Response by anglers to a differential harvest regulation on three black bass species at Skiatook Lake, Oklahoma

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1 9 Response y nglers to differentil hrvest regultion on three lck ss species t Skitook Lke, Oklhom Jmes M. Long U.S. Geologicl Survey, Oklhom Coopertive Fish nd Wildlife Reserch Unit, Nturl Resource Ecology nd Mngement, 007 Agriculture Hll, Oklhom Stte University, Stillwter, OK, Rndy G. Hyler Deprtment of Zoology, Oklhom Stte University, Stillwter, OK, Present ddress: Iow Deprtment of Trnsporttion, Office of Loction nd Environment, 800 Lincoln Wy, Ames, IA Willim L. Fisher U.S. Geologicl Survey, Oklhom Coopertive Fish nd Wildlife Reserch Unit, Nturl Resource Ecology nd Mngement, 007 Agriculture Hll, Oklhom Stte University, Stillwter, OK, Present ddress: U.S. Geologicl Survey, New York Coopertive Fish nd Wildlife Reserch Unit, Fernow Hll, Cornell University, Ithc, NY Angler responses to differentil hrvest regultion on lck ss, Micropterus spp. t Skitook Lke, Oklhom ws ssessed from 1997 to This regultion llowed nglers to hrvest 15 spotted ss, M. punctultus (Rfinesque) of ny size nd six lrgemouth ss, M. slmoides (Lcepède) nd smllmouth ss, M. dolomieu Lcepède greter thn 356 mm (in ggregte) per dy. Anglers ility to differentite spotted ss incresed fter the first yer of the study, ut their willingness to trget or hrvest spotted ss declined. Men ngler ctch rtes (numer of fish per ngling hour) for ll three species remined stedy throughout the study. Totl hrvest of lrgemouth ss nd smllmouth ss ws reduced y 1999 while totl hrvest of spotted ss remined stedy throughout the study period. Despite the more lierl regultions s incentive, the regultion filed to ccomplish the primry ojective of incresing ngler hrvest of spotted ss ecuse of high rtes of voluntry ctch nd relese Oklhom Acdemy of Science. INTRODUCTION Size limits re populr mong fisheries mngement gencies to ffect chnges to the popultion structure of sport nd forge fish (Fox 1975; Novinger 1984; ut see Wilde 1997). In the southestern USA, mny reservoirs contin comintion of lck ss species Micropterus spp., such s lrgemouth ss, M. slmoides (Lcepède), smllmouth ss, M. dolomieu Lcepède, nd spotted ss, M. punctultus (Rfinesque) tht re mnged concurrently, often with common minimum size limit. However, some fisheries iologists (Kornmn 1990; Buynk et l. 1991; Buynk 1995) hve found tht certin species, especilly spotted ss, tend to stockpile (n overundnce of smll individuls) under minimum-size limits. With common minimum-size limit nd susequent stockpiling, densitydependent processes, such s competition for resources, result in slower growth nd decrese of lrger fish in the fishery. As result, Novinger (1987) suggested the use of differentil lck ss hrvest regultion to control the undnce of slow-growing spotted ss. For such regultion to work,

2 10 J. M. LONG, R. G. HYLER nd W.L FISHER however, nglers hve to e le to correctly identify ech lck ss species. Differentil lck ss hrvest regultions hve rrely een used, presumly ecuse nglers hve difficulty correctly identifying spotted ss. However, such regultion ws successfully implemented on lck ss in Cve Run Lke, Kentucky (Buynk et l.1991), nd susequently sttewide (Buynk 1995), y using presence of tooth ptch on the tongue to differentite etween lrgemouth ss nd spotted ss. Although 10% of the lrgemouth ss in Cve Run Lke lso hd tooth ptch, Buynk (1995) presumed tht informing nglers of the tooth ptch chrcteristic to distinguish spotted ss from lrgemouth ss ws sufficient informtion to llow them to distinguish the two