Lower Fraser River Sockeye Recreational Hook and Release Mortality Study

Transcription

1 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Prelimiary Ivestigatios ito Short-term Hookig Mortality of Sockeye Caught ad Released at Grassy Bar, Fraser River, British Columbia, 8 Prepared for: the Fraser Salmo ad Watersheds Program (joitly maaged by the Pacific Salmo Foudatio ad the Fraser Basi Coucil) ad Fisheries ad Oceas Caada, Lower Fraser Area Prepared by: J. O. Thomas ad Associates Ltd. 137 Kooteay Street Vacouver, BC V5K 4R1 February 9

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3 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Prelimiary Ivestigatios ito Short-term Hookig Mortality of Sockeye Caught ad Released at Grassy Bar, Fraser River, British Columbia, 8. by J. O. Thomas ad Associates Ltd. February 9

4 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Prelimiary Ivestigatios ito Short-term Hookig Mortality of Sockeye Caught ad Released at Grassy Bar, Fraser River, British Columbia, 8. J. O. Thomas ad Associates Ltd. Copyright February 9 Pacific Salmo Foudatio, Fraser Salmo ad Watersheds Program. All Rights Reserved. No part of this publicatio may be reproduced, stored i a retrieval system, or trasmitted, i ay form or by ay meas, electroic, mechaical, photocopyig, recordig, or otherwise, without prior permissio from the Pacific Salmo Foudatio, Fraser Salmo ad Watersheds Program, Vacouver, BC. ad Fisheries ad Oceas Caada, Lower Fraser Area, Delta, BC. Recommeded citatio: J. O. Thomas ad Associates Ltd. 9. Prelimiary Ivestigatios ito Short-term Hookig Mortality of Sockeye Caught ad Released at Grassy Bar, Fraser River, British Columbia, 8. Report prepared for the Fraser Salmo ad Watersheds Program (joitly maaged by the Pacific Salmo Foudatio ad the Fraser Basi Coucil) ad Fisheries ad Oceas Caada, Lower Fraser Area. February 9: 49 pp. Cover photo: Ball, Cathy. Voluteer aglers bottom bouce fishig at Grassy Bar, Fraser River, British Columbia. Photo take August 19, 8. For further iformatio about this documet ad about the Pacific Salmo Foudatio (PSF) ad the Fraser Salmo ad Watersheds Program (FSWP) cotact: Pacific Salmo Foudatio #3-168 West 7th Aveue Vacouver, BC V6J 4S6 Tel: Fax: Geeral salmo@psf.ca This address is beig protected from spambots. You eed JavaScript eabled to view it. Web: For further iformatio about Fisheries ad Oceas Caada, Lower Fraser Area cotact: Fisheries ad Oceas Caada Lower Fraser Area 1 Aacis Parkway, Uit 3 Delta, BC V3M 6A Tel: Fax: Web: ii

5 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study TABLE OF CONTENTS TABLE OF CONTENTS...iii LIST OF FIGURES... iv LIST OF TABLES... iv LIST OF APPENDICES - FIGURES AND TABLES... iv EXECUTIVE SUMMARY...vii 1. INTRODUCTION...1. METHODS Study Area...3. Determiatio of Sample Size Data Collectio Aglig Effort Sockeye Hadlig, Trasport, ad Holdig...4 Hadlig ad Trasport...4 Holdig ad Release Referece ( Cotrol ) Group Necropsies Physiological Samplig Evirometal Data Aalysis of Mortality Data Hookig Mortality Rate Factors Ifluecig Mortality RESULTS Overall Catch ad Mortality Hookig Mortality Estimates Factors Ifluecig Mortality DISCUSSION RECOMMENDATIONS AND LIMITATIONS ACKNOWLEDGMENTS REFERENCES...4 APPENDICES...6 iii

6 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study LIST OF FIGURES Figure 1. A priori determiatio of sample size () eeded for estimatig a sigle proportio (mortality rate) ad provide a 95% cofidece iterval with varyig margis of error (d). 3 Figure. Frequecy distributio of agler play time ad trasport hadlig time to holdig pes for sockeye hooked i a bottom bouce hook-ad-release study at Grassy Bar i the Fraser River Figure 3. Daily umber of fish held for 4-h observatio i the et pes ad observed mortalities (bars) compared to average daily water temperatures from i-situ data loggers located i-river ear the aglig site ad the holdig et pe (lies) at Grassy Bar i the Fraser River LIST OF TABLES Table 1. Descriptive statistics for catch ad mortality of sockeye caught by bottom bouce gear at Grassy Bar i the Fraser River by primary hookig locatio Table. Compariso of fish coditio (A) at time of capture ad (B) after the 4-h holdig period for sockeye agled by bottom bouce gear (hooked group) ad captured by beach seie (referece group) at Grassy Bar, Fraser River... 1 Table 3. Estimates of short-term (4-h) catch-ad-release mortality of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, ucorrected ad corrected for hadlig mortality usig a adjusted rate estimator. The 95% cofidece iterval (95% CI) for the adjusted rate estimator is provided i paretheses. Mortalities are provided by umber () ad percet. No-destructive physiological samples are icluded (A) ad excluded (B) from estimates for compariso Table 4. Maximum likelihood (Pearso s chi-square) ad Fisher s exact test (for small sample sizes) results assessig various aglig-related factors, fish holdig desities, ad temporal biases ifluecig the short-term (4-h) mortality of sockeye caught with bottom bouce gear at Grassy Bar, Fraser River. Codig for variables is show i paretheses LIST OF APPENDICES - FIGURES AND TABLES Appedix 1 - Figure 1. Detailed ortho photo mosaic map of the geeral locatio of the lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study showig boat access at Islad Park, the Grassy Bar study site ad alterate et pe site at Calamity Bar... 7 Appedix 1 - Figure. Detailed ortho photo mosaic map of the Grassy Bar study site for the lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study showig the primary aglig site (red) ad the locatio of the holdig et pes (blue)... 8 Appedix - Figure 1. Daily Ecouter Form Appedix - Figure. Idividual Sockeye Ladig Form... 3 Appedix - Figure 3. Holdig Form iv

7 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix - Figure 4. Necropsy Form Appedix - Figure 5. Diagrammatic view of a salmoid head illustratig hook ijury locatios adapted from Mogillo (1984) Appedix 3 - Table 1. Aglig catch summary by date, study week ad species at Grassy Bar, Fraser River Appedix 3 - Table. Beach seie (referece group) catch summary by date, study week ad species at Grassy Bar, Fraser River Appedix 4 - Table 1. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad specific hookig locatio. 95% cofidece itervals (95% CI) are provided Appedix 4 - Table. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad leader legth (feet). 95% cofidece itervals (95% CI) are provided Appedix 4 - Table 3. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad hook size. 95% cofidece itervals (95% CI) are provided Appedix 4 - Table 4. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad amout of bleedig at time of capture. 95% cofidece itervals (95% CI) are provided Appedix 4 - Table 5. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad amout of scale loss. 95% cofidece itervals (95% CI) are provided Appedix 4 - Table 6. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for fish that were beached or ot beached at time of capture. 95% cofidece itervals (95% CI) are provided v

8 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 5 - Figure 1. Compariso of hourly holdig pe (dashed) ad aglig site (solid) water temperatures at Grassy Bar, Fraser River (lower plot). The upper plot shows deviatio of the holdig pe water temperature from that of the aglig site Appedix 6 - Figure 1. Voluteer aglers fishig with bottom bouce gear at Grassy Bar, Fraser River (photograph by Cathy Ball)... 4 Appedix 6 - Figure. Typical bottom bouce gear (photograph by Cathy Ball)... 4 Appedix 6 - Figure 3. Typical hookig locatio (left maxillary) observed i the recreatioal sockeye bottom bouce fishery (photograph by Bill Otway) Appedix 6 - Figure 4. No-destructive physiological samplig of a hooked ad laded sockeye (photograph by Cathy Ball) Appedix 6 - Figure 5. Holdig pes ad predator et cofiguratio i the side chael situated at the souther (tail) ed of Grassy Bar, Fraser River (photograph by Jim Thomas) Appedix 6 - Figure 6. Release of a live, vigorous sockeye after the 4-h holdig period (photograph by Cathy Ball) Appedix 6 - Figure 7. Beach seiig for referece group fish (photograph by Cathy Ball). 45 Appedix 7 - Figure 1. Fraser River sockeye timig ad daily escapemet estimates (smoothed) past Missio, British Columbia, by major stock group (Jue to September, 8) Appedix 7 - Table 1. Daily ad weekly study period estimates of sockeye abudace at Grassy Bar, Fraser River based o estimates of sockeye migratig past Missio from August 3 to August 31, 8. (Source: Pacific Salmo Commissio, August 6, 8). The umber of sockeye hooked i the study ad the percet of hooked to migratig sockeye are preseted Appedix 8-1. Derivatio of Newcombe-Wilso hybrid score cofidece itervals for the differece betwee two biomial proportios vi

