DECLARATION OF BLAIN PARKER - PAGE 1

Josh Newton, OSB#983087

jn@karnopp.com

John W. Ogan, OSB#06594

jwo@karnopp.com

(541)382-3011

360 SW Bond Street, Suite 400

Bend, OR 97702

Of Attorneys for

Confederated Tribes of 

The Warm Springs Reservation

Of Oregon

Thomas A. Zeilman, WSBA# 28470

tzeilman@qwestoffice.net

(509)575-1500

Cell: (509) 949-7942

402 E. Yakima Ave., Suite 710

P.O. Box 34

Yakima, WA 98907

Attorney for

Confederated Tribes and

Bands of the Yakama Nation

Brent H. Hall, OSB# 992762

brenthall@ctuir.org

(541)429-7407

46411 Timíne Way 

Pendleton, OR 97801

Attorney for

Confederated Tribes

Of the Umatilla Indian Reservation

UNITED STATES DISTRICT COURT

DISTRICT OF OREGON

AUDUBON SOCIETY OF PORTLAND, WILDLIFE Civil No. 15-665-SI

CENTER OF THE NORTH COAST, ANIMAL LEGAL

DEFENSE FUND, CENTER FOR BIOLOGICAL DECLARATION OF

DIVERSITY, FRIENDS OF ANIMALS, BLAINE PARKER 

Plaintiffs, 

v. 

U.S. ARMY CORPS OF ENGINEERS, U.S. FISH AND 

WILDLIFE SERVICE, USDA WILDLIFE SERVICES, 

Defendants.

_________________________________________________

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DECLARATION OF BLAIN PARKER - PAGE 2

I, Blaine L. Parker, declare as follows:

1. I am a Fisheries Scientist in the Fish Management Department at the Columbia River 

Inter-Tribal Fish Commission (hereinafter CRITFC) where I have worked since 1991.

CRITFC provides fisheries technical services to the four federally recognized Indian 

tribes that founded the organization and govern its affairs; the four tribes include the 

Yakama Nation, the Confederated Tribes of the Warm Springs, the Confederated 

Tribes of the Umatilla Indian Reservation and the Nez Perce Tribe. CRITFC’s 

technical services include support for salmon harvest management coordinated 

through the processes of the Pacific Salmon Treaty, Pacific Fisheries Management 

Council, and United States v. Oregon court orders and management agreements, 

scientific research regarding many aspects of the salmon, sturgeon and lamprey lifecycles, technical support for water quality management including tribal fish 

consumption rates, genetic assessments at CRITFC’s Hagerman laboratory, and 

analysis of fish passage survival at federal and non-federal dams throughout the 

Columbia Basin.

2. I have Bachelor of Science in Fish and Wildlife Management from Montana State 

University (1985), and a Masters of Zoology from Idaho State University (1991). 

3. I have worked with the tribes for over two decades to help protect and restore their 

treaty fishery resources. I have listened to tales of Celilo Falls, attended feasts, 

funerals and name givings. 

4. I have actively participated in forums related to managing predation on salmonids

generally, and avian predation specifically, in the Columbia River basin since 1997. 

With regard to avian predation management, I have worked in various forums,

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assisting in field research, attending professional meetings, and co-management 

planning for both estuary and inland avian predation issues on behalf of CRITFC’s 

member tribes.

5. I have reviewed the draft (2014) and final (2015) environmental impact statements, 

written by the U.S. Army Corps of Engineers, titled “Double-crested Cormorant 

Management Plan to Reduce Predation of Juvenile Salmonids in the Columbia River 

Estuary” (hereinafter FEIS). I am familiar with much of the materials and analyses 

upon which the Corps of Engineers and U.S. Fish and Wildlife Service based their 

decisions. I have also reviewed the plaintiffs’ Motion for Preliminary Injunction, 

Memorandum in Support of Plaintiffs’ Motion (hereinafter Plaintiffs’ Memorandum 

in Support), as well as the Plaintiffs’ Complaint for Declaratory and Injunctive Relief.

My declaration will respond specifically to the Plaintiffs’ Memorandum in Support.

6. I have visited the Columbia River estuary numerous times over the past eighteen

years and have become very familiar with the bird species of the area. I have noted 

that there are numerous species of piscivorous birds – including three species of 

cormorants (Brandt’s, double-crested, and pelagic), Caspian terns, several species of 

gulls and two species of pelicans – concentrated in a relatively small area of the 

estuary. Many of these birds consume out-migrating salmonid smolts as part of their 

diets. During peak smolt migration time (April through early June), it is 

commonplace to view dozens of birds carrying smolts in their beaks. 

7. East Sand Island colony double-crested cormorants (DCCOs) consume on average 

eighteen tons of fish each day of the 120 day long breeding season. On average, this 

daily tonnage includes 3,776 pounds of salmon and steelhead smolts. Years ago, 

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DECLARATION OF BLAIN PARKER - PAGE 4

when the colony was smaller the impacts to smolt numbers would have been 

considerably smaller (Figure1).