species. Buynk et l. (1991) found the numer of lrgemouth ss tht nglers misidentified s spotted ss to decrese in the yers following the regultion chnge. As result, the differentil hrvest regultion t Cve Run Lke ws considered very successful ecuse it met the gols of incresed spotted ss hrvest, decresed lrgemouth ss hrvest, nd incresed lrgemouth ss popultion undnce (Buynk et l. 1991; Buynk 1995). At Skitook Lke, Oklhom fisheries iologist with the Oklhom Deprtment of Wildlife Conservtion (ODWC) noticed drmtic increse in the numer of the spotted ss eginning in 1992 (ODWC 1995). A differentil hrvest regultion, imed t incresing the numer of spotted ss hrvested y nglers while minimizing hrvest of lrgemouth ss nd smllmouth ss, ws implemented in 1997 (Long 2000). Modeled fter the successful exmple t Cve Run Lke, Kentucky (Buynk et l. 1991), spotted ss t Skitook Lke were defined s ny lck ss species tht hd tooth ptch on the tongue nd ws not smllmouth ss. Beginning in 1997, nglers t Skitook Lke could hrvest up to 15 spotted ss of ny size per dy wheres only six, in ggregte, lrgemouth ss nd smllmouth ss 356-mm TL could e hrvested per dy. Previously, ll lck ss hd to e 356-mm TL to e hrvested t the rte of six, in ggregte, per dy. The ojectives of this study were to estimte ctch nd hrvest of lck ss nd to evlute the ttitudes nd opinions of nglers fter implementtion of the differentil hrvest regultion on lck ss t Skitook Lke, Oklhom. METHODS Study site Skitook Lke is 4,266-h flood control reservoir, creted in 1984 when the U.S. Army Corps of Engineers (USCOE) impounded Hominy Creek, nd is locted 8 km west of Skitook, Oklhom (ODWC 1995) (Figure 1). The lke ws filled in stges from Octoer 1984 to July 1989 to increse productivity (ODWC 1995) nd pulic fishing ws llowed eginning in My Lrgemouth ss occurred nturlly, ut were supplementlly stocked during ( ) nd fter ( ) reservoir filling nd non-ntive smllmouth ss were stocked in 1990 nd 1991 (ODWC 1995; Long nd Fisher 2005). Spotted ss occurred nturlly in the system nd were not stocked. Fishing is one of the most populr recretionl ctivities on Skitook Lke nd fishing pressure from lck ss tournment nglers is prticulrly high (ODWC 1995). Most ngler effort on Skitook Lke is directed towrd lck ss nd crppie, Pomoxis spp. (Zle nd Stus 1991). Fish hitt in Skitook Lke is chrcterized y deep cler wter with steep rocky shorelines, prticulrly in the lower end of the lke, with undnt stnding nd fllen timer (Long nd Fisher 2006). Skitook Lke is highly dendritic, with 257 km of shoreline nd shoreline development index of 11.3, men depth of 9.7 m, nd mximum depth of 31 m (ODWC 1995). The trophic stte of the lke rnges from oligotrophic ner the dm to eutrophic t the

3 DIFFERENTIAL HARVEST ON BLACK BASS SPECIES 11 Figure 1. Creel survey sections (A-H) t Skitook Lke, Oklhom used from 1997 to 1999 to document ngler ttitudes towrd differentil hrvest regultion on lck ss. The str indictes the pproximte loction of Skitook Lke in the stte. upper end (Long nd Fisher 2006) nd the resident lck ss community segregtes ccording to these trophic sttes (Long nd Fisher 2005); lrgemouth ss were uniform in undnce cross the lke, spotted ss were more undnt in the eutrophic upper end, nd smllmouth ss were more undnt in the oligotrophic lower end. Creel survey To ssess ngler ttitudes nd to monitor ctch nd hrvest fter implementtion of the differentil hrvest regultion, two-stge proility roving creel survey ws used (Roson 1991) with interceptinterviews of nglers conducted y ot. Smpling effort ws llocted y month (Mrch-Octoer) nd dy type (weekdys nd weekend dys) nd time of dy ws rndomly