[1] Nearly 500,000 Springers Predicted For Columbia Next Year

Acknowledging that their old way of doing things didn't seem to be working anymore, Columbia Basin harvest managers blended the results from seven different harvest models and have come up with 470,000 springers (to river mouth) as their preseason estimate of next year's upriver spring chinook run. That would be the largest run since 1938, when fish counters began tallying chinook at the brand new Bonneville Dam, surpassing the 440,000-fish return in 2001.

In 1995, fewer than 13,000 spring chinook made it back to the river.

They didn't exactly explain how they did it, but a Dec. 9 memo from the technical advisory committee that crunches the numbers in the US v. Oregon process said they have looked at non-linear relationships, ocean conditions and sibling relationships.

With conditions in the North Pacific likely switching into a colder, wetter phase [cool PDO], it has been tough for harvest managers to adjust, not to mention just keeping up with the coming and going of El Nino and La Nina conditions.

In 2008, ocean conditions were great for young salmon. Canadian scientists reported the coldest water in 50 years and plankton blooming from one side of the Gulf of Alaska to the other.

Just a few years earlier, in 2004, they reported the hottest water in 45 years.

However, with recent conditions that good, the harvest managers' years-long reliance on their simple linear relation between jacks, the precocious males that return a year earlier than the major component of the run, and the two-ocean fish that return later, has simply broken down.

Last year's spring chinook jack count was off the charts, around 80,000, which put it about 4 times higher than the last record count, which presaged the 2001 return of 440,000 springers. Some scientists have theorized that the good conditions may have boosted the one-ocean males' natural propensity to return.

The TAC memo noted that in four of the last six years, the actual return has been less than the forecast by an average 45 percent, though their 2007 return was pretty close to being on the money.

They say they looked at more than a dozen models to produce the estimated 2010 return and developed a range of 264,000 to 810,000 adults. Then they picked the seven models with the best hindcast performance and narrowed that range down between 366,000 to 528,000--470,000 is the average of all the models.

In 1995, only about 1,800 spring/summer chinook returned to the lower Snake, hatchery and wild.

They said that included 272,000 spring chinook heading for the lower Snake, with a wild ESA-protected component of 73,400 fish and more than 57,000 springers heading for the upper Columbia, with about 5,700 of them wild, and listed.

Upriver tribal fisheries and Idaho sporties have complained in recent years about getting shorted their share of the spring chinook, so the harvest managers say they have developed a more cautious management regime this year, that will allows a large cushion for error, to ensure the upper river fishers receive their fair share.

The harvests will be managed for a run size about 30 percent below the actual estimate, which will reduce harvest rates in the lower river fisheries compared to recent years.

The missed predictions in recent years led to higher non-treaty spring catches in the Columbia than treaty catches in 2008 and 2009. Treaty fishers will be allowed 14.3 percent of the spring run, non-treaty harvesters 2.7 percent. -Bill Rudolph

[2] Biop Judge Says Salmon Plan Is Close

In late November, federal agencies were pleasantly surprised at the reception the latest additions to their Columbia Basin ESA salmon plan received in U.S. District Judge James Redden's courtroom. The judge told federal officials at a Nov. 23 hearing that it was a great move to take the hydro BiOp back to Washington and work on it.

But Redden also said it will take a little more work to get the BiOp add-ons to pass muster under the strictures of the Administrative Procedures Act.

That extra work could involve restarting consultation over the biological opinion that would be limited to adding the Obama administration fixes, now lumped together in something called the Adaptive Management Implementation Plan. This course of action would also allow for insertion of the documents used to develop the AMIP into the administrative record.

Redden asked for help on the subject, and the feds are expected to brief him before Christmas. He specifically wanted to know whether they will voluntarily reinitiate such a limited consultation. He also solicited any other "creative, constructive suggestions." Plaintiffs will get a chance to respond.

Federal attorney Coby Howell said the feds had real concerns about reinitiation because it could renew the whole cycle of litigation over the salmon plan. At a previous hearing, Howell had told the judge that the feds would not reinitiate any consultation.

