Sa

Pa

b

a

ARRAH

KAACS

1

fidsacurSt2

rrAAov

h0

Fisheries Research 161 (2015) 252–260

Contents lists available at ScienceDirect

Fisheries Research

j ourna l ho me pa ge: www.elsev ier .com/ locate / f i shres

urvival of wild Atlantic salmon (Salmo salar) after catch and releasengling in three Irish rivers

atrick G. Gargana,∗, Trevor Stafforda, Finn Øklandb, Eva B. Thorstadb

Inland Fisheries Ireland, 3044 Lake Drive, Citywest Business Campus, Dublin 24, IrelandNorwegian Institute for Nature Research (NINA), Trondheim, Norway

r t i c l e i n f o

rticle history:eceived 26 August 2013eceived in revised form 30 January 2014ccepted 7 August 2014andling Editor George A. Rose

eywords:tlantic salmonngling

a b s t r a c t

The practice of catch and release (C&R) in salmon rod fisheries has become increasingly common dueto the widespread decline in salmon abundance in the North Atlantic over the past two decades. ManyIrish Atlantic salmon rivers are only open for catch and release (C&R) angling since a change in salmonmanagement in 2006. Success of Atlantic salmon surviving to contribute to the spawning stock followingC&R was studied in three rivers. In total, 76 fish were tagged with radio transmitters post C&R angling.Survival to spawning was greater for fly caught (98%) than lure caught fish (55%). Hence, survival afterC&R was dependent on gear type. Hook location may have influenced C&R mortality in the lure capturedfish. All fish bleeding at the hook wound or hooked in the throat died. Simultaneous hooking in the upper

atch and releaseurvival

and lower mouth may also have contributed to reduced survival. There was an overall net upstreammovement post release with many salmon moving more than 10 km upstream. Results demonstratedthat, when conducted using proper guidelines, survival of salmon after C&R can be high. Opening riversto C&R angling can be successful as a tool to provide information on salmon stock status while notsignificantly impacting on salmon survival.

© 2014 Elsevier B.V. All rights reserved.

. Introduction

The practice of catch and release (C&R) in Atlantic salmon rodsheries has become increasingly common due to the populationecline in the North Atlantic over the past decades (ICES, 2013). Inome areas of Canada and USA, C&R has been practiced since 1984,nd in more recent years it has been widely used in many Europeanountries, both as a result of statutory regulation and through vol-ntary practice. Reported rates of C&R (expressed as % of the totaleported rod catch) vary from 14% in Norway to as high as 73% incotland and 84% in Russia, reflecting varying management prac-ices and angler and stakeholder attitudes among countries (ICES,013).

C&R angling is a relatively recent phenomenon in Ireland. Theate of C&R in rod fisheries has increased from 5% of the totaleported catch in 2004 to 35% in 2012, with an estimated 12,000tlantic salmon released in 2012. Since 2006, the management of

tlantic salmon in Ireland has been based on scientific assessmentf all 141 salmon rivers, aiming at achieving river specific conser-ation limits (CL). Only the salmon surplus above the CL is available

∗ Corresponding author.E-mail address: paddy.gargan@fisheriesireland.ie (P.G. Gargan).

ttp://dx.doi.org/10.1016/j.fishres.2014.08.005165-7836/© 2014 Elsevier B.V. All rights reserved.

for harvest. This has resulted in approximately 40% of rivers beingopen for harvest, a further 40% of rivers being clearly below the CLand closed to fishing, and with the last 20% of rivers being open toC&R angling only. C&R angling is permitted because there is lackon information on salmon runs, and the angling catch generatedby C&R can be used in conjunction with a rod exploitation rate toprovide an estimate of the overall salmon stock status. This esti-mate can be compared against the river specific CL to determineif it is being met. In addition to providing rod catch data, riversopen for catch and release angling generate economic activity andemployment opportunities. While the angling methods permit-ted in the rivers open to C&R angling are restricted (use of singlebarbless hooks and no use of worm as bait), there is still a possi-bility of some mortality associated with C&R. For this reason, onlyrivers determined to be above a salmon fry threshold establishedby electro-fishing, or rivers estimated to be meeting >65% of CL,are open for C&R angling. However, concern has been expressedregarding the impact of catch and release angling on salmon mor-tality in rivers failing to meet conservation limits.

With proper fish handling and water temperatures below 20 ◦C,

Atlantic salmon mortality after C&R may be low (Dempson et al.,2002; Thorstad et al., 2003). Most studies of the effects C&R inAtlantic salmon have been performed in North America, and manystudies rely on fish being kept in tanks or cages after C&R, which

s Rese

m(bteimTv

Alasmrrfaws

2

2

ic

Fi

P.G. Gargan et al. / Fisherie

ay not be representative for fish being released back to the riverThorstad et al., 2008). More realistic results may be obtainedy tagging fish with radio or acoustic transmitters and recordinghe behaviour and survival of free-swimming fish in their naturalnvironment after C&R (Donaldson et al., 2008). In previous stud-es using radio or acoustic transmitters, fly fishing has been the

ain angling method (Whoriskey et al., 2000; Jensen et al., 2010;horstad et al., 2003, 2007). However, gear type may influence sur-ival rates (Arlinghaus et al., 2007).

