A report by the Oregon Department of Fish and Wildlife

Transcription

1 NEHALEM RIVER FALL CHINOOK SALMON ESCAPEMENT INDICATOR PROJECT CUMULATIVE PROGRESS REPORT A report by the Oregon Department of Fsh and Wldlfe for work conducted pursuant to Natonal Oceanc and Atmospherc Admnstraton Award Numbers: : NA07FP : NA17FP : NA17FP2458 and U.S. Secton, Chnook Techncal Commttee Project Numbers: N98-17, N98-16, C99-14, C00-10, C00-11, C00-13, N01-17, and C02-05 Jody Whte Hal Weeks Bran Rggers June

2 TABLE OF CONTENTS LIST OF FIGURES...3 INTRODUCTION...4 OBJECTIVES...5 STUDY AREA...6 DATA COLLECTION METHODS...8 Mark-Recapture...8 Spawner Surveys...9 Rado Telemetry Estmatng Termnal Catch Future Genetc Analyses DATA ANALYSIS METHODS Spawner Escapement Estmates Rado Telemetry Creel Data Analyss RESULTS Spawner Escapement Estmates Spawnng ground survey calbratons Age Composton Rado Telemetry Habtat Use and Spawnng Ground Resdence Tme Termnal Harvest Estmates DISCUSSION ACKNOWLEDGMENTS REFERENCES APPENDIX A APPENDIX B

3 Lst of Fgures Fg. 1. Nehalem Rver watershed map wth capture stes noted. Fg 2. Fg 3A. Temporal dstrbuton of fall chnook taggng n the Nehalem Rver, Fg 3B. Temporal dstrbuton of fall chnook taggng n the North Fork Nehalem Rver, Lst of Tables Table 1. Nehalem Rver fall chnook survey reaches. Table 2. Nehalem Rver basn fall chnook spawner escapement estmates. Table 3. Precson and bas estmates for Nehalem Rver basn spawner escapement estmates. Table 4. Prelmnary expanson factors for Nehalem Rver fall chnook spawnng ground surveys. Table 5. Summary of Nehalem Rver basn fall chnook standard survey expanson coeffcents of varaton. Table 6. Age structure of Nehalem Rver fall chnook. Table 7. Dstrbuton of fall chnook spawnng n manstem and trbutary habtat strata as nformed by rado telemetry. Table 8. Estmated recreatonal catch of fall chnook n the Nehalem Rver basn,

4 INTRODUCTION The Oregon Department of Fsh and Wldlfe (ODFW) s conductng a mult-year, multbasn study desgned to develop methods that provde relable estmates of fall chnook salmon (Oncorhynchus tshawytscha) spawner escapements for Oregon coastal streams. Chnook salmon orgnatng n Oregon coastal rvers north of Elk Rver are northmgratng and vulnerable to fsheres off of southeast Alaska and Brtsh Columba. The U.S. Canada Pacfc Salmon Treaty establshed the Pacfc Salmon Commsson (PSC) to provde a framework to manage salmon fsheres. The 1999 modfcaton to the Treaty defnes an aggregate abundance based management (AABM) regme whereby harvests wll vary wth abundance. A broader goal of ths treaty s to restore and rebuld producton of naturally spawnng chnook (PSC 1997). In order to accomplsh these goals and montor the rebuldng of specfc chnook stocks, the PSC s Chnook Techncal Commttee (CTC) assesses three elements for each stock: 1) spawner escapement level, 2) fshery harvest and explotaton rate, and 3) subsequent producton from spawners. Data on dfferent chnook stocks provded by PSC partcpants (Canada and U.S. state, federal, and trbal agences) are used n the PSC s Chnook Model that generates nformaton on yearly pre- and post-season cohort abundance estmates. These estmates are used by the PSC to montor the relatve health of chnook stocks under PST jursdcton and to set ocean harvest levels. Currently, Oregon coastal chnook stock assessment nformaton comes from a standard spawner survey program, a voluntary angler-returned catch card system, and two explotaton rate ndcator stocks. These tradtonal montorng programs do not supply the CTC wth adequate nformaton that s requred for the management and rebuldng of Oregon s coastal chnook stocks. ODFW has conducted standard surveys for more than 50 years to montor the status of chnook stocks along coastal Oregon (Jacobs et al. 2000). A total of 56 standard ndex spawner surveys (45.8 mles) are montored throughout 1,500 stream mles on an annual bass to estmate peak escapement levels and track trends of north-mgratng stocks. Although counts n these standard surveys may be suffcent to ndex long-term trends of spawner abundance, they are consdered nadequate for dervng dependable annual estmates of spawner escapement. There are many weaknesses assocated wth usng standard surveys as a means to estmate fall chnook escapement. These surveys were not selected randomly and can not be consdered representatve of coast-wde spawnng habtat. Also, fall chnook are known to spawn extensvely n manstem reaches and large trbutares, whch are not conducve to vsual surveys. To provde estmates of escapements, ndex counts must be calbrated to known populaton levels. Obtanng accurate estmates of fall chnook spawner densty n these manstem reaches s extremely dffcult. Typcally, these areas exhbt wde varatons n stream flow and turbdty that create dffcult and sometmes dangerous survey condtons and that can result n unrelable vsual counts. Alternatve methods wll be employed and a more relable estmate may be possble by way of calbrated carcass counts. 4

