Lessons Learned from Nesting Male Bluegills

Transcription

1 Lessons Learned from Nesing Male Blegills by Donna Abler, Mark Kaemingk, & Dave Willis.Le'salk blegill! Sch fn and sefl creares, righ? Js focs on he recreaional vale of hese fish for a second. Blegills are ypically hngry and readily bie on a large variey of bais and lres. This makes hem a perfec and exciing cach for novice anglers. Pls, rophy -sized 'gills are perfec for any level of experienced angler. And, for hose who haven' learned he re vale of gian blegills, js ndersand his... a wo pond blegill sis near he op of way oo many bcke liss. If we haven' sold yo on he recreaional vale of hese fish, hen yo probably are one of hose wih bass fever. Remember, blegills also serve an imporan role as a food sorce for hose bass! Largemoh bass need a plenifl spply of smaller fish as prey, and blegills fill ha niche very nicely. As a maer of fac, 28 POND BOSS blegills are he backbone of he food chain for sohern bass lakes. Wha facors ms he consider as daddy blegill picks o his special locaion o hach his offspring? Now le's ake a sep back. For blegill o be so fn o cach or serve as bass food, hey need o sccessflly reprodce and recri (i.e., srvive o adlhood) ino he fishery. One of he A sbsrae core sample from he boom of Wes Long Lake. firs seps in reprodcion is for a male blegill o clean and defend his nes. He will hen arac a female who will deposi her eggs in he nes. B, before his happens, wha is going hrogh he male blegill's mind as he selecs his nesing sie? Wha facors ms he consider as daddy blegill picks o his special locaion o hach his offspring? Afer all, his may be one of he bigges "decisions" of his life as passing on his genes o fre generaions is one of he bigges goals of his exisence. As sch, cerain locaions wihin a lake or pond may improve his chances of achieving his goal. So, a sccessfl male shold "know" wha he is doing and selec a spawning sie ha will opimize his abiliy o sccessflly hach and raise his yong. The prpose of or sdy was o learn from hese male blegills js wha habias pond owners and managers shold proec o mainain a healhy poplaion of blegills. We decided o ake a lesson from male blegills in a small ( acres) naral lake, Wes Long Lake, locaed on he Valenine Naional Wildlife Refge in he Sandhills region of Nebraska. This region of he sae prodces some rophy blegills, so he blegills ms be doing somehing righ. Why no learn from he bes? Or firs and primary objecive was o find some blegill colonies or nesing sies. We acally aemped his projec in 21 b fond i o be very challenging. In he Sandhills, a majoriy of he blegill spawn only once per year, which is differen from sohern poplaions ha ypically have mliple spawns. So, iming was everyhing. We were fornae his pas Jne of 211. We imed i perfecly and fond a day wih very lile wind and good waer clariy. Very lile wind is RARE in his locaion. We slowly moored arond he perimeer of he lake wih wo people on he bow of he boa wearing November/December 211