9 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study EXECUTIVE SUMMARY The o-tidal portio of the Lower Fraser River supports a substatial recreatioal fishery durig the summer whe chiook (Ocorhychus tschawytscha) ad sockeye (O. erka) are migratig upstream. I particular, the greatest fishig effort occurs durig periods whe sockeye retetio is permitted. Sockeye retetio periods vary iter-aually ad rage from uder oe week to several weeks, depedig o sockeye abudace ad co-migratig stocks of cocer. Bottom boucig is the predomiat aglig techique for sockeye i the Fraser River. To date, o data has bee collected or aalyzed to quatify catch-ad-release (CR) mortality rates for this fishery. The purpose of this pilot year study was to quatify short-term (4-h) mortality rates of sockeye salmo i specific aglig locatios, evirometal coditios ad sockeye stock assemblages ecoutered i 8. A prelimiary ivestigatio of aglig-related variables ad their ifluece o mortality was also coducted. The study was coducted usig voluteer aglers over 15 days betwee August 5 ad September, 8 at Grassy Bar i the Fraser River. I total, the study collected ad aalyzed data from 173 hooked ad laded sockeye ad 13 sockeye captured by beach seie as a referece ( cotrol ) group. All sockeye were tagged ad held i et pes for 4-h observatio prior to release back ito the river. Net pes were situated i a side chael close to the aglig site. Primary hookig locatios were observed to be o the outside of the mouth or body (88% of all laded sockeye). Of this group, most were specifically hooked i the left maxillary boe (75%). Some fish exhibited bleedig at the time of capture (18%). However, all the fish that were released alive after 4-h showed o sigs of bleedig ad all but two fish were released i vigorous coditio. Total mortality was calculated usig a simple adjusted (additive fiite) method where the hookig mortality is computed as the differece betwee the total mortality rate observed i the hooked group of sockeye ad the mortality rate observed i the referece group. Oly two mortalities were witessed i the study ad catch-adrelease mortality was estimated to be 1.% (95% cofidece iterval of %-4.1%). The two fish that died were hooked i the dorsal ad vetral surface of the body posterior to the head, respectively. No mortalities were observed i the referece group. Despite the low mortality estimates, it should be oted that this study was coducted at a sigle fishig locatio where abudaces of sockeye were low, sample sizes were small, ad i-river evirometal coditios were relatively favourable for adult sockeye migratio. Issues surroudig loger-term mortality or ultimate survivability of the hooked or referece fish to the successful completio of spawig were ot addressed i this study. Additioal studies may be required to further ivestigate aglig-related variables, ad ay log-term or cumulative effects of catch-adrelease o mortality. vii

10 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study It is also recommeded that this study be coducted over the full 4-year Fraser sockeye cycle to help determie if there are iter-aual variatios i short-term mortality uder differig stock compositios ad abudaces. viii

11 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study 1. INTRODUCTION The o-tidal portio of the Lower Fraser River (from Chilliwack to Hope, B.C.) supports a substatial recreatioal fishery durig the summer whe chiook (Ocorhychus tschawytscha) ad sockeye (O. erka) are migratig upstream (Mahoey 5, 6, 7). I particular, the greatest fishig effort occurs durig periods whe sockeye retetio is permitted. Sockeye retetio periods vary iteraually ad rage from uder oe week to several weeks, depedig o sockeye abudace. Harvest opportuities are depedet upo i-seaso abudace determied through test fisheries. If abudace permits, the regulatios have geerally allowed the daily harvest of two () sockeye. While the sockeye recreatioal fishery is traditioally a catch-ad-keep (CK) fishery, the catch-ad-release (CR) of fish is commo for aglers that have either reached their daily limit or choose to release udersized fish, fish that are begiig to display secodary sexual characteristics, or o-target species (Kristiaso ad Strogitharm 6). Substative umbers of sockeye ca be released i this fishery. Betwee 4 ad 6, DFO creel surveys estimated the harvest of over 7, sockeye but also the release of over 1, sockeye (this icludes sockeye hooked durig directed chiook fisheries) (Mahoey 5, 6, 7). The predomiat aglig techique to catch sockeye i the Fraser River bar fishery is bottom boucig (also kow as flossig ). Bottom boucig employs log leaders (usually greater tha 3 meters i legth) ad barbless J-shaped hooks, commoly sized 1 to 3/. Ofte the hook is baited with wool ad/or a brightly coloured corkie. The gear is cast ito the river with a weight system that bouces o the river bottom. As the lie drifts or travels alog the river bottom, the leader/hook combiatio drags ( flosses ) through the mouth or across the body of restig or swimmig salmo causig the lie to stop or hesitate. The agler reacts to this iterruptio i the lie drift by abruptly draggig back o the lie causig the hook to embed primarily ito the outside of the salmo s jaw (maxillary boe), mouth, or head. Other hookig locatios have also bee oted, to a lesser extet, usig this method. Bottom boucig is successful for aglig sockeye because they do ot readily bite o lures or bait. Ofte, other salmo species such as chiook ad coho, are also caught usig this method. A secodary method of fishig for sockeye, called bar fishig, uses a weight system that stabilizes a lure (spi ad glow) close to the river bottom. The river curret activates the lure ad salmo willigly strike at the lure. This techique focuses primarily o catchig chiook give they do actively bite o lures (ulike sockeye), but other species icludig sockeye, ca be caught icidetally. Salmo that strike bar fishig lures are primarily hooked o the iside of the mouth. Capture by recreatioal fisheries gear ca result i a umber of cosequeces o the physical coditio of the fish. For example: hookig ijuries, bleedig, scale loss, fi frayig, tissue abrasio, mucous loss, ad sub-dermal ijuries ca be commo durig the hookig, fightig, ladig, uhookig, ad release procedures. While 1

12 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study there has bee speculatio that the locatio ad degree of the hookig ijuries origiatig from bottom boucig results i low mortality rates, this issue has ot bee quatified. The mai objective of this prelimiary study was to estimate short-term (4-h) sockeye mortality represetative of recreatioal catch ad release practices icorporatig typical bottom bouce fishig gear ad techiques that commoly occur i the Fraser River maistem bar fisheries from August to September. A secodary objective was to assess the ifluece of selected aglig-related variables o hookig mortality rates. This would iclude as the respose (depedet) variable, dead or alive at the ed of the 4-hour holdig period, ad various predictor (idepedet) variables such as; hookig locatio, presece of bleedig, agler playig time, leader legth, hook size, beachig, ad scale loss. The results preseted i this report are specific to the evirometal coditios, stock assemblages, fishig locatio, fishig effort, agler profile, capture techiques ad time periods i this year s study. Mortality rates are short-term (4-h) estimates oly. Our study does ot coclude what the log-term or cumulative effects associated with hookig, hadlig or holdig have o ultimate survival or successful spawig of sockeye ecoutered i the study.