This time, Howell said he didn't know if reinitiation could be as limited and as simple as inserting the AMIP into the BiOp. "It could take a very long time," he told the judge. "We've been at this for four years now. We don't want to go into that cycle again."

He recommended that the AMIP simply be added to the current BiOp under the 9th U.S. Circuit Court of Appeals' record-review rules.

But the judge was still unsure whether APA guidelines would be satisfied if such a course of action were pursued. "I'm not convinced on it," he said.

Earthjustice attorney Todd True, representing plaintiff environmental and fishing groups, argued that there was no precedent for doing what Howell had suggested.

Once the legal issues are resolved, Redden indicated that he would likely OK the plan. He just wants to make sure the Niners won't send the BiOp back to his court on a technicality.

It seemed clear to everyone that the plan will be appealed by plaintiffs once the judge signs off on it.

Plaintiff groups got the message loud and clear after Redden voiced praise for the salmon plan--both the BiOp and the AMIP--calling it a "good piece of work."

And though the judge still had concerns about some specific actions, he didn't complain too much that the feds didn't take his May advice and boost spill at dams and add more flows above BiOp levels.

Obama officials, led by NOAA head Jane Lubchenco, actually did take many of his recommendations to heart, since the AMIP calls for more actions to improve habitat, more monitoring, and a contingency plan that includes looking at breaching lower Snake dams if the runs start to crash.

Redden had said in May that he would likely can the plan without more estuary and tributary restoration actions, monitoring of results and contingency planning for drastic actions like breaching dams and drawing down John Day Pool to boost juvenile fish survivals.

Before the lunch break, the judge said he realized that a settlement plan with both sides "was probably never going to work," and he stumped for one of his pet issues.

"If we can get more water without chopping down the temples [the dams] on the Snake," he said, "I want to talk about that [after lunch] ... that's not in anything, and I think it would cover an awful lot of problems."

But in the afternoon session, Redden seemed a little less concerned about adding more water and dam spill to the BiOp equation.

In their last filing before the hearing, the feds were quite adamant about sticking to their BiOp barging policy that cut spill for two weeks in May and boosted barging young fish from lower Snake dams. Otherwise, they said they would be gambling with the survival of the ESA-listed Idaho steelhead runs and operating counter to the best available science.

But Justice Department attorney Howell told the judge that at this point, they don't know whether they will go to maximum transport in the spring, and no final decision has been made on when to terminate summer spill.

Howell may have been unaware that just a few days before the hearing, NOAA Fisheries had released a preliminary report of its latest research on fish barging.

The report found that wild steelhead barged from the Snake down through the hydro system in 2006 returned at about three times the rate of inriver migrating wild steelhead that were not detected at the Snake dams (1.46 percent versus 0.57 percent--see story 3). Non-detected fish pass the dams via turbine or spillway, rather than a route that bypasses them around turbines. Inriver migrating wild spring chinook returned at a slightly higher rate than barged wild chinook (0.84 percent versus 0.73 percent).

Terry Flores, executive director of Northwest RiverPartners, a coalition of BPA customers, said it was very clear that Redden was impressed with the Obama administration's review, and that he was interested in getting the AMIP included in the record without much second-guessing of its elements.

She said it was obvious that Redden was not buying plaintiffs' allegations that they had been shut out of settlement talks.

The feds have until Dec. 21 to tell the judge how they plan to add the AMIP to the BiOp. -B. R.

[3] Judge Questions Legality Of BiOp Additions

With less than a week before they squared off in his courtroom, U.S. District Judge James Redden was still trying to get federal agencies and environmental and fishing groups to agree on a plan to manage the Columbia River for the next 10 years.

But chances of a settlement seemed slim to none before they were scheduled to meet on Nov. 23 in Redden's courtroom to consider the Obama administration's additions to the hydro 2008 BiOp (see story 2).