This study was undertaken to derive data on the success oftlantic salmon surviving to contribute to the spawning stock fol-

owing C&R. The aim was to test the management assumption thatll released fish can be included in the estimate of the spawningtock in the rivers with C&R angling only. Information on anglingethods were collected, and behaviour and survival after C&R were

ecorded by equipping individual fish with radio transmitters andeleasing them immediately back to the river. Results from two dif-erent angling methods (spinning lures and flies) were compared,nd results were related to gear type, playing time, handling time,here the fish were hooked, water temperature and fish length and

ex.

. Materials and methods

.1. Study sites

C&R angling was carried out on three Irish rivers, the Owenmoren county Mayo, the Mulkear in county Limerick and the Feale inounty Kerry (Fig. 1). The Owenmore (precipitation area 341 km2,

ig. 1. Location of the study rivers Owenmore, Mulkear and Feale and their precip-tation areas in Ireland.

arch 161 (2015) 252–260 253

main stem channel of 20 km) is a productive spate river with anannual average rod catch (2009–2013) of 880 Atlantic salmon. TheMulkear (precipitation area 661 km2, main stem channel of 23 km)is a large tributary of the Shannon catchment with an averageannual rod catch (2009–2013) of 970 Atlantic salmon. The Feale(precipitation area 1151 km2, main stem channel of 24 km) has anannual average rod catch (2009–2013) of 1350 Atlantic salmon.

2.2. Fish capture, tagging and release

Tagging was conducted on the Owenmore River during Augustand September 2006 and 2007, on the Feale during September 2006and on the Mulkear during September 2007. The salmon includedin this study were tagged during or slightly after the peak periodof salmon runs in these rivers. Fly fishing only was used to captureAtlantic salmon on the Owenmore, a combination of fly and lurefishing on the Feale and lure fishing only on the Mulkear (Table 1).Flies were artificial flies ranging in hook size from 10 to 14. Thelures were spinning lures (Flying C type lures).

Field staff were in the vicinity of anglers along the riverbankprior to tagging all fish. Anglers were instructed to play fish in thenormal way and fish were landed using a standard landing net ordirected into a purpose built polyester landing bag. The presence ofa scientist did not alter the playing or landing of salmon during thestudy. Fish were exposed to air for less than 20 s. Capture methodand the time taken from hooking to landing were recorded. Hookswere removed after noting hook size, the number of hooks imbed-ded and the position of the hooks. Fish were inserted into a cylindertube filled with water, which allowed the head to be under waterduring tagging. Fish were inspected for damage or wounds whichmay have been inflicted by hooks. Fork length, sex and conditionof fish were recorded. The fish were characterised as fresh run ifthey had a bright silvery colour, thin mucous layer and/or sea lice(Lepeophtheirus salmonis). Sea lice are marine parasites, and theirpresence usually indicates that the fish have been in fresh waterless than a week (although some salmon lice may survive longer,Finstad et al., 1995).

All fish (n = 76, Table 1) were one-sea-winter salmon (with theexception of one multi-sea-winter salmon from the Feale) in the47–74 cm length range. The fish were tagged with model F2120radio transmitters from Advanced Telemetry Systems (ATS), USA(flat with outline dimensions 21 mm × 52 mm × 11 mm, mass in air15 g). Programmed battery life was seven months. Each transmitterhad a unique frequency within the 173,200–173,500 MHz range.Similar transmitters had no effect on swimming performance ofAtlantic salmon >45 cm in laboratory swim trials (Thorstad et al.,2000). Transmitters were attached externally to fish below the dor-sal fin and secured with stainless steel wire. Time taken to tag eachfish was recorded. After tagging, tags were checked for signal emis-sion and fish were held in the water until fully recovered beforebeing released.

2.3. Monitoring of tagged fish

Tracking of tagged fish was conducted in October–January (i.e.,until after spawning). Fish were tracked at a minimum of fourweeks intervals on the Owenmore and on a weekly basis on theFeale and Mulkear using a 3-element Yagi antenna connected to areceiver (model R2000, ATS). Main channels and tributaries wereradio tracked on foot or by boat. A vehicle was used to track fishwhere roads followed the river course. The entire catchment was

monitored during each tracking survey with a few exceptions whenhigh water did not allow tracking of lower main channel areas. Dis-tances fish moved along rivers were calculated using Arc View 9.2(Esri, USA).

254 P.G. Gargan et al. / Fisheries Research 161 (2015) 252–260

Table 1Details on the characteristics of the tagged fish and angling details.

Owenmore Feale Feale Mulkear

Number of fish tagged 52 12 3 9Number of fish recorded post tagging 48 12 3 8Number of fish survived to spawning 47 (98%) 12 (100%) 2 (67%) 4 (50%)Gear type Fly Fly Lure Lure

Number by hook type and size (size 10:12:14:4)Single 0 9 (4:5:0:0) 3 (0:0:0:3) 0Double 13 (3:9:1:0) 2 (2:0:0:0) 0 0Trebble 39 (2:29:8:0) 1 (1:0:0:0) 0 9 (0:0:0:9)

Fish characteristicsFork length (mean, range, SD) 58 (44–74, 6.3) 59 (49–73, 7.0) 60 (59–63, 2.3) 56 (48–66, 5.5)Sex (number; male:female) 22:30 9:03 1:02 6:03Number (%) fresh run 26 (50%) 2 (17%) 2 (67%) 0 (0%)