selected for smpling (Pollock et l.1994; Mlvestuto nd Hudgins 1996) (Tle 1). Additionlly, ecuse lrge proportion of effort ws expected to come from fishing tournments nd holidys, dvnced notice of these high use events were chosen s smpling dys in plce of rndomly selected dys when possile. Smpling effort for months nd dy type ws proportionl to effort sed on counts of crs t ot rmps on Skitook Lke provided y the U.S. Army Corps of Engineers (unpulished dt). Bsed on these crcount dt, too few nglers were present during Decemer, Jnury, nd Ferury (4% comined of totl nnul cr count) to wrrnt smpling so effort ws llocted to the remining months. Time of dy ws prtitioned eqully etween morning (AM) nd evening (PM), which chnged ccording to sesons (e.g., more dylight ville in summer thn fll). Time of dy (AM/PM) ws llocted mong survey dys eqully in 1997, ut proportionlly in 1998 nd 1999 sed on trends in effort oserved in 1997 (Hyler 2000). The lke ws divided into eight sections of equl shoreline distnce tht served s strting nd stopping loctions for the creel clerk (Figure 1). The creel clerk spent n equl mount of time in ech section, interviewing nd counting nglers to otin n instntneous count for ech section

4 12 J. M. LONG, R. G. HYLER nd W.L FISHER Tle 1. Smpling effort mong strt for creel survey t Skitook Lke, Oklhom from 1997 to Surveys were one-hlf dy long, occurring during morning (AM) or evening (PM). Dy type is numer of dys per week nd time of dy is proility of selection for smpling. WD = weekdy nd WE = weekend dy. Proility of smpling during AM on WD nd WE ws 0.5 for ll months in Eight sections were smpled ech survey dy nd time per section ws llocted eqully per dy. Proility Proility Numer of AM of AM Totl survey of WD smpling Numer of smpling Month time per dy per week on WD WE per week on WE Mrch 6 hours April 6.6 hours My 6.6 hours June 7.3 hours July 7.3 hours August 6.6 hours Septemer 6 hours Octoer 5.3 hours (Pollock et l. 1994). Ech creel dy, the clerk trveled y ot in rndomly chosen direction (clockwise or counter-clockwise) eginning in rndomly chosen section (A- H) nd completed the circuit within the time of dy llocted. Anglers ctively fishing were pproched y the clerk in ot with trolling motor nd sked if they would prticipte in the survey. Those nglers tht greed to prticipte were sked questions regrding their knowledge of the regultion chnge, if they were wre tht spotted ss could e distinguished from lrgemouth ss y tooth ptch on the tongue, if they were wre tht smllmouth ss could e identified y externl ody colortion, nd whether or not they felt the regultion chnge ws necessry. Anglers were then sked how this regultion would chnge their fishing hits towrd spotted ss (effort nd hrvest), how often they kept the ss they cught, how mny ss they hd cught, nd if they plnned on keeping the ss they cught tht dy. Anglers tht hd completed the survey previously in survey yer were considered repets nd only their effort, ctch, nd hrvest informtion ws collected. All ss found in ngler possession were identified nd counted y the creel clerk. STATISTICAL ANALYSES Angler count dt were used to estimte totl nnul fishing effort using the method descried y Pollock et l. (1994) nd 95% confidence intervls were clculted using stndrd errors clculted from pooled vrinces from the following dy-type strt: weekdys, weekdys with tournments, weekdy holidys, weekend dys, weekend dys with tournments, nd weekend holidys. This method produces n estimte of totl effort, which ws more useful for our purposes thn estimtes of men effort, ut it lso precludes the use of trditionl hypothesis testing procedures such s ANOVA to determine differences mong yers, we so relied on overlpping confidence intervls to determine sttisticl significnce mong yers. For ech survey dy, men ngler ctch per unit effort (CPUE; per ngler hour) nd hrvest per unit effort (HPUE; per ngler hour) ws clculted using the men-ofrtios estimtor ecuse effort ws sed