5 The goal of ths project s to develop precse estmates of spawner escapement n the North Fork and manstem Nehalem Rver basns, and to dentfy survey ndces that can be used to estmate spawner abundance for the NOC and MOC stock aggregates. The North Fork Nehalem Rver and the South Fork Coos Rver were orgnally selected by the CTC for feasblty studes of escapement and calbraton efforts. The North Fork Nehalem was studed from 1998 through 2001, wth dsappontng results. Prmary effort shfted to the manstem Nehalem n In each case, a mark-recapture experment was beng conducted to obtan an estmate of fall chnook populatons n each rver. Varous survey ndces are beng used to estmate spawner abundance n trbutary and manstem spawnng habtat ncludng foot and boat surveys to obtan lve fsh counts and carcass counts. All or a combnaton of these methods wll be assessed to provde a chnook salmon spawner escapement to coastal Oregon rvers. Rado-telemetry was used to dentfy the dstrbuton of chnook spawners n the Nehalem basn n 2000 and 2001 between manstem and trbutary spawnng strata whch may contrbute to the tunng of ndces of abundance. A statstcal creel survey s beng conducted n the Nehalem Basn as a means of calbratng Oregon s angler-returned catch card estmates of recreatonal salmon take n rvers. Work n the manstem Nehalem wll contnue through the 2003 feld season. OBJECTIVES 1. Estmate the total escapement of adult chnook from ocean fsheres nto the Nehalem Rver wthn ± 25% of the true value 95% of the tme and to estmate the age specfc proportons of the escapement wthn ± 5% of the true value 95% of the tme. Specfc tasks that must be completed to acheve the overall objectve are: a) Estmate the spawnng escapement of chnook salmon n North Fork Nehalem Rver ( ) and the manstem Nehalem Rver ( ) such that the estmate s wthn ± 25% of the true value 95% of the tme, and estmate age/sex specfc proportons of that spawnng escapement such that the estmate s wthn ± 5% of the true value 95% of the tme. b) Estmate the sport harvest of chnook salmon n Nehalem Rver and Bay such that the estmate s wthn ± 25% of the true value 95% of the tme, and estmate age/sex specfc proportons of that harvest such that the estmates are wthn ± 5% of the true value 95% of the tme. 2) Determne the approprate spawner survey methodology that can be mplemented at the aggregate level to estmate chnook spawner abundance n the other fve Chnook producton rver systems n the NOC, by measurng several ndexes of spawner abundance usng ODFW s standard spawnng survey methods. 3) Estmate adult chnook salmon spawner dstrbuton among manstem and trbutary spawnng areas by rado telemetry (2000 and 2001 only). 5

6 STUDY AREA The Nehalem Rver s one of the eght chnook producton rver systems n the North Coast aggregate wth a manstem length of over 120 mles (Fgure 1). The rver s located entrely n the Oregon coastal mountan range wth a maxmum watershed elevaton of 3,510 ft. Average annual rver dscharge s 2,672 cubc feet per second (cfs) and hstorcally has ranged from 34 70,300 cfs. Peak dscharges typcally occur durng the wnter rany season from November untl February. Upland areas of the watershed are domnated by commercal tmberlands and floodplans are predomnately pastureland. Nehalem Rver Basn Beneke Creek Fshhawk Creek Nehalem Rver Telemetry Fxed Stes Tradtonal Surveys Humbug Creek Oak Ranch Creek North ForkNehalem Rver Waterhouse Falls Salmonberry Rver Nehalem Rver Rock Creek Nehalem Rver East Fork Nehalem Rver Cook Creek Taggng Area Fgure 1. Map of the Nehalem Rver watershed showng capture and taggng locatons on the North Fork and manstem. The Nehalem chnook stock has been labeled as a fall run (Ncholas and Hankn 1988). Most observed fall chnook spawnng peaks n November. Oregon coastal fall chnook are consdered ocean-type chnook and are a late-maturng stock wth females maturng prncpally at age 5 and males prncpally at age 4 (Ncholas and Hankn 1988). However, the fact that chnook start enterng Nehalem Bay n May and are found spawnng as early as September n the manstem as well as headwater trbutares suggests that a smaller component of sprng/summer run fsh s also present (Germond and Boechler 1988). 6

7 Hstorcally ( ) the only assessment of run-sze was by means of vsual surveys taken on foot at nonrandom standard spawnng stes. Counts of lve and dead chnook are used to generate a spawner densty ndex (peak fsh/mle). We do not know the relatonshp of ths ndex to the actual escapement. Dependng on the year, from 1.0 to 5.2 mles have been surveyed. Hodges and Jacobs (1997) and Rggers (1999, per. comm.) have estmated a total of 121 mles of spawnng habtat. Zhou and Wllams (1999) used ths hstorc data and several untested assumptons about the relatonshp of the peak counts and the spawner abundance to analyze the stock- recrutment relatonshp from The resultant producton curve allowed the authors to estmate an nterm bologcally based escapement goal requred by the new agreement. The MSY goal was estmated as 6,989 spawners (90% CI: 5,789-9,405). Fgure 2 llustrates these hstorc escapement estmates Year Fgure 2. Estmated escapements of fall chnook n Nehalem Rver from from Zhou and Wllams (1999). Ncholas and Hankn (1988) summarzed commercal harvest data from fsh-packng plants from 1896 untl commercal harvest was elmnated n the early 1950 s. Commercal harvests ranged from 8,000 18,000 fsh. Relable freshwater recreatonal harvest data before 1964 s lmted. Compared to other coastal rvers, the Nehalem Rver chnook stock has had mnmal hatchery nfluence (Walls 1961, Ncholas and Hankn 1988). Seventy-sx hatchery releases (36 were sprng run stocks) over nnety years have ranged from 15,600 to 1,460,000 chnook juvenles. All but three releases occurred before All fsh were off-ste hatchery releases and most were fngerlngs or of unknown age. Three smolt releases of Trask Rver stock occurred n the early 1970 s. 7

8 DATA COLLECTION METHODS Mark-Recapture Chnook spawner escapement was estmated usng a two-event mark-recapture experment. In the North Fork Nehalem, trappng was conducted at a fsh ladder that was desgned to ad wth fsh passage around a bedrock falls. The trap s located approxmately 14 mles uprver from the mouth, and about eght mles above head of tde. Chnook salmon were trapped, tagged and released from md-september through md-november at the North Fork Nehalem Rver trap. In 2000 and 2001, a wer was constructed at approxmately rver mle 8. In the manstem Nehalem, chnook salmon were captured through tangle nettng, and at a wer located n Mohler at approxmately rver mle 12. Through the course of ths study, we adjusted our capture and markng efforts to begn n August n order to capture and mark the entre run of fall chnook. (Fg 3) Nehalem Manstem Fall Chnook Taggng Number Tagged Julan Week Fgure 3A. Tmng of fall chnook taggng n the manstem Nehalem, Nehalem North Fork Fall Chnook Taggng Number Tagged Julan Week Fgure 3B. Tmng of fall chnook taggng n the North Fork Nehalem,