Angling practicesWater temperature at tagging (mean, range, SD) 13 (11–16, 1.3) 13 (13–14, 0.5) 14 (14–14, 0) 10 (9–12, 1.22)

aPfimSt3ts8

2

wtaiviftvIetevbsfcl2efaS

3

3

v

3 females with mean fork length 57 cm (range 53–63 cm, SD 3.7).One fish was characterised as fresh run. These fish were angled at amean water temperature of 11 ◦C (range 9–14 ◦C, SD 2.1). Hence, sex

Time played in minutes (mean, range, SD) 5.8 (3–9, 1.8)

Time handled in minutes 2.2

Total time playing and handling 8.0

Fish having moved upstream were deemed to have survivedfter C&R. Five fish (7%) were never recorded after tagging (Table 1).ossible explanations may be tag failure, unreported recaptures, orsh leaving the rivers. The five fish that disappeared were threeales and two females, with mean fork length 61 cm (range 54–70,

D 8.4). The survival results are based on the 71 fish recorded afteragging. These fish were found during all tracking surveys, except8% missing during one of the surveys and 12% missing duringwo of the surveys. One fish was not detected during three of theurveys, but when detected in December it had moved upstream.1 km from being tagged in September.

.4. Data analyses

Statistical comparisons between those fish dying and survivorsere not performed due to the low number of fish suffering mor-

ality. However, statistical comparisons were made between flynd lure captured fish to characterise the C&R fishery and examinef there were any differences between the angling methods rele-ant for fish performance and survival after C&R (all tagged fishncluded, sample sizes given in Tables 1 and 2). Data from the dif-erent rivers were combined as we have no reason a priori to expecthat river characteristic would alter the interaction between sur-ival and river site across treatment effects in a systematic fashion.ndependent samples t-tests were used to test for possible differ-nces between fly and lure captured fish in mean fork length, wateremperature at C&R, playing time and handling time, assumingqual or unequal variances based on Levene’s test for equality ofariances. One-way ANOVA was used to compare handling timeetween fish captured with single, double and treble hooks. Pear-on chi square test was used to test for possible differences inrequencies among fly and lure captured fish (frequencies of fishaptured on single, double and treble hooks and frequency of hookocation), except chi square with continuity correction was used for

× 2 tables (frequency of males and females), or Fisher’s test whenxpected count was less than five in any of the cells (frequency ofresh run fish). Effect of fish length on playing time was tested using

linear regression. Statistical analyses were performed using SPSStatistics version 21 (IBM, USA).

. Results

.1. Fish survival after catch and release

Overall, 92% of the Atlantic salmon recorded after tagging sur-ived post C&R (65 of 71 salmon, Table 1). Three fish were stationary

5.8 (4–8, 1.2) 5.3 (5–6, 0.6) 4.1 (3–6, 0.9)2.3 2.0 2.18.1 7.3 6.2

(radio transmitter signal detected at <100 m from release location)throughout all monitoring periods (Fig. 2). Two fish were station-ary during the first monitoring period and recorded having moveddownstream in subsequent periods. One fish moved downstreamduring the first and second monitoring period and then remainedstationary (Fig. 2). Hence, all these six fish were presumed not tohave survived.

The survival rate was higher for fly caught (98%, 59 of 60) thanfor lure caught salmon (55%, 6 of 11) (Fisher’s exact test, p < 0.001,Table 1). The high survival of fly caught salmon was consistentover two years on the Owenmore (100% survival in 2006, 21 of21 fish – and 96% survival in 2007, 26 of 27 fish), and between theOwenmore and the Feale (100% survival). No tagged salmon werereported recaptured by anglers in any of the rivers.

The six fish presumed to have died after C&R were 3 males and

Fig. 2. Net displacement from the point of tagging for dead fish by date detected.

P.G. Gargan et al. / Fisheries Research 161 (2015) 252–260 255

Table 2Characteristics of gear type, hook type and hooking location.

Type of hook Fly Lure

Number of hooks Single Double Trebble Single TrebbleNumber of salmon hooked 9 15 40 3 9Hooking location (1, 2 or 3 hooks attached) Single Double (1:2) Trebble (1:2:3) Single Trebble (1:2:3)Jaw (upper, lower) 6 7 (3:4) 21 (14:7:0) 1 7 (5:2a:0)Maxillary bone 2 5 (5:0) 15 (8:7:0) 2 3 (3a:0:0)Tongue, upper mouth 0 2 (2:0) 3 (2:1:0) 0 0

ddg4pt(ca

us4tjitdtt

3

AtwcTca

2ctcaplslo

hfit(fi1

j2l

Throat or belly 0 0

Unknown (hook fell out) 1 1

a To identify gear type and hooking location resulting in bleeding.

istribution, body length and water temperature at angling timeid not differ between those not surviving and the tagged fish ineneral (Table 1 and below). The playing time (mean 4.5 min, range–6, SD 0.8), handling time (mean 2.0 min, range 2–2, SD 0) and totallaying and handling time (mean 6.5 min, range 6–8, SD 0.8) forhe mortalities were among the shorter periods in the total sampleTable 1 and below). Of the salmon that did not survive, one wasaptured by fly in the Owenmore and five on lures on the Mulkearnd the Feale (Table 1).

The fly captured salmon mortality (n = 1) was hooked in thepper jaw on a double barbed hook size 10. The lure capturedalmon mortalities were captured on single barbless hooks, size

(n = 1), or on barbed treble hooks size 4 (n = 4). Of these lure cap-ured salmon, one was hooked in the maxillary, one in the loweraw, one in both the lower and upper jaw, one in both in the max-llary and in the upper jaw and one in the throat. Notably, the onlywo fish recorded as having bled at the hook wound in the entireata set were among the dead fish, as were the only fish hooked inhe throat, and two of the three fish noted as being hooked in bothhe upper and lower mouth.