8. CRITFC initiated a field study in 1997 to assess the impacts of fish-eating colonial 

waterbirds (i.e., terns, cormorants, and gulls) on the survival of juvenile salmonids in 

the lower Columbia River. (Collis et al. 2000) The research objectives in 1998 were 

to: (1) determine the location, size, nesting chronology, nesting success, and 

population trajectories of breeding colonies of fish-eating birds in the lower Columbia 

River; (2) determine diet composition of fish-eating birds, including taxonomic 

composition and energy content of various prey types; (3) estimate forage fish 

consumption rates, with special emphasis on juvenile salmonids, by breeding adults 

and their young; (4) determine the relative vulnerability of different groups of 

juvenile salmonids to bird predation; (5) identify foraging range, foraging strategies, 

and habitat utilization by piscivorous waterbirds; and (6) test the feasibility of various 

alternative methods for managing avian predation on juvenile salmonids and develop 

recommendations to reduce avian predation, if warranted by the results. (Collis et al. 

2000)

9. Collis et al., (2000), estimated that Caspian terns in the Columbia River estuary 

consumed 10.8 million juvenile salmonids (range = 7.4 – 15.2 million), or 

approximately 11% (range = 8% - 16%) of the estimated 95 million out-migrating 

smolts that reached the estuary during the 1998 migration year. The best estimate the 

number of juvenile salmonids consumed by double-crested cormorants in the estuary 

was 4.6 million (range = 2.2 – 9.2 million), or approximately 5% of out-migrating 

smolts (range = 2% - 10%) that reached the estuary in 1998. A rough estimate of the 

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number of juvenile salmonids consumed by glaucous-winged/western gulls in the 

estuary was 1.3 million (range = 0.4 – 3.9 million). Thus the estimated total 

consumption of juvenile salmonids by fish-eating colonial waterbirds in the Columbia 

River estuary was 16.7 million smolts (range = 10.0 – 28.3 million smolts), or 18% 

(range = 11% – 30%) of those smolts that reached the estuary in 1998. (Collis et al. 

2000).

10. Using an average colony size of 12,000 pairs - or 24,000 individuals - and the average 

weight eaten per bird per day of 1.5 lbs. I calculated the colony would on average 

consume 36,000 pounds of assorted fish each day. When expanded to the entire 

breeding season, the amount of fish consumed by the colony expands to a total of 

4,320,000 pounds. Using the long-term average percentage of salmonids in the diet of 

11.8% (BRNW 2015) multiplied by 4,320,000 pounds gives a conservative estimate 

of 509,760 pounds of smolts eaten annually (Figure 2). 

11. The numbers of smolts consumed during the late 1990’s was a wakeup call to 

researchers and managers to the magnitude of the avian predation problem. Since 

that initial research pointed out the problem, and during the seventeen years of 

research that followed, the impact to out-migrating smolts has escalated as the colony 

on East Sand Island (ESI) significantly expanded. (Figure 1). I calculated that in the 

decade from 2003-2013, East Sand Island DCCO’s consumed 126.7 million smolts, 

with the majority of the loss occurring in the four year period from 2010-2013 (Figure 

3). In 2013, the DCCOs from ESI consumed 16.3 million smolts. To estimate 

potential savings to the year’s smolt out-migration via the potential removal of 3,489 

adult DCCOs, I used the average annual value of 11 million smolts consumed and the 

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DECLARATION OF BLAIN PARKER - PAGE 6

average colony size of 10,776 pairs and estimated a potential savings of 1.8 million 

smolts. 

12. Compensatory mortality is an issue that Plaintiffs address in Plaintiffs’ Memorandum 

in Support as well as their Complaint. I have also reviewed the FEIS and the related 

documents that form the basis of Plaintiffs’ assumptions regarding compensatory 

mortality. I reviewed: (1) the application of compensatory mortality in the Federal 

Columbia River Hydropower System biological opinion (FCRPS BiOp) and the FEIS

relative to base and current periods (e.g., gap analysis); (2) susceptibility of juvenile 

salmon to avian predation (Hostetter et al. 2012); and (3) related documents from the 

Plaintiffs’ Memorandum in Support.

13. The FEIS adequately describes NOAAs gap analysis relative to the DCCO predation 

in the lower Columbia River and estuary:

The NOAA Fisheries’ 2014 Supplemental FCRPS Biological Opinion 

does not apply compensatory mortality to any of the RPA actions, 

including avian predation management (NOAA 2014). NOAA Fisheries 

Gap Analysis for determining RPA 46 colony size targets on East Sand 

Island (Appendix D) assumed that compensatory mortality, no matter what 

level it may be in actuality, would be similar between the “base” and 

“current” periods. The ultimate difference between the two periods results 

from the effect that the increase in DCCO abundance has had on 

salmonids populations; thus, the resulting target colony size to get back to 

the “base period” consumption rate under any level of compensation that 

is similar between the two periods would still need to be between 5,380 to 

5,939 breeding pairs. 

(FEIS at § 4.2.5 & App. C). 