13 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study. METHODS.1 Study Area The site chose for this study was at Grassy Bar (Appedix 1, Figures 1 ad ). This bar is located i the Fraser River, 4 km dowstream of the Islad Park boat lauch, ear Chilliwack, British Columbia. Despite beig oly accessible by boat, this is oe of the more popular bars o the Fraser River for aglig sockeye (Mahoey 6). Grassy Bar allows opportuities for aglers to bottom bouce, primarily targetig sockeye, by castig directly from the shore, or by castig from boats achored close to shore. Our study focused o sockeye salmo caught by aglers usig bottom bouce gear oly ad fishig either from shore or from boats ear shore ad situated i water less tha 1m deep ad with relatively slow river curret (< 1.m/s).. Determiatio of Sample Size A a priori aalysis was coducted to determie adequate sample sizes eeded to provide 95% cofidece limits aroud mortality rates (assumig a worst case sceario proportio of p =.5 (widest variace)) for the CR mortality ad several margis of error (d=.8 to.3). Figure 1 illustrates the results of determiatio of sample size () for each margi of error (d) at a 95% cofidece iterval (where z = 1.96) usig the followig formula (Fleiss 1981, Gerstma 3): = z p(1 p) d The aalysis suggests that a miimum sample size of 15 fish (agled or referece group) would be sufficiet to achieve a margi of error of.8 aroud the mortality estimate, 95% of the time. Sample sizes of approximately 4 fish were set as idividual goals for the referece group ad the CR sample to provide more precise margis of error i the rage of.5. These goals were highly depedet o fish abudace ad catch success. Sample size () Sample size determiatio for a sigle proportio margi of error (d) Figure 1. A priori determiatio of sample size () eeded for estimatig a sigle proportio (mortality rate) ad provide a 95% cofidece iterval with varyig margis of error (d). 3

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15 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Durig active catch ad ladig periods, techicias oly observed the aglers they could properly track ad record all aspects of the fish playig ad ladig data ad hadle released sockeye. If eeded, trasport/holdig bags cotaiig sockeye were held i-river util they could be properly trasferred to the holdig pes. The bags were achored i-river usig rebar hammered ito the riverbed. I-river holdig areas were carefully selected to provide sufficiet flow, depth ad water temperature coducive to optimum fish health ad situated so as ot to iterfere with aglig. Holdig ad Release Sockeye were held for 4-h observatio i holdig pes comprised of a floatig square frame (4m x 4m) with a attached et of similar legth-width dimesios ad a maximum hagig depth of 3m. The four bottom corers of the et were secured to the river bottom with 14kg achors. The floatig frames were costructed of 15mm diameter PVC pipig, filled with urethae foam at the coectio joits to ehace stregth ad flotatio. The ettig was comprised of 5mm mesh kotless seie webbig. Floatig Styrofoam sheets were placed o the water surface of the pe to esure sockeye would ot jump out of the pe. I additio, the primary et pe was surrouded by a achored ad floated predator et measurig 3m log x 6m deep. Give the dimesios of the et, the maximum volume of the holdig pe is 48m 3. However, the volume of water i the et pe varied depedig o the bottom topography where the et pe was situated ad the amout of water flow aroud the et. Assumig a maximum fish holdig desity of 1kg/m 3, the holdig capacity of the et pe whe situated i m uiform depth was estimated to be approximately 18 adult sockeye (average weight/sockeye =.5kg). To isure miimum egative effects associated with crowdig, holdig capacities were set at a maximum of 1 fish per et pe (i.e. approximately 1 sockeye per 5 liters of water). Net pes were located i a low flow (<.5 m/sec) side chael 4m south of the primary aglig site o Grassy Bar (see Appedix 1 - Figure ). This locatio was withi close i-river walkig distace from the aglig site ad out of the mai avigatio chael of the river ad therefore did ot itrude ito ay of the shore or boat-based fishig operatios. I order to comply with Trasport Caada uder the Navigable Waters Protectio Program, the et pes were marked with sigs ad high-visible flaggig for safety ad as a avigatio aid. Fish bags cotaiig sockeye were slowly walked i-river from the poit of ladig to the holdig et pe site. All sockeye delivered to the et pes were liberated ito the pes by placig the hadlig/trasport bag iside the et ad opeig the zipper to allow the sockeye to swim freely ito the pe. The tag umber, time of etry ito the pe ad coditio of each fish was recorded (Fish Holdig Form - Appedix - Figure 3). At the completio of the 4-hour holdig period, all sockeye i the pe were idividually caught by a log-hadled kotless mesh et. The physical coditio of the fish was adjudicated, the tag umber was oted ad the time of release recorded o the Fish Holdig Form. Radom fish were also measured for fork legth ad 5

16 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study biological tissue samples take for DNA aalysis. Live sockeye were released directly ito the river to cotiue their migratio. All dead sockeye were examied to determie the cause of death. Appedix 6 - Figure 6 shows a typical release of a live ad vigorous sockeye after the 4-h holdig period. To alleviate cocers of vadalism, theft ad liability, a campsite was set up ear the et pe site ad two techicias provided aroud-the-clock (4-h) moitorig ad security..3.3 Referece ( Cotrol ) Group Experimetal hadlig ad holdig of fish for observatio ca potetially itroduce additioal or ukow biases i hookig mortality estimates. While the magitude of these biases may be ukow, our study followed similar studies ad aalyses (Nelso 1998, Millard et al. 3, Pollock ad Pie 7) that assume that istataeous mortality associated with hookig ad release is idepedet of the mortality associated with experimetal hadlig ad holdig. By icorporatig a additioal group of sockeye that were captured without beig hooked ad stadardizig the hadlig ad holdig methods for both groups of fish, we were able to estimate hookig mortality as the differece betwee the fiite total mortality rate observed i the hooked (treatmet) fish ad the fiite mortality rate observed i the o-hooked referece (cotrol) group of fish. Sockeye for the referece group were captured usig a 13m (L) x 5.5m (D) beach seie with 5cm mesh webbig. Beach seiig was coducted immediately upstream of the primary Grassy Bar aglig site i a effort to elimiate disruptio of agler effort. The seie was set i a dowstream directio from a outboard-powered alumium boat. Oce the full et legth was deployed ad towed, the et was the closed ad hauled ito shore, eclosig a small area of water alog the river bak. Efforts were take to miimize escapes of fish by securig the lead lie to the river bottom ad elevatig the cork lie. Oce the et was secured, techicias first couted ad released all o-sockeye species ad the placed sockeye i the hadlig/trasport bags. Sockeye were the walked i-river to the et pe, where they were tagged, recorded ad released ito the pe. Care was take to miimize udue stress to captured fish while maitaiig similar hadlig ad trasfer methods to the et pes as those used for hooked fish. Start ad ed times were recorded for each set, alog with the umber of fish caught by species, adipose ficlip mark status for chiook ad coho, ad which sockeye were take for physiological samples. Appedix 6 - Figure 7 documets the beach seiig crew haulig i the et for collectio of sockeye for the referece group..3.4 Necropsies All sockeye mortalities were examied exterally ad iterally i a effort to quatify the cause of death (Necropsy Form - Appedix - Figure 4). Exteral observatio focused o scale abudace/loss, the locatio ad degree of wouds or bleedig, umber of sea lice ad coditio of fis. The iteral examiatio looked for wouds ad bleedig iside the mouth, body cavity ad gill area, with gill observatios to 6

17 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study iclude colour, degree of siltatio o filamets ad presece of mucus. The gut cavity was examied to determie iteral bleedig, damage to orgas, tissue bruisig or gapig ad idetify sex ad goad maturity. Each mortality was measured for fork legth ad tissue sampled for DNA aalysis..3.5 Physiological Samplig Physiological samplig was coducted o a umber of sockeye caught ad released i the study i order to assess post-aglig recovery rates ad other physiological effects o short-term survival. A variety of o-ivasive (blood samples, scale samples, legth, weight, gill biopsy, fat probe readig, muscle biopsy) ad ivasive samples (liver, kidey, muscle, reproductive tissues) were collected for assessmet from both the hooked (treatmet group) fish ad fish captured by beach seie (referece group). The detailed methodology ad results from this samplig are to be documeted i a separate report. Appedix 6 - Figure 4 shows techicias performig a typical o-ivasive physiological sample for blood o a recetly hooked ad laded sockeye..3.6 Evirometal Data Air ad water temperatures ad meteorological coditios were recorded hourly durig the day by techicias at the aglig site. I additio, water temperature i the et pe ad several meters offshore at the lower ed of the aglig site were cotiuously moitored over the study period usig submerged Oset Computer HOBO Water Temp Pro v data loggers. Data loggers were programmed to record temperatures every 3 miutes. Dissolved oxyge levels were measured at 7h ad 18h daily. Measuremets were take i the Fraser River just orth ad adjacet to the aglig site at Grassy Bar i a water depth of approximately 1m ad immediately upstream of the et pes i a depth of approximately 1.5m usig a Haa Istrumets Oxy-Check dissolved oxyge meter..4 Aalysis of Mortality Data.4.1 Hookig Mortality Rate The primary objective of our study was to evaluate the short-term (4-h) mortality rate of hooked sockeye usig gear commo to the o-tidal Fraser River recreatioal fishery. We used a simple, additive or adjusted hookig mortality rate for our aalysis. This is equivalet to the adjusted mortality rate (Nelso 1998), the simple model (Wilde et al. 3, Wilde ad Pope 8), ad the additive fiite mortality rate (Millard et al. 3, 5). This method assumes that the two mortality compoets associated with hook ad release ad experimetal hadlig ad holdig were idepedet. A additive relatioship is assumed betwee the two rates observed at the ed of the 4-h holdig period, ad fiite hookig mortality is 7