The additions went through a review that included a semi-secret independent scientific exam. That exam pronounced the overall salmon plan "sound," and even better after the add-ons, which were housed collectively in an addition called the Adaptive Management Implementation Plan (AMIP).

But in letters sent to parties in the litigation, Redden wondered if the add-ons were even legal. The AMIP included some of the recommendations Redden made in a May 18 letter outlining his concerns. At the time, he said the BiOp, as it stood, was not likely to pass his muster.

But the judge now even questioned whether NOAA Fisheries could legally add the AMIP to the hydro BiOp, and whether the court could even consider it in a ruling on the pending motions for summary judgment on the legality of the feds' latest salmon plan.

"Is the AMIP part of the BiOp, or an impermissible post hoc rationalization?" the judge asked, using language borrowed from plaintiffs.

Redden also questioned why the documents presented by the feds for in camera review to supposedly back up the AMIP were being withheld from public review. He pointed out that if the AMIP were part of the BiOp, some of these documents should be part of the administrative record.

He also wanted to know if the feds could reinitiate consultation for the sole purpose of inserting the AMIP into the record "... and/or making it part of the final agency action? What steps would be required. Will defendants take those steps?"

He asked the litigants if the court could remand the 2008 BiOp for the "limited purpose" of including the AMIP and its supporting documents.

Those questions seemed to cheer some BPA customers. Terry Flores, executive director of Northwest RiverPartners, said it seemed like the judge was looking for a way to get the AMIP into the BiOp.

However, Redden also asked for advice on how to proceed if he concluded that the Obama add-ons were a "post hoc rationalization," so that it was not proper for the court to review the AMIP.

"Should I simply rule on the pending motions for summary judgment without considering the AMIP?" he asked.

He reminded the parties that his May 18 letter had noted that the BiOp "appears to be flawed," and said federal defendants needed to convince him that the AMIP was properly before the court, or take the necessary steps to include it in the BiOp.

"I am still hopeful that Federal Defendants can make this BiOp work, but they cannot sidestep requirements of the APA [Administrative Procedures Act]."

In a long footnote, the judge said the feds had misinterpreted his May 18 letter. He said he did not "invite" them to circumvent the APA and develop additional actions to bolster the BiOp, but was trying to help the parties in "jointly exploring all possible legal avenues," to come up with a solution.

According to Redden, his May 18 missive was intended to move the parties toward a settlement, not "an invitation to 'further explain' the final agency action."

Redden said it was difficult to see how the feds' unilateral development of added mitigation and contingency measures could be characterized as an "explanation."

Plaintiffs had turned down a chance to meet with all parties back in August, which could have included mediation. Instead, they wanted a private meeting with the feds, with certain preconditions of their own, which the feds abruptly turned down.

In an August filing with the court, plaintiffs said it appeared the feds "either intentionally or unintentionally substantially misread" their position outlined in an earlier letter that called for a status conference--which necessarily would have included all parties to the BiOp--to voice their concerns about the process the Obama administration was going through to develop its final position on the hydro BiOp. By then, plaintiffs were well aware the new administration was going to support the ongoing salmon plan.

Without any explanation, the judge denied the plaintiffs' request and gave Obama officials more time to study the BiOp.

Up to that point, plaintiffs had presented their positions to administration officials in a pair of hour-long "listening sessions." Defendant-intervenors got equal time.

Federal officials also heard from agency scientists and independent ones, as well, who weighed in on the scientific merit of the salmon plan.

When the AMIP was released Sept. 15, the feds said in a response to the judge that they had tried outreach with the plaintiffs, but the talks went nowhere and they did not believe that "continued discussions in an effort to reach a global resolution would be fruitful."

In their response to the court, the feds also argued that the AMIP was legal because it followed the judge's line of thinking in his May 18 letter that referred to the concept of "adaptive management" being flexible enough to allow the implementation of additional or modified actions under the existing BiOp.

The feds say the AMIP was simply a further refinement of the RPA [Reasonable, Prudent Alternative] implementation of the hydro BiOp.