.2. Characterisation of the fishery and angling methods

There were no differences between fly caught and lure caughttlantic salmon in fork length (t-test assuming equal variances,

= 0.66, p = 0.51), proportion males and females (chi-square testith continuity correction, �2 = 0.50, p = 0.48), or proportion of fish

haracterised as fresh run (Fisher’s exact test, p = 0.18) (Table 1).he water temperature at C&R was higher for fly caught than lureaught fish (mean 13 ◦C vs. 11 ◦C, t-test assuming unequal vari-nces, t = 2.73, p = 0.019, Table 1).

Of the fly caught salmon, 14% were captured on a single hook,3% on a double hook and 63% on a treble hook (Table 1). Of the lureaught salmon, 25% were captured on a single hook and 75% on areble hook (Table 1). There was no difference in proportion fishaptured on single, double and treble hooks between fly caughtnd lure caught salmon (Pearson chi square test, df = 2, �2 = 3.58,

= 0.17). However, all lure caught salmon were captured usingarger hooks (size 4) whereas hook size was smaller for fly caughtalmon (size 10–14). In the Owenmore and Mulkear, all flies andures had barbed hooks. In contrast, in the Feale, 67% of the flies (8f 12) and 67% of the lures (2 of 3) had barbless hooks.

For fish captured on flies with double hooks, 10 fish (67%) wereooked by one of the hooks, 4 fish (27%) by both hooks and for onesh the hook (7%) fell off at capture. For fish captured on flies withreble hooks, 25 fish (63%) were hooked by one hook and 15 fish38%) by two hooks. For fish captured on lures with treble hooks, 5sh (50%) were hooked by one hook, 4 fish (40%) by two hooks and

fish (10%) by all three hooks.

Of the fly caught salmon, 53% were hooked in the upper or lower

aw, 34% in the maxillary bone, 8% in the tongue or upper mouth,% in the belly, and 3% lost the hook when landed (Table 2). Of the

ure caught salmon, 50% were hooked in the upper or lower jaw,

1 (1:0:0) 0 1 (0:0:3)0 0 0

42% in the maxillary bone and 8% in the throat (Table 2). There wasno difference in distribution of hook locations between fly caughtand lure caught salmon (Pearson chi square test, df = 4, �2 = 2.93,p = 0.60).

The playing time (time from hooking to landing the fish) wasgenerally short, on average 5.6 min (Table 1). Playing time increasedwith increasing fish length, but fish length explained only 11% ofthe variation in playing time (linear regression, r2 = 0.11, p = 0.004).Handling time (from landing to release) was on average 2.2 min,resulting in a total playing and handling time of average 7.8 min(Table 1). Playing time was longer for fly captured than lure cap-tured salmon (t-test assuming unequal variances, t = 3.8, p = 0.001),whereas handling time did not differ between the groups (t-testassuming equal variances, t = 1.3, p = 0.19). In summary, total hand-ling time was longer for fly captured than lure captured salmon(t-test assuming equal variances, t = 2.7, p = 0.009).

Handling time did not differ between fish captured with single,double or treble hooks (one-way ANOVA, df = 2, F = 0.87, p = 0.43,all fish combined). Handling time did not differ between fish cap-tured on barbed or barbless hooks (t-test assuming equal variances,t = −0.80, p = 0.43, all fish combined). Results were similar when flyand lure captured fish were tested separately (results not shown).

3.3. Fish behaviour after catch and release

The fish that survived (n = 65) showed an overall net upstreammovement post release (Figs. 3 and 4). Of the Owenmore fish thatmoved upstream, the majority travelled more than 3 km, withmany fish moving more than 10 km upstream (Figs. 3 and 4). Thisis not unexpected as fish were captured in the lower and mid-mainchannel, and considerable spawning takes place in the upper mainchannel and head water tributaries. Three individuals moved sev-eral kilometres downstream after release, but subsequently movedupstream. The longest downstream migrations made by Owenmorefish were six fish in January, most likely after spawning. The netdisplacement since the previous detection event (Fig. 4) shows thetype and extent of fish movements during the season.

The majority of Feale salmon remained stationary or movedupstream in the first and second month after C&R (Figs. 3 and 4).An initial downstream migration was evident for four fish soonafter release and three subsequently moved considerable distancesupstream. Three of the four surviving salmon from the Mulkearmoved upstream and were stationary during the entire studyperiod (Figs. 3 and 4). Hook placement did not demonstrate markeddifferences in fish displacement after tagging (Fig. 5).

4. Discussion

A high survival to spawning was recorded for fly caught Atlantic

salmon (98%) in the present study, which is similar to resultsfound in previous Atlantic salmon catch and release studies inCanada, Norway and Russia (92–100% survival, Dempson et al.,2002; Thorstad et al., 2007; Jensen et al., 2010; Whoriskey et al.,

256 P.G. Gargan et al. / Fisheries Research 161 (2015) 252–260

ate fo

2ssrtmrfifi

dsrmtio

Fig. 3. The extent of net movements by d

000). A lower survival rate (84%) was recorded in the Aberdeen-hire Dee, Scotland (Webb, 1998). The high survival for fly caughtalmon in the present study was consistent between years andivers. However, the survival rates differed among gear types, ashe survival rate for fish captured with spinning lures (55%) was

uch lower than for fly caught salmon. This is in accordance withesults in a study of rainbow trout (Oncorhynchus mykiss), wheresh caught by spinning lures were injured more frequently thansh caught by fly (Meka, 2004).