18 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study computed as the differece betwee the total mortality observed i the hooked fish ad the total mortality rate observed i the referece fish. I our study, cofidece limits for d, the simple differece betwee two proportios, were geerated usig the Newcombe-Wilso Hybrid Score method (Newcombe 1998). The Wald-type "classical" asymptotic methods were ot used because they ca yield osesical upper cofidece itervals that are greater tha 1.. This type of aberracy is referred to as "overshoot" ad is oe of several problems see with the classical methods whe sample size is small or observed probabilities are ear oe or zero. Appedix 8 details the derivatio of the Newcombe-Wilso hybrid score cofidece itervals..4. Factors Ifluecig Mortality A secodary objective of our study was to evaluate the factors that iflueced mortality. The effect of aglig-related variables o mortality of hooked fish has bee evaluated i similar studies with simple logistic regressio aalysis (Meard 1995, Millard et al. 3, 5). I these studies, the data is fit usig the stadard logistic regressio model p i = e λ (1 + e λ ), where p i is the probability of mortality ad e λ is a liear fuctio of explaatory variables (for example: hook size, hookig locatio, presece of exteral bleedig, sex, legth, scale loss, etc.). Maximum likelihood estimates of the coefficiets are evaluated for goodess of fit prior to iclusio i the logistic regressio aalysis. Variables exhibitig sigificace (P <.1) i mortality rates are further evaluated to provide odds ratios ad other associated logistic regressio parameters. I our study, Pearso chi-square, Fisher s exact tests, ad logistic regressios (where applicable) were performed usig software developed by Joh C. Pezzullo (see Refereces: Other resources). 8

19

20

21 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Agler play time Trasport hadlig time Frequecy >15 Miutes Figure. Frequecy distributio of agler play time ad trasport hadlig time to holdig pes for sockeye hooked i a bottom bouce hook-ad-release study at Grassy Bar i the Fraser River. Table 1. Descriptive statistics for catch ad mortality of sockeye caught by bottom bouce gear at Grassy Bar i the Fraser River by primary hookig locatio. Hookig locatio Variable Iside mouth Maxillary boe All other outside Total Total umber caught Mortality (%) Mea playig time (miutes) Beached (%) Bleedig observed (%) Vigorous coditio at capture (%) Mea trasport hadlig time (miutes) Predomiat hook size (type: %) 3/: /: /: /: 77.5 Predomiat leader legths (rage ft: %) 1-1: : : : 77. The physical coditio of hooked ad referece group fish was visually assessed at time of capture ad after the 4-h holdig period usig the followig criteria: 1) vigorous ad ot bleedig, ) vigorous ad bleedig, 3) lethargic ad ot bleedig, 4) lethargic ad bleedig, ad 5) dead. The majority (97.6%) of hooked fish were i a vigorous coditio at time of capture (8.3% ot bleedig, 17.3% bleedig) (Table ). Oly.3% of the hooked fish were reported as lethargic (1.7% ot bleedig,.6% bleedig). Noe of the beach seied sockeye exhibited ay bleedig at the time of capture with 96.1% beig reported as vigorous ad 3.9% as lethargic. No fish died durig iitial capture, hadlig or trasport either by aglig or by beach seiig. At 11

22 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study the time of release, o fish were reported as bleedig i either study group. Except for the two mortalities oted i the hooked group, 97.7% were released after 4-h as vigorous with o bleedig ad 1.% as lethargic with o bleedig. All of the beach seied fish were released after 4-h alive ad i vigorous coditio. Table. Compariso of fish coditio (A) at time of capture ad (B) after the 4-h holdig period for sockeye agled by bottom bouce gear (hooked group) ad captured by beach seie (referece group) at Grassy Bar, Fraser River. A. Coditio at time of capture: Study Group Vigorous, ot bleedig Vigorous, bleedig Lethargic, ot bleedig Lethargic, bleedig Dead Total Hooked Percet of total 8.3% 17.3% 1.7%.6% % 1.% Referece Percet of total 96.1% % 3.9% % % 1.% B. Coditio at time of release: Study Group Vigorous, ot bleedig Vigorous, bleedig Lethargic, ot bleedig Lethargic, bleedig Dead Total Hooked Percet of total 97.7% % 1.% % 1.% 1.% Referece Percet of total 1.% % % % % 1.% Other species, particularly chiook, were also hooked ad laded usig bottom bouce gear durig the study. Aside from otig the total umber hooked ad laded, o other aglig statistics were collected ad o mortality estimates were made for these fish. 3. Hookig Mortality Estimates No mortalities were observed i ay sockeye that were subjected to o-ivasive physiological samplig at time of capture or after the 4-h holdig period. However, for completeess, mortality estimates are preseted iclusive ad exclusive of these samples (Table 3). The short-term hookig mortality rate usig the adjusted (additive) model ad icludig o-ivasive physiologically sampled sockeye was estimated to be 1.% with lower ad upper 95% cofidece itervals of zero to 4.1%, respectively. Excludig the physiological samples resulted i a short-term mortality estimate of 1.4% with lower ad upper 95% cofidece itervals of zero to 4.8%, 1

23 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study respectively. The adjusted mortality rate is equivalet to the straightforward percet mortalities (the umber that died () divided by the umber laded (N)), sice o mortalities were observed i the referece group. Cofidece itervals reflect the rage of possible mortality rates adjusted for the referece group sample. For added compariso, adjusted mortality estimates ad 95% cofidece itervals associated with idividual aglig-related factors are preseted i Appedix 4. These estimates iclude fish sampled o-ivasively for physiological studies. Due to the limited umber of mortalities ad small sample sizes associated with each idividual aglig variable, cautio should be take whe assessig these estimates. Also, idividual aglig variables may ot act idepedetly o mortality. Large cofidece itervals for some mortality estimates are a testamet to this ucertaity. Table 3. Estimates of short-term (4-h) catch-ad-release mortality of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, ucorrected ad corrected for hadlig mortality usig a adjusted rate estimator. The 95% cofidece iterval (95% CI) for the adjusted rate estimator is provided i paretheses. Mortalities are provided by umber () ad percet. No-destructive physiological samples are icluded (A) ad excluded (B) from estimates for compariso. Adjusted catch-ad-release Total caught Mortalities mortality estimate (%) Gear (N ) Percet (95% CI) A. Icludig o-destructive physiological samples: Bottom bouce (-4.1) Beach seie (referece group) 13 B. Excludig o-destructive physiological samples: Bottom-bouce (-4.8) Beach seie (referece group) Factors Ifluecig Mortality Aglig-related variables, fish holdig desities, ad temporal biases were evaluated idividually for sigificace o mortality (P <.1) usig maximum-likelihood estimates (Pearso s chi-square, Fisher s exact test) (Table 4). The oly variables that exhibited sigificat ifluece o mortality were hookig locatio ad the occurrece of bleedig at time of capture. Due to the variety of possible hookig locatios oted i the study (15 i total), ad very low mortalities observed, assessmet of this variable o mortality ca be somewhat difficult to quatify. Based o the hookig locatios observed i this year s data ad i order to simplify this assessmet, hookig categories were grouped ito two major categories as follows: 13

24 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Table 4. Maximum likelihood (Pearso s chi-square) ad Fisher s exact test (for small sample sizes) results assessig various aglig-related factors, fish holdig desities, ad temporal biases ifluecig the short-term (4-h) mortality of sockeye caught with bottom bouce gear at Grassy Bar, Fraser River. Codig for variables is show i paretheses. Variable Chi-square test p-value Fisher's exact test Hook locatio 1 (body sag=, all other locatios=1) Hook locatio (all outside locatios=, maxillary boe=1) 1.31 < Bleedig at capture (o=, yes=1) Agler play time (<5 mi=, >5 mi=1) Coditio at capture (vigorous=, lethargic=1) Beachig (o=, yes=1) Air Exposure (less tha 15 sec=, greater tha 15 sec=1) Leader Legth (9 leader legths ragig from 8 to 16 feet) Hook Size (4 hook sizes ragig from 1/ to 4/) Scale loss (oe=, light to moderate=1) Fish desities i the holdig pe a (less tha fish/day=, greater tha fish/day=1) Temporal bias (hook locatio by study week) (=Sags, 1=all other locatios) Temporal bias (mortalities by study week) (=Alive, 1=Dead) a. icludes both hooked ad referece group fish Hook locatio 1 which compared fish hooked iside or outside the mouth versus those sagged i the body (dorsally or vetrally) ad Hook locatio which grouped those fish hooked i the maxillary boe versus all other outside the mouth hookig locatios. Dorsal or vetral body hookig locatios (sags) had a sigificat ifluece o mortality (chi-square=1.31, 1 d.f., p<.1). Oly 15 sockeye (8.7%) 14