2 polarized snglasses (o c hrogh he glare of he sn on he waer). Upon locaing a colony or nes sies we wold ge a GPS locaion so we cold rern o hese sies a a laer dae. Once we were finished we rerned o he Soh Dakoa Sae Universiy (SDSU) camps where we randomly picked 25 oher mapped locaions on he lake ha blegills were no sing as nes sies, b ha were a he same average deph as or colonies. We hen cold compare environmenal characerisics a he nes sies wih characerisics a he random sies and deermine wha he blegills seemed o be seeking. If here was no difference in a characerisic beween he random and nes sies, we wold assme ha facor is no imporan in he male's "decision" (remember, hese are insincive decisions, no conscios decisions, we believe) o selec ha sie. On he oher hand, a difference wold sgges ha his characerisic cold be imporan in he male's decision o choose ha locaion. For example, if emperare was lower a he nesing sies compared o he random sies we cold conclde ha male blegills are seeking areas in he lake which provide cooler emperares dring nesing. So, how do we decide which variables are mos imporan o male blegills when picking a siable nes locaion? We chose o measre characerisics ha have previosly been imporan in oher nesing sdies on blegills and oher cenrarchids (oher members of he snfish family, sch as largemoh and smallmoh bass). These characerisics inclded emperare, dissolved oxygen, how firm he lake boom was, ype of sbsrae on Exper Advice For The Resls Yo Wan From Yor Pond or Lake! 31 Years Experience Raising Fish Pond Analysis Managemen Sraegy Fish Socking Trobleshooing Lake and Pond Design Bob Lsk P.O. Box 483, Whiesboro, Texas pondboss@exoma.ne Yo Fish... We Do he Res! Vollmar Pond & Lake Managemen Lake Design Fish Socking Locaed in Vegeaion Managemen Grass Carp Fredericksbrg, TX Sie Evalaion Habia Enhancemen Serving he Texas Monhly Mainenance Aeraion/Fonains Hill Conry- as well as Managemen Plans Fishery Srveys cenral, soh and wes Texas Conac: Brad Vollmar lakemanagemen@gmail.com he boom of he lake, informaion on ypes and densiies of aqaic vegeaion, and shoreline fech. Fech is a erm indicaing he disance over which a wind acs o prodce waves. Shoreline fech essenially refers o how exposed a locaion is o wind and wave acion ha cold desroy a nes. For example, a nes locaed in a Mark Kaemingk wih he core sampler sed o ake sbsrae samples from he boom of Wes Long Lake. Removing he sbsrae sample from he core sampler. PONDBOSS 29 ~

3 proeced bay cold have a very shor disance over which wind cold prodce waves, while a nes locaed on he main par of he lake cold have a long disance of open waer over which large waves cold be developed. A week afer locaing he nesing colonies we rerned o he lake o measre all of hese characerisics a boh he blegill nesing colonies and a he random sies we seleced. Wha did we end p learning from hese male blegills? We fond a oal of five blegill nesing colonies in Wes Long Lake (Figre 1). Male blegills were no picky abo sbsrae ype as we fond no differences in sbsrae composiion beween random and nesing sies (Figre 2). However, emperare appeared o be slighly lower a he nesing sies compared o he random sies (Figre 3). Were hey seeking cooler Donna Abler measring dissolved oxygen a one of he nesing sies Figre 1. Wes Long Lake, Cherry Cony, Nebraska wih blegill nesing sies (yellow sars) and random sies (ble riangles). 1 >- 2 C :, C" ~ ;f?. 2 Sand Clay Sil Organic Soil composiion 1 >- 2 C :, C" I.. ;f? Srface waer emperare l C) Donna Abler and Jason Agsprger measring he deph a one of he nesing sies. Figre 2. Percen composiion (sand, clay, sil, organic maerial) ofsoil samples aken a he boom of he lake from blegill nesing (op) and random (boom) sies in Wes Long Lake, Nebraska. Figre 3. Srface waer emperare ( C) 3 PONDBOSS November/December 211