14. Plaintiffs’ Memorandum in Support (at 3 – 4) argues that DCCOs consume weak, 

injured fish in “poor” condition, and that these “weakened” fish would eventually die 

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in the ocean (due to other mortality factors). In other words, fish that the DCCO

consume would die anyway, and thus the mortality inflicted by the DCCO is

compensatory, not additive. Plaintiffs’ argument that compensatory mortality negates 

the benefit of using any control measures against DCCOs implicitly assumes that 

100% of these weak and injured fish would not survive to adults. Plaintiffs assert

that actions to reduce predation impacts by DCCOs in the estuary are meaningless, 

and result in no real benefit. I do not believe the data support this claim. 

15. As identified in the FEIS, after more than seventeen years of avian predation 

research, there is no solid evidence showing that the East Sand Island DCCO colony 

exclusively preys on weak or injured fish. No quantitative estimates for 

compensatory mortality rates have been generated either. In fact, estimating 

compensatory mortality in the estuary given all the variables is inherently challenging 

because: (1) lack of a controlled estuary environment to conduct such a study; (2) 

difficulty of generating test and control groups; (3) temporal and spatial variables 

that affect predation patterns, such as nesting behaviors, prey preference, and prey 

abundance; and (4) uncertainty with regard to ocean survival rates. In their analysis, 

NOAA, USFWS and the Corps did not specify or assume a specific quantifiable level 

of compensatory mortality. Such an assumption would have been unfounded and met 

with skepticism in the scientific community.

16. Compensation is analytically irrelevant as to effects on adult salmon populations as

long as one properly assumes that the current level of compensatory effects is no 

greater than or is less than the compensatory effects that occurred during the base

period. No evidence has emerged that would indicate that compensatory effects have

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increased in the current case compared to the base case. Rather, recent information 

indicates that fish condition for migrants originating above Bonneville has improved 

compared to the base case, which would reduce the level of compensatory mortality 

that could be applied to the predation by DCCO. 

17. Plaintiffs refer to research results presented in Hostetter et al. (2012). In this peerreviewed article, the authors analyzed Snake River juvenile salmon and their 

susceptibility to predation as a result of their physiological condition. The

researchers identified primary factors influencing juvenile salmon susceptibility to 

predation in the Snake River and concluded that fish in weaker (i.e. “poor” condition) 

were preyed upon at a higher rate than healthy (or “good” condition) fish. The report

points out that fish that were deemed in “good” and “fair” condition also experienced 

avian predation, but at lower rates. The report indicates that DCCO do not exclusively 

prey upon weak and “poor” condition fish, but also prey upon fish in “good” 

condition. Overall this is a valuable piece of research. However caution needs to be 

taken when applying the Hostetter (2012) results to the DCCO predation occurring in 

the lower Columbia River estuary. A few points merit consideration:

• The authors evaluated migrant steelhead tagged at Lower Monumental 

and Ice Harbor dams on the Snake River – a freshwater river, far 

removed geographically from the lower Columbia River estuary. 

• In the Snake River, DCCOs rely heavily upon juvenile salmon for their 

prey, whereas in the estuary, DCCOs not only prey on juvenile 

salmonids, but also prey on a variety of other marine forage fish. 

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• In the Snake River, juvenile steelhead and spring chinook are actively 

migrating, while in the estuary, juvenile salmon may be actively 

migrating or may be rearing and feeding as they transition from a 

freshwater environment to salt water. 

• Water conditions are different between the freshwater and the 

ocean/estuary plume (temperature, turbidity, etc.) making the likely

susceptibility of salmon migrants to predation by diving DCCO’s is 

these two environments different. 

• The sizes of avian colonies in the Snake River are orders of magnitude 

smaller than the ESI DCCO colony.

18. Considering these differences, I believe it is inappropriate to assume that 

DCCOs would behave the same and select for, or prey upon, juvenile salmon 

in the Snake River in the same manner as they would in the Columbia River 

estuary. Not only are the environmental conditions between the Snake River, 

a freshwater river, and the lower Columbia River estuary, a salt water plume, 

vastly different; so are the physiological states of the juvenile salmon. 

19. It is also inaccurate to equate “susceptibility” to predation with “compensatory 

mortality”. Juvenile fish condition can improve over time, as is evidenced by 

the return of adults whose condition had been labeled “poor” at the juvenile 

life stage. One of the most common injuries noted was “descaling” and fish 

can and do overcome this temporary condition. 

20. The Hostetter paper noted that colony size also played an important factor in 

susceptibility to DCCO predation. A larger colony of DCCOs will have a 

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larger depredation effect on prey resources compared to a smaller colony. 

Colony size complicates any attempt to apply the results from the Snake River

study. The ESI colony in the estuary is approximately two orders of 

magnitude larger than the Snake River colonies (~325 bp @ Foundation 

Island versus ~10,776 bp at East Sand Island) 

21. There is no direct evidence or measurement of compensation for estuary 

migration of steelhead that have already survived the migration through the 

hydrosystem. Lyons et al. (2011), observes that the “degree to which avian 

predation on juvenile salmonids in the Columbia River basin is additive 

versus compensatory is currently unknown.” 