9 Taggng occurred on a daly bass to mnmze the the effect on upstream mgraton was delayed. Trapped salmon were placed nto a hooded cradle for taggng and nspecton. Usng a Dennson Mark II taggng gun, an anchor tag was placed on the left sde of the dorsal. Tags dsplayed a unque number and were of a neutral color, as not to bas recovery of tagged fsh. Each anchor-tagged fsh was gven a left opercle mark wth a paper punch. Ths double dentfcaton was appled to negate tag loss. Fork length, sex, tag number, and presence of fn clps were recorded before release. A scale sample was taken from each chnook for later age analyss. Begnnng n 2002, we dscontnued the use of numbered anchor tags. Rather, fsh were marked wth operculum punches and clppng the rght axllary appendage at upper rver ste only). Locaton and number (one or two) of punches served to dentfy the week of capture and markng. After taggng each fsh was allowed to recover n the aerated lve well and subsequently released to contnue ts upstream mgraton. Spawner Surveys The second event of the two event mark-recapture experment nvolves actvely locatng chnook carcasses upstream of the markng stes. Spawnng ground surveys were conducted to recover carcasses and record lve counts. Carcasses were sampled for length, sex, scales, tag dentfcaton number, and operculum punch. Surveys desgnated as part of the random survey desgn were conducted on a weekly bass. The survey desgn conssted of a random selecton of survey reaches wthn two strata, manstem and trbutary. Surveyors collected basc bologcal and physcal data ncludng lve counts and carcasses counts. Each carcass was sampled for scales, length, and sex. Sampled carcasses were marked to prevent re-samplng. All of these surveys were performed accordng to ODFW spawner survey protocol (ODFW 1998). Surveys were walked n an upstream drecton and at a pace adapted to weather and vewng condtons. Surveys were not conducted f the bottom of rffles could not be seen. Surveyors worked n pars and each wore polarzed glasses to ad n locaton and dentfcaton of lve fsh. The trbutary and manstem strata were determned accordng to ODFW coho spawner dstrbutons. For the purpose of ths study, trbutary strata were defned as those stream areas that supports habtat that s conducve to coho (Oncorhynchus ksutch) spawnng as documented n the ODFW database of coho spawnng dstrbuton (Jacobs and Nckelson 1998). The random survey desgn n trbutary reaches ncorporated all coho surveys selected through the Envronmental Montorng and Assessment (EMAP) selecton process as part of the montorng assocated wth the Oregon Plan for Salmon and Watersheds (Frman 1999) that overlapped wth chnook spawnng habtat. Addtonal surveys were selected randomly to ncrease the samplng rate. Manstem strata for the two calbraton stes were desgnated as those areas that were downstream of coho spawner dstrbuton and ncluded all rver and trbutary areas upstream of tdewater. Surveys were conducted on foot n manstem strata when flows permtted safe navgaton. Surveyors floated these manstem surveys n nflatable kayaks durng perods of hgher flows. Manstem surveys were conducted on a regular bass as flow and vsblty allowed. Four manstem surveys totalng 4.9 mles and equatng to 100% of the avalable habtat were conducted above the trap on the North Fork Nehalem Rver n 1998 through (Table 1). Kayaks were used n order to access and search both rverbanks. Surveyors searched all areas of the banks, pools, and other low energy areas where carcasses are lkely to be deposted. Sx surveys totalng 5.2 mles and equatng to approxmately 29% of the avalable trbutary habtat were conducted above the trap on the North Fork Nehalem Rver (Table 1). Table 1. Lst of standard and random fall chnook surveys conducted n the North Fork Nehalem and manstem Nehalem Rver durng ths project. Start and endponts desgnates reach breaks and are not necessarly surveys boundares. Lengths are n mles. 9

10 Table 1A. Nehalem Basn Standard Surveys Conducted Annually Sub-basn Reach Reach ID Mles Manstem Cook Crk Cronn Crk Humbug Crk E. Humbug Crk Salmonberry Salmonberry R North Fork Soapstone Crk Table 1B. Randomly selected surveys conducted n the North Fork Nehalem Rver. Locaton Reach Start End Segment Length Nehalem Rver Manstem: Nehalem R, N Fk Sally Cr Gods Valley Cr Nehalem R, N Fk Gods Valley Cr Lost Cr Nehalem R, N Fk Lost Cr Sweet Home Cr Nehalem R, N Fk Lost Cr Sweet Home Cr Nehalem R, N Fk Sweet Home Cr Fall Cr Trbutary: Lost Cr. Mouth Head Waters Sweet Home Cr. Mouth Sweet Home Cr Nehalem R, N Fk Fall Cr. Nehalem R, N Fk Nehalem R, N Fk Nehalem R N Fk Nehalem R, N Fk Nehalem R, N Fk Nehalem R N Fk Nehalem R, Lttle Nehalem R, N Fk Nehalem R, Lttle Nehalem R, Lttle

11 Table 1C. Nehalem Random Fall Chnook Surveys Random Surveys Conducted n 2000 Chnook Habtat Type Reach ID Reach Start End Manstem Nehalem R Cook Cr Lost Cr 1.1 Manstem Nehalem R Helloff Cr Bastard Cr 1.9 Manstem Nehalem R Snark Cr Salmonberry R 3 Manstem Salmonberry R Mouth Hatchery Cr 0.3 Length (mles) Manstem Salmonberry R Buck Canyon Belfort Cr 0.5 Manstem Salmonberry R Tunnel Cr Salmonberry R, S Fk 1.2 Manstem Salmonberry R Salmonberry R, S Fk Bathtub Cr 0.4 Manstem Salmonberry R Beldng Cr Knney Cr 0.96 Manstem Nehalem R Salmonberry R Cronn Cr 1.9 Manstem Nehalem R Cronn Cr Trb Manstem Nehalem R Spruce Run Cr George Cr 3.2 Manstem Nehalem R George Cr Humbug Cr 1.5 Manstem Nehalem R Humbug Cr Quartz Cr 1.8 Manstem Nehalem R Cow Cr Klnes Cr 0.5 Manstem Nehalem R Klnes Cr Moores Cr 0.6 Manstem Fshhawk Cr Mouth Beneke Cr 0.7 Lttle Fshhawk Manstem Fshhawk Cr Beneke Cr Cr 1.5 Manstem Nehalem R Fshhawk Cr Slaughters Cr 1.4 Manstem Nehalem R Strum Cr Squaw Cr 0.7 Manstem Nehalem R Calvn Cr Ford Cr 1.5 Manstem Nehalem R Cedar Cr Oak Ranch Cr 0.5 Manstem Nehalem R Crooked Cr Cook Cr 0.4 Manstem Rock Cr Bear Cr Ivy Cr 1.5 Manstem Rock Cr Bear Cr Ivy Cr 1 Manstem Rock Cr Selder Cr Fall Cr 1.6 Manstem Rock Cr Fall Cr Gnger Cr 2.5 Manstem Nehalem R Rock Cr Beaver Cr 2.1 Manstem Nehalem R Cedar Cr Weed Cr 1.3 Trbutary Foley Cr E Foley Cr Crystal Cr 1.2 Trbutary Anderson Cr Mouth Headwaters 1.12 Trbutary Cook Cr Hanson Cr Cook Cr, S Fk 0.86 Trbutary E Humbug Cr Mouth Headwaters 1.18 Trbutary Beneke Cr Glmore Cr Walker Cr 1 Trbutary Lttle Fshhawk Cr Mouth Headwaters 2.3 Trbutary Fshhawk Cr Lttle Fshhawk Cr Alder Cr 0.9 Nehalem Random Fall Chnook Surveys