25 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study were hooked i these locatios, however they were the oly hookig locatios associated with observed mortalities i this study. Hookig locatios outside the mouth or o the body also had a sigificat ifluece o hookig mortality whe compared to fish hooked i the maxillary boe (chi-square=6.8, 1 d.f., p=.14). The presece of bleedig at the time of capture was also foud to be a sigificat factor i the mortality of hooked sockeye (chi-square=9.7, 1 d.f., p=.). All other aglig-related variables collected i this study (agler play time, coditio at capture, beachig, air exposure, leader legth, hook size, ad scale loss) did ot idividually exhibit ay sigificat ifluece o the probability of mortality. No sigificat ifluece o mortality was foud whe comparig observed to expected mortalities of fish whe desities of fish were greater tha or less tha fish/day i the holdig pe (chi-square=1.38, 1 d.f., p=.41). Hookig locatios were also evaluated by study week to determie if there were ay sigificat temporal biases. No sigificat differeces were foud betwee weeks whe saggig locatios were compared to all other hookig locatios (chisquare=.66, d.f., P=.719). Temporal biases i mortality were also evaluated by comparig observed to expected mortalities by study week. No sigificat biases i mortality were oted betwee weeks (chi-square=.8, d.f., p=.67). Due to the lack of ay observed mortalities for the majority of the explaatory variables, further assessmet of the relatioship betwee mortality ad most of the aglig variables i our study usig odds ratios ad logistic regressio aalysis was iappropriate, eve for those exhibitig sigificat ifluece (hook locatio ad bleedig at capture). This methodology requires at least oe mortality (ad preferably more) to be preset i both variables beig assessed. Otherwise, odd ratios approach zero or ifiity ad are meaigless for comparig the odds or probabilities of death associated with the agler-related variable i questio. Oly oe variable (beachig) exhibited a sigle mortality i both categories (i.e. beached or ot beached) beig assessed. However, chi-squared ad Fisher s exact tests did ot show a sigificat differece i observed ad expected mortality betwee fish that were beached or ot beached. Water temperatures were cotiuously moitored i the Fraser River ear the aglig site ad i the holdig pe throughout the study. Hourly temperatures for the two sites are preseted i Appedix 6 Figure 1. The average daily water temperature i the river was relatively steady from August 5 to August 3 varyig betwee a high of 19.5 o C o August 8 to a low of 18. o C o August 3. Temperatures dropped steadily i the third study period from 15.8 o C o August 9 to 14.4 o C o September. Hourly water temperatures i the holdig pe were ot sigificatly differet from those recorded i the river ear the aglig site (t=11.4, 68 d.f., P<=.1). Temperatures i the holdig pe deviated aywhere from 1.5 o C below to.5 o C above water temperatures at the aglig site (Appedix 5 Figure 1). Due to the similarity i water temperatures observed i the river ear the aglig site ad i the holdig pe, it is ulikely that water temperature had a sigificat ifluece o mortality. The two mortalities both occurred sometime betwee August 6 ad August 7 whe the water temperature i the holdig pe raged betwee 18. o C ad 19.1 o C. Eight other study days had temperatures withi 15

26 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study this rage ad five days had temperatures above 19.1 o C whe fish were held for observatio ad o mortalities occurred. Dissolved oxyge (DO) levels were also sigificatly differet betwee the two sites (t=3.5, 58 d.f., P<=.1). DO cocetratios averaged 9.4mg/l i the river ear the aglig site ad 8.9mg/l i the et pe. Miimum levels of DO were recorded at 8.mg/l i the et pe o August 6, 7h. Despite the differeces oted betwee the two sites, cocetratios i the et pe were well withi suitable rages (> 5mg/l) to support the health of migratig adult salmoids (Bjor ad Reiser 1991). The daily umber of sockeye held i the et pes varied from zero o August 3 ad September to a high of 6 (53 referece, seve hooked) o August 1 (Figure 3). The average daily umber of sockeye that were held for observatio was 1. The average umber of referece sockeye i the holdig pe was 6 per day, ad average umber of hooked sockeye was 14 per day. The two mortalities were observed o a sigle day whe the umber of fish beig held was higher (3) tha the overall average (1). However, o sigificat biases were oted whe comparig mortalities whe fish desities were less tha or greater tha fish/day (Table 3). Number of Sockeye #Holdig Mortalities Aglig site Holdig Pe Water Temperature ( o C) Aug 5 Aug 6 Aug 7 Aug 8 Aug 9 Aug 19 Aug Aug 1 Aug Aug 3 Aug 9 Aug 3 Aug 31 Sep 1 Sep Figure 3. Daily umber of fish held for 4-h observatio i the et pes ad observed mortalities (bars) compared to average daily water temperatures from i-situ data loggers located i-river ear the aglig site ad the holdig et pe (lies) at Grassy Bar i the Fraser River. Visual observatios ad post-mortem assessmet cocluded that oe of the two mortalities i this study was directly attributable to hookig by a aterior vetral sag. This type of hookig evet was relatively ifrequet i the study (6% of the hooked fish). I this particular case, iteral hemorrhagig oted i the ecropsy suggested that the hook had puctured or lacerated the heart or liver leadig to the probable cause of death. The other mortality oted i the study was associated with a dorsal sag hookig locatio (% of the hooked fish). This fish was also a victim of a severe seal bite ijury o its posterior dorsal surface. No sig of iteral bleedig 16

27 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study was oted durig the ecropsy, which suggests the seal bite may have bee a cotributig cause of death. 17

28 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study 4. DISCUSSION Abudaces of sockeye i the Fraser River were aticipated to be low i 8. Preseaso ru size estimates raged from 1.85 to.9 millio sockeye (75 ad 5% probability levels, respectively) compared to the cycle average of 4.4 millio sockeye. Actual iseaso estimates totalled approximately 1.16 millio sockeye escapig past the Fraser River hydroacoustic statio at the Missio bridge by the ed of August (Pacific Salmo Commissio, August 6, 8 News Release). I additio, migratio timig of Summer stocks ito the river was approximately oe week earlier tha expected ad most peaks were observed prior to start of the study (see Appedix 7 - Figure 1). The targeted samplig goal of approximately 4 sockeye i each of the hookig ad referece groups was ot achieved i this year s study. Overall catches were lower tha aticipated, particularly durig the latter two weeks of the study ad coicidig with sigificatly reduced i-river sockeye abudaces. Estimates of sockeye i the Grassy Bar area of the Fraser River declied from almost, i the first study week to less tha, by week 3 (Appedix 7 Table 1). Despite the lower tha expected sample sizes attaied, maximum margis of error at 95% cofidece are estimated to be i the rage of 7 to 1% for the hooked ad referece group samples sizes attaied, respectively. This prelimiary study was coducted at a sigle fishig bar locatio ad durig relatively good evirometal coditios for i-river sockeye migratio. It provides a good framework for future studies to assess catch-ad-release mortalities over a wider rage of aglig locatios, evirometal coditios, ad stock groups. Uder the coditios for this year s study, short-term (4-h) mortality estimates of hooked sockeye was low (1.% mortality with a 95% cofidece iterval of zero to 4%). The data collected i this study showed that the majority of sockeye caught by aglers were hooked i or ear the maxillary boe with little to o bleedig. Although oly two mortalities were observed, evaluatio of aglig-related variables suggests that fish hooked by saggig, particularly i the vetral surface, have a relatively high probability of dyig as a result of pucture wouds or laceratio of vital iteral orgas compared to other methods of hookig. However, durig this study oly 6.4% of the agled fish were hooked i this locatio. The presece of bleedig at the time of capture that resulted from hookig was also a variable that exhibited a strog likelihood of death. Agai, a small percetage (18%) of the fish hooked i this study showed sigs of bleedig at the time of capture. Excludig the two fish that died, all of the fish that exhibited light to moderate bleedig at the time of capture were later released alive ad vigorous after 4 hours with o sigs of bleedig. No appreciable iflueces o mortality were foud for the remaider of aglig-related variables assessed i our study. Additioal work with larger sample sizes, ad uder a variety of coditios, would be of iterest to explore the aglig (or capture) related iflueces further. 18