22. The only way DCCO predation would have no effect on adult returns is if the 

DCCO predation is 100% compensatory, that is if DCCO’s consumed only 

juvenile salmonids destined to die before reaching maturity. There is no 

evidence of such an extraordinarily selective consumption pattern. While not 

all juvenile salmonids survive to adulthood, many injured fish do. 

23. The Corps of Engineers has spent millions of dollars to improve fish passage 

through the federal hydrosystem. These improvements have positively 

affected fish condition and survival and are evident when comparing reach 

survivals across the last decade for fish passing through the hydrosystem 

(Figure 4). Of these, steelhead have shown the greatest survival improvement 

of the last 10 years. This increase in survival would imply a smaller 

proportion of fish in poor condition under current conditions, compared to 

conditions existing during the base case period of 1987 to 2002 dates.

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24. Descaling is the most common injury noted for migrating fish at the dams. Figure 5

depicts seasonal descaling observations for spring chinook and steelhead at 

Bonneville dam from 2002 to 2014. There is a clear decreasing trend in descaling 

over this period. Fish fitness and condition entering the estuary, as a function of 

descaling rates measured at Bonneville Dam, is improving across years. This data 

would seem to support a conclusion that lower numbers of “poor” condition fish 

transiting Bonneville Dam are now present in the estuary (Figure 5).

25. The previous analysis used data from the Fish Passage Center Website and looked at 

all descaling rates, including scale losses in the following categories: less than 5% 

over the body; scale loss of 5% to 20%; and greater than 20% descaling. Most of the 

descaling is accounted for in the lowest two categories. Only fish in the greater than 

20% descaled category are labeled as in “poor” condition. Overall current descaling 

levels for both species appears to be less than 5%. For context, Hostetter (2012)

reported 35% of steelhead tagged at Ice Harbor and Lower Monumental dam were 

either in the 5-20% or, greater than 20% descaled range. Not only is fish condition as 

sampled at Bonneville Dam improving (across years), but only a small percent of this 

overall descaled group (and this group is itself a small percent of the overall 

population) would be considered in “poor” condition. Even assuming Hostetter’s 

findings were transferable to the estuary, fewer poor condition fish are observed 

entering the estuary than were observed in the Snake River. In light of this 

information, DCCO predation is better characterized as additive, not compensatory 

mortality. 

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26. Plaintiffs contend that hatchery fish are particularly susceptibility to avian predation. 

Plaintiffs Memorandum in Support at 3 – 4. There are many listed hatchery stocks 

throughout the Columbia and Snake Rivers and actions that reduce predation on 

hatchery fish are also helping to increase survival of salmonids generally as well as 

listed wild populations.

27. For certain species, a DCCO preference for hatchery fish can be shown. However, 

Hostetter concluded that the release location is an important factor in determining 

susceptibility to avian predation. It is logical to infer that hatchery fish released close 

to the ESI DCCO colony could be preyed upon at a higher rate than other fish who 

may be dispersed during their in-river migration. While hatchery steelhead migrants 

have a higher susceptibility to DCCO predation in the Lower Snake River, this has 

not been shown in the Columbia River estuary. This may be partially explained by 

the fact that DCCO predation in the estuary occurs hundreds of miles away from the 

hatchery release locations upstream of Bonneville Dam. In fact, most hatchery 

steelhead are released far from the estuary. Ryan et al. (2003), indicates no difference 

in predation for wild and hatchery steelhead by DCCO., stating: “thus a recovery 

effort based on reducing avian predation in the estuary could produce measurable 

gains for wild steelhead stocks.” (Ryan et al. 2003). The Roby et al. (2014) annual 

report also supports this conclusion.

28. Plaintiffs discount the impact of DCCO predation on listed salmon and steelhead by 

asserting that cormorants prey more on hatchery fish than wild fish. Plaintiffs 

Memorandum in Support at 4. Plaintiffs’ assertion ignores the fact that hatchery fish 

are included in assessing an Evolutionarily Significant Unit (ESU) status in the 

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context of their contributions to conserving natural self-sustaining populations. 

(NMFS Policy 2005). NMFS has included hatchery fish in all of the listed salmon 

and steelhead populations above Bonneville Dam. (NMFS 2014).

29. As indicated in Table 1, DCCO predation on Snake River steelhead is well above the 

estimated 3.4% from the NOAA gap analysis. Upper Columbia steelhead have 

similar but slight higher predation rates compared to the Snake River migrants. In all 

years but one, 2013, steelhead predation by DCCO was nearly twice and as much as 

and in some years 5 times higher than the gap analysis value. The average predation 

rate from 2008 – 2014 is 9.3%, which is nearly three times higher than the estimated 

gap analysis. If one assumes that the action agencies achieve the dam passage 

survival goal of 96% for steelhead and spring chinook, this level of mortality roughly 

equates to making these fish pass slightly more than two additional dams. When 

coupled with the NOAA gap analysis it is clear that DCCO predation pose a threat to 

migrating salmonids to level where management action needs to be taken. (Table 1). 