The low number of fish suffering mortality in the present studyid not allow for statistical comparisons between those dying andurvivors. However, a descriptive inspection of the results did noteveal any particular characteristics of the individuals suffering

ortality compared to survivors with respect to fish size, sex, water

emperature, whether they were fresh run in the river or not, play-ng time, handling time, use of barbed vs. barbless hooks, or the usef single, double or treble hooks.

r individual fish which survived (n = 65).

A notable difference between fly and lure captured Atlanticsalmon, however, was the larger hooks used for all lure capturedfish. Moreover, the only two fish bleeding at the hook wound in theentire sample were salmon mortalities captured by lure, as werethe only fish hooked deep in the throat, and two of the three fishnoted to be simultaneously hooked in the upper and lower mouth.Salmon most likely die after C&R from wounds caused from angling,or exhaustive exercise due to the extent of the intracellular acidosiswithin the muscle (Wood et al., 1983). The larger size of hooks usedwith spinning lures may have resulted in larger hook wounds, agreater extent of deep hooking and bleeding, and a greater extent ofsimultaneous hooking in the upper and lower mouth – and therebya higher mortality. Meka (2004) similarly suggested that hook size

may have been an important factor influencing the number of hookpoints penetrating rainbow trout during angling, which in turncaused increased injury to sensitive locations, associated bleeding,and subsequent mortality. Large hooks may be more difficult to

P.G. Gargan et al. / Fisheries Research 161 (2015) 252–260 257

sh sin

saGlotctf

rawctfiai

Fig. 4. Net displacement of live fi

wallow than small hooks, but may cause greater tissue damaget the wound site (Pauley and Thomas, 1993; DuBois et al., 1994).jernes et al. (1993) speculated that the greater depth and gape of

arger hooks may lead to deeper hook penetration and greater riskf contact with critical organs. As all fly captured fish were cap-ured on small hook sizes compared to the larger hook size of fishaptured by lures in the present study, it was not possible to isolatehe effect of hook size alone. We suggest that hook size should beurther investigated as a mortality factor after C&R.

Bartholomew and Bohnsack (2005) found in their extensiveeview that catch-and-release angling mortality varied greatlymong and within species, and that anatomical hooking locationas the most important mortality factor. Other studies also indi-

ate that anatomical hooking location and associated bleeding is

he most important factor influencing mortality of angler-caughtsh (e.g., Falk et al., 1974; Warner, 1976; Loftus et al., 1988; Nuhfernd Alexander, 1992; Arlinghaus et al., 2007). Simultaneous hook-ng in the lower and upper mouth may reduce oxygen uptake during

ce the previous detection event.

playing of the fish because it to some extent closes the mouth. Wefind no studies discussing simultaneously hooking in the lower andupper mouth in the scientific literature, but this is sometimes men-tioned by anglers as a factor negatively impacting the condition ofthe salmon at release (E.B. Thorstad, personal observation). Hookcharacteristics and hook types are shown to impact the hookinglocations and endpoints in C&R events in a number of studies, butthe results vary widely among studies, perhaps due to interspecificvariation (Muoneke and Childress, 1994; Cooke and Suski, 2005;Arlinghaus et al., 2007).

Water temperature is an important factor in determining sur-vival of Atlantic salmon after release, explaining 72% of the variationin survival from Atlantic salmon C&R angling (Dempson et al.,2002). Mortality after C&R angling may increase at high water tem-

◦

peratures, and temperatures above 18–20 C may have a negativeeffect on survival (Wilkie et al., 1996, 1997; Anderson et al., 1998;Dempson et al., 2002; Thorstad et al., 2003). The water tempera-tures in this study of 9–16 ◦C were unlikely to impact on survival.

258 P.G. Gargan et al. / Fisheries Research 161 (2015) 252–260

h line

Ffwstpwwtaimt8Sdto

dei(wpbTt

Fig. 5. Net displacement of fish during the first fifty days plotted (wit

urther, differences in water temperature cannot explain the dif-erences in mortality between fly and lure captured salmon as theater temperature at C&R was lower and not higher for the lure

almon in general, and the temperature at C&R for individualshat failed to survive was among the lowest in the total sam-le. Catch-and-release mortality of rainbow trout and mountainhitefish (Prosopium williamsoni) increased when daily maximumater temperature was higher than 20 ◦C and mortality of brown

rout (Salmo trutta) increased when daily maximum water temper-ture was at or exceeded 23 ◦C (Boyd et al., 2010). C&R took placen August and September in the present study and temperature

ay have a more significant effect during peak summer tempera-ures when water temperatures may reach 18 ◦C or more. In 2012,8% of the Irish salmon rod catch were caught between June andeptember, and 69% between July and September. This reflects theominance of the one sea winter fish in the catch, and this study canherefore be considered as reflective of the time when the majorityf the angling catch is taken in Ireland.

