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Darter Reproductive Seasons

Author(s): Clark HubbsReviewed work(s):Source: Copeia, Vol. 1985, No. 1 (Feb. 11, 1985), pp. 56-68Published by: American Society of Ichthyologists and Herpetologists (ASIH)Stable URL: http://www.jstor.org/stable/1444790.

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COPEIA, 1985, NO. 1OPEIA, 1985, NO. 1changes in kinosternid turtles. J. Herpetol. 6:183-189.

MCPHERSON, R. J., AND K. R. MARION. 1981. Sea-sonal testicular cycle of the stinkpot turtle (Ster-notherusodoratus)in central Alabama. Herpetolog-ica 37:33-40.MITCHELL,J. C. 1982. Population ecology and de-mography of the freshwater turtles Chrysemys ictaand Sternotherus doratus.Unpubl. PhD DissertationUniv. Tennessee, Knoxville.. (in press). Variation in the male reproductivecycle in a population of painted turtles, Chrysemyspicta, from Virginia. Herpetologica.MOLL, E. 0. 1973. Latitudinal and intersubspecificvariation in reproduction of the painted turtle,Chrysemys icta. Herpetologica 29:307-318.. 1979. Reproductive cycles and adaptations,p. 305-331. In: Turtles perspectives and research.M. Harless and H. Morelock (eds.). John Wiley andSons, New York.NIE, N. H., C. H. HULL, J. G. JENKINS, K. STEIN-BRENNERNDD. H. BENT. 1975. Statistical packagefor the social sciences. McGraw-Hill Book Co., NewYork.RISLEY, . L. 1933. Observations on the natural his-

tory of the common musk turtle, Sternotherusodor-atus (Latreille). Pap. Mich. Acad. Sci. Arts Lett. 17:685-711.

changes in kinosternid turtles. J. Herpetol. 6:183-189.MCPHERSON, R. J., AND K. R. MARION. 1981. Sea-sonal testicular cycle of the stinkpot turtle (Ster-notherusodoratus)in central Alabama. Herpetolog-ica 37:33-40.MITCHELL,J. C. 1982. Population ecology and de-mography of the freshwater turtles Chrysemys ictaand Sternotherus doratus.Unpubl. PhD DissertationUniv. Tennessee, Knoxville.. (in press). Variation in the male reproductivecycle in a population of painted turtles, Chrysemyspicta, from Virginia. Herpetologica.MOLL, E. 0. 1973. Latitudinal and intersubspecificvariation in reproduction of the painted turtle,Chrysemys icta. Herpetologica 29:307-318.. 1979. Reproductive cycles and adaptations,p. 305-331. In: Turtles perspectives and research.M. Harless and H. Morelock (eds.). John Wiley andSons, New York.NIE, N. H., C. H. HULL, J. G. JENKINS, K. STEIN-BRENNERNDD. H. BENT. 1975. Statistical packagefor the social sciences. McGraw-Hill Book Co., NewYork.RISLEY, . L. 1933. Observations on the natural his-

tory of the common musk turtle, Sternotherusodor-atus (Latreille). Pap. Mich. Acad. Sci. Arts Lett. 17:685-711.

. 1938. Seasonal changes in the testes of themusk turtle SternotherusodoratusL. J. Morphol. 63:301-317.SAINTGIRONS,H. 1982. Reproductive cycles of malesnakes and their relationships with climate and fe-male reproductive cycles. Herpetologica 38:5-16.SPEAT, R. H. 1973. Seasonal variation in the tubularand interstitial areas of the testes in Sternothaerusodoratus L. Unpubl. MS Thesis, East. Ill. Univ.,Charleston.STEEL,R. G. D., ANDJ. H. TORRIE. 1960. Principlesand procedures of statistics. McGraw-Hill Book Co.,New York.TINKLE, D. W. 1961. Geographic variation in repro-duction, size, sex ratio and maturity of Sternotherusodoratus Testudinata: Chelydridae). Ecology 42:68-76.ZAR,J.H. 1974. Biostatistical analysis. Prentice-Hall,Inc., Englewood Cliffs, New Jersey.ZUG, G. R. 1972. Walk pattern analysis of crypto-diran turtle gaits. Anim. Behav. 20:439-443.DEPARTMENT OF BIOLOGY, UNIVERSITY OF

RICHMOND,RICHMOND,VIRGINIA 23173. Ac-cepted 20 April 1984.

. 1938. Seasonal changes in the testes of themusk turtle SternotherusodoratusL. J. Morphol. 63:301-317.SAINTGIRONS,H. 1982. Reproductive cycles of malesnakes and their relationships with climate and fe-male reproductive cycles. Herpetologica 38:5-16.SPEAT, R. H. 1973. Seasonal variation in the tubularand interstitial areas of the testes in Sternothaerusodoratus L. Unpubl. MS Thesis, East. Ill. Univ.,Charleston.STEEL,R. G. D., ANDJ. H. TORRIE. 1960. Principlesand procedures of statistics. McGraw-Hill Book Co.,New York.TINKLE, D. W. 1961. Geographic variation in repro-duction, size, sex ratio and maturity of Sternotherusodoratus Testudinata: Chelydridae). Ecology 42:68-76.ZAR,J.H. 1974. Biostatistical analysis. Prentice-Hall,Inc., Englewood Cliffs, New Jersey.ZUG, G. R. 1972. Walk pattern analysis of crypto-diran turtle gaits. Anim. Behav. 20:439-443.DEPARTMENT OF BIOLOGY, UNIVERSITY OF

RICHMOND,RICHMOND,VIRGINIA 23173. Ac-cepted 20 April 1984.

Copeia, 1985(1), pp. 56-68

Darter Reproductive SeasonsCLARKHUBBS

Twenty-nine darters have reproductive intervals demonstrated and geographicvariation is shown for three species based on ten or more populations. The datafrom most populations are in accord with an hypothesis of multiple spawningby individual females.The length of darter reproductive seasons varies with latitude. Populationsfrom the southern United States breed over longer intervals than those frommore northern locations. Most of the difference is based on earlier initiation insouthern than in northern regions; whereas, the end of the breeding season tendsto be similar at different latitudes. The spawning season is longer in stenothermalhabitats than it is in eurythermal habitats (of various latitudes). The data are inaccord with hypotheses that photoperiod plays a major role in reproductiveinitiation and temperature is important in reproductive termination.