30. I agree with Linda R. Wires, an expert witness for the plaintiffs, that PIT Tag data can 

provide valuable insights on impacts to specific salmon populations. I use Snake 

River steelhead Deschutes River Basin Spring Chinook to illustrate this point.

31. As shown in Table 2, spring chinook released from Warm Springs National Fish 

Hatchery suffer a higher rate of predation by DCCOs when compared to DCCO 

predation rates for upper Columbia spring chinook or mid-Columbia spring chinook. 

Since the detections on ESI were attributed to the “bird colony” and not specifically 

attributed to either the Caspian tern colony or the DCCO colony at East Sand Island, 

estimates were made assuming all the predation occurred from either Caspian terns 

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(Low Range) or DCCO (High Range). The correct number is somewhere in between 

the low and high range, however DCCOs typically have higher predation rates on 

spring chinook compared Caspian terns and account for the greater portion of spring 

chinook take on ESI. 

32. With my colleagues at CRITFC, I investigated the relationship between DCCO 

colony size and pikeminnow abundance in the estuary and we found no evidence to 

suggest the size of the ESI colony limits pikeminnow abundance, nor will a reduction 

of the ESI colony lead to an increase in predation of juvenile salmonids by 

pikeminnow. This investigation is in response to the plaintiff’s assertion that 

pikeminnow are the primary prey base after the juvenile salmonid migration season 

and that a reduction in the ESI DCCO colony could cause pikeminnow abundance to 

increase, thereby increasing pikeminnow predation on juvenile salmonids. 

33. Pikeminnow are known to prey on juvenile salmonids and have been the target of a 

long term predator removal program in the Columbia River Basin. There are no 

abundance estimates for pikeminnow in the estuary, so in order to investigate the 

relationship between the ESI DCCO colony and pikeminnow abundance in the 

estuary, we used Catch Per Unit Effort (CPUE) angling data from the Northern 

Pikeminnow Sport-Reward Program from 1998-2013 from Bonneville Dam to the 

river mouth, and DCCO census data from the same time period. (PSMFC 2015, 

BRNW 2015) . CPUE is the number of fish caught per angler-hour and provides an 

index of fish density. For this investigation, we assumed CPUE and abundance are 

positively related (e.g. if the pikeminnow population increased, we would expect that 

angling efficiency would also increase) and used CPUE as a surrogate for abundance. 

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If the plaintiff’s claims were true (i.e., a decrease in the ESI DCCO colony will lead 

to more pikeminnow in the estuary), CPUE and the DCCO colony size on ESI should 

be inversely related.

34. A linear regression analysis using sixteen years of historic data provided evidence 

that pikeminnow abundance has not been reduced even as the DCCO colony size on 

ESI has increased. (Figure 6). Similarly, this analysis provides evidence that removal 

of DCCOs from ESI will not lead to increased predation of juvenile salmonids by 

pikeminnow. 

35. Similar to pikeminnow, the plaintiffs claimed that a colony reduction at ESI could 

lead to an increase in the number of American shad and, consequently, a decrease in 

juvenile salmonid survival. Plaintiffs’ Memorandum in Support at 13. We review this 

claim in the following paragraphs.

36. For this analysis, we used shad passage data at Bonneville Dam as a surrogate for 

shad abundance. A linear regression analysis showed no relationship with shad 

passage data at Bonneville Dam with ESI colony size in years 1998-2014 (Figure 7). 

This provides strong evidence that shad populations in the Columbia Basin will not 

be affected, positively or negatively, by a colony reduction at ESI.

37. Collis et al.(2000) noted that the East Sand Island double-crested cormorant colony 

was the largest in the world. Since that time it has continued to grow and still 

remains the largest colony of double-crested cormorants in the world (Figure 1). 

However, the tremendous size of this colony, being orders of magnitude greater than 

the average double-crested colony size of ~250 pairs, is a potential liability for the

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species, with the potential for catastrophic loss from diseases, natural events, and 

anthropomorphic disasters such as oil or chemical spills.

38. It is readily apparent that the colony has produced a tremendous number of fledglings 

over the past seventeen years. In the period from 1997 to 2013, the East Sand Island 

colony produced approximately 354,000 fledglings.

39. Not all of the fledglings survived, but with first year survival rates of 0.48, and 

second year survival at 0.75, the East Sand Island colony growth was likely due, in 

significant part, to its location and abundant forage base and less likely due to 

continued immigration. Monitoring population levels at breeding colonies is difficult 

due to bird movement and other factors. Nevertheless, the following information 

indicates that coastal colonies may be increasing. Regarding the counts in 

Washington’s San Juan Island, Jessica Adkins and Dan Roby (2010) estimated that in 

2009, 595 breeding pairs of cormorants were distributed in four colonies. They 

observed that, “missing data makes direct comparisons to previous years problematic, 

even within this subregion.” They further noted that it is “difficult to establish a clear 

trend for the number of double-crested cormorants breeding in the San Juan Islands 

sub-region during 1998-2009. Considering that Carter et al. (1995) reported that only 

twenty-five breeding pairs nested at one colony in this sub-region in 1992, it appears 

that numbers of double-crested cormorants breeding pairs in the San Juan Islands 

have increased dramatically since the early 1990’s but are currently relatively stable.” 