The duration that a fish is angled may increase physiologicalisturbance, time needed to recover and mortality (Arlinghaust al., 2007). Extended playing and handling times were a signif-cant mortality factor in a review study of C&R angling mortalityBartholomew and Bohnsack, 2005). The playing time increasedith increasing fish size in the present study, in accordance with a

revious Atlantic salmon study in Norway (Thorstad et al., 2003),ut not to the extent that playing time seemed to affect survival.he fish that died were not among the largest salmon included inhe study. Further, playing and handling time of the fish that died

of best fit with SE fitted in R using ggplot2) against hook placement.

were among the shorter periods in the total sample, indicating thatplaying time and handling did not explain the mortality.

Air exposure is also associated with C&R-related physiologicaldisturbance and mortality (Ferguson and Tufts, 1992; Schreer et al.,2005), and there may be interactive effects of air exposure durationand water temperature on survival and physiological disturbances(Gingerich et al., 2007; Gale et al., 2011). The results of Gingerichet al. (2007) indicate that at low to moderate water temperatures,extended air exposure may result in little mortality. However, athigh water temperatures, short-term mortality (within 48 h) can besubstantial, especially for fish that experience extended air expo-sure durations. Richard et al. (2013) found that water temperaturenegatively impacted reproductive success of salmon kept in thewater, but in the temperature range of 12–17 ◦C, air exposure timehad a greater negative impact on fitness than water temperature.Depending on the temperature, reproductive success can be up totwo or three times higher for salmon kept in the water comparedwith those exposed to air for 10 s and with those exposed to air for>10 s, respectively. Thus, the conditions in which C&R is conductedinfluence the success of the practice in terms of conservation. Con-sequently, Richard et al. (2013) conclude that precaution must betaken to limit C&R in warm water periods and avoid air exposureprior to release. Minimum air exposure, low to moderate watertemperatures, short playing time and careful handling most likely

contributed to the high survival post C&R in the present study.

The time spent in the river prior to being angled did not seem toinfluence survival post C&R. A high proportion of fish captured wasdescribed as coloured, indicating that they had spent some time in

s Rese

fPicttis

iCBbotovsatb(epo

md1mmwmqOduWs

rbaeAcrtsmpiCobt

2ttw5wwpr

P.G. Gargan et al. / Fisherie

reshwater, while 39% of the fish were characterised as fresh run.hysiological disturbance from angling and mortality may be largern bright Atlantic salmon than in kelts (Brobbel et al., 1996), indi-ating that the stage of freshwater migration may be important forhe effects of catch-and-release. However, similar to the results inhe present study, Thorstad et al. (2007) did not find any differencesn survival between newly ascended salmon and salmon that hadtayed longer in the river before being caught and released.

Another factor that can influence the impact of a hooking events the presence or absence of barb on the hook (Muoneke andhildress, 1994; Cooke and Suski, 2005; Arlinghaus et al., 2007).artholomew and Bohnsack (2005) found that fish captured onarbed hooks had marginally higher mortality than those capturedn barbless hooks. The use of barbless hooks can reduce handlingime and air exposure, and may reduce tissue damage at the pointf hook entry. There were no clear indications that the use of barbeds. barbless hooks affected handling time or mortality in the presenttudy, but the number of fish captured on barbless hooks was rel-tively low. Since the majority of data available support the notionhat use of barbless hooks is beneficial for discards and can onlyenefit fish, the use of barbless hooks is generally recommendedMuoneke and Childress, 1994; Cooke and Suski, 2005; Arlinghaust al., 2007). In Irish rivers open only for C&R angling, byelaws onlyermit the use of barbless hooks and in certain circumstances flynly angling.

Previous studies of Atlantic salmon have shown that C&Ray alter the upstream migration pattern and result in unusual

elays, downstream movements, erratic displacement (Webb,998; Mäkinen et al., 2000; Thorstad et al., 2003, 2007) anday even reduce the ultimate distance a fish was willing toigrate (Tufts et al., 2000). While some downstream movementas evident in the month after release in the present study,ost fish exhibited considerable upstream movement in subse-

uent months. For the river with the most data available, thewenmore, salmon generally remained stationary or moved shortistances upstream in the two months after tagging. The majority ofpstream fish movement in December was over greater distances.horiskey et al. (2000) and Jensen et al. (2010) concluded that

almon behaviour seemed little altered after C&R angling.Webb (1998) concluded that, if treated with care, most fresh-

un and early summer salmon returned to the river by anglersehave normally and survive to spawn. The results of Bendocknd Alexandersdottir (1993) in freshwater Chinook salmon fish-ries in Alaska, Thorstad et al. (2003) and Dempson et al. (2002) fortlantic salmon in Norway and Newfoundland, support the use ofatch-and-release regulations as an effective management tool toeduce sport fishing mortality. Richard et al. (2013) also concludedhat C&R is an effective management tool towards maintaining theocio-economic benefits from recreational fishing while ensuring ainimal impact on the exploited population, pending appropriate

ractices. Results from the present study concur with these find-ngs. However, a small per cent mortality must be expected during&R, even during fly fishing. Hooking location may have been onef the factors influencing C&R mortality in the present study. Fishleeding from the hook wound and/or deeply hooked in the gills orhroat had a low survival rate, and should therefore not be released.