29 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study 5. RECOMMENDATIONS AND LIMITATIONS For our study, we assumed that the effects of hadlig, trasport ad holdig worked idepedetly betwee the agled (hooked) fish ad the referece (cotrol) group. We also assumed that the beach seie method of capture for the referece group had o measurable effect o short-term mortality. Based o our results, ad particularly the lack of ay mortalities i the referece group, our assumptios appear to be reasoable. A simple adjusted method was therefore used to provide a estimate of hookig mortality ad cofidece itervals aroud this estimate. If mortalities had bee observed i the referece group, it would have bee relevat to further estimate ad compare mortalities usig a coditioal mortality methodology that does ot make similar assumptios of idepedece betwee the hooked fish ad the referece group. This model is described i detail by Millard et al., 5. Their model suggests there is a measurable ad depedet impact of cofiemet (holdig-related mortality) that affects the mortality of both the hooked fish ad the referece group of fish. The use of a referece (or cotrol) group of fish is critical to the assessmet of hookig mortality regardless of which methodology (adjusted or coditioal) is used. We therefore highly recommed the use of a suitable referece group of sockeye i ay future catch-ad-release studies to isure these assessmets of mortality ca be properly evaluated. The referece group must be take from the same populatio of sockeye as the agled sockeye ad similar umbers of fish should be obtaied for both groups. It is importat to ote that the beach seie method used i this year s study met these stadards ad proved to be a practical, effective ad reliable method for capturig referece group fish with miimal harm. We oly produced a sigle short-term CR mortality estimate usig a sample of aglers that we believe to be represetative of a typical Fraser River bottom bouce bar fishery that targets sockeye. Techiques are variable amog aglers ad locatios ad as such, may oly be idicative of the study group. Further studies alog with comparisos to techiques ad aglig statistics from agler surveys with similar characteristics would be useful. DFO reports from this year s limited sockeye fishery were uavailable for compariso at the time of this report. No sockeye were observed durig our study that were caught by other bar fishig techiques (for example, spi ad glow lures). Therefore, the results from our study ca oly be related to the bottom bouce fishery ad may ot be idicative of all bar fishig techiques that might capture sockeye. This mortality estimate also oly applies to sockeye salmo, sice observatios ad aalysis of other species caught usig bottom bouce gear may be differet ad were ot icluded i the study. Our mortality estimates are based o a short-term holdig period of 4 hours. Although some fish health variables were icorporated i the study, o other edpoits, besides 4-h mortality were evaluated. Therefore, we caot quatify the post-release mortality beyod the 4-h period, or estimate actual spawer success of the hooked or referece sockeye. It is possible for example, that fish observed i this study are more likely to succumb to icreased predatio (both atural ad fishig) as a result of physiological stresses, or icreased disease progressio 19

30 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study associated with hadlig (scale or slime loss, abrasios). Ultimately, this could lead to reduced spawer success (percet spaw), embryo viability ad egg-to-fry survival. Alteratively, sockeye held for observatio i et pes could be afforded sufficiet time ad protectio from predators to heal from ijuries or recover from stress associated with hookig or capture. These fish may actually have a greater chace at survival tha those fish released back ito the river immediately after hookig (or capture). Commets regardig seal bites were oted for approximately seve sockeye i the study, however this data was ot cosistetly collected or aalyzed. A severe seal bite was oted as a possible cotributig factor i oe of the two observed mortalities. The prevalece ad severity of seal bites i the hookig ad referece group could be a sigificat cotributig factor i mortality ad eeds to be cosistetly adjudicated ad documeted ad further aalyzed i future studies. Additioal data regardig hadlig ad trasfer times for fish i the referece group would also be useful. This data was ot formally recorded for each idividual fish i the referece group ad could ot be fully evaluated i this year s data. Additioal comparisos betwee agler-related variables ad their ifluece o mortality may also be of importace if mortality rates i future years are higher (or differet) tha those witessed i the pilot year. It would be very iterestig to see if relative hookig locatio data chages ad whether these chages affect mortality betwee years. Differet sizes of weights used by aglers i this fishery may also have a ifluece o hookig locatio as a result of differig behaviour of the gear. This data should be recorded ad aalyzed i future studies. The developmet of secodary sexual characteristics has also bee suggested as a factor leadig to the release of sockeye i a typical bottom bouce fishery. The sex or the extet of sexual maturity may also be a cotributig factor i the survival of these fish after a hookig evet. Male or female fish or fish that are more mature may be less able to tolerate the stresses associated with catch-ad-release. Future studies should attempt to collect ad quatify sex ad sexual maturity (or at least, sexual dimorphism) of captured sockeye ad the possible ifluece of this o mortality. Sice this study was oly coducted at oe gravel bar, it may ot be uiversally represetative of all bars or fishig sites o the Fraser River. There may be differet physical or evirometal coditios betwee bars that could ultimately affect mortality rates. Although our study site was coducted at a popular bar fishig locatio ad is believed to be typical, give its limited spatial ad temporal scope, the results may ot ecessarily be represetative of the wider rage of evirometal coditios ad locatios that are available i the Fraser River for these fisheries. Studies ad comparisos of aglig characteristics, gear ad techiques at other sites may help to determie if differeces exist. This study also was coducted i a year with low agler effort throughout the Fraser River. As a result, idividual sockeye likely had few, if ay, multiple captures by recreatioal aglers. I years whe sockeye retetio is permitted ad agler effort

31 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study is cosiderably greater, multiple captures might be more commo, particularly at bars further upstream from our study locatio. I fact, our study locatio is ear where aglig starts durig the summer moths, with further aglig opportuities existig upstream approximately 5 km to Hope. Therefore, the estimates at Grassy Bar may uderestimate the loger-term mortality for fish that are hooked ad released multiple times. Future studies should be aware of this variable ad assess multiple hookig evets, if possible, for potetial added ifluece o mortality. Fraser River sockeye have multiple stock compositios ad varyig abudaces over a typical four-year cycle. They also experiece variable i-river coditios durig their migratio upstream i ay give year. To accout for iter-aual variability i i-river fishig ad evirometal coditios, fish abudace ad stock compositio, we recommed coductig this study over a four-year cycle period. A sigle year study, particularly durig a year of low sockeye abudace whe evirometal coditios are favourable, may ot ecessarily be represetative of mortality rates witessed i a year whe abudaces are higher or coditios are less favourable. Agler-related variables may also have sigificatly differet iflueces o mortality i relatio to aual chages i evirometal, regulatory, biological, or abudace-based compoets. Timig of the study should be coordiated with up-to-date iseaso escapemet estimates i order to maximize sample sizes while maitaiig coservatio priciples ad improvig cost:beefit ratios to the study. Substative umbers of chiook were caught i this study by the beach seie. No data o stock origi was collected except to ote that all fish had itact adipose fis. Future studies should iclude plas to collect biological ad tissue samples from chiook caught i the beach seie for DNA stock aalysis. The o-site study team observed ad ecoutered umerous istaces of illegal ighttime activity durig the study. Drift gillettig was observed i the maistem Fraser ad the side chael of Grassy Bar, alog with heavy caliber weapos fire, ad vessel movemets related to a proximate drug grow operatio. These occurreces resulted i the eed for costat vigilace ad raised cocers for the safety of staff, equipmet ad sockeye that were beig held i the et pes. Future studies eed to review site security measures ad implemet commuicatio protocols with crimial eforcemet ad emergecy services agecies. 1