5 DIFFERENTIAL HARVEST ON BLACK BASS SPECIES on incomplete fishing trip informtion (Mlvestuto 1996). Men nnul CPUE ws rnk-trnsformed nd compred mong yers with nlysis of vrince (ANOVA) nd Tukey s post-hoc test (Zr 1999). A lrge numer of zeros precluded nlysis of nnul HPUEs. Dily totl ctch nd hrvest estimtes were computed y multiplying men dily ngler CPUE nd HPUE y men dily effort estimtes for n verge dily totl ctch nd hrvest estimte for ech dy-type. These estimtes were then multiplied y the numer of dys in the study period to otin totl ctch nd hrvest estimte for ech dy-type. Totl ctch nd hrvest estimtes for ech dy-type were summed to estimte the totl nnul ctch nd hrvest for ech lck ss species nd 95% confidence intervls were clculted using stndrd errors clculted from pooled vrinces s ws done with totl fishing effort (Pollock et. l. 1994). Totl ctch nd hrvest estimtes were deemed significntly different etween yers for ech lck ss species sed on overlpping 95% confidence intervls. Anglers responses to questions concerning their knowledge of the regultion chnge, ilities to distinguish spotted ss from lrgemouth nd smllmouth ss, nd responses to the remining survey questions were compred using Chi-squre contingency tles. When significnt differences were found, the proportions of responses were rcsine squre-root trnsformed (eqution 13.7 of Zr 1999) nd compred mong yers using the multiple comprison procedure for proportions outlined in section of Zr (1999) with stndrd errors for the difference etween proportions sed on different smple sizes (eqution of Zr 1999). We only tested for differences mong yers ecuse our interest ws focused mostly on ngler responses over time. RESULTS From 395 to 868 ngler surveys were completed ech yer from 1997 to 1999 (Tle 13 2). Most nglers were fishing y ot (from 88% to 89%) nd for lck ss (from 43% to 50%). Less thn 3% in ny yer declined to e interviewed, resulting in high interview rte (from 97% to 98% including repets). Some interviews were conducted with nglers who were interviewed previously in survey yer (from 14% to 23%) nd this ws highest t the end of the study period. Bsed on these surveys, it ws estimted tht nglers expended from high of 182,599 hours of fishing in 1997 to pproximtely 136,000 hours in 1998 nd Angler ctch rtes for lrgemouth ss (ANOVA, P = 0.73), smllmouth ss (ANO- VA, P = 0.98), nd spotted ss (ANOVA, P = 0.37) did not significntly chnge throughout the study period (Tle 3). However, totl ctch estimtes vried mong yers for most species, except smllmouth ss. Totl ctch of lrgemouth ss ws similr etween 1997 nd 1998 nd etween 1998 nd 1999; spotted ss totl ctch ws similr etween 1997 nd 1998 nd etween 1997 nd 1999, ut doule in 1999 from Unidentified ss (i.e., those ss not identified y nglers prior to eing interviewed y creel clerk ecuse they either were not wre of the identity or did not tke notice of the identity) ctch rtes decresed y the end of the study period. Very few lck ss were oserved y the creel clerk to e hrvested in ech study yer (rnge: 2 26), resulting in hrvest rte estimtes for ll lck ss species elow 0.1 fish per hour nd totl hrvest estimtes elow 3,000 fish. Totl hrvest estimtes for lrgemouth ss were similr etween 1997 nd 1998 nd etween 1997 nd 1999, ut reduced 85% from 1998 to Smllmouth ss totl hrvest ws the lowest in 1999 compred to the other study yers nd spotted ss totl hrvest did not significntly chnge mong yers. Awreness y nglers of the new regultion nd their ility to identify ech of the three lck ss species produced mixed results over the study period (Tle 4). Slightly more thn hlf of nglers were