Copeia, 1985(1), pp. 56-68

Darter Reproductive SeasonsCLARKHUBBS

Twenty-nine darters have reproductive intervals demonstrated and geographicvariation is shown for three species based on ten or more populations. The datafrom most populations are in accord with an hypothesis of multiple spawningby individual females.The length of darter reproductive seasons varies with latitude. Populationsfrom the southern United States breed over longer intervals than those frommore northern locations. Most of the difference is based on earlier initiation insouthern than in northern regions; whereas, the end of the breeding season tendsto be similar at different latitudes. The spawning season is longer in stenothermalhabitats than it is in eurythermal habitats (of various latitudes). The data are inaccord with hypotheses that photoperiod plays a major role in reproductiveinitiation and temperature is important in reproductive termination.

REPRODUCTIVE seasons have been ascer-tained for many darters (Page, 1983;Kuehne and Barbour, 1983); however, most re-

ports relate to observations of spawning occur-rence during collection intervals with few re-

REPRODUCTIVE seasons have been ascer-tained for many darters (Page, 1983;Kuehne and Barbour, 1983); however, most re-

ports relate to observations of spawning occur-rence during collection intervals with few re-

peated efforts. Although Page (1983) opinedthat only one clutch was produced each season,my data suggest long reproductive seasons withmultiple spawnings (Hubbs, 1983). Addition-ally, Gale and Deutsch (1985) provide data dem-

peated efforts. Although Page (1983) opinedthat only one clutch was produced each season,my data suggest long reproductive seasons withmultiple spawnings (Hubbs, 1983). Addition-ally, Gale and Deutsch (1985) provide data dem-? 1985 by the American Society of Ichthyologists and Herpetologists1985 by the American Society of Ichthyologists and Herpetologists

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onstrating multiple spawnings for Etheostomaolmstedi in Pennsylvania. My opinion that mostdarters have multiple clutches has been ex-pressed in several papers but the data base hasbeen presented in detail only in Hubbs andStrawn (1957a) who showed that groups of ovasequentially differentiated from the pool of im-mature ova. Herein, I report known dates ofreproduction for several populations of threedarters and for one or more populations of 26additional species. Those data are in generalagreement with "Natural History" data pre-sented by Page (1983) and Kuehne and Barbour(1983) except that my information often sub-stantially extends the previously reported re-productive seasons.MATERIALS AND METHODS

The data reported here are derived primarilyfrom my previous hybridization experiments(Hubbs, 1967). The procedures were to obtaindarters from a variety of geographic locationsand return them to Austin. The stocks weremaintained without feeding at ca 15 C. Femaleswith clear, translucent eggs were considered tobe ripe and used for hybridization (or control)experiments. During most experiments someeggs developed embryos that hatched into suc-cessful larvae; therefore, this conservative mea-sure of reproduction is used here. Only thosefemales whose eggs were fertilized are reported.If I were to use clear, translucent eggs as theindex for reproduction, an occasional addition-al reproductive day would have been reported(especially for species that were tested infre-quently and their reproductive criteria not aswell understood). Females held under those lab-oratory conditions ceased producing eggs in 4to 5 days after 50 to 90% of them had ovulated.Consequently, it is apparent that at least half,and presumably all, females were in reproduc-tive cycle at the times of capture. Samples earlyor late in the reproductive seasons reported hereor of poorly understood species may have hadsmaller fractions of females reproductive, butthis occurred in fewer than 1%of the samples.For the data reported here female capture wasup to five days prior to the recorded date. Eachdate is considered as a datum even though thatdate may have been represented by 50 ripe fe-males on each of three separate years. Each yearhad similar reproductive seasons, thus poolingof years did not distort the data base.The data are for known occurrence of ripe

females; it is presumed that females in naturalpopulations were equally ripe at additional in-termediate dates as all samples from within theappropriate reproductive seasons had numer-ous reproductive females. The data reportedare for occurrence of reproductive females, thusthe seasons recorded may be shorter than thosethat occur in nature as some females may havebeen reproductive before and/or after thosedates recorded in my data.The localities reported here are the same asthose reported in Hubbs (1967). Commonly,adjacent localities are pooled. Most samplingwas from the years 1954 through 1967. As sev-eral leap years occurred within that time frame,Feb. is considered to have 29 days.

ETHEOSTOMA LEPIDUMThe greenthroat darter reproductive seasonhas been reported as Oct. or Nov. through Maywith populations in stenothermal environmentshaving a longer spawning season than those inmore eurythermal environments (Hubbs andStrawn, 1957a). These data reported here (Fig.1) corroborate that report. It should be notedthat the more stenothermal environments (S.

Concho, Mt. Home, S. Guadalupe) have longerrecorded reproductive seasons than the moreeurythermal extensively collected environ-ments (Hunt, Ingram, Junction). The green-throat darter is basically a springrun species.Thus, it is scarce or absent from very eury-thermal locations. Collectively (all populationspooled) greenthroat darter eggs are shown tohave been fertilized on 178 of 181 days in Nov.through April (the exceptions are 20 Feb., 31March, 25 April). Thus the species is intensivelyreproductive for six months and reproductionis also recorded for Sept., Oct., May and June,or at least some level of reproduction demon-strated for 10 months. Additionally, I recordtranslucent eggs from females obtained in BlueSpring, New Mexico, in Aug. 1983; Hubbs andStrawn (1957a) recorded breeding females(based on translucent eggs) in July.At the South Guadalupe locality, greenthroatdarter females were reported to be reproduc-tive in June, July and Aug. (Hubbs and Strawn,1957a) (the present report records fertilized eggsfrom that locality in the other nine months).That paper also reported spawning (the numberof eggs spawned was equivalent to the numberof ripe eggs in dissected females) in the labo-ratory (with densities equivalent to those on

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COPEIA, 1985, NO. 1

Etheosfoma lepidumI I I I I I

emoemoem. ? - - " - * -

Sept Oct Nov Dec Jon Feb Mar Apr May Jun

Fig. 1. Known reproductive dates for Etheostoma lepdum from 12 regons.