In a Nov. 18 letter to all parties, the judge asked them to be ready on Nov. 23 to discuss whether the feds' promise to develop new, equally effective mitigation actions through "adaptive management" squared with the requirement that the actions should be fairly specific and "reasonably certain to occur."

But he also put plaintiffs on the spot, asking the state of Oregon, the Nez Perce Tribe, and environmental and fishing groups whether the AMIP contained positive measures that would enhance the BiOp, and what other measures they wanted to implement. And "as a practical matter, what more can Federal Defendants do?"

The judge also wanted to know why the feds weren't ready to implement certain actions now to improve listed species, rather than wait until their numbers dropped so much as to trigger contingencies.

Redden wondered why the feds still withheld certain documents from public review that may or may not have supported the feds' claim that the AMIP was based on the best available science.

"How can the court properly evaluate whether federal defendants did in fact use the best available science when they refuse to disclose the 'science' that was used to develop the AMIP?" the judge asked. "How do Federal Defendants justify withholding these documents?"

Redden ended his letter by acknowledging that the feds had made a good-faith effort to address the original flaws in the 2000 BiOp, especially by working with other parties "to attempt to ensure" that the new BiOp's tributary and estuary mitigation actions are reasonably certain to occur.

But he said the feds could still "do more to ensure that those habitat actions are reasonably certain to result in the predicted benefits. The AMIP suggests that they agree," he added.

In their last filing on Oct. 23, the feds defended the habitat improvement actions in the BiOp, but said survival benefits were not guaranteed because the kind of standard that plaintiffs want was impossible to achieve.

Redden told all parties he wanted them to focus on the AMIP's positive attributes and suggest additional measures to improve the BiOp--either through negotiation or "appropriate procedural avenues."

The word from the federal trenches was that Redden's missives were greeted with "muted pessimism."

It was fairly clear what plaintiffs want before they would be satisfied. Oregon Gov. Ted Kulongoski was blunt about that in a recent op-ed in The Oregonian, where he said he wanted a more aggressive approach to hydro actions--more flow and spill at dams, a reservoir drawdown at John Day Pool--and getting lower Snake dam-breaching studies under way now so their removal can begin if the fish "are not on a clear path to recovery within 10 years."

RiverPartners' director Flores said it was pretty clear the judge thought highly of the AMIP and wanted to get it in the BiOp. She hoped that Redden noticed that a lot of what Oregon wants is already there, and would be triggered by declines in fish populations.

Federal attorneys have already pointed out that many studies would have to be completed before a drawdown at John Day or dam breaching could be judged beneficial to the Snake River stocks.

Lower Columbia tribes did not seem too concerned about the prospects of latest courtroom face-off. Charles Hudson, spokesman for the Columbia River Inter-Tribal Fish Commission, said the Accord tribes were focused on implementing Fish Accords projects.

"No one here is burning daylight trying to figure out whether the APA concerns are a tweak or a poison pill."

The feds have since released documents and emails turned over to the judge for his review. One included a synopsis from a government staffer who attended a July meeting between independent scientists and NOAA head Dr. Jane Lubchenco, where they told her that the science behind the BiOp could not have been done better. The panel had reportedly said dam breaching would take a very long time, and would have very positive effects in the long run, but extremely negative short-term effects could negate the long-term positives. -B. R.

[4] Barges Still Beat River For Moving Steelhead

This year's annual research review sponsored by the Corps of Engineers came up with few surprises, but added support for more fish barging on the Snake River, a position that has the feds' policy at odds with a federal judge and environmental groups.

The latest information on barging fish from the Snake River presented by NOAA Fisheries scientists at the Dec. 3-6 Walla Walla gathering backs up earlier data used to justify the transportation policy incorporated in the 2008 BiOp. The latest data--from the 2006 outmigration, when the court-ordered spill operation was fully in place--show that barged steelhead returned at nearly three times the rate of inriver migrating juveniles.