12 Chnook Habtat Type Reach ID Reach Start End Manstem Cook Cr Mouth Dry Cr 1.1 Manstem Nehalem R Bastard Cr Snark Cr 1 Manstem Salmonberry R Mouth Hatchery Cr 0.3 Manstem Salmonberry R Hatchery Cr Buck Canyon 1.2 Manstem Salmonberry R Buck Canyon Belfort Cr 0.5 Manstem Salmonberry R Belfort Cr Preston Cr 0.7 Length (mles) Manstem Salmonberry R Preston Cr Tank Cr 1.2 Manstem Salmonberry R Salmonberry R, S Fk Bathtub Cr 0.4 Manstem Salmonberry R Salmonberry R, N Fk Beldng Cr 1.1 Manstem Salmonberry R Beldng Cr Knney Cr 0.96 Manstem Nehalem R George Cr Humbug Cr 1.5 Manstem Nehalem R Humbug Cr Quartz Cr 1.8 Manstem Nehalem R Osweg Cr George Cr 0.5 Manstem Nehalem R Fshhawk Cr Slaughters Cr 1.4 Manstem Nehalem R Slaughters Crk Crawford Crk 1.5 Manstem Nehalem R Northrup Cr Sager Cr 2.4 Manstem Nehalem R Sager Cr Lousgnot Cr 1.5 Manstem Nehalem R Lousgnot Cr Grub Cr 1 Manstem Nehalem R Grub Cr Deep Cr 1.9 Manstem Nehalem R Deep Cr Fshhawk Cr 2.6 Manstem Nehalem R Battle Cr Deer Cr 0.7 Manstem Nehalem R Crooked Cr Cook Cr 0.4 Manstem Nehalem R Nehalem R, E Fk Knckerson Cr 1.7 Manstem Nehalem R Nehalem R, E Fk Knckerson Cr 1.4 Manstem Nehalem R Nehalem R, E Fk Knckerson Cr 0.75 Manstem Nehalem R Knckerson Cr Coon Cr 1.7 Manstem 26097, seg 3 Rock Cr Bear Cr Ivy Cr 1.2 Manstem 26097, seg 4 Rock Cr Bear Cr Ivy Cr 2.4 Manstem 26097, seg 7 Rock Cr Bear Cr Ivy Cr 0.91 Manstem Nehalem R Cedar Cr Weed Cr 1.3 Manstem Nehalem R Weed Cr Clear Cr 1 Trbutary Foley Cr E Foley Cr Crystal Cr 1.2 Trbutary Anderson Cr Mouth Headwaters 1.12 Trbutary Lost Cr Mouth Headwaters 1.14 Trbutary Fall Cr Mouth Headwaters 0.98 Trbutary Buster Cr Mouth Lttle Rock Cr 1 Trbutary Beneke Cr Glmore Cr Walker Cr 1 12

13 Random Fall Chnook Surveys Conducted n 2002 Chnook Habtat Type Reach ID Reach Start End Manstem Nehalem R Anderson Cr Cook Cr 1.3 Manstem Cook Cr Mouth Dry Cr 1.1 Manstem Nehalem R Cook Cr Lost Cr 1.1 Manstem Nehalem R Fall Cr Helloff Cr 1.1 Manstem Nehalem R Bastard Cr Snark Cr 1 Manstem Salmonberry R Mouth Hatchery Cr 0.3 Manstem Salmonberry R Hatchery Cr Buck Canyon 1.2 Manstem Salmonberry R Belfort Cr Preston Cr 0.7 Length (mles) Manstem Salmonberry R Preston Cr Tank Cr 1.2 Salmonberry R, Manstem Salmonberry R Tunnel Cr S Fk 1.2 Manstem Nehalem R Salmonberry R Cronn Cr 1.9 Manstem Nehalem R Cronn Cr Trb Manstem Nehalem R Spruce Run Cr George Cr 3.2 Manstem Nehalem R George Cr Humbug Cr 1.5 Manstem Nehalem R Humbug Cr Quartz Cr 1.8 Manstem Nehalem R Quartz Cr Osweg Cr 1 Manstem Nehalem R George Cr Cow Cr 1 Manstem Nehalem R Moores Cr Buster Cr 1.3 Manstem Nehalem R Buster Cr Fshhawk Cr 1.5 Manstem Nehalem R Fshhawk Cr Slaughters Cr 1.4 Manstem Nehalem R Squaw Cr Northrup Cr 2.5 Manstem Nehalem R Sager Cr Lousgnot Cr 1.5 Manstem Nehalem R Lousgnot Cr Grub Cr 2.3 Manstem Nehalem R Deep Cr Fshhawk Cr 2.6 Unnamed Trb, Manstem Nehalem R Nehalem R Adams Cr 0.5 Manstem Nehalem R Adams Cr Calvn Cr 1.3 Manstem Nehalem R Lundgren Cr Battle Cr 1.9 Manstem Nehalem R Deer Cr Gus Cr 0.8 Manstem Nehalem R Deer Cr Gus Cr 1.9 Nehalem R, E Manstem Nehalem R Cook Cr Fk 2.2 Manstem Nehalem R Nehalem R, E Fk Knckerson Cr 1.7 Manstem Nehalem R Nehalem R, E Fk Knckerson Cr 1.4 Manstem Nehalem R Knckerson Cr Coon Cr 1.7 Manstem 26097, seg 4 Rock Cr Bear Cr Ivy Cr 2.4 Manstem 26097, seg 7 Rock Cr Bear Cr Ivy Cr 0.91 Trbutary Foley Cr E Foley Cr Crystal Cr 1.2 Foley Cr, Trb Trbutary Foley Cr Dry Cr Q