Fig . .nown reproductivedates for Etheostomaepidum rom ]2 regions.

spawning riffles) every 4.9 days at 19.6 C andevery 4.8 days at 20.4 C [the average temper-ature of central Texas springs is ca 20 C (Hubbs,1971)]. As Hubbs and Martin (1965) showedthat greenthroat darter females lay eggs pri-marily in daylight, it is assumed that the clutchesin nature occur every five days (previous aver-ages rounded to 5 days as nocturnal spawningsunlikely). A female from the South Guadalupewould lay 52 clutches per year based on theknown interval of fertilized eggs or 73 clutchesbased on observations of translucent eggs. Theegg volume approximates 7%of female volume.If we use a conservative figure of 5% of femalevolume, the summed annual contributions are260 and 365% of female volume.

ETHEOSTOMASPECTABILEThe orangethroat darter has a recorded re-productive season in central Texas that is verysimilar to that for the greenthroat darter. Themajor difference is that orangethroat dartersoccupy more eurythermal environments, thuslack the year-round reproduction that prevailsfor greenthroats occupying springruns (Fig. 2).For example at Junction both species are firstrecorded as reproductive on 12 Nov. In gen-

eral, reproduction is recorded over longer in-tervals for the stations at which that species ismore abundant (North Guadalupe, Hunt, Kerr-ville, Austin for orangethroats) (S. Concho, In-gram for greenthroats). Relatively rare species

are seldom collected and thus seldom recordedas ripe. The data reported here parallel thosepreviously reported for the same species in Tex-as by Hubbs (1961) and by Hubbs et al. (1968).They do extend the initiation of reproductioninto late Oct. Marsh (1980) has shown that thetermination of spawning may be delayed untilJuly in artificially cool hypolimnetic releasewaters in the Guadalupe River downstream fromCanyon Reservoir. The natural reproductiveseason in Texas would thus be seven monthswith a seminatural nine-month season. Assum-ing a five-day interbrood interval this wouldmean 42 to 54 spawns per year.The reproductive season in Arkansas extendsfrom mid-Feb. to early June, and in Missourifrom early April to early June (Fig. 2). Thislatter period is in accord with a March throughMay reproductive season in Kansas (Cross, 1967)and Missouri (Pflieger, 1975) but suggests myfirst Missouri samples were well after the firstspawning. The Arkansas season correspondswith or is slightly longer than that of late Feb.or March to May reported by Miller and Ro-bison (1973) for Oklahoma. The Arkansas pat-tern occurs in both the White River (E. s. spect-abile) and Illinois River (E. s. pulchellum)tributaries (contrast White R. and Clear Cr.).

The spawning season of orangethroat dartersvaries with latitude. In the south, it extends forseven months, farther north (Arkansas) it lastsalmost four months, yet farther north (Mis-souri) it lasts three months and toward the

S. Concho-San Saba-Junction

AustinKerrvilleMt.Home-N. Guad-Ingram-

HuntS. Guod-

Frio-Nueces-

I I I

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HUBBS-DARTER REPRODUCTIVE SEASONS

Etheosfoma spectobileI I I I I I I II 1 1 1II I I

?~~~?+ 1 ?elll l-? elele

-~~~ ~~ ~~~~~~~ ~ ~~P a lm eel elOM. e e l ? ? ? ee

- aliso 0

mei?0

elmOe --::_- : eeelMMO? ellSM W Mel e *? e? *

6 * OW *0 OM *o e * QM WW o * es *eo # * * t

-~ ~ ~~~~ee *lee eltl ?* *llll *e eli *l ? eso 4W 04" am 0 a -0 *-0 go 40 0 00 Me a@ # e,,.-I leil i ::...*:llelllel iie*le el ?"- *"

*- tI I l i I I iii I*** I*Ii I t 1411 * / * i*~ ~ ~ ~ _1??l I I ,Ite e l eeel ee ii ii eI C ?I t I i II I IIitiel tI

-r *mW ee -mme -*? * mo * -- ee *.1 i

el ? ell i eeleHiilMIl * 4il* ? ll

I I i I I I

r Loose Cr.-Mo. I Maries -[ White R. -

BrushCr.-Ark- LittleWildcat

Clear Cr. -Mt, Cr. -

Oklahoma -Lampassas -

Solado -Georgetown -

S. Concho -Junction -

Austin -San Marcos -

ComfortKerrville-N.Guad.-Ingram -

Hunt -Oct Nov Dec Jan Feb Mar Apr May

Fig. 2. Knownreproductivedates for Etheostomapectabilerom 20 regions.

northern limit (Michigan) two months [earlyApril to early June (Winn, 1958)]. Winn's re-port of peak reproduction in Kentucky andTennessee during the first week in April cor-responds better with the Missouri-Kansas sea-son than with that of Michigan. The majorityof the north-south difference in breeding sea-son lies in the initiation [Oct. (Texas) to April(Michigan)] rather than the end [mid-May (Tex-as) to early June (Arkansas-Missouri-Michi-gan)]. Assuming equivalent interbrood intervalsand equivalent individual clutch numbers inequal-sized females, Michigan females wouldhave to survive 3.5 spawning seasons to producethe same number of offspring as Texas femaleswould produce in one year.PERCINA CAPRODES

The logperch has been considered to repre-sent two species (the southern P. carbonaria andthe northern P. caprodes)by Thompson (1978),an action endorsed by Morris and Page (1981),and Page (1983) but not by Kuehne and Bar-

bour (1983). My Texas stocks would be P. car-bonaria and my Oklahoma, Arkansas and Mis-souri stocks P. caprodes if the two taxa areconsidered distinct species.The Texas stocks have been recorded asbreeding fromJan. throughJune (Hubbs, 1961)and Oct. and Nov. (Stevenson, 1971). The latterreport relates to spawning migrations and pre-sumably involves a prespawning migration andnot actual spawning. The locality referenced byStevenson is in the Kerrville locality includedin Fig. 3. That locality has a recorded breedingseason of Jan. through May (presumably alsolate Dec.) but definitely not including Nov. dur-ing which month many logperch were exam-ined at the same time that orangethroat darterfemales are reproductive. The present datademonstrate that the season is mid-Dec. to mid-May.