6 14 J. M. LONG, R. G. HYLER nd W.L FISHER Tle 2. Summry sttistics of creel surveys conducted t Skitook Lke, Oklhom from 1997 to 1999 to ssess ngler ttitudes nd ctch nd hrvest fter implementtion of lck ss differentil hrvest regultion. Only totl effort ws tested for differences; similr suscript letters indicte no significnt difference mong yers sed on overlpping 95% confidence intervls. Vrile Numer of dys surveyed Numer of surveys completed Totl effort (ngler hours; 95% confidence intervl) 182, , ,671 (161,945 (115,932 (114, ,253) 157,988) 158,533) Method of fishing Bot (%) Dock (%) Shore (%) Species sought Bss (%) Crppie (%) Hyrid striped ss (%) Other (%) Nothing in prticulr (%) Interview type Interviewed (%) Declined (%) Repet (%) wre of the regultion chnge throughout the study (Chi-squre, P = 0.08). The ility of nglers who reported they knew how to identify spotted ss y the presence of tongue ptch (Chi-squre, P < 0.01) nd how to identify smllmouth ss y externl ody colortion (Chi-squre, P < 0.01) incresed fter 1997 (multiple comprison, P < 0.05). In 1997, pproximtely 54% of nglers knew to look for tongue ptch to identify spotted ss nd out 77% knew to identify smllmouth ss y externl colortion. These vlues incresed y out 10 percentge points for oth questions fter Angler opinion regrding the necessity of the regultion ws not independent of yer (Chi-squre, P < 0.01; Tle 5), ut the multiple comprisons indicted tht the nglers who responded no opinion (from 60% to 66%) nd yes (indicting they elieved the regultion chnge ws necessry; from 32% to 34%) were the sme mong yers; those nglers who responded tht the regultion ws not necessry decresed from 8-6% in to 2% in How nglers expected the regultion to ffect their fishing effort directed towrd spotted ss depended on yer (Chi-squre, P < 0.01). The percentge of nglers who thought their effort would increse (from 4% to 7%) or decrese (from 0% to 1%) did not chnge mong survey yers. The proportion of nglers replying tht their effort directed towrd spotted ss would not chnge ws high ( 89%) nd ecme higher during the lst two yers of the study (94% nd 96% in 1998 nd 1999). Similrly, the nticipted

7 DIFFERENTIAL HARVEST ON BLACK BASS SPECIES Tle 3. Comprisons of ctch per unit effort (CPUE; numer of fish per ngler hour), hrvest per unit effort (HPUE), totl ctch nd totl hrvest estimtes (confidence intervls [CI]) of lrgemouth, smllmouth, spotted nd unidentified ss t Skitook Lke from 1997 to N is numer of fish oserved hrvested, which ws used to estimte HPUE nd totl hrvest. Similr suscripts indicte no significnt difference mong yers within species nd ctch/hrvest sttistic ctegory. Yer CPUE HPUE (N) 1 Totl ctch (95% CI) Totl hrvest (95% CI) Lrgemouth ss (17) 24, (17,951 31,313) (164 1,482) (26) 27,577 1,540 (18,900 36,254) (374 2,706) <0.01 (2) 31, (31,720 32,262) ( ) Smllmouth ss <0.01 (3) 4, (2,777 7,213) (98 358) <0.01 (4) 8, (4,047 12,201) (105 1,325) <0.01 (3) 5, (5,882 6,094) (57 89) Spotted ss (17) 14,478 1,391 (8,828 20,128) (241 2,541) (10) 8, (5,229 12,489) (58 1,314) (6) 16, (16,377 16,751) ( ) Unidentified ss NA 13,390 NA (9,092 17,688) NA 7,897 NA (4,529 11,265) c NA 4,135 NA (4,035 4,235) 1 HPUE ws not tested due to lrge numer of zeros in the dt 15