4 proecion of he soh shore? How do we make sense o of hi s informaion and where do we go from here? Well, i seems ha here are a few sie characerisics ha male blegills in his lake seek when searching for he bes locaion in he lake o bild heir ness. They don' seem o care mch abo sbsrae ype or wha he boom of he lake is like in erms of soil composiion (or maybe hese sandhill lakes don ' have mch variey in sbsrae). Raher, hey are looking for areas ha are slighly lower in emperare, eiher closer o or farher away from pariclar sbmergen vegeaion ypes, locaed on he soh side of he lake, and farher away from shore compared o all he oher poenial nesing areas in he lake. We were srprised by some of hese variables as anoher sdy in a more complex Soh Dakoa glacial lake (Gosch e al. 26) idenified boom sbsrae, sbsrae firmness, sbmergen vegeaion densiy, and dissolved oxygen o be imporan in he nes selecion process. These resls were differen han wha we fo nd for Nebraska Sandhill blegills, which is a prime example on why Donna Abler and Jason Agsprger measring sbsrae firmness a one of he nesing sies. waer, or did some oher seleced characerisic case he cooler emperare? We don ' know ha answer. We also noiced ha sbmergen vegeaion was farher away from he nesing colonies compared o he random sies (Figre 4). We wonder, did hey seek sies away from he vegeaion or did heir aciviy case he plans o be redced? A majoriy of he random sies had sbmergen vegeaion growing righ wihin he sie and i was a differen ype of vegeaion han fond near he nesing sies (Figre 5). Ah, now we were geing somewhere. Maybe he pondweed was aracive o he males, or maybe i grows over a cerain sbsrae? Maybe here is some minor characerisic in sbsrae ha we didn' measre? Maybe he problem was he sar dckweed? Maybe hey waned o avoid i, or maybe i was over some minor, ndesirable sbsrae. Sar dckweed is differen han mos oher ypes of dckweeds as all he oher dckweeds are caegori zed as floaing plans; however, sar dckweed, in pariclar, can grow in dense mas rooed o he boom of he lake. Males seemed o prefer areas farher offshore compared o or random sies (Figre 6). Hmm, he wind blows once in a while in Nebraska, so maybe hey didn' wan o be in shallow waer oo close o shore where wave acion wo ld affec he ness? Finally, all nesing colonies were locaed along he soh shore of he lake, indicaing a srong preference for his area in he lake (Figre l and 7). Given ha he smmer prevailing winds are from a soherly direcion, i sre seems he male blegills were seeking he 32 POND BOSS 1 >, 2 ;f Disance o sbmergen vegeaion (cm] Figre 4. Disance o neares sbmergen vegeaion (cenimeers) a nesing (op) and random (boom) sies in Wes Long Lake, Nebraska. 1 >, 2 ;f Disance o shore (ml Figre 6. Disance o shore (meers) from nesing (op) and random (boom) sies in Wes Long Lake, Nebraska. 1 >, '-' 2 Cl) CY Cl) :::?f. 2 () o-{lee 1<:' Figre 5. Neares sbmergen vegeaion ype (pondweed, coonail, sar dckweed) 1 >, 2 ;f Soh fech (ml Figre 7. Soh shoreline fech (meers) November/December 211

5 ( j. ~p Hybrid Cafish Largemoh Bass All Types of Perch and Minnows Elecro-Shocking and Lake Managemen Sar dckweed (Lemna rislca) sdying differen sysems is imporan. Wha happens in one lake is no always re in anoher lake. Wha happens in one pond is no always re for anoher pond. Or nesing sdy now provides biologiss wih a emplae o work from when rying o idenify habia feares ha are imporan for blegill spawning in Nebraska Sandhill lakes. These areas cold be proeced or oher areas of he lake cold be enhanced or proeced from wind o perhaps provide siable spawning areas for blegills. These blegill poplaions end o be low in abndance, and spawning sie limiaion or nes srvival may be one explanaion. Nex year, if yo have ime, ake a look a yor pond and locae any nesing colonies ha yo can. ls here any paern or rhyme or reason hey are locaed where hey are? Maybe yo will find similar paerns as we fond in or sdy... or maybe no. The hogh of learning somehing from hese magnificen creares keeps s waning o sdy hem more and more. Js remember, an imporan par of having a good blegill poplaion in yor pond ress pon he male blegill and his decision on where o nes. We wold like o sincerely hank he Pond Boss family and especially hose who donaed o he Jesse W. Wes Endowmen ha made his projec possible. Wiho yor help, his projec wold no have been compleed. We horoghly enjoyed his opporniy o learn more abo blegill and hope oher opporniies arise in he fre o conine o learn abo hem and oher species hrogh his endowmen. Abo he ahors: Donna Abler is an ndergradae sden majoring in Wildlife and Fisheries Sciences a SDSU. Mark Kaemingk is a Ph.D. sden and Dave Willis is Deparmen Head in he Deparmen of Naral Resorce Managemen a SDSU ~ / Henneke Rsll Ha1:cllery HallenHle,TX info@hennekehachery.com POND BOSS 33