The logperch is commonly found in the samestreams as the orangethroat darter. The twospecies tend to partition riffles with logperch inthe deeper water or associated with larger rocksthan the orangethroat darter. Nevertheless the

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COPEIA, 1985, NO. 1Percina coprodes

II

Missouri-Arkansas-

OklahomoBrozos Syst.-San Saba R.-

Junction-Pedernales R.-

Austin-Cummins Cr -San Marcos-

Gonzales-Comfort-

Kerrville-Ingram-

Hunt-

???? ? ? ??

? ? ?Y ?? ??? Y

? ???

?? ???

??? ?? ?????

? ?

Dec Jan Feb Mar Apr MayFig. 3. Knownreproductivedates for Percina aprodesrom 15 regions.

two species are commonly taken in the sameseine haul. Therefore, logperch females wereavailable for examination for ripe eggs on mostof those dates orangethroat darters were ex-amined. Both species had numerous reproduc-tive individuals at five localities (Ingram, Kerr-ville, Comfort, Austin,Junction). At each localityorangethroat darters were reproductive beforelogperch (+56, +52, +24, +41 and +52 days,respectively, x = 45 days earlier), but the dataon last reproduction are more equivocal (-3,+7, -29, -14, 0, x = 8 days later). The obviousconclusion is that the breeding season for log-perch starts later but ends at about the sametime as that for orangethroat darters in centralTexas. That season would be mid-Dec. or earlyJan. to mid-May. In a similar fashion, the re-productive season for logperch in Arkansas andMissouri starts later but ends at about the samedate as that of orangethroat darters.The breeding season for male logperch is sub-stantially longer than that for female logperchas various Etheostomax P. caprodeshybrids wereproduced in Nov., a month before the initiationof female reproduction. This observation is inaccordance with the generalization that for mostfishes males are reproductive earlier (and long-er) than females (Lagler et al., 1977; Nikolski,1963).The spawning season for female logperch inTexas is Dec. to mid-May; Arkansas, mid-Marchto mid-May (Miller and Robison, 1973, list late

March or April for Oklahoma); Missouri, Apriland May (Pflieger, 1975) (my data cover onlyMay); southern Michigan, April to late May orearly June, and northern Michigan, mid-Juneto late July (Winn, 1958). Except for northernMichigan (where orangethroat darters do notoccur) the pattern is very similar to that of or-angethroat darters, progressively shorterspawning seasons with more northerly latitudes.The majority of the change is in spawning ini-tiation and little difference in the date of theend of the reproductive season.MISCELLANEOUS PERCINA

Bigscale logperch.-The reproductive season forPercina macrolepida n its natural range has notbeen previously recorded. Ripe females areknown to occur from 26 Feb. to 14 April [allfrom central Texas localities (Fig. 4)]. The oc-currence of small individuals (ca 25 mm SL) inLake Texoma in early June suggests a similarreproductive interval there. The available dataon male reproduction show no additional re-productive interval.Duskydarter.-The breeding season for Percinascierahas been reported as late May to earlyJulyin Illinois (Page and Smith, 1970) and Feb. toJune in Texas (Hubbs, 1961). My present dataslightly expand that reported two decades agowith substantialJan. reproduction recorded. In

I I I I I

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HUBBS-DARTER REPRODUCTIVE SEASONSPercina and Ammocrypta Species

I I I I

E.Texas-Arkonsas-

Missouri-Oklahoma-Louisiana -Gonzales-E. Texas-

Austin-San Marcos-

Gonzales-C.Texas-

i I I t t IA.vvoxP evidesP phoxocepholaP copelondiP nigrofascialoP shumardi

P sciero

* * o*r * ***am- e "am ?0 1~o Oa

? ? la ? m ? ee

P mocrolepidoI I I I I IDec Jan Feb Mar Apr May Jun

Fig. 4. Knownreproductivedates for seven speciesof Percinaand Ammocryptaivax.

the reasonably stenothermal waters of the SanMarcos River, dusky darters are known to bereproductive from 12 Jan. to 9 June (Fig. 4).Other localities (with more thermal variation)have not been shown to have reproductive in-dividuals for such a long interval but for themost part have not been sampled as frequently.The reproductive initiation for male duskydarters is considerably earlier than for the fe-males recorded here. Several males from Austinhad visible sperm that fertilized eggs (of Ethe-ostoma) n late Dec. and early Jan. The first datewas 29 Dec., or nearly a month before any fe-males from that population have been shown tobe ripe.The reproductive interval of dusky darters inSan Marcos is five months, but in Illinois Pageand Smith (1970) list an interval of less than twomonths. Populations from all four Texas areashave known reproductive intervals of three ormore months.Riverdarter. The reproductive season for Per-cina shumardi has been reported to be April inKansas (Cross, 1967), April and May in Illinois(Thomas, 1970) and possibly June or July in

Manitoba (Scott and Crossman, 1973). Starnes(1977) opines that in Tennessee the river darterspawns in Feb. and March. My data apply onlyto one location in the Guadalupe River nearGonzales, Texas, where river darters are shownto be reproductive from 14 Jan. to 22 April, orfor more than 3 months (Fig. 4). The evidenceon male reproductive intervals is essentially thesame as that for females.The recorded reproductive season for riverdarters in Texas is longer than that for anyother geographic area. Reproductive initiationis markedly earlier in the south and the end issomewhat later in the north.Blackbandeddarter.-The reproductive seasonfor Percina nigrofasciatahas been reported to beFeb. to April in Louisiana and early May to earlyJune near Auburn, Alabama (Mathur, 1973).My record from eastern Louisiana on 29 April(Fig. 4) suggests that all of April is within thereproductive interval in Louisiana.Channel darter.-The reproductive season forPercina copelandihas been reported as 9-23 Julyin northern Michigan (Winn, 1958) and April