32 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study 6. ACKNOWLEDGMENTS We ackowledge ad thak the may people that helped to brig this study from cocept to completio. We sicerely apologize to aybody we may have missed. From Fisheries ad Oceas Caada, Lower Fraser Area, we would like to thak: Sue Grat, Head of the Sockeye ad Pik Aalytical Program; Joe Tadey, Program Head; ad Jaso Mahoey, Biologist, of the Chum, Pik ad Recreatioal Fisheries Program; ad Debra Seddo, Recreatioal Fishery Maager. All were actively ivolved i the study throughout its developmet ad durig the field compoet ad provided valuable edits ad commets for the fial report. From the B.C. Iterior Area: Timber Whitehouse, Area Chief for coordiatig sample desig reviews from other DFO staff. From the Sciece Brach at the Pacific Biological Statio: Chuck Parke, Biologist, Salmo Assessmet, ad Ala Cass, Biologist, Divisio Maagemet for their thoughtful ad careful review ad commets regardig the study desig. From Simo Fraser Uiversity: David Patterso, Habitat Research Biologist with Fisheries ad Oceas Caada located at the Cooperative Resource Maagemet Istitute, School of Resource ad Evirometal Maagemet ad Carl Schwarz, Professor, Departmet of Statistics ad Actuarial Sciece. Both added valuable cotributios to the physiological compoet ad determiatio of sample size ad statistical study desig, respectively. David s thorough ad critical review ad commets provided for the fial report was also very much appreciated. From the Fraser River Aborigial Fishery Secretariat (FRAFS): Peter Nickli ad Mike Staley for providig useful commets ad directio durig the iitial formulatio of the project ad the fializatio of the basic study desig. Very special thaks to Mark Sauders, Director, ad Adrew Stegema, Maager of the Fraser Salmo ad Watersheds Program (FSWP) at the Pacific Salmo Foudatio (PSF) for their support ad cotributios i steerig ad providig joit fudig of the project with help from the Fraser Basi Coucil (FBC) ad Fisheries ad Oceas Caada, Lower Fraser Area. May thaks also to Bill Otway ad Ed George of the British Columbia Wildlife Federatio (BCWF) ad Rod Clapto of the British Columbia Federatio of Drift Fishers (BCFDF) for their support ad may cotributios to commuity ivolvemet, help i recruitig voluteer aglers, ad provisio of photographic images (Bill Otway) to help documet the study. May thaks to all the voluteer fisherme: Ala Abbey, Nicole Abbey, Sadra Abbey, Erki Ayca, E. Black, Adre Bligat, Wes Bowerma, Bria Brow, Steve Brow, Craig Butler, Ke Charles, David Chwakliski, Rod Clapto, Steve Crawford, Doug Cruise, Mark Cybulskie, Gordo Dewa, Peter Driege, Lee Eeld, Terry Edersby, Alisha Forster, Bria Forster, Wade Forster, Norm Fowler, Da Fraz, Roger Fraz, Ia Freer, Ed George, Cathy Gerrard, Kolta Gerrard, Darre Goldig, Les Goldig, Mafred Hartma, Phat Hayh, Adam Hodgis, Sea Hooper, Rady Humphreys, Milo Ilic, Adrew Johs, Raymod Johs, Mike Kajzar, Marv Keedy, George Krah, Coie Kruger, Kevi Kut, Bill Lamot, Norm Libby, Rady Lidquist, Steve Ligefelter, Larry Meeboer, Phillip Milliga, Corey Mitchell, Brett Morga,

33 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Jerry Mueller, Mike Negreiff, Bill Nelso, Fred Nichols, Rick Nichols, Jihae Park, Roger Payer, Gord Pe, Keith Pouli, Do Provezao, Matt Provezao, Mitchell Provezao, Rob Rady, Greg Rideout, Jim Risslig, Rick Robertso, Bill Schoute, Alex Sztuhar, Doald Tekley, Mike Urbo, Ke Va Diest, Troy Vaderhage, Will Vaderhage, Dayto Wies, Ray Wod, Fred Ypma, Gle, ad Shau. Please accept our sicere apologies for ay omissios or misspelligs i this list. Thaks to all the techicias ad support persoel who worked diligetly both i the field ad office to collect, record, photograph, aalyze ad report the data. From J. O. Thomas ad Associates Ltd.: Cathy Ball for her help i the field ad photographs for the report, as well as admiistratio of the project; Bruce Cahusac for his help with the study desig, proposal, aalysis, ad reportig; ad Kyle Thomas for aroud-the-clock techical expertise i the field. Also, thaks to Isaac Aleck of the Cheam First Natio ad Frak Kwak of the Fraser Valley Salmo Society (FVSS) ad Upper Fraser Valley Sport Fish Advisory Committee (SFAC) who both worked diligetly collectig ad recordig data i the field. May thaks also to Lester Mussell from the Skwah First Natio ad his crew for their valuable assistace ad expertise brought to the beach seiig compoet of the study. We would like to thak Michael R. Doaldso, Ph.D. cadidate, Cetre for Applied Coservatio Research, Forest Scieces Cetre, Uiversity of British Columbia ad his support team for cotributios to the study desig ad separate field collectio, aalysis, ad reportig of data for the physiological samplig compoet of the study. Also, a fial thaks to Jeifer Feiberg, Reporter, for her iterest i the study ad article writte for the Chilliwack Progress Commuity Newspaper (August 7, 8). 3

34 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study 7. REFERENCES Bjor, T. C., ad D. W. Reiser Habitat Requiremets of Salmoids i Streams. America Fisheries Society Special Publicatio 19: (Note: this publicatio is i Chapter 4 i Iflueces of Forest ad Ragelad Maagemet o Salmoid Fishes ad Their Habitats [W. R. Meeha, editor].). Fleiss, J. L Statistical Methods for Rates ad Proportios. d Editio. New York: Joh Wiley & Sos, 35 pp. Gerstma, R. 3. Chapter 19: Sample Size, Precisio, ad Power i StatPrimer. Kristiaso, G., ad D. Strogitharm. 6. The evolutio of recreatioal salmo fisheries i British Columbia. Report to the Pacific Fisheries Resource Coservatio Coucil. Mahoey, J. 5. Fraser River Recreatioal Fishery Assessmet. DFO Memoradum. Mahoey, J. 6. Fraser River Recreatioal Fishery Assessmet. DFO Memoradum. Mahoey, J. 7. Fraser River Recreatioal Fishery Assessmet. DFO Memoradum. Millard, M. J., S. A. Welch, J. W. Fletcher, J. Mohler, A. Kahle, ad K. Hattala. 3. Mortality associated with catch ad release of striped bass i the Hudso River. Fisheries Maagemet ad Ecology 1: Millard, M. J., J. W. Mohler, A. Kahle, ad A. Cosma. 5. Mortality associated with catch-ad-release aglig of striped bass i the Hudso River. North America Joural of Fisheries Maagemet 5(4): Nelso, K. L Catch-ad-release mortality of striped bass i the Roaoke River, North Carolia. North America Joural of Fisheries Maagemet 18(1): 5-3. Newcombe, R. G Iterval estimatio for the differece betwee idepedet proportios: compariso of eleve methods. Statistics i Medicie 17: Pollock, K. H., ad W. E. Pie, III. 7. The desig ad aalysis of field studies to estimate catch-ad-release mortality. Fisheries Maagemet ad Ecology 14: Tadberg, D Calculator for Cofidece Itervals aroud the Differece betwee Two Proportios (Microsoft Excel). Dowload available from the Ceter for Evidece-based Medicie (CEBM) website, Departmet of Primary Care, Old Road 4

35 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Campus, Headigto, Oxford, OX3 7LF, Uited Kigdom. Wilde, G. R., K.L. Pope, ad R.E. Strauss. 3. Estimatio of fishig touramet mortality ad its samplig variace. North America Joural of Fisheries Maagemet 3(3): Wilde, G. R., ad K. L. Pope. 8. A simple model for predictig survival of aglercaught ad released largemouth bass. Trasactios of the America Fisheries Society 137(3): Other resources: -way Cotigecy Table Aalysis, revised /4/8 by Joh C. Pezzullo. Logistic Regressio calculator, versio 5.7., by Joh C. Pezzullo with istructio modificatios by Kevi M. Sulliva. Hosmer, D.W., ad S. Lemeshow.. Applied Logistic Regressio, d Editio. Joh Wiley & Sos, New York: 39 pp. Roser, B. 6. Fudametals of Biostatistics. Thomso/Brooks Cole Publishers; 6th Revised editio (March 16, 5): 868 pp. 5

36

37 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 1 - Figure 1. Detailed ortho photo mosaic map of the geeral locatio of the lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study showig boat access at Islad Park, the Grassy Bar study site ad alterate et pe site at Calamity Bar. 7