Regarding cormorant colonies in Oregon they write, “In 2009, an estimated 2,384 

breeding pairs of double-crested cormorants nested at 22 colony sites along the 

Oregon Coast. This is a modest increase from the 2003 and 2006 estimates of 2,216 

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and the 1,903 breeding pairs at 24 and 21 colony sites, respectively. Regarding the 

Columbia River estuary, Carter (1995) notes that the “number of breeding pairs in 

this sub-region approximately doubled in 10 years, from an estimated 7,270 breeding 

pairs in 1998 to an estimated 14,032 breeding pairs at in 2007.” This increase is likely 

due in part to the average nesting success of 1.83 birds per breeding pair, and not 

from continued immigration (Figure 8).

40. Some fledglings emigrated from the estuary, but generally speaking fledglings return 

to nest in the region were they were raised. Since the average number of fledglings 

per nest is 1.83, the population of double-crested cormorants at East Sand Island 

nearly doubled at the end of each breeding season. In some years nesting success 

exceed two fledglings per nest, thereby doubling the DCCO population on ESI at the 

end of those breeding seasons. There are thousands of sub-adults and non-breeding 

adults scattered across the western region. Minor decreases in the number of breeding 

adults at ESI due to management actions should not cause irreparable harm to the 

western population. 

41. In the years of 2011, 2012 and 2013 the ESI DCCO fledged approximately 68,151 

birds in just three years. If all of the fledglings survived to adulthood, they would be 

more than enough to replace the entire western population. However, survival of 

fledglings is limited. On average, approximately 48% of fledglings survive to age 

year one. Using this survival rate to year one, the past three years produced 32,713 

age one birds to help with population stabilization at a three-year mean fledgling rate 

of 1.65 fledglings per nest for those years, which is less than the long term average of 

1.83 fledglings per nest. 

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• 2011: 1.33 (fledged per pair) x 13,045 pairs = 17, 350 fledgling x 0.48 (Van 

Der Veen 1973) = 8,328 survival to age 1. 

• 2012: 1.26 x 12,301 = 15,499 fledglings x 0.48 = 7,440 age 1 birds. 

• 2013: 2.36 x 14,916 = 35,302 fledglings x 0.48 = 16,945 age 1 birds.

42. During 1997-2000, stomach contents of double-crested cormorants were sampled at 

East Sand Island. The sampling procedures typically involved harvesting birds in 

flight with shotguns. During this period, approximately six hundred cormorants were

collected for stomach analysis, yet the total colony size expanded in these years from

5,023 to 7,162 breeding pairs. 

43. It is important to note that the population estimates for East Sand Island are typically 

reported as “breeding” or “nesting” animals, either as “pairs” or “individuals.” (FEIS 

at 3-17; FEIS Table C-1.2). Counts of breeding pairs on East Sand Island are 

obtained from aerial photographs showing occupied nests. (FEIS App. C, at 7 & 26). 

This census method is used, for among other reasons, because individuals that are 

nesting can be more readily counted than non-nesting birds.

44. These counts however, do not include immature double-crested cormorants, which 

although present are not ready to breed until they are three to four years of age. Nor 

do the census estimates include individual sexually mature cormorants that for one 

reason or another are not part of a breeding pair. 

45. While the majority of nesting activity in the Columbia River estuary occurs on East 

Sand Island, the total population of cormorants in the estuary is undoubtedly larger 

than just those birds nesting at East Sand Island or elsewhere in the estuary. 

Case 3:15-cv-00665-SI Document 55 Filed 05/06/15 Page 18 of 30
DECLARATION OF BLAIN PARKER - PAGE 19

46. Although the colony size at ESI has seemingly stabilized since 2006 (Figure1), there 

is little evidence to suggest that colony is limited by habitat and will not continue to 

expand. The stabilization observed from 2006 – 2014 can be explained by 

management activities that included habitat constriction. Without, habitat 

constriction and hazing, the colony may have continued to grow. Furthermore, there 

is evidence that DCCOs are increasingly colonizing habitat in the estuary, away from 

ESI. For example, Lyons (2014) showed an increase in the number of nesting birds 

on Astoria Megler Bridge and on upper estuary navigation markers (Table 3). This 

suggests that ESI colony produces and disburses young DCCOs to colonize new 

nesting sites in the estuary.

47. In a 2014 final report prepared for the Corps, Lyons et al. discussed the benefits to 

reducing DCCO predation. 

Despite these uncertainties, it is clear that actions to reduce predation on 

juvenile salmonids by double-crested cormorants nesting at East Sand Island 

will not by themselves recover ESA-listed anadromous salmonid populations 

originating upstream of Bonneville Dam. Reductions in cormorant predation 

in the estuary could, however, result in increases in salmonid population 

growth rates comparable to some other salmonid recovery efforts in the 

Columbia River basin, particularly for steelhead populations. Reducing 

cormorant predation could also benefit ESA-listed salmonid populations 

originating downstream of Bonneville Dam, non-listed salmonid populations 

that also have significant cultural and economic value, and other species of 

conservation concern that we did not consider (e.g., Pacific lamprey).