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COPEIA, 1985, NO. 1

E.Texos-E.Texas-E.Texas-E.Texas-E.Texos-

Okla.-E.Texas-RioGondeSystem

Texas EtheostomaE. fonticolo Oct Nov Dec Jon Feb Mor Apr May Jun Jul

E.histrioE. osprigeneE chlorosomumE. grocileE.proelioreE.rodio um

E. grohomi

Nov Dec Jan Feb Mar Apr MayFig. 5. Knownreproductivedates for eight species of Etheostomarom Texas and Oklahoma.Note thedata for Etheostomaonticolaare on a differentscale.

and May in Kansas (Cross, 1967). The knownreproductive season in Oklahoma extends from4 April to 29 June (Fig. 4). The two June datapoints were obtained by Hubbs and Bryan (1975)from stocks obtained from the Blue River nearits spring source (a stenothermal location). Thebreeding season in the north is substantiallyshorter than that in the south.Slenderhead darter.-The reproductive seasonfor Percina phoxocephalahas been reported tobe late May to early July in Illinois (Page andSmith, 1971) and late April into May in Missouri(Pflieger, 1975). My data for a Missouri stockare supportive of Pflieger's report (Fig. 4).Gilt darter.-The reproductive season for Per-cina evides has been reported to be in May inVirginia (Denoncourt, 1969). Pflieger (1975)observed breeding males in late May in Mis-souri. I have obtained ripe females in late Apriland early May in Arkansas (Fig. 4).

AMMOCRYPTA

My data relate to only one species of sanddarter, Ammocryptaivax. There is essentially noinformation on the reproductive season of the

scaly sand darter. Williams (1975) noted thattuberculate males occur from mid-April to mid-Aug. My record of a ripe female in east Texason 8 April (Fig. 4) is the only report on a femalereproductive date. I also record fertilization ofdarter eggs by a male scaly sand darter on 5April.TEXAS/OKLAHOMA ETHEOSTOMA

Rio Grande darter.-The reproductive intervalof Etheostomagrahami has been recorded as lateMarch to early June (Harrell, 1980) but Strawnand Hubbs (1956) report that spawning will oc-cur at regular intervals if the temperature re-mains near 20 C. My record of early Jan. ripefemales (Fig. 5) is in accord with a prolongedreproductive interval in stenothermal waters. Itis likely that the reproductive cycle for the RioGrande darter is essentially the same as that ofthe greenthroat darter.Orangebellydarter.-The reproductive intervalfor Etheostoma adiosumhas been reported to beMarch through May for the Blue River, Okla-homa, by Scalet (1973). My data for Oklahomapopulations are in accord with Scalet's reportbut in east Texas reproduction (classification

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HUBBS-DARTER REPRODUCTIVE SEASONSbased on Hubbs, 1982) extends from at leastlate Feb. through mid-April (Fig. 5). Arkansas/Missouri - EtheostomaI I I ICypressdarter.-The reproductive interval forEtheostomaproeliarehas been reported to be Apriland May in Illinois and as early as Jan. in Lou-isiana (Burr and Page, 1978). My data suggestprolonged spawning from earlyJan. to mid-Aprilin east Texas (Fig. 5).Slough darter.-The reproductive season ofEtheostomagracilehas been reported to be Marchin Texas (Collette, 1962) and late May and earlyJune in Illinois (Braasch and Smith, 1967). Mydata indicate the breeding season starts in Tex-as (east) at least by 24 Jan. (Fig. 5). The dem-onstrated Texas reproductive season is morethan two months and that reported for Illinoisis no more than a month.Bluntnose darter.-The reproductive season ofEtheostoma hlorosomum as been reported to beApril in Kansas (Cross, 1967) and May in Illinois(Smith, 1979). My data for Texas populationsdemonstrate early Jan. to late March reproduc-tion in east Texas (Fig. 5). The known spawningseason in Texas populations is longer than thatreported for more northern localities.Mud darter.-Little is known of the reproduc-tive season of Etheostomaasprigene. Forbes andRichardson (1908) suggested a March to Mayreproductive season for Illinois and Becker(1983) stated that spawning occurs in April andMay at Havana, Illinois. In east Texas repro-ductive females are recorded from 14 Feb. to26 March (Fig. 5).Harlequin darter.-Little is known of the repro-ductive season of Etheostomahistrio.Kuehne andBarbour (1983) reported females apparentlyready to spawn in mid-March in Mississippi andHubbs and Pigg (1972) reported ripe femalesin Feb. That record is the 13 Feb. spawningrecorded here (Fig. 5). Additional east Texasspawning is recorded for 28 and 29 March.Fountain darter.-Etheostoma fonticola has beenrecorded to be reproductive in all months inSan Marcos River (Strawn, 1956). Schenck andWhitesides (1977) reported apparent spawningpeaks in Aug. and late winter. My data (Fig. 5)documenting fertilized eggs during 10 months(the exceptions are Aug. and Sept.) supportStrawn's thesis of continuous spawning.

Mo.-Ark.-Mo.-

Ark.-Mo.

Ark.-Ark.-Mo.-Mo.

Ark.-Ark.-

E.caeruleum

E.nianguaeE julioeE. terozonumE euzonumE. stigmaeumE flabelloreE. blennioides

E.punclulatumE.zonale

I

Mo.-Ark.-

I I I I IFeb Mar Apr May JunFig. 6. Knownreproductivedates for ten speciesof Etheostomarom Arkansasand Missouri.