8 16 J. M. LONG, R. G. HYLER nd W.L FISHER Tle 4. Percent of nglers responding yes when sked out knowledge of the regultion chnge, ility to distinguish spotted ss y the presence of tooth ptch, nd ility to distinguish smllmouth ss y externl ody colortion during creel survey t Skitook Lke, Oklhom conducted from Similr suscripts indicte no significnt differences mong yers s determined y multiple comprisons for proportions. Response Knowledge of regultion chnge Aility to distinguish spotted ss y tooth ptch Aility to distinguish smllmouth ss y colortion Tle 5. Percentge of responses y nglers regrding their opinion of the necessity of regultion chnge, nd its effect on their fishing effort nd hrvest of spotted ss in the future during creel survey t Skitook Lke, Oklhom conducted from Similr suscripts indicte no significnt differences mong yers s determined y multiple comprisons for proportions. Response Ws the regultion chnge necessry? Yes No No opinion Effects on fishing effort towrd spotted ss? Increse No chnge Decrese Unsure Effects on ngler hrvest of spotted ss? Increse c No chnge c Decrese Unsure level of effect on ngler hrvest of spotted ss depended on yer (Chi-squre, P < 0.01). The percentge of nglers expecting to increse their hrvest of spotted ss ws different every yer, declining from 38% in 1997 to 21% in In contrst, the percentge of nglers who reported to not chnge their hrvest of spotted ss incresed every yer, from 54% in 1997 to 76% in The tendency for nglers to keep lck ss for hrvest depended on yer (Chisqure, P < 0.01; Tle 6). Those who reported to never (men = 42%), or rrely (men = 27%) keep the lck ss they cught did not chnge mong yers. The percentge of nglers who sometimes hrvested their lck ss ws t its low of 3% in 1997, nd incresed to n verge of 12% fterwrds. Conversely, the percentge of nglers who responded to lwys hrvest their lck ss ws t its high in 1997 t 11%, flling to 6% or less fterwrds. When sked if they plnned on hrvesting ny of the lck ss they cught tht dy, 62% to 66% sid no, 24% to 28% responded yes, nd <12% sid mye, nd these results

9 DIFFERENTIAL HARVEST ON BLACK BASS SPECIES 17 Tle 6. Percentge of responses y nglers regrding the frequency t which they kept lck ss for hrvest nd whether they would keep ny ss cught tht dy when sked during creel survey t Skitook Lke, Oklhom conducted from Similr suscripts indicte no significnt differences mong yers s determined y multiple comprisons for proportions. Response How often do you keep the ss you ctch? Never Rrely Sometimes Usully Alwys Do you pln on keeping ss cught tody? Yes No Mye were not significntly different mong yers (Chi-squre, P 0.05). DISCUSSION These results indicte tht lierlizing the hrvest of spotted ss s n ngler incentive ws n ineffective tool for mnging lck ss in Skitook Lke, Oklhom. Those nglers who reported they either never or rrely kept the ss they cught mde up over two-thirds of the smple, which didn t chnge over time s the regultion ws implemented. The nglers who reported they would not chnge their fishing effort directed towrd spotted ss incresed over time from nerly 90% to 96%. The nglers who reported no chnge in spotted ss hrvest mde up t lest 50% of the smple, which incresed linerly over time to comprise 76% of the smple. These incresing trends of not trgeting or hrvesting spotted ss were in direct contrst to the intention of the regultion chnge to encourge the reduction of the spotted ss popultion in Skitook Lke with lierlized creel nd length limits. Contrry to the results of Buynk et l. (1991), nglers t Skitook Lke ppered unwilling to differentilly hrvest lck ss to produce the desired mngement