A 2005 court order from U.S. District Judge James Redden called for more spill at lower Snake dams than the feds wanted. The feds say the best science shows that cutting spill for two weeks in May to get more fish in barges would benefit spring chinook and steelhead more than letting them migrate inriver during that period.

Last week, the NMFS scientists reported that the barged component of the 2006 steelhead run returned at a 1.46-percent rate, while the non-detected group--fish that went past Snake dams and McNary via spillway or turbines--only showed a 0.57-percent smolt-to-adult return (SAR) rate.

The researchers, led by NOAA Fisheries biologist Doug Marsh, found that SAR rates started high when they began PIT-tagging juveniles in late April, but fell over the next month, then rose again in the third week of May.

They reported that SARs actually hit zero for several days in the middle of the migration when barged SARs were above 2 percent.

However, the 2006 results showed no significant benefit to wild spring chinook from barging--wild inriver SARs were 0.84 percent, while barged SARs averaged 0.73 percent.

Another survival study piggybacked onto the transportation analysis that looked at the potential value of releasing barged fish further downriver below Bonneville than current operations call for (all the way to Astoria), also showed mixed results--no benefit for spring chinook but about a 30-percent boost in steelhead survival for the fish released near Astoria.

Researchers reported they are still having a hard time getting data on Snake fall chinook, which have a complicated lifestyle. Some migrate late in the year, while others hold back in reservoirs until the following spring. For September/October transported groups, their SAR rate was relatively high, 1.89 percent, but fish tagged in the summer and barged showed a SAR of only 0.14 percent (5-fish sample).

The court-ordered spill at federal dams may have played a role in increasing the number of juvenile fish that swam all the way to the ocean. NOAA scientist Bill Muir reported that the 2009's cool water, high flows and spill all helped spring chinook achieve a 53-percent survival rate through the hydrosystem this year, while steelhead set a record, nearly 70 percent.

"High spill rates, coupled with surface passage structures at all four Snake dams in 2009, early arrival of steelhead compared to past years, and a delayed start to transportation resulted in a greater number of non-PIT-tagged smolts in the Snake River than in earlier years," read the abstract of Muir's study. "As a result, fewer PIT-tagged steelhead were eaten near the confluence of the Snake and Columbia rivers by piscivorous birds, resulting in increased estimated survival through the Snake River."

Muir and fellow NOAA scientist Robert Emmett have also been tracking the arrival time of forage fish (food for young salmon) in the ocean off the Columbia River, hoping that some day fish managers may be able to better time ocean entry of juvenile fish and improve their survival.

Using two bottom-mounted echo sounders off the river mouth, they were able to track forage fish and meso-plankton populations. So far, they have found abundance levels rose by mid-May in the past two years, which they hope to correlate with higher salmonid survivals.

They said preliminary estimates point to "exceptionally" high salmon survival in 2008 and early 2009, which was probably good for young spring chinook migrating to and away from the Washington/Oregon coast. But they cautioned that later migrators like fall chinook and coho "probably had poor survival because of high Humboldt squid predation."

Canadian researchers reported continuing acoustic tag work to track spring chinook from the Snake River all the way to Vancouver Island. They said 2009 results comported with previous results from 2006 and 2008 showed no difference in survival from spring chinook from the Snake and Yakima rivers. Fish from the Yakima cross four fewer federal dams in their migratory route. The scientists say their results are inconsistent with the theory of delayed mortality--i.e. higher mortality for the Snake spring chinook because they pass more dams.

They also found little difference in the overall survival of barged and inriver migrators. Inriver fish survived at a higher rate between Bonneville and Astoria, but by the time the fish were detected 560 kilometers away at Lippy Point, off Vancouver Island, survival slightly favored the barged component.

Their take-home message was that marine survival appears to be lower than in the hydrosystem or estuary, "therefore, the role of the ocean needs to be considered when formulating conservation plans."