ARKANSAS/MISSOURI ETHEOSTOMABanded darter.-The reproductive season forEtheostoma onalehas been reported as April andMay in Oklahoma (Miller and Robison, 1973)and Kansas (Cross, 1967), April in Missouri(Pflieger, 1975) and May and June in Illinois(Forbes and Richardson, 1908) and Pennsyl-vania (Lachner et al., 1950). Additionally, Burrand Mayden (1979) record ripe females on 20July in western Kentucky. My data show Ar-kansas reproduction from late March to earlyJune and Missouri reproduction from mid-Aprilto late May (Fig. 6). The longest recorded re-productive interval is for Arkansas stocks(southern).Stippled darter.-The reproductive season forEtheostomapunctulatumhas been reported as May(Miller and Robison, 1973), April and May withmales in breeding color as late asJuly (Pflieger,1975), May (Kuehne and Barbour, 1983) and

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COPEIA, 1985, NO. 1probably April (Cross, 1967). My data, primar-ily based on a stock in a spring near Fayetteville,Arkansas, have the breeding season at least frommid-Feb. through mid-May (Fig. 6). As thisspecies has a relatively restricted geographicrange (Cloutman, 1980), it is likely that my datawould apply to stenothermal waters (a preferredhabitat) throughout its range.Greensidedarter.-The reproductive season forEtheostomablennioides has been reported as lateMarch and early April in Missouri (Pflieger,1975) late April in Kentucky (Kuehne and Bar-bour, 1983) and April and May in Michigan(Winn, 1958). Pflieger and Winn suggested thatgreenside darters cease breeding earlier thanother darters in Missouri, Michigan, Kentuckyand Tennessee. My data support early repro-duction of greenside darters with the Arkansasseason in late Feb. to late March and the Mis-souri season in April (Fig. 6). Numerous samplesof darters in both regions had reproductive fe-males of other species but non-reproductive fe-male E. blennioidesthroughout May.Fantail darter.-The reproductive season forEtheostomaflabellare has been reported to beApril to June and perhaps July (Page, 1983) atvarious localities. It has been recorded as Apriland May in Missouri (Pflieger, 1975). My datasupport his conclusion with reproductive fe-males recorded on many days during those twomonths (Fig. 6).Speckleddarter.-The reproductive season forEtheostomastigmaeumhas been reported to beApril in Kentucky and Tennessee (Winn, 1958),April and May in Kansas (Cross, 1967) and Mis-souri (Pflieger, 1975) and late March to earlyApril in many localities (Howell, 1978). My datafor Arkansas stocks suggest that the inclusiverange listed for the several locations is correct(Fig. 6). I have records of ripe females from 20March to 16 May and numerous additional rec-ords of clear eggs from females on other datesincluding some as late as 30 May.Arkansas saddled darter.-The only data avail-able on the reproductive season for Etheostomaeuzonumare that provided by Hubbs and Strawn(1957b) on fertilized eggs obtained in May. Inow have data on fertilized eggs from 30 Marchto 12 May (Fig. 6).Missourisaddled darter.-The reproductive sea-son for Etheostoma etrazonumhas been reported

as April and May (Pflieger, 1975). My data arein accord with that season with ripe femalesoccurring between 2 April and 30 May (Fig. 6).Yokedarter.-The reproductive season for Ethe-ostomajuliae has been reported to be in May inMissouri (Pflieger, 1975) and April to early Julyin Arkansas (Hill, 1968). My data based on Ar-kansas stocks are in accord with a late repro-ductive season (Fig. 6). The earliest ripe femaleswere 9 May; seven species from the same lo-calities were reproductive in April. I have alsoobtained ripe females in late June supportingHill's report of early July reproduction.Niangua darter.-Pflieger (1975) reportedspawning activities by Etheostomanianguae inearly April. My documentation of a ripe femaleon 20 April (Fig. 6) is in general agreement withPflieger and suggests extended spawning.Rainbow darter.-The reproductive season forEtheostomacaeruleumhas been reported as lateMarch to May in Missouri (Pflieger, 1975), earlyApril to early June in Michigan (Winn, 1958)and April to June in Wisconsin (Becker, 1983).My Missouri data support the season reportedby Pflieger (Fig. 6). My Arkansas data showspawning from late Feb. to late May. The re-productive season is two to three months in mostareas.

DISCUSSIONDarters in most geographic regions treatedhere have breeding seasons extending over sev-eral months. The cumulative data suggest thatin stenothermal environments in Texas threedarter species (E. lepidum, E. grahami and E.

fonticola) are reproductive all year. In addition,fertilized eggs have been obtained over inter-vals of 273 (E. lepidum), 203 (E. spectabile),150(P. sciera), 143 (P. caprodes), 100 (E. proeliare),99 (P. shumardi), 96 (E. caeruleum), 88 (E. gra-hami), 86 (E. punctulatum), 76 (E. chlorosomum)and 71 (E. gracile, E. radiosum,E. tetrazonum,E.stigmaeumand E. flabellare) days. Except for E.blennioidesand E. juliae, the other species havedata for fewer than five days of reproduction.If eggs have been removed from a female ononly one occasion, obviously, only one repro-ductive day can be reported. Documentation ofprolonged spawning must follow study over aprotracted interval that is not available for thespecies with fewer than ten known days of re-production. Thirteen species are known to be

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HUBBS-DARTER REPRODUCTIVE SEASONS

reproductive for more than two months. Eachspecies has been shown to have most females inreproductive cycle throughout that interval;thus, individual females are reproductive forthat time interval. Data on E. lepidum and E.spectabile uggest that interbrood intervals rangefrom 4 to 10 days dependent upon stream tem-perature. Most streams are at 15-20 C duringthe reproductive season-at those tempera-tures interbrood intervals are 5-10 days.Therefore, females of the 13 species have thepotential of a minimum of six spawnings an-nually; if the stream temperatures are warmer,the minimum number of spawnings would be12. The maximum number of clutches per yearis 73.The spawning season for central Texas dart-ers is long. The recorded season for E. lepidumis 273 days and ripe eggs have been obtainedperiodically during the other 93 days. The doc-umented length of the season in individualstenothermal environments is 246 (S. Guada-lupe), 215 (Mtn. Home) and 211 (S. Concho)days and that of extensively sampled euryther-mal environments 164 (Junction), 167 (San Saba)and 162 (Ingram) days. Thermal stability playsa substantial role in the length of the repro-ductive season. Whenever the temperature be-comes warm (=ca 24 C) spawning activity slowsor ceases. Each eurythermal population showsspawning season initiation during decliningdaylength.The breeding season for E. spectabile n Texasis quite similar to that of eurythermal popula-tions of E. lepidum. The summed reproductiveseason is 203 days and individual populationsare known to be reproductive for at least 147(Ingram) to 187 (N. Guadalupe) days. The ini-tiation of reproduction is consistently duringperiods of decreasing daylength. Marsh's (1980)documentation of extended spawning in artifi-cally cooled waters shows that temperature hasan effect on length of spawning season. No sub-stantial shift in spawning season with latitude isapparent among Texas populations. There is asuggestion of a shift between the northernmostTexas sample (Lampassas) and the others as itstarts last and ends last. The Arkansas popula-tions have markedly shorter seasons (ca 100 days)than the Texas populations. The majority ofthe change is at spawning initiation (Feb. vs Nov.)with little change in last spawning (early Junevs mid-May). The more northern populationscontinue the trend with shorter spawning sea-sons that start in March (Pflieger, 1975; Winn,1958) and end in early June.