14 Trbutary Anderson Cr Mouth Headwaters 1.12 Trbutary Cook Cr Harlss Cr Patt Canyon 1 Trbutary Cook Cr Cook Cr, E Fk Hoevett Cr 0.66 Trbutary Lost Cr Mouth Headwaters 1.14 Trbutary Salmonberry R Buck Canyon Belfort Cr 0.5 Trbutary Cronn Cr, N Fk Mouth Headwaters 0.54 Cronn Cr, M Trbutary Cronn Cr Cronn Cr, N Fk Fk 1 Trbutary Humbug Cr Mouth Cedar Cr 0.88 Trbutary Humbug Cr Bg Cr Alder Cr 1.18 Trbutary E Humbug Cr Mouth Headwaters 1.18 W Humbug Cr, Trbutary W Humbug Cr Beaver Cr Trb A 1 Trbutary Beneke Cr Mouth Glmore Cr 1.15 Trbutary Beneke Cr Glmore Cr Walker Cr 1 Trbutary Hamlton Cr Mouth Headwaters 1.14 Trbutary Hamlton Cr Mouth Headwaters 0.86 Trbutary Rock Cr Gnger Cr Martn Cr 1.08 Trbutary Rock Cr Gnger Cr Martn Cr 0.98 Trbutary Rock Cr Weed Cr Olson Cr 0.39 Trbutary Rock Cr Olson Cr Rock Cr, N Fk 1.08 Trbutary Wolf Cr Mouth Wolf Cr, N Fk 1.3 Rado Telemetry Adult fall chnook salmon n the manstem Nehalem were rado tagged n 2000 and 2001 to understand spawner dstrbuton between manstem and trbutary habtat strata. Rado-taggng was conducted n conjuncton wth the frst capture event of the mark-recapture experment. Transmtters were placed nto the esophagus of each adult wthout the use of anesthetcs and then released. Fsh were selected by a systematc sample wth a random start. Only healthy fsh were tagged. We used seven-volt, dgtally encoded Lotek rado transmtters. Each transmtter weghs 13 g n water and s 16 X 83 mm n dmensons wth a 30 cm whp antennae and a battery lfe of 265 days. Snce some of the transmtters had already been used, the expected remanng battery lfe vared from days dependng on the transmtter s use hstory. Transmtters used sx channels (MHz), 9 ( ), 10 ( ), 14 ( ), 18 ( ), 21 ( ), and 22 ( ). Each frequency conssted of multple codes, so that each transmtter had a unque dentfer. Trackng methods was done usng three fxed statons to record mgraton tmng one at the mouth of Humbug Creek, one at the mouth of Deep Creek, and the thrd at a prvate resdence n Vernona. At approxmately two week ntervals, one surveyor drove the rver basn locatng fsh and documentng the extent of upstream movement wth a GPS unt. One day of aeral trackng was accomplshed n cooperaton wth the Oregon State Polce. 14

15 Estmatng Termnal Catch Creel Survey Desgn Rovng-access and rovng-rovng survey desgns were employed dependng on geographc area and fshng method (Pollock et al. 1994). For the rovng access pont survey, anglers that completed fshng were ntervewed as they leave a boat landng or marna and anglng effort was determned from the total number of anglers that left the sampled access pont durng the day. Access pont surveys are approprate for areas wth only one or two access ponts and effort s determned by usng data generated from ntervews durng the samplng perod as opposed to an nstantaneous measure used n a rovng survey. In rovng surveys, a surveyor move or rove through a fshng area makng angler or boat counts to determne effort (pressure counts) after whch they conduct angler ntervews. Rovng-access surveys are used when most anglers are concentrated at numerous, known locatons (e.g. marnas) and anglers are ntervewed as they leave an area once fshng s completed. However, wth rovng-rovng style surveys, anglers are not concentrated Catch Areas for the Nehalem Bay and Rver Creel Project. Catch Area Descrpton 1 Ocean An area wthn 1 mle of the mouth of the bay that les outsde an magnary lne drawn perpendcular across the west ends of the jettes. 2 Lower Nehalem Bay The bay area from a lne perpendcular across the west end of the jettes up to a lne perpendcular across the bay at the State Park Boat Ramp. 3 - Upper Nehalem Bay A lne perpendcular across the bay at the State Park Boat Ramp up to and ncludng the frst vsble porton of the North Fork Nehalem Rver. 4 Tdewater The manstem Nehalem Rver from an magnary lne drawn across the rver just upstream of the North Fork mouth upstream to the Roy Creek Brdge. 5 Manstem below Falls Nehalem Rver from the Roy Creek Brdge upstream to the base of the Nehalem Rver Falls. 6 Manstem above Falls All areas open to chnook fshng upstream of the Nehalem Rver Falls at known locatons (bank anglers) and a surveyor moves through the fshery ntervewng anglers whle they are stll fshng. The surveys were stratfed by catch area, month, day (weekend, weekday), and angler type (bank or boat). Anglers were further dvded nto two groups, prvate and guded anglers, and post-stratfed f catch rates were found to dffer. Angler ntervews ncluded the number of hours fshed, number of anglers n the boat or on shore, the number of salmonds caught or released (by speces), and resdency of the angler. All data was entered nto hand-held electronc dataloggers. Fsh checked were sampled for scales, length measured, sex dentfed, and the number and types of fn marks noted. If an adpose fn s mssng a detecton wand wll be used to determne f a coded wre tag s present. If present, the snout wll be removed for future tag decodng. Nehalem Bay and Tdewater (Catch Areas 1-4) 15