In rivers open for angling and harvesting salmon in Ireland in012, 37% of salmon were captured by fly fishing, 32% by lure andhe remainder by worm and prawn fishing (Irish salmon logbookagging scheme). For rivers where catch and release angling onlyas permitted, the percentage of salmon taken by fly fishing was

3%, while 33% were captured by lure fishing, both methods used

ith single barbless hooks. The three rivers in the present studyere all above conservation limit and all angling methods wereermitted. Results indicate that the management assumption thateleased Atlantic salmon can be included in the estimate of the

arch 161 (2015) 252–260 259

spawning stock in Irish rivers with C&R angling only would be validfor fly captured (98% survival) but not for lure captured salmon (55%survival). Therefore, any interpretation on risks associated withcatch and release fishing depend upon the characteristics of thefishery in terms of gear used, proportion of fish captured by geartype, angler release practices, and water temperatures when catchand release activities occur. Further studies are required regardingthe appropriateness of allowing catch and release fishing usinglures, and by allowing catch and release angling at water tempera-tures above 18 ◦C.

In conclusion, results showed that, when conducted usingproper guidelines, and at low to moderate water temperatures, sur-vival of fly captured salmon after C&R angling was high. The resultsgenerally demonstrated a careful treatment of the Atlantic salmonduring C&R angling in these Irish rivers, with a short playing andhandling time, minimum air exposure and a low occurrence of deephooking (i.e., hooking in gills and throat). Hence, in rivers withouta surplus of salmon above the conservation limit, permitting C&Rangling using appropriate methods can be successful as a tool toprovide information on salmon stock status while not significantlyimpacting on salmon survival.

Acknowledgements

The authors would like to thank the angling clubs on the Owen-more, Feale and Mulkear for their cooperation during this study andindividual anglers who provided salmon for tagging and release.Inland Fisheries Ireland staff are acknowledged for their assistanceduring tagging and tracking on all three rivers. E.B. Thorstad waspartly supported by the Norwegian Research Council project Sal-CaRe no. 216416/O10. Dr. Fred Whoriskey and Tony Holmes areacknowledged for their helpful comments on the revised versionof the manuscript.

References

Anderson, W.G., Booth, R., Beddow, T.A., McKinley, R.S., Finstad, B., Økland, F., Scru-ton, D., 1998. Remote monitoring of heart rate as a measure of recovery in angledAtlantic salmon, Salmo salar (L.). Hydrobiologia 371/372, 233–240.

Arlinghaus, R., Cooke, S.J., Lyman, J., Policansky, D., Schwab, A., Suski, C., Sutton,S.G., Thorstad, E.B., 2007. Understanding the complexity of catch-and-release inrecreational fishing: an integrative synthesis of global knowledge from histori-cal, ethical, social, and biological perspectives. Rev. Fish. Sci. 15, 75–167.

Bartholomew, A., Bohnsack, J.A., 2005. A review of catch-and-release angling mor-tality with implications for no-take reserves. Rev. Fish Biol. Fish. 15, 129–154.

Bendock, T., Alexandersdottir, M., 1993. Hooking mortality of Chinook salmonreleased in the Kenai River, Alaska. N. Am. J. Fish. Manage. 13, 540–549.

Boyd, J.W., Guy, C.S., Horton, T.B., Leathe, S.A., 2010. Effects of catch-and-releaseangling on salmonids at elevated water temperatures. N. Am. J. Fish. Manage.30, 898–907.

Brobbel, M.A., Wilkie, M.P., Davidson, K., Kieffer, J.D., Bielak, A.T., Tufts, B.L., 1996.Physiological effects of catch and release angling in Atlantic salmon (Salmo salar)at different stages of freshwater migration. Can. J. Fish. Aquat. Sci. 53, 2036–2043.

Cooke, S.J., Suski, C.D., 2005. Do we need species-specific guidelines for catch-and-release recreational angling to effectively conserve diverse fishery resources?Biodivers. Conserv. 14, 1195–2005.

Dempson, J.B., Furey, G., Bloom, M., 2002. Effects of catch and release angling onAtlantic salmon, Salmo salar L., of the Conne River, Newfoundland. Fish. Manage.Ecol. 9, 139–147.

Donaldson, M.R., Arlinghaus, R., Hanson, K.C., Cooke, S.J., 2008. Enhancing catch-and-release science with biotelemetry. Fish Fish. 9, 79–105.

DuBois, R.B., Margenau, T.L., Stewart, R.S., Cunningham, P.K., Rasmussen, P.W., 1994.Hooking mortality of northern pike angled through ice. N. Am. J. Fish. Manage.14, 769–775.

Falk, M.R., Gillman, D.V., Dahlke, L.W., 1974. Comparison of Mortality BetweenBarbed and Barbless Hooked Lake Trout. Technical Report Series CEN/T-74-1.Department of Environmental Fisheries and Marine Services, Winnipeg, Mani-toba.

Ferguson, R.A., Tufts, B.L., 1992. Physiological effects of brief air exposure in exhaus-

tively exercised rainbow trout (Oncorhynchus mykiss): implications for catch andrelease fisheries. Can. J. Fish. Aquat. Sci. 49, 1157–1162.

Finstad, B., Bjørn, P.A., Nilsen, S.T., 1995. Survival of salmon lice, Lepeophtheirussalmonis Krøyer, on Arctic charr Salvelinus alpinus (L.) in fresh water. Aquacult.Res. 26, 791–795.