The breeding season for logperch in Texasis substantially shorter than that for either E.lepidumor E. spectabile.The cumulative seasonis 143 days and individual populations are knownto spawn for up to 140 days. The major differ-ence is in the date of first spawning (Dec. orJan. vs Oct., Nov. or Dec.) and most Texaspopulations start spawning at the time of shortdaylength or shortly after. There is little dif-ference in the date of reproductive terminationin eurythermal populations. The breeding sea-son for logperch in Arkansas (62 days) is shorterthan that for Texas populations and again themajority of that difference is in reproductiveinitiation (Feb. vs March) not termination (mid-May vs early June). The spawning season in Mis-souri seems displaced seasonally but Pflieger's(1975) report of April breeding suggests thatthe actual season is April through early June,again different dates of spawning initiation andcomparable termination dates. Winn's (1958)report of April to early June reproduction insouthern Michigan is in accord with a delay ininitiation of spawning but little difference intermination.

Geographic comparisons of spawning seasonwithin a species are in accord with a pattern oflonger seasons in the south than in the north.Additionally, comparisons among geographi-cally restricted species show the same pattern,with Texas species often spawning for most ofthe year, and those from Arkansas or Missourispawning for two to three months. Few reportsfor more northern species are for more thantwo months of spawning.The reproductive seasons for darters vary ex-tensively from essentially continuous spawningin stenothermal waters in southern locationsthrough prolonged winter/spring spawning ineurythermal waters in southern locations to rel-atively brief spawning at northern latitudes.Much effort has been focused on the causal fac-tors for initiation of spawning but much lessattention has been directed to causal factors fortermination of spawning. Especially for organ-isms with substantial geographic variation inspawning seasons it is possible that differentmechanisms could apply. The variations in thereproductive seasons for E. spectabilemay pro-vide insight into reproductive cues. Althoughannual clocks may play a role in reproductivestimulation, Marsh's (1980) demonstration of achange of the date of termination associatedwith an artificial change in environmental tem-perature suggests, at least, that termination isnot totally dependent on an endogenous rhythm.

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25-

15

50

-5

Edwards PlateouLmpossos

- N.W.Arkansas' W.CentralMissouri- Urbono,ILL

Adrian,MIAiggins Loke,MI

I . I t t - I I I IJ 'F'M' A'M J'A S O N D J

Fig. 7. Annual thermalcyclesfor seven locationsderivedfrom NOAA (1974). The localitiesare thoseclosestto the regions most closelystudiedfor darterreproductionn the centralUnited States.Knowndatesfor Etheostomaspectabile eproductive initiation andterminationare designatedby arrows.

The commonly discussed environmental cuesare light and temperature. In addition, foodsupplies must be sufficient to provide metabo-lites for gamete production; the wide scatter(standard deviation = 20 + eggs) in fecundityof equal-sized females recorded for E. lepidumand E. spectabile(Hubbs et al., 1968) is best ex-plained by variations in food supplies.The air temperature cycles (Fig. 7) for thevarious locations inhabited by E. spectabileshowthe expected colder weather in more polar lo-cations. In addition, the summer temperaturesare more similar than are the winter tempera-tures. The major exception is that summers innorthern Michigan (Higgins Lake) are about 3C colder than in southern Michigan (Adrian)whereas the winters are only about 4 C colder.The same comparison between Lampassas,Texas, and NW Arkansas shows differences of2 C and 5 C. The temperatures for first spawn-ings vary widely (17, 9.5, 5, 6, 5.5 C) from southto north. The distinction between southern andnorthern populations must be even greater thansuggested by spawning dates as the stimulus forspawning must precede actual egg deposition.Thus, in the areas with the warmer tempera-tures an earlier date would have even warmerconditions and the areas with the colder tem-peratures would be even colder than these ofthe actual spawning date.The pattern of environmental temperaturesfor spawning termination shows much moresimilarity with all between 21.5 and 23.7 C.

16

15 :N14

0 ~13-12

I / I Kerrvilne,TXaompasos TXI0-/ s' T --eFayettevitle,ARKII : -Jefferson City,MO:/ \:,';-.:';;-sUrban , ILLAdrion,MT9 v.j Higgins Lake, MI{ ti I I : IJ:FM AM J A SO N D J

Fig. 8. Annuallight cyclesfor seven localitiesde-rivedfrom Smithsonian 1896). The localities are inthe regionsmostcloselystudied for darterreproduc-tion in the central United States. Known dates forEtheostomapectabileeproductiveinitiation and ter-minationare designatedby arrows.