The Canadians tagged slightly smaller fish in 2008 and 2009, but the size of their acoustic tags makes it necessary for them to use larger fish than the Corps of Engineers studies, which use a completely different and smaller tag, allowing researchers to even track subyearlings, though their work is limited to tracking fish in the river.

Working with scientists from the Pacific Northwest National Lab, the 2009 Corps-sponsored work focused on the lower 50 kilometers of the estuary.

They reported that most of the spring chinook in their study made the 253-kilometer swim from Bonneville to Astoria in about three days, with 90-percent survival for about the first 200 kilometers, but only 84 percent made it to Astoria (22 km to river mouth) and 76 percent to East Sand Island, just 8 kilometers from the river mouth.

The researchers said subyearling fall chinook survival was relatively poor in 2009, with only 67 percent surviving from Bonneville Dam to East Sand Island, and steelhead fared even worse, with only about 53 percent making it from the last dam to the island at river kilometer 8. -B. R.

[5] Birds Rule Lower River

Despite a program to move some salmon-munching terns away from the mouth of the Columbia, researchers say tern and cormorant populations are still growing there, and they've got the evidence to prove it.

The researchers detected more than 80,000 PIT tags from bird colonies in the Basin this year--most in the lower estuary near the river mouth--but about 20 percent were found on islands in the reservoir behind McNary Dam.

The latest results were announced earlier this month at the Corps of Engineers' annual research review in Walla Walla, where scientists said the 80,000 PIT tags represent a minimum of 3.6 percent of all PIT-tagged juvenile fish released into the basin in 2009.

That adds up to 7 million to 16 million smolt sandwiches a year, on average.

With the western population of double-crested cormorants growing at a 3-percent clip as a whole, the lower estuary number of about 12,000 breeding pairs was up 10 percent from 2008. That means more than 40 percent of the entire western population of the cormorants is located on East Sand Island, close to the mouth of the Columbia.

In 2008, nearly 10,000 nesting pairs of terns were counted on East Sand Island, where they had been relocated from an upriver site at Rice Island a few years earlier.

The scientists estimated about 9 percent of the tern diet was made up of salmonids this year, down from 12 percent in 2008. In 2008, about 30 percent of the diet was salmonids.

However, a closer look at the data shows that nearly 10 percent of all the juvenile steelhead detected at Bonneville Dam were consumed by birds downriver, along with nearly 3 percent of the spring/summer chinook smolts that had been detected passing the dam.

Another important finding is the high mortality level of young fall chinook released in the lower Columbia. Researchers estimated about 30 percent of the PIT-tagged subyearlings released below Bonneville Dam ended up on the tern and cormorant colonies near the mouth of the river.

Other research with steelhead found that nearly 10 percent of PIT-tagged steelhead were consumed by waterbirds in McNary Pool and about 2 percent in John Day/The Dalles Pool.

The scientists also reported that in 2008, more than 20 percent of PIT-tagged steelhead released at Lower Monumental Dam on the lower Snake were later consumed by avian predators in the estuary.

For steelhead released into the mid-Columbia, the researchers found that about 5 percent were eaten in McNary Pool and 2 percent in JD/The Dalles pools.

They also estimated that the colony (486 pairs) of Caspian terns in the Potholes area of the upper Columbia was responsible for knocking off about 14 percent of the upper Columbia steelhead run.

"A comparison of predation between different avian species and colonies indicated that Caspian terns on East Sand Island, Crescent Island, and Potholes Reservoir consumed the largest proportion of available PIT-tagged steelhead, followed by double-crested cormorant colonies on East Sand and Foundation islands," read a study abstract. "Predation by gulls and American white pelicans was relatively minor in comparison to that of terns and cormorants."

White pelicans may not be a problem, but California brown pelicans, listed for protection under the ESA, are showing up in large numbers. In April, the first brown pelican was sighted at East Sand Island. By the middle of June, nearly 13,000 of them were roosting on the island. That's nearly twice the previous high count for June, according to other researchers' weekly updates. East Sand Island has turned out to be the pelicans' largest known post-breeding nighttime roost site.