(Lyons et al., 2014).

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Literature cited

Hostetter, N. J., A. F. Evans, D. D. Roby, and K. Collis. 2012. Susceptibility of juvenile 

steelhead to avian predation: the influence of individual fish characteristics and river 

conditions. Transactions of the American Fisheries Society 141:1586-1599.

BRNW 2015. http://www.birdresearchnw.org, Bird Research Northwest. 1 May 2015.

PSMFC 205. http://www.pikeminnow.org, Pacific States Marine Fisheries Commission. 1 May 

2015.

Lyons, D. E., D. D. Roby, A. F. Evans, N. J. Hostetter, and K. Collis. 2011. Benefits to 

Columbia River anadromous salmonids from potential reductions in avian predation on 

the Columbia Plateau. Final Report for the U.S. Army Corps of Engineers – Walla Walla 

District. 

Lyons, D. E., D. D. Roby, A. F. Evans, N. J. Hostetter, and K. Collis. 2014. Benefits to 

Columbia River anadromous salmonids from potential reductions in predation by doublecrested cormorants nesting at the East Sand Island Colony in the Columbia River Estuary. 

Final Report for the U.S. Army Corps of Engineers –Portland District. 

NMFS (National Marine Fisheries Service). 2005. Policy on the Consideration of HatcheryOrigin Fish in Endangered Species Act Listing Determinations for Pacific Salmon and 

Steelhead. Federal Register 70:123(28 June 2005):37204–37216.

NMFS. 2014. Final Rule to Revise the Code of Federal Regulations for Species Under the 

Jurisdiction of the National Marine Fisheries Service. Federal Register 70:71(April 14, 

2014):20802–20817.

Roby, D. D., K. Collis, D. E. Lyons, J. Y. Adkins, Y. Suzuki, P. Loschl, T. Lawes, K. Bixler, A. 

Peck-Richardson, A. Patterson, S. Collar, A. Piggott, H. Davis, J. Mannas, A. Laws, J. 

Mulligan, K. Young, P. Kostka, N. Banet, E. Schniedermeyer, A. Wilson, A. Mohoric, A. 

Evans, B. Cramer, M. Hawbecker, N. Hostetter, A. Turecek, J. Zamon, and D. 

Kuligowski. 2014. Research, monitoring, and evaluation of avian predation on salmonid 

smolts in the lower and mid-Columbia River. Final 2013 Annual Report to the U.S. Army 

Corps of Engineers and the Bonneville Power Administration, Portland, Oregon.

Ryan B. A., S. G. Smith, J. A. M. Butzerin, and J. W. Ferguson. 2003. Relative vulnerability to 

avian predation of juvenile salmonids tagged with passive integrator transponders in the 

Columbia River estuary, 1998-2000. Transactions of the American Fisheries Society 

132:275–288.

USACE (US Army Corps of Engineers). 2014. Double-crested cormorant management plan to 

reduce predation of juvenile salmonids in the Columbia River estuary. Draft 

Environmental Impact Statement, Portland, Oregon.

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DECLARATION OF BLAIN PARKER - PAGE 22

USACE. 2015. Double-crested cormorant management plan to reduce predation of juvenile 

salmonids in the Columbia River estuary. Final Environmental Impact Statement, 

Portland, Oregon.

Zabel R. W., 2014 memorandum to R. Graves, Northwest Fisheries Science Center, on 

preliminary survival estimates for the passage of spring-migrating juvenile salmonids 

through Snake and Columbia River dams and reservoirs.

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Appendix A – Figures and Tables

Figure 1. Numbers of breeding pairs of double-crested cormorants at East Sand Island from 

1997-2014. The solid line represent the average colony size of 10, 776 pairs for 1997-2014.

Graph courtesy of the Bird Research Northwest – Real Time Research website.

Figure 2. The annual proportion of juvenile salmonids in the diet of double-crested cormorants 

from East Sand Island from 1999-2013. Graph courtesy of Bird Research Northwest.

0

5,000

10,000

15,000

20,000

199719981999200020012002200320042005200620072008200920102011201220132014

Breeding Pairs

Annual Colony Size

Average (1997-2013)

0%

5%

10%

15%

20%

25%

30%

35%

40%

199920002001200220032004200520062007200820092010201120122013

Percent Salmonids of Prey 

Biomass

Annual Proportion of Salmonids in the Diet

Average (1999-2012)

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Figure 3. Numbers of salmonids consumed by double-crested cormorants from East Sand 

Island, 2003 to 2013. The average annual consumption (11 million smolts) indicated by the solid 

line on the graph. Graph courtesy of Bird Research Northwest.