2 s Rese

G

G

G

I

J

L

M

M

M

N

P

R

60 P.G. Gargan et al. / Fisherie

ale, M.K., Hinch, S.G., Eliason, E.J., Cooke, S.J., Patterson, D.A., 2011. Physiologicalimpairment of adult sockeye salmon in fresh water after simulated capture-and-release across a range of temperatures. Fish. Res. 112, 85–95.

ingerich, A.J., Cooke, S.J., Hanson, K.C., Donaldson, M.R., Hasler, C.T., Suski, C.D.,Arlinghaus, R., 2007. Evaluation of the interactive effects of air exposure durationand water temperature on the condition and survival of angled and released.Fish. Res. 86, 169–178.

jernes, T., Kronlund, A.R., Mulligan, T.J., 1993. Mortality of Chinook and Cohosalmon in their first year of ocean life following catch and release by anglers. N.Am. J. Fish. Manage. 13, 524–539.

CES (International Council for the Exploration of the Sea), 2013. Report of the Work-ing Group on North Atlantic Salmon (WGNAS). ICES CM 2013/ACOM:09.

ensen, J.L.A., Halttunen, E., Thorstad, E.B., Næsje, T.F., Rikardsen, A.H., 2010. Doescatch-and-release angling alter the migratory behaviour of Atlantic salmon?Fish. Res. 106, 550–554.

oftus, A.J., Taylor, W.W., Keller, M., 1988. An evaluation of lake trout (Salvelinusnamaycush) hooking mortality in the upper Great Lakes. Can. J. Fish. Aquat. Sci.45, 1473–1479.

äkinen, T.S., Niemelä, E., Moen, K., Lindström, R., 2000. Behaviour of gill-net androd-captured Atlantic salmon (Salmo salar L.) during upstream migration andfollowing radio tagging. Fish. Res. 45, 117–127.

eka, J.M., 2004. The influence of hook type, angler experience, and fish size oninjury rates and the duration of capture in an Alaskan catch-and-release rainbowtrout fishery. N. Am. J. Fish. Manage. 24, 1309–1321.

uoneke, M.I., Childress, W.M., 1994. Hooking mortality: a review for recreationalfisheries. Rev. Fish. Sci. 2, 123–156.

uhfer, A.J., Alexander, G.A., 1992. Hooking mortality of trophy-sized wild brooktrout caught on artificial lures. N. Am. J. Fish. Manage. 12, 634–644.

auley, G.B., Thomas, G.L., 1993. Mortality of anadromous coastal cutthroat trout

caught with artificial lures and natural bait. N. Am. J. Fish. Manage. 13,337–345.

ichard, A., Dionne, M., Jinliang, W., Bernatchez, L., 2013. Does catch and releaseaffect the mating system and individual reproductive success of wild Atlanticsalmon (Salmo salar L.)? Mol. Ecol. 22, 187–200.

arch 161 (2015) 252–260

Schreer, J.F., Resch, D.M., Gately, M.L., Cooke, S.J., 2005. Swimming performance ofbrook trout after simulated catch-and-release angling: looking for air exposurethresholds. N. Am. J. Fish. Manage. 25, 1513–1517.

Thorstad, E.B., Næsje, T.F., Leinan, I., 2007. Long-term effects of catch-and-releaseangling on Atlantic salmon during different stages of return migration. Fish.Res. 85, 330–334.

Thorstad, E.B., Økland, F., Finstad, B., 2000. Effects of telemetry transmitters onswimming performance of adult Atlantic salmon. J. Fish Biol. 57, 531–535.

Thorstad, E.B., Næsje, T.F., Fiske, P., Finstad, B., 2003. Effects of hook and release onAtlantic salmon in the River Alta, northern Norway. N. Am. J. Fish. Manage. 60,293–307.

Thorstad, E.B., Næsje, T.F., Mawle, G.W., Policansky, D., 2008. The Atlantic salmonC&R story. In: Aas, Ø. (Ed.), Global Challenges in Recreational Fisheries. BlackwellPublishing, Oxford, UK, pp. 219–222.

Tufts, B.L., Davidson, K., Bielak, A.T., 2000. Biological implications of catch and releaseangling of Atlantic salmon. In: Whoriskey, F.G., Whelan, K.E. (Eds.), ManagingWild Atlantic Salmon. Atlantic Salmon Federation, St. Andrews, New Brunswick,pp. 195–225.

Warner, K., 1976. Hooking mortality of landlocked Atlantic salmon, Salmo salar, in ahatchery environment. Trans. Am. Fish. Soc. 105, 365–369.

Webb, J.H., 1998. Catch and release: the survival and behaviour of Atlantic salmonangled and returned to the Aberdeenshire Dee, in spring and early summer.Scott. Fish. Res. Rep. 62, 1–15.

Whoriskey, F.G., Prusov, S., Crabbe, S., 2000. Evaluation of the effects of catch-and-release angling on the Atlantic salmon (Salmo salar) of the Ponoi River, KolaPeninsula, Russian Federation. Ecol. Freshw. Fish 9, 118–125.

Wilkie, M.P., Brobbel, M.A., Davidson, K., Forsyth, L., Tufts, B.L., 1997. Influences oftemperature upon the postexercise physiology of Atlantic salmon (Salmo salar).Can. J. Fish. Aquat. Sci. 54, 503–511.

Wilkie, M.P., Davidson, K., Brobbel, M.A., Kieffer, J.D., Booth, R.K., Bielak, A.T., Tufts,B.L., 1996. Physiology and survival of wild Atlantic salmon following angling inwarm summer waters. Trans. Am. Fish. Soc. 125, 572–580.

Wood, C.M., Turner, J.D., Graham, M.S., 1983. Why do fish die after severe exercise?J. Fish Biol. 22, 189–201.