Gulls in the region are adding more salmonids to their diets as well, according to the report, which said "recent increases in numbers of smolt PIT tags recovered on Miller Rocks in The Dalles Pool, where about 4,600 pairs of gulls now nest, have raised concerns about the impact of gull predation on survival of salmonid smolts."

Researchers said this year, 5,500 smolt PIT tags were deposited on the Miller Rocks gull colony, compared to 4,211 tags deposited in 2008, and the increase in consumption likely reflects both an increase in size of the gull colony, as well as an increase in foraging intensity at the nearby John Day Dam and The Dalles Dams. "The magnitude of predation on salmonid smolts by Miller Rocks gulls appears to be unique to this gull colony," researchers concluded.

Scientists estimated that gulls alone ate 80,000 or so salmonids at John Day--between 1.5 and 3 percent of the nearly 4 million smolts that swam by during the three-month study period.

Other work has been done to monitor the effectiveness of efforts to reduce tern predation and begin action to move cormorants.

Using satellite tags, researchers tracked 36 double-crested cormorants nesting at East Sand Island. Cormorants were tracked this fall to sites in the Puget Sound region (n=15); lower Columbia River (n=5); northern California (n=3); interior British Columbia (n=1); John Day Dam (n=1); and Salton Sea, Calif. (n=1).

The Corps of Engineers established two new colony sites for terns in interior Oregon, both at Summer Lake Wildlife Area. Caspian terns have colonized both islands, for a total of 15 pairs. Five terns that had been banded in the Columbia River estuary were again seen at the Summer Lake tern islands.

Oregon State University scientist Dan Roby said two other sites built in 2008 were more successful. The Crump Lake tern island in Warner Valley, Ore., attracted about 700 pairs of terns. Eighteen terns that had been banded in the Columbia River estuary were re-sighted on Crump Lake Island.

He said more than 80 percent of the diet of the Crump Lake and Summer Lake terns is made up of tui chub.

But another site, ready last year at Fern Ridge, had the same success rate as last year--zero.

Roby said his group has also been studying the nesting ecology of Caspian terns in San Francisco Bay, as part of a Corps proposal to build another site for terns in 2010.

The largest Caspian tern colony in the Bay Area is on Brooks Island, where about 10 percent of their diet is already made up of salmonids. Roby said fish managers are concerned that adding more terns from the Columbia River estuary might reduce survival of ESA-listed salmonids from the Sacramento River.

Recoveries of over 2,000 smolt-coded wire tags from the Brooks Island tern colony found that 98 percent of the smolts consumed by terns were non-ESA-listed fall-run chinook. Nearly all of the coded wire tags recovered from the tern colony (99.7 percent) were from smolts released from net pens in San Pablo Bay. -B. R.

[6] Questions Over Corps' Going Acoustic

A new report from NOAA Fisheries has raised some questions over the use of acoustic tags to measure survival of juvenile fish.

Based on data collected in 2007 on juvenile spring chinook tagged and released at Lower Granite Dam, the report found that acoustic-tagged [AT] fish generally had higher survival than PIT-tagged fish in the Snake River, "but consistently had lower survival in the Columbia River."

Since the Corps of Engineers has decided to use the acoustic tags as a gold standard for measuring survival at federal hydro dams, the findings have raised some serious questions about some of the results, especially since the differences in survival may be related to flows, time of release, and a potential tag effect. The acoustic tags are much larger than PIT tags and require a suturing technique to be implanted in the small fish. But researchers can pinpoint dam passage routes with AT fish, while PIT-tagged fish must enter a dam's bypass system to be detected.

The report says researchers had found similar results from another group that compared acoustic and PIT-tags in 2006 (Hockersmith et al, 2007), and found slightly higher survivals for AT fish in the Snake and slightly lower in the Columbia.