16 A rovng-access creel survey was used for all bay and tdewater locatons. Access ponts were sampled proportonally to the monthly effort observed at each landng n Surveyors traveled a predetermned schedule of wat and travel tme, wth access ponts randomly chosen, movng between the eght access ponts ntervewng anglers. The samplng schedule wll allow each access pont to be sampled proportonal to the amount of anglng effort. Amount of effort per access pont was calculated from ntervew data gathered n Two surveyors ntervewed boat anglers as they return from fshng. To allevate problems wth dfferng effort due to tme of day and tdal cycles, each day wll be surveyed n ts entrety. At each locaton, all boats returnng to the marna were ntervewed f possble. If large numbers of boats return to the dock and all cannot be ntervewed, the surveyor ntervewed a systematc random sample. Because the pressure counts recorded total number of boats n each catch area, all boats regardless of target speces or actvty were ntervewed. If a contacted boat has fshed for multple fsh types (e.g. salmon and crabbng or bottom fshng), two ntervews are completed, one for the salmon anglng and an addtonal one for non-salmon actvtes. Smlarly, f a sngle boat fshed multple areas, multple ntervews are completed - one ntervew for each area fshed. Fshng effort n Catch Areas 1-4 s estmated by countng boats from several vantage ponts around the bay. Pressure counts typcally take less than 30 mnutes to complete and are consdered nstantaneous. Four or fve pressure counts, dependng on tme of year, wll be recorded throughout the day at assgned three hour tme ntervals. Boats n moorage and kayaks are not ncluded n the count. Manstem Nehalem Rver (Catch Areas 5-6) Both boat and bank anglers were ntervewed on the manstem Nehalem below Nehalem Rver Falls (Catch Area 5). Surveys began n early to md-august, dependng on water condtons and anglng effort. One surveyor began samplng the manstem Nehalem Rver n late-august. Hstorcally, rverne anglng effort s nsgnfcant untl water flows ncrease (usually n September) and large numbers of fsh move nto the rver. Each surveyor worked four, ten-hour days a week, two weekend days and two-week days. A day was stratfed nto an AM shft and a PM shft. AM shfts began at 6:00 and ended at 4:00 and PM shfts were from 11:00 9:00. AM shfts were sampled at twce the rate as PM shfts. For bank anglers, a rovng-rovng style survey was used. A surveyor moved through Catch Area 5 (ncludng the shore areas just below the Roy Creek Brdge n Catch Area 4) randomly ntervewng anglers. Anglng effort or pressure counts took place at three ntervals dependng on day length by drvng the manstem and Andersen Creek roads and countng all people fshng. Pressure counts conssted of countng all cars located n the catch area that are parked n locatons used by anglers. Pressure counts typcally take less than 45 mnutes and are consdered nstantaneous. Once the pressure count s complete, the surveyor ntervewed anglers untl the next scheduled pressure count. Intervews conssted of the same nformaton gathered n the boat surveys. However, a sample conssted of ntervewng a group of anglers that are attrbuted to each car. Non-anglers n the catch area were also ntervewed to estmate the use by non-anglers and approprately adjust the effort count. The rovng surveyor on the manstem Nehalem also sampled boats that have completed fshng at Mohler Sand and Gravel. There are only three access ponts n Catch Area 5 that anglers can use to launch boats. The most upstream put-n s the Beaver Slde, several mles downstream s the Mohler Sand and Gravel access and the most downstream landng s Roy Creek. Effort was be determned by countng tralers at the Beaver Slde putn durng the bank angler pressure count. Samplng was not been scheduled for the Nehalem Rver above the Nehalem Rver Falls (Catch Area 6). Perodc surveys n determned that angler effort and catches n the area were too small to sgnfcantly affect the catch estmate for the basn and dd not warrant the requred survey effort. 16

17 Future Genetc Analyses The populaton structure of fall chnook n the Nehalem Rver basn s unknown. There may be more than one dstnct breedng populaton of fall chnook. We suspect that the upper basn fall chnook are dstnct from other manstem Nehalem groups based on mgraton tmng and dstance traveled. It could be that there are addtonal dstnctons to be drawn among groups n the man Nehalem basn. To make ths determnaton possble, ODFW feld crews collected tssue samples (a rayed fn clp) from chnook collected by the brood program and from carcasses collected on spawnng grounds. Collected tssue samples are stored n ethanol and are archved wth Dr. Mchael Banks of OSU s Hatfeld Marne Scence Center. Dr. Banks wll be collaboratng wth other coastal labs n the establshment of a DNA baselne for fall chnook that wll be a sgnfcant frst step toward genetc stock dentfcaton. DATA ANALYSIS METHODS Spawner Escapement Estmates The Chapman verson of the Peterson mark/recapture formula was used to estmate fall chnook escapement above trap stes. Estmates were derved usng the followng formula: ˆ ( M + 1)( C + 1) N = R + 1 where ( ) Nˆ = the estmated populaton of fall chnook above the trap for calbraton ste. M = the number of fall chnook tagged at the trap ste. C = the number of fall chnook recovered on the spawnng grounds. R = the number of recovered tagged fall chnook. The assumptons for use of the Peterson estmator are: 1. all fsh have an equal probablty of beng marked at the trap ste; or, 2. all fsh have an equal probablty of beng nspected for marks; or, 3. marked fsh mx completely wth unmarked fsh n the populaton between events; and, 4. there s no recrutment to the populaton between capture events; and, 5. there s not trap nduced behavor; and, fsh do not lose ther marks and all marks are recognzable. Assumptons 1 and 2 are presumed not to hold true for trappng on the North Fork Nehalem Rver and manstem Nehalem Rver. The proporton of chnook marked at the trap stes vares due to flow condtons and trap neffcences. The same holds true on the spawnng grounds for carcass collecton. However, nformaton about sze and age selectvty durng the two capture events can be estmated through a battery of tests (Appendx A) to determne f further stratfcaton of the data set s approprate to meet the assumptons. Assumpton 3 wll be estmated by data from the spawnng grounds stratfed by area and tme. Ch-square analyss wll be used to determne f there are sgnfcant dfferences between the strata. If dfferences are found, the Darroch (1961) maxmum lkelhood estmator wll be used. If the resultng estmate s wthn 10% of the pooled Peterson estmator, the stratfed estmate wll not be used for smplcty sake. 17

18 Assumptons 4 and 5 do not apply to ths stuaton. Only adult chnook salmon mgratng upstream of the trap stes were used n the mark-recapture study and recrutment to the populaton s not possble. The second capture event s an actve samplng technque to collect carcasses wthn the spawnng areas upstream of the trap stes and trap nduced behavor wll not occur. However, for the frst event, trap nduced behavor can occur and age/sex selectvty s estmated as dscussed for sze bas. Tag loss (assumpton 6) was assumed to be zero because of the use of multple tags. All tags were assumed to be dentfed f present. Through the use of mutlaton marks and anchor tags, traned feld crews should observe each tagged fsh. The uses of multple marks (ncludng tags and an operculum punch) have been shown to assure the dentfcaton of marked fsh on the spawnng grounds (Pahlke et al. 1999). A bootstrap technque was used to estmate varance, bas and confdence ntervals of the populaton estmate (Buckland and Garthwate 1991, Mooney and Duval 1993). The fate of chnook that pass by each trappng faclty were dvded nto several capture hstores to form an emprcal probablty dstrbuton as follows: 1. marked and harvested n fshery (= H ), ths was assumed zero, 2. marked and were captured out of the experment area (= F ), 3. marked and recaptured on the spawnng grounds (= R ), 4. marked and never seen agan (= Mˆ - R ), 5. unmarked and nspected on the spawnng grounds, and (= C - R ), 6. unmarked and never seen (= N ˆ - Mˆ - C + R ), where M = the number of fsh tagged at a trap ste (event 1), C = the number of carcasses nspected on spawnng grounds (event 2), R = the number of marked fsh recovered on spawnng grounds (event 3), and N s the populaton estmate. A random sample of sze N was drawn wth replacement from the emprcal probablty dstrbuton. Values for the statstcs M *, C *, R * were calculated and a new populaton sze N * estmated. We repeated ths process 1,000 tmes to obtan samples for estmates of varance, bas and bounds of 95% confdence ntervals. Varance was estmated by: B Â ˆ * b= 1 v( N ) = 2 ( ˆ * ˆ * N ( b) - N ) B -1 where B equals 1,000 (the number of bootstrap samples). The 95% confdence ntervals of the estmate are taken as +/- 1.96*s( N ) from the bootstrap smulaton. The 95% relatve precson of the estmate s thus 1.96*s( N )/ Nˆ. * ˆ To estmate the statstcal bas, the average or expected bootstrap populaton estmate was subtracted from the pont estmate (Mooney and Duvall 1993:31). * ˆ 18