Those data reflect the last known date forspawning and if a stimulus period is considered,the most northern population has the lowestspawning thermal maximum and the slowestwarming. Thus, a time lag between the cue tostop spawning and the actual stop would havethe greatest thermal consistency among the cuetemperatures in northern populations. The ma-jor exception in termination of intraspecificspawning seasons is the later time for P. caprodesin northern Michigan; however, it is this areathat has much reduced mid-summer warming.The pattern of light cycles and spawning in-tervals shows the opposite pattern (Fig. 8).Spawning initiation is 9 hrs 10 min daylight to12 hours daylight. In this instance the short day-length is for southern locations and any stimuluswould involve a prior interval with longer day-light; the longer daylight figures are for north-ern populations and for these the preceding in-tervals are for less daylight. In effect, daylengthfor initiation of reproductive stimuli is likely tobe reasonably concordant among the popula-tions. The major difference would be that forsouthern populations it occurs in decreasingdaylength and it would be likely to involve in-creasing daylength in northern populations.There is somewhat less variation betweendaylength of last spawnings between 13 hrs 40min daylight in the south and 15 hrs 10 min inthe north. Although the variation of daylengthat end of spawning is not dissimilar to those forspawning initiation, they also correspond well

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HUBBS-DARTER REPRODUCTIVE SEASONSwith season of the year. More critically, the sub-stantial change in date of spawning terminationwith thermal change (Marsh, 1980) suggests amajor role of temperature in determining theend of the spawning season. An hypothesis thattemperature plays a major role in spawning ter-mination is supported by the year-round spawn-ing of populations (E. lepidum, E. grahami, E.fonticola) inhabiting stenothermal waters. Sim-ply, some factor has turned on reproductionand a thermal turn-off would not occur as fe-males would not experience that level of ther-mal extreme during their entire lives.The experiments on E. lepidumby Hubbs andStrawn (1957a) should be reevaluated in thiscontext. Reproductive females continued to de-posit eggs throughout their lives at varied day-lengths between 0 and 24 hours light. No dif-ference in egg production could be correlatedwith daylength. However, when the water tem-perature was raised from 20 to 23 C, there wasa marked drop in reproductive activity. Thiscorrelates well with the observed temperaturesin the environment when reproduction ceases(in Texas eurythermal environments they arethe same as for E. spectabile).Additionally, thetemperature (24 C) above which E. lepidumeggincubation success is low (Hubbs, 1961; Hubbset al., 1969), is quite similar to that at whichreproduction ceases.

ACKNOWLEDGMENTSThe field studies for this research were doneunder a series of NSF grants including GB 3206.I also thank officials of the states of Arkansas,Missouri, Oklahoma and Texas for numerous

collecting permits. I have benefited from dis-cussions with Lawrence M. Page, Edie Marshand Gary P. Garrett on darter reproduction.This manuscript has been improved by reviewsof a preliminary draft by Dr. Page and RobertA. Kuehne. A large number of associates havecontributed to the field and laboratory work,most notably Alex Peden, Neal Armstrong,William F. Hettler, F. Douglas Martin and KirkStrawn.

LITERATURECITEDBECKER, . C. 1983. Fishes of Wisconsin. Univ. Wis-consin Press.BRAASCH,M. E., ANDP. W. SMITH. 1967. The lifehistoryof thesloughdarter,EtheostomaracilePisces,Percidae).Ill. Nat. Hist. Surv. Biol. Notes 58.

BURR, B. M., ANDR. L. MAYDEN.1979. Records offishes in western Kentucky with additions to theknown fauna. Trans. Ky. Acad. Sci. 40:58-67., AND L. M. PAGE. 1978. The life history ofthe cypress darter, Etheostomaproeliare, in MaxCreek, Illinois. Ill. Nat. Hist. Surv. Biol. Notes 106.CLOUTMAN, D. G. 1980. Etheostoma punctulatum(Agassiz). Stippled darter, p. 684. In: Atlas of NorthAmerican freshwater fishes. D. S. Lee et al. (eds.).North Carolina State Mus. Nat. Hist.

COLLETTE, . B. 1962. The swamp darters of thegenus Hololepis Pisces, Percidae). Tulane Stud. Zool.9:115-211.CROSS,F. B. 1967. Handbook of fishes of Kansas.Misc. Publ. Mus. Nat. Hist. Univ. Kansas 45.DENONCOURT,. F. 1969. A systematic study of thegilt darter, Percina evides (ordan and Copeland)(Pisces, Percidae). Unpubl. PhD Diss., Cornell Univ.FORBES, . A., AND R. E. RICHARDSON. 908. Thefishes of Illinois. Illinois Nat. Hist. Survey, Urbana.GALE,W. R., ANDW. G. DEUTSCH.1985. Fecundityand spawning frequency of captive tessellated dart-er-fractional spawners. Trans. Amer. Fish. Soc.114.HARRELL,H. L. 1980. Etheostomagrahami (Girard)Rio Grande darter, p. 652. In: Atlas of North Amer-ican freshwater fishes. D. S. Lee et al. (eds.). NorthCarolina State Mus. Nat. Hist.HILL, L. G. 1968. Inter- and intrapopulational vari-ation of vertebral numbers of the yoke darter, Ethe-

ostomajuliae. Southwest. Nat. 13:175-191.HOWELL,W. M. 1978. Taxonomy and distributionof the period fish, Etheostomastigmaeum,with thevalidation and redescription of EtheostomadavidsoniHay. Unpubl. PhD Diss., Cornell Univ.HUBBS,C. 1961. Developmental temperature toler-ances of four etheostomatine fishes occurring inTexas. Copeia 1961:195-198.. 1967. Geographic variations in survival ofhybrids between etheostomatine fishes. Bull. TexasMem. Mus. 13.1971. Competition and isolation mechanismsin the Gambusiaaffinis x G. heterochirhybrid swarm.Ibid. 19.1982. A checklistof Texas freshwater ishes.Texas Parks and Wildlife Tech. Series 11.1983. Handbook of darters (review). Copeia1983:581.

,AND C. BRYAN.1975. Ontogenetic rates andtolerances of the channel darter, Hadropteruscope-landi. Texas J. Sci. 24:623-625., ANDP. S. MARTIN.1965. Effects of darknesson egg deposition by Etheostomalepidum females.Southwest. Nat. 4:302-306.,ALEX E. PEDEN AND MICHAEL M. STEVENSON.

1969. The developmental rate of the greenthroatdarter, Etheostomalepidum. Amer. Midi. Nat. 81:182-188., AND J. PIGG. 1972. Habitat preferences ofthe harlequin darter, Etheostomahistrio, in Texasand Oklahoma. Copeia 1972:193-194.

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Fecundity and egg size in two central Texