the U.S. Army Engineers aimed at evaluating predation impacts on passing fish stocks.

California sea lion abundance in Astoria near the Columbia mouth is at a record high right now and there has even been one Steller sea lion hauling out there, which is unusual, according to ODFW researcher Bryan Wright.

On Tuesday there were approximately 450 hauled out in the East Mooring Basin.

"Given what Doug saw that suggests there may be about a thousand or so between the mouth and St. Helens right now," Wright said.

Sea lions seem to be taking advantage of the smelt surge. And perhaps spawning salmon are too.

Lower Columbia catch rates have been quite low, indicating perhaps the run has yet to arrive in any number, and/or the fish are not hungry enough to bite at lures. Last week state officials sampled 2,209 salmonid anglers (including 795 boats) with 104 adult spring chinook and two steelhead taken in the lower Columbia River.

"Catch rates were likely affected by a large abundance of smelt, many of which are nearing the end of their life cycle and at least some of which have made it as far upstream as the Sandy River," according to a joint staff weekly update. "Dead and dying smelt were easily visible in most areas of the Columbia, both near the shoreline and on the surface of the river. Large numbers of California sea lions were also observed moving upstream last week."


Staff
Sudden Large Smelt Run Likely Reason for High Numbers of Sea Lions Plying Lower Columbia River
Columbia Basin Bulletin, March 29, 2013

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