19 Bas ˆ = ˆ - ˆ, where * ( N ) N N Nˆ * B Â b= = 1 Nˆ B * ( b) Rado Telemetry Rado telemetry nformaton was used to partton the basn-wde make-recapture estmate nto trbutary and manstem strata. Several assumptons must be taken nto consderaton n order to effectvely use telemetry data: 1) fsh tagged are typcal of the populaton of nterest, and 2) behavor s not altered by handlng or the presence of a tag, and 3) survval s not altered by handlng or presence of a tag Fsh were selected by a systematc random sample over the entre run at manstem wer, whch mnmzed any bas n selecton of tagged fsh (assumpton 1). From the mark-recapture experment, data on selectvty of fsh ether by sze, sex or tmng was avalable to assess any bas n the taggng procedure f t exsts. However, snce the fsh that are avalable to the mark-recapture experment and the telemetry study should be based smlarly, based selecton should not be a problem for the telemetry study. The populaton of nterest s the dstrbuton of tagged fsh n the Nehalem Rver, snce that s the only nformaton the mark-recapture estmate wll be usng. Changes n survval between tagged and non-tagged fsh (assumpton 3) were assessed by anecdotal nformaton gathered on the number of pre-spawn mortaltes of rado tagged fsh compared to the observed pre-spawn mortalty of anchor tagged fsh n the watershed. The fracton of chnook located n each stratum (trbutary or manstem) was estmated by (Cochran 1977): n pˆ = nˆ h, where nˆ = n - n - n - n, and f m l n = number of fsh wth transmtters that spawned n ether a trb. or manstem statum, n h = fsh wth transmtters returned from anglers, n f = fsh wth transmtters that dd not contnue mgratng up the Nehalem Rver, n m = fsh wth transmtters that ded before spawnng, and n l = transmtters that were regurgtated, batteres faled, or not recorded agan. The estmated varance of p s: var( pˆ ) = pˆ (1 - pˆ ) nˆ -1 Therefore the estmated number of chnook ( Nˆ ) n each stratum s: Nˆ = pˆ Nˆ, where Nˆ = the chnook salmon escapement estmate from the mark-recapture experment. The varance of the estmated chnook populaton n stratum s (Goodman 1960): 19

20 Peak count s the largest sum of the lve and carcass counts recorded on a sngle day for each survey. The peak counts are expressed as fsh per unt length and averaged by each stratum. The hgh stratum of the manstem was entrely surveyed; thus peak counts of each survey were summed. Expandng the average peak count for the other strata derved an escapement ndex for the total length of habtat n each stratum. Average peak count per mle n each strata (S) was calculated as follows: S = ( where n  = 1 [ ( p ) Nˆ 2 + ( Nˆ 2 var ˆ var ) pˆ var( Nˆ ) var( pˆ )] var( N ) =  - n  P ) /( M = 1 ) n = the number of surveys P = peak count of the sum of carcasses and lve chnook n survey M = length of survey (mles) Creel Data Analyss The Nehalem Rver creel survey s stratfed by month, catch area, and angler type (shore or boat). Dependng on harvest rates, anglers could be further post-stratfed nto prvate trps and guded trps. Data analyss procedures for post-stratfcaton of prvate and guded trps wll follow Bernard et al. (1998) f harvest rates dffer sgnfcantly between the trp types. Mssng data ponts from surveyor llness or equpment falures wll be treated as random events and removed from the samplng frame. Bernard et al. (1998) descrbes several other events whch must be taken nto account durng analyss that can bas harvest estmates ncludng 1) zero ntervews, but anglng effort was counted, 2) zero harvest rate, but effort was counted, and 3) very low (1-2) numbers of ntervews but wth harvest. If any of these stuatons are encountered and deemed to bas the dataset, the data wll be treated as mssng data ponts and the substtuted values derved from methods descrbed n Bernard et al. (1998) and Guthre et al. (1991). Rovng-Access Survey: Harvest wll be determned separately for kept fsh and for released fsh. Estmated harvest per sample day n a partcular stratum s (Pollock et al. 1994, Bernard et al. 1998) Hˆ = Eˆ cpue where, denotes samplng days, Ê = estmated effort, and c pue =average catch per unt. Because the rovng-access surveys only ntervew completed angler trps average catch per unt effort s estmated as the rato of means (Hoeng et al. 1997): 20

21 cpue = m  k= m hk 1, where  k= 1 e k k denotes ndvdual anglers, m denotes the number of anglers ntervewed, h s the number of fsh caught durng fshng trps that were ntervewed, and e s the length n hours of fshng trps of ntervewed anglers. Varance of cpue s estmated as (Bernard et al. 1998): m  k= 1 v( cpue ) = 2 e m 2 ( h - e cpue ) k k ( m -1). Fsh harvested per catch/month strata equals: Hˆ d  Hˆ = 1 = D d where, d = number of sampled days n stratum, and D = total avalable samplng days n stratum. Daly effort s estmated as: Eˆ r  x t= 1 = T r t where, t denotes the ndvdual rovng count of anglers r = number of pressure counts per day, and T = the length of the samplng perod (usually day length). Snce effort s determne systematcally and not randomly the varance equaton s (Wolter 1985): r 2 Â( xt - x( t-1) ) ˆ 2 t= 2 v( E ) = T 2 r ( r -1). The varance of the daly harvest s (Goodman 1960 as cted by Bernard et al. 1998): 21