result. Buynk et l. (1991) found tht nglers helped ccomplish their mngement gols of incresing hrvest of the smller, undesirle spotted ss, which ws incentivized through the enctment of regultion. At Skitook Lke, however, nglers ppered unwilling to utilize the enefits of the regultion chnge nd ecme even less willing to hrvest fish over the course of this study. In survey of 47 stte fisheries chiefs, Quinn (1996) found tht lck ss ws the species group tht showed the lrgest increse in voluntry ctch-nd-relese from the 1980s to the 1990s; up to 250% increse in some instnces. Ntionwide, this increse hs een ttriuted to vriety of resons including n evolving conservtion ethic of nglers, the influence of tournments, ngler concern with the helth of the fishery, nd the influence of fishing orgniztions (Quinn 1996). Which of these or other fctors, singulrly or in concert, hs influenced the high rte of voluntry ctch-nd-relese t Skitook Lke is unknown nd worthy of further study. Fishing tournment ctivity, s suggested y Quinn (1996), could hve plyed

10 18 J. M. LONG, R. G. HYLER nd W.L FISHER role in explining ngler unwillingness to hrvest ss t Skitook Lke. During this study, Skitook Lke consistently rnked s one of the top five reservoirs in Oklhom for fishing tournments sed on numer of nglers prticipting (Gillilnd 1997, 1998, 1999). Thus, fishing-tournment ctivity cn e viewed s surrogte for the degree of speciliztion y ngler groups. More specilized nglers tend to e disproportiontely influenced y fishing medi nd orgniztions, which hve generlly promoted ctch-nd-relese fishing (Quinn 1996, Myers et l. 2008). The degree of non-hrvest tendency mong ss nglers t Skitook Lke followed speciliztion grdient: 100% of tournment nglers reported to never or rrely keeping ss for hrvest compred to 90% of devoted ss nglers, nd 84% of occsionl ss nglers (Hyler 2000). As result, the lrge mount of tournment ctivity likely plyed role in preventing the regultion from succeeding. With incresing speciliztion nd concomitnt rtes of voluntry ctch nd relese y lck ss nglers, fisheries mngers will hve reduced cpcity to ffect lck ss popultions through the use of size nd g limits lone (Allen et l. 2008). To ddress this, mngers will hve to ecome etter t determining nd ddressing ngler motivtions (Wilde nd Ditton 1994, Ditton 1996) if they wnt to continue to use size nd g limits s tool for mnging lck ss popultions. ACKNOWLEDGMENTS We thnk D. Fenner, M. Brown, S. Fletcher M. Willis, nd E. Tejn for help with field work. K. Pope (Nersk Coopertive Fish nd Wildlife Reserch Unit), B. Wentroth (Oklhom Deprtment of Wildlife Conservtion), nd two nonymous reviewers provided constructive comments tht improved this mnuscript. Oklhom Deprtment of Wildlife Conservtion provided funding for this project with Federl Aid in Sportfish Restortion Grnt, F-41-R. The Oklhom Coopertive Fish nd Wildlife Reserch Unit is jointly supported y the U.S. Geologicl Survey, Oklhom Stte University, the Oklhom Deprtment of Wildlife Conservtion, the Wildlife Mngement Institute, nd the U.S. Fish nd Wildlife Service. Any use of trde, product, or firm nmes is for descriptive purposes only nd does not imply endorsement y the U.S. Government. REFERENCES Allen MS, Wlters CJ, Myers RM Temporl trends in lrgemouth ss mortlity, with fishery implictions. N Am J Fish Mn 28: Buynk GL, Kornmn LE, Surmont A, Mitchell B Evlution of differentil-hrvest regultion for lck ss in Cve Run Lke, Kentucky. N Am J Fish Mn 11: Buynk GL Evlution of differentil-lck ss size limit regultion on lrgemouth nd spotted ss. Frnkfort (KY): Kentucky Deprtment of Fish nd Wildlife Resources