The 2007 data also showed a trend of higher survival for AT fish at two lower Snake dams, but higher survival for PIT-tagged fish at Columbia River dams. However, due to low numbers of replicates--about 400 AT fish were released each week for 10 weeks during April and May--the precision needed for a statistically significant difference in survival between the AT and PIT-tag groups was not quite there. If researchers want greater test sensitivity, the report says more AT fish are needed in future studies.

What the 2007 weekly data did show was that AT fish exhibited lower survivals to McNary Dam for the first five releases, a trip that usually took about a week. In one release, the difference in survival between the AT and PIT-tag groups was about 30 percent.

According to the report, the Hockersmith study had used low samples of AT fish, with far fewer replicates than called for by the study design. But the 2007 data used more fish, which in turn, imparted more statistical power to its results.

The report says, overall, the AT/PIT relative survival to McNary was .89 for fish released through May 5 and 1.00 for fish released from May 9- May 15. By the time the fish got to John Day Dam, the earlier AT groups had a 19 percent lower survival rate than the earlier PIT-tagged groups, and the later AT groups a 9 percent lower survival rate than the PIT-tagged groups.

However, the Corps has already changed the focus of its survival studies to the lower river. In 2009, it began an AT survival study that tracked fish from John Day Dam through the estuary.

The report pointed out that other recent field studies to compare survival between the two types of tags have shown no differences, but they were limited to distances of 100 km or less. The NMFS report said the higher survival rates for PIT-tagged fish only showed up over distances of 200 km or more.

The NMFS report said more work needs to be done to examine potential relationships between fish size and tagging effects--preliminary results have suggested that relative survival between AT and PIT groups in 2007 "was likely lower for smaller fish."

"Furthermore," said the report, "acoustic-tagged fish in this study fared better in the lab than in the river, suggesting that laboratory studies overall may not adequately represent the experience of fish migrating in the Columbia River Basin."

The researchers have tried to sort out what environmental and biological factors might be responsible for the observed differences. They said initial covariate analyses suggest that relative survival to McNary was associated with tag burden, fork length, fish condition factor, water temperature, and river discharge, but it was difficult to sort out which factors played the most important roles. So difficult, they said, that it took hours of time, "even on powerful computers. Analyses of 2007 data were delayed in part because of this difficulty."

The report also noted that 2008 data became available before the 2007 report was finished, and the added year of information will likely be of great benefit to the analyses, and will be reported when complete.

Initial survival results from 2008 presented at last year's Corps' research review showed similar differences in the AT/PIT survivals. In fact, the first seven out of the 10 weekly releases showed higher survivals for PIT-tagged fish to McNary, some 20 percent or more.

Flow in the Snake in 2008 was fairly low until after the May 3 release, when it climbed to 100 kcfs by May 8, declined some until around May 15, when the freshet began; the May 13 weekly release was the first time all year that AT survivals beat PITs at McNary--about 20 percent better.

In 2007, the spring flow regime was quite different. It increased steadily from late April to May 1, when it reached about 100 kcfs, then dipped the following week and peaked on May 13. The biggest differences in survival--about 20 percent less for the AT fish--showed up in the May 1 and May 3 release groups.

"Although we were unable to find a direct connection between environmental conditions and survival, said the report, "the survival/flow patterns we observed indicate that a connection is likely. Thus we recommend further analyses of these relationships."

The NMFS study also found that analyses of detection probabilities showed that AT fish did not likely behave in the same manner as PIT-tagged fish, but that neither was more susceptible to avian predation.

John Ferguson, fish ecology division head at the NMFS Science Center in Seattle, told NW Fishletter that his agency is no longer collecting data in this area of research, but after the 2008 data is completely analyzed, a clearer picture of tag effects may result.

The report found survival differences between AT and PIT-tagged subyearlings more pronounced. Subyearlings are typically smaller than yearling fish when they migrate, and their size may limit the effectiveness of the AT tags. Mean relative survival (AT/PIT) to McNary Dam was .42 before June 25, and only .33 after that date, when flows decline and water temperatures are on the rise. -B. R.

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