22 ˆ ˆ 2 2 v( H ) = E ( cpue ) + cpue v( Eˆ ) - v( cpue ) v( Eˆ and the varance for each catch/month stratum s: ) ˆ s1 v( H ) = D( D - d ) d s 2 1 =  ( Hˆ - Hˆ ) 2 2, d -1 + D d d  = 1 v( Hˆ ), where Total harvest s the sum of all catch n each strata and the total varance of the catch s the sum of all strata varances (Pollock et al. 1994). Rovng-Rovng Surveys: The only dfference n estmaton between the rovng rovng survey and the rovng access survey s the catch per unt effort (cpue) estmator. Wth rovng surveys anglers are ntervewed that have not completed fshng and the mean of ratos estmator should be used (Pollock et al. 1994). cpue m hk  k= ek = 1, where n k denotes ndvdual anglers, m denotes the number of anglers ntervewed, h k s the number of fsh caught for an ntervewed angler, e k s the length n hours fshed for an ntervewed angler, and n s the number of ntervews for each day. The varance s calculated as (Jones et al. 1995): v( cpue ) Ê m hk  ek Á k= 1 = Ë ek m m  = 1 - cpue e k ˆ 2. RESULTS Spawner Escapement Estmates We marked between 98 and 335 adult (> 600 mm fork length) fall chnook n the North Fork Nehalem basn from 1998 to 2001, and from 348 to 1,941 adult fall chnook n the mantem Nehalem from 2000 to Success n capture and markng mgratng fall chnook vared dependng on run sze, tmng of operatons, and flow condtons. We experenced greater success as we learned from experence and covered a greater proporton of the run, and as we mproved wer desgn. 22

23 Carcasses nspected n spawnng ground surveys ranged from 49 n the Nehalem North Fork n 2001 to nearly 2,900 n the manstem Nehalem n Numbers of marked chnook recaptured ranged from 0 to 281. Our percentage recapture ranged from 0 to 14.5%, also n the Nehalem manstem n Table 2 summarzes results for numbers of chnook marked, carcasses nspected and marked chnook recaptured. We estmated spawner escapement numbers based on a pooled Peterson model. We also present estmates n Table 2 for stratfed Peterson estmates based on sex, sze and both sex and sze for the manstem Nehalem. In all cases but one, the stratfed estmates were wthn 5% of the fully pooled Peterson estmate. The sngle excepton was the estmate for the manstem Nehalem n 2000 stratfed by both sex and sze. We feel that ths estmate s drven strongly by the low numbers of female chnook recaptured that year, and that ths estmate s not relable. We conducted ch-square tests for random assortment marked and unmarked chnook across sub-basns, and by Julan week n 2000 and 2001 (Appendx B). In most cases, we reject the null hypothess of random assortment of these chnook. Accordngly, we performed stratfed Darroch estmates of abundance. These are also presented n Table 2 and show close agreement wth the fully pooled Peterson estmates. Therefore, we present the fully pooled Peterson estmates of spawner escapement as our best estmates based on the work performed n ths study. The 95% relatve precson of our estmates were wthn the 25% objectve for the Nehalem manstem n 2001 and 2002 (Table 3). However, they were wthn 25% only n 1999 on the North Fork Nehalem. The falure to recover any marked carcasses n 2001 spawnng ground surveys on the North Fork Nehalem was very dsappontng, and prevents us from puttng forward an escapement estmate for that year. Number of marked carcasses recovered s the prmary element contrbutng to the level of precson of a spawner abundance estmate. We attrbute the mproved precson over tme n the manstem Nehalem to feld crew experence n learnng how to conduct surveys and where to look for marked carcasses. 23

24 Table 2: Spawner populaton estmates wth numbers of chnook marked, carcasses nspected and marked chnook recaptured durng four years of work n the Nehalem Rver basn Table 2A: Manstem Nehalem spawner escapement estmates Pooled 95% Stratfed Estmates Darroch Est Nehalem Manstem Mark Carcass Recaptures Tag Loss Peterson Est Rel Prec'n Sex Strat Sze Strat S&S Strat tme space R/M R/C 2002 Both Sum> n/a 19, % 19,656 19,355 19, % 9.70% <600 mm , % 96.99% 95.89% 98.42% 98.42% 6.38% 6.12% , % 13.98% , % 8.08% , % 9.06% Males Sum> , % 11.37% <600 mm , % 6.59% , % 15.57% , % 8.56% , % 10.10% Females Sum> , % 8.06% <600 mm % 0.00% , % 10.19% , % 7.83% % 7.11% 2001 Both Sum> % 12, % 13,172 12,067 12, % 6.42% <600 mm % 97.07% 97.74% 97.37% 97.72% 0.00% 0.00% , % 6.70% , % 6.47% % 4.76% Males Sum> , % 7.45% <600 mm % 0.00% , % 6.43% , % 8.20% % 4.76% Females Sum> , % 4.91% <600 mm % 0.00% % 8.70% , % 4.72% % 2000 NA NA Both Sum> % 10, % 10,758 8,802 8, % 3.06% <600 mm % 82.43% 75.01% 13.33% 9.09% , % 3.57% , % 3.54% % 1.09% Males Sum> , % 1.54% <600 mm % 4.55% , % 2.47% , % 1.69% % 0.00% Females Sum> , % 5.03% <600 mm % % 6.45% , % 5.15% % 3.13% 24 Nehalem cumul progress report 98 02

25 Table 2A: Manstem Nehalem spawner escapement estmates wth numbers of marked Chnook, carcasses nspected, and marked Chnook recaptured. North Fork Nehalem 1998 Both Sum> % % % Males Sum> % Females Sum> % Both Sum> % % % Males Sum> % Females Sum> % Both Sum> % % % Males Sum> % Females Sum> % 0.00% 2001 Both Sum> n/a n/a 0.00% 0.00% Males Sum> n/a 0.00% 0.00% Females Sum> n/a 0.00% 0.00% 25

26 Table 3: Fall chnook spawner escapement estmates wth assocated 95% confdence ntervals, relatve precson and bas estmate for the Nehalem Rver ( ) and the Nehalem North Fork ( ). Bootstrap Smulaton 95% CI Standard 95% Rel Precson Bas % Bas Rel Bas Escapement Estmate Year Mean Standard Devaton CV (s.d.*1.96)/mean (Pld Ptrsn - Btstrp Mn) (Bas/sd) 977 Nehalem North Fork % % % Nehalem North Fork % % % Nehalem North Fork % % % n/a Nehalem North Fork 2001 n/a n/a n/a n/a n/a n/a n/a n/a n/a Nehalem Rver % % % Nehalem Rver % % % Nehalem Rver % % % Nehalem cumul progress report 98 02