0

3

6

9

12

15

18

21

24

27

30

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Smolts Consumed (millions)

Annual Salmonid Smolt Consumption

Average (2003-2012)

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Figure 4. Annual average survival estimates for PIT-tagged yearling Chinook salmon and 

steelhead, hatchery and wild fish combined (Chinook Salmon represented on the left chart and 

Steelhead on the right chart). Vertical bars represent 95.5% confidence intervals. Horizontal 

dashed lines are 95% confidence interval endpoints for 2014 estimates. The “Y” axis is 

Estimated Survival Probability. (Chart is a reproduction from the September 18, 2014 Survival 

Memorandum from Richard W. Zabel (NOAA). Link: 

http://www.nwdwc.usace.army.mil/tmt/agendas/2014/1015_2014_Preliminary_Survival_Estimat

es_Memo.pdf

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Figure 5. Average annual descaling rates at Bonneville Dam, Second Powerhouse, for chinook 

and steelhead from 2002-2014.

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Table 1. Estimated annual predation rates (95% lower and upper confidence intervals) on 

tagged ESA-listed Snake River Steelhead by double-crested cormorant and Caspian terns nesting 

on East Sand Island in the Columbia River during 2008 and 2013. (2014 preliminary estimate 

final report is not complete) All PIT-tagged fish were last detected passing Bonneville Dam on 

the lower Columbia River. Predation rates are only for in-river migrants. Predation rates were 

adjusted to account for tag loss due to on-colony detection efficiency and deposition rates (Evans 

et al. 2012; BRRN 2013) Table generated from data from the 2013 Annual Bird Monitoring 

reports located on the Bird Research Northwest Website at: 

http://www.birdresearchnw.org/FINAL_2013_Annual_Report.pdf

ESI Doublecrested 

Cormorants

ESI 

Caspian 

Terns

Year Location Species ESU/DPS

Detected 

@ Bon

Predation 

Rate*

Predation 

Rate

2008 ESI Steelhead

Snake 

River 19,572 16.8% 14.3%

2009 ESI Steelhead

Snake 

River 23,311 18.5% 14.6%

2010 ESI Steelhead

Snake 

River 40,024 8.5% 14.0%

2011 ESI Steelhead

Snake 

River 7,028 6.0% 11.8%

2012 ESI Steelhead

Snake 

River 4,768 5.4% 10.0%

2013 ESI Steelhead

Snake 

River 8,516 2.5% 12.7%

2014 ESI Steelhead

Snake 

River 8,812 7.8% 8.6%

2008-2014 

average 9.3% 12.3%

*based on tag deposition value of 0.43

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Figure 6. East Sand Island double-crested cormorant numbers plotted against the Catch Per Unit 

Effort of northern pikeminnows from the Sport Reward fishery check stations in the Columbia 

River downstream of Bonneville Dam for the years 1998-2013.

Figure 7. Annual counts of East Sand Island double-crested cormorants paired with annual 

passage counts of American Shad at Bonneville Dam from 1998-2013.

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Table 2. Estimations and Comparison for ESI Avian Predation Rates of Warm Springs Nation 

Fish Hatchery Spring Chinook From 2007 to 2013. 

Year

Release 

Gr. Released*

Bonn 

Detection*

ESI 

Detection

(1737)

Predation Rate 

 WSNFH

DCCO Predation 

 Rate

CATE 

Predation 

Low End High End

UCR 

Spring**

MCR 

Spring**

UCR 

Spring**

2007 WSNFH 

tagged

2.7% 1.7% 2.9%

2008 WSNFH 

tagged

22354 3.6% 4.2% 3.9%

2009 WSNFH 

tagged

10619 3610 21 1.0% 1.9% 2.7% 3.5% 2.9%

2010 WSNFH 

tagged

22297 10034 910 16.2% 30.2% 3.3% 4.6% 3.7%

2011 WSNFH 

tagged

18702 10847 318 5.2% 9.8% 5.6% 1.9% 5.9%

2012 WSNFH 

Rel

14937 3829 77 3.6% 6.7% 2.1% 1.6% 2.3%

WSNFH 

tagged

14937 4929 108 3.9% 7.3%

Round 

Butte

7489 5241 62 2.1% 3.9%

2013 WSNFN 

tagged

14979 8688 139 2.9% 5.3% 3.0% 0.7%

2014 6.1%

Average 5.0% 9.3% 3.3% 2.9% 3.2%

* Data from USFWS-Columbia River Fisheries Program Office. Reports 2012-2014. Release 

Numbers were verified and generate for past years using PIT Taggis queries.

**Predation Rates as reported in the FEIS Appendix C.

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Figure 8. Annual nesting success of East Sand Island double-crested cormorants from 1997-

2013. The average nesting success is 1.83 fledglings per nest. Graph courtesy of the Bird 

Research Northwest.org

Table 3. Number of breeding pairs of double-crested cormorants nesting on the Astoria-Megler 

Bridge and channel markers in the upper estuary near Miller Sands Spit, Woody Island, and 

Fitzpatrick Island. Reproduced from Lyons (2014).

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

19971998199920002001200220032004200520062007200820092010201120122013

Young Raised Per Breeding Pair

Annual Nesting Success

Average (1997-2012)

These data not available in 2014

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