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39 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix - Figure 1. Daily Ecouter Form. Fraser River Sockeye Recreatioal Hook & Release Mortality Study Daily Ecouter Form Date: (dd-mmm-yyyy) Shift (AM/PM): Observer Name: Locatio: Water Temp ( o C): Air Temp ( o C): ANGLER HOUR WEATHER STRIKES HOOKUPS LOSSES LANDINGS COUNT J.O.Thomas & Associates Ltd. 8 Weather Codes: Species Codes: 1 = Clear 5 = Widy CO = Coho SO = Sockeye = Broke Cloud 6 = Calm CN = Chiook DV = Dolly Varde 3 = Overcast 7 = Fog ST = Steelhead CT = Cutthroat Trout 4 = Rai CM = Chum SR = Sturgeo PK = Pik SU = Sucker 9

40 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix - Figure. Idividual Sockeye Ladig Form. Fraser River Sockeye Recreatioal Hook & Release Mortality Study Idividual Sockeye Ladig Form IDENTIFICATION Date: (dd-mmm-yyyy) Locatio: Observer ID: Agler: boat shore Fish Bagged?: Y N Bag #: Tag #: Sex: M F U CAPTURE CONDITION DATA (circle oe coditio per variable oly) Time Hooked: : Hook Retrieval: (hh:mm - 4 h clock) hook removed lie cut Time Laded: : Fish Coditio: (hh:mm - 4 h clock) vigorous lethargic dead Netted?: Y N Bleedig: oe light moderate heavy Beached?: Y N Scalig: oe light <5% moderate heavy 5 to 5% >5% Air exposure: < 15 sec > 15 sec GEAR DESCRIPTION (circle oe) Gear Type: bottom boucig bar fishig beach seie (cotrol) Hook Size: 1 1/ / other: Leader Legth (ft.): HOOK LOCATION (see diagram - check oe oly) Iside Mouth: Upper jaw / iside 1 Gills 5 Roof of mouth Togue 6 Esophagus 3 Floor of mouth 7 Corer of mouth / iside 4 Lower jaw / iside 8 Other (specify) Outside Mouth: Dorsal Sag (body behid 9 Maxillary boe 13 head & above lateral lie) Head / exterior 1 Operculum 14 Eye 11 Vetral Sag (body behid head & below lateral lie) 15 Chi / exterior 1 Other (specify) COMMENTS: J.O.Thomas & Associates Ltd. 8 3

41 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix - Figure 3. Holdig Form. 31

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43 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix - Figure 5. Diagrammatic view of a salmoid head illustratig hook ijury locatios adapted from Mogillo (1984). 33

44 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 3 - Table 1. Aglig catch summary by date, study week ad species at Grassy Bar, Fraser River. Date Average Number of losses ----Number of umber of hookups aglers Sockeye Chiook Coho Number of ladigs ----Sockeyea Chiook Coho 5-Aug 6-Aug 7-Aug 8-Aug 9-Aug Week Aug -Aug 1-Aug -Aug 3-Aug Week Aug 3-Aug 31-Aug 1-Sep -Sep Week Total a. Totals iclude 5 sockeye that were removed from the study due to icomplete data records. Noe of these 5 fish died. Of the 173 remaiig sockeye, 5 were o-destructively sampled for physiology studies. All 5 sockeye were held for 4-h observatio ad oe died durig the study. Appedix 3 - Table. Beach seie (referece group) catch summary by date, study week ad species at Grassy Bar, Fraser River. Number of sets Socke4 Tc Sim Chiook Jack Chiook Adult Chum Sturgeo 7-Aug Aug 1-Aug Aug a. Totals iclude 17 sockeye that were were removed from the mortality study for destructive physiological samples. A additioal 17 of the remaiig 13 fish were o-destructively sampled. Noe of the o-destructively sampled fish died durig the study. 34

45 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 4 - Table 1. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad specific hookig locatio. 95% cofidece itervals (95% CI) are provided. Release coditio Hookig locatio Specific hookig locatio Vigorous, ot bleedig Lethargic, ot bleedig Dead Total Percet dead Percet of total Adjusted mortality rate (%) (95% CI) Iside mouth Upper jaw Roof of mouth 1. Esophagus -- Corer of mouth Gills Togue -- Floor of mouth Lower jaw Other Iside mouth total Maxillary boe total Other outside mouth Dorsal sag ( ) Head Eye Chi 11.6 Operculum -- Vetral sag ( ) Other Other outside mouth total (-17.3) Grad total (-4.1) 35

46 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 4 - Table. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad leader legth (feet). 95% cofidece itervals (95% CI) are provided. Release coditio Hookig locatio Leader legth (ft) Vigorous, ot bleedig Lethargic, ot bleedig Dead Total Percet dead Percet of total Adjusted mortality rate (%) (95% CI) Iside mouth ukow Iside mouth total Maxillary boe ukow 1. Maxillary boe total Other outside mouth (.9-.7) ukow Other outside mouth total (-17.3) Grad total (-4.1) 36

47 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 4 - Table 3. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad hook size. 95% cofidece itervals (95% CI) are provided. Release coditio Hookig locatio Hook size Vigorous, ot bleedig Lethargic, ot bleedig Dead Total Percet dead Percet of total Adjusted mortality rate (%) (95% CI) Iside mouth / / Iside mouth total Maxillary boe 1/ 1. / / / Maxillary boe total Other outside mouth / / (.7-1.3) Other outside mouth total (-17.3) Grad total (-4.1) 37

48 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 4 - Table 4. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad amout of bleedig at time of capture. 95% cofidece itervals (95% CI) are provided. Release coditio Hookig locatio Bleedig at capture Vigorous, ot bleedig Lethargic, ot bleedig Dead Total Percet dead Percet of total Adjusted mortality rate (%) (95% CI) Iside mouth Noe Light 1. Moderate Iside mouth total Maxillary boe Noe Light Moderate 1. Maxillary boe total Other outside mouth Noe Light (3.8-4.) Moderate Other outside mouth total (-17.3) Grad total (-4.1) 38

49 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 4 - Table 5. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for the primary hookig locatios (iside mouth, maxillary boe, or other outside mouth) ad amout of scale loss. 95% cofidece itervals (95% CI) are provided. Release coditio Hookig locatio Scale loss at time of capture Vigorous, ot bleedig Lethargic, ot bleedig Dead Total Percet dead Percet of total Adjusted mortality rate (%) (95% CI) Iside mouth Noe Light -- Moderate Iside mouth total Maxillary boe Noe Light Moderate Maxillary boe total Other outside mouth Noe (.5-.) Light Moderate Other outside mouth total (-17.3) Grad total (-4.1) 39

50 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 4 - Table 6. Adjusted estimates of short-term (4-h) catch-ad-release hookig mortality rates of sockeye salmo at Grassy Bar i the Fraser River, usig bottom bouce gear, corrected for hadlig mortality. The umber of fish hooked, the release coditio after the 4-h holdig period ad the percet i the sample are preseted for fish that were beached or ot beached at time of capture. 95% cofidece itervals (95% CI) are provided. Release coditio Beached? Vigorous, ot bleedig Lethargic, ot bleedig Dead Total Percet dead Percet of total Adjusted mortality rate (%) (95% CI) Yes (-7.5) No (-5.4) Grad total (-4.1) 4

51 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 5 - Figure 1. Compariso of hourly holdig pe (dashed) ad aglig site (solid) water temperatures at Grassy Bar, Fraser River (lower plot). The upper plot shows deviatio of the holdig pe water temperature from that of the aglig site. 41

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53 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 6 - Figure 3. Typical hookig locatio (left maxillary) observed i the recreatioal sockeye bottom bouce fishery (photograph by Bill Otway). Appedix 6 - Figure 4. No-destructive physiological samplig of a hooked ad laded sockeye (photograph by Cathy Ball). 43

54 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 6 - Figure 5. Holdig pes ad predator et cofiguratio i the side chael situated at the souther (tail) ed of Grassy Bar, Fraser River (photograph by Jim Thomas). Appedix 6 - Figure 6. Release of a live, vigorous sockeye after the 4-h holdig period (photograph by Cathy Ball). 44

55 8 Lower Fraser River Sockeye Recreatioal Hook ad Release Mortality Study Appedix 6 - Figure 7. Beach seiig for referece group fish (photograph by Cathy Ball). 45