Fisheries Bulletin No p. Ditton RB Understnding the diversity mong lrgemouth ss nglers. In: Mirnd LE, DeVries DR, editors. Multidimensionl pproches to reservoir fisheries mngement. Bethesd (MD): Americn Fisheries Society. p Fox AC Effects of trditionl hrvest regultions on ss popultion nd fishing. In: Clepper H, editor. Blck ss iology nd mngement. Wshington, D.C.: Sport Fishing Institute. p Gillilnd G Oklhom ss tournments. Oklhom City (OK): Oklhom Deprtment of Wildlife Conservtion Annul Report F-44-D. 22 p. Gillilnd G Oklhom ss tournments. Oklhom City (OK): Oklhom Deprtment of Wildlife Conservtion Annul Report F-44-D. 19 p. Gillilnd G Oklhom ss tournments. Oklhom City (OK): Oklhom Deprtment of Wildlife Conservtion Annul Report F-44-D. 20 p. Hyler RG Response of nglers to differentil hrvest regultion on three lck ss species in Skitook Lke, Oklhom [MSc thesis]. Stillwter (OK): Oklhom Stte University. 110 p. Aville from: OSU Lirry. Kornmn LE Evlution of 15-inch size limit on lck ss t Gryson Lke. Frnkfort (KY): Kentucky Deprtment of Fish nd Wildlife Resources Fisheries Bulletin No. 90. Kuehl RO Sttisticl principles of reserch design nd nlysis. Belmont (CA): Duxury Press. 686 p. Long JM Evlution of differentil hrvest regultion on lck ss popultions in Skitook Lke [PhD disserttion]. Stillwter (OK): Oklhom Stte University. 123 p. Aville from: OSU Lirry. Long JM, Fisher WL Distriution nd undnce of lck ss in Skitook Lke, Oklhom fter introduction of smllmouth ss nd lierlized

11 hrvest regultion on spotted ss. N Am J Fish Mn 25: Long JM, Fisher WL Anlysis of environmentl vrition in Gret Plins reservoir using principl components nlysis nd geogrphic informtion systems. Lke nd Res Mn 22: Mlvestuto SP Smpling the recretionl creel. In: Murphy BR, Willis DW, editors. Fisheries techniques: 2nd edition. Bethesd (MD): Americn Fisheries Society. p Mlvestuto SP, Hudgins MD Optimum yield for recretionl fisheries mngement. Fisheries 21(6): Myers R, Tylor J, Allen M, Bonvechio TF Temporl trends in voluntry relese of lrgemouth ss. N Am J Fish Mn 28: Novinger GD Oservtions on the use of size limits for lck sses in lrge impoundments. Fisheries 9(4):2-5. Novinger GD Evlution of 15-inch minimum length limit on lrgemouth ss nd spotted ss ctches t Tle Rock Lke, Missouri. N Am J Fish Mn 7: Oklhom Deprtment of Wildlife Conservtion Surveys nd recommendtions - Skitook Reservoir. Oklhom Deprtment of Wildlife Conservtion Performnce Report Project No. 44-D-9. DIFFERENTIAL HARVEST ON BLACK BASS SPECIES Pollock KH, Jones CM, Brown TL Angler survey methods nd their pplictions in fisheries mngement. Bethesd (MD): Americn Fisheries Society, 371 pp. Quinn S Trends in regultory nd voluntry ctch-nd-relese fishing. In: Mirnd LE, DeVries DR, editors. Multidimensionl pproches to reservoir fisheries mngement. Bethesd (MD): Americn Fisheries Society, pp Roson DS Roving creel surveys. In: Guthrie D, Hoenig JM, Hollidy M, Jones CM, Mills MJ, Moerly SA, Pollock KH, Tlhelm DR, editors. Creel nd ngler surveys in fisheries mngement. Bethesd (MD): Americn Fisheries Society, pp Wilde GR Lrgemouth ss fishery responses to length limits. Fisheries 22(6): Wilde GR, Ditton RB A mngement-oriented pproch to understnding diversity mong lrgemouth ss nglers. N Am J Fish Mn 14: Zle AV, Stus K Development of white crppie fishery in stge-fill impoundment in Oklhom. Oklhom Deprtment of Wildlife Conservtion. Federl Aid in Sportfish Restortion Finl Report F-41-R. Zr JH Biosttisticl Anlysis, 4 th ed. Englewood Cliffs (NJ): Prentice Hll. 875 pp. Received: My 18, 2012; Accepted Septemer 21,

12 20 J. M. LONG, R. G. HYLER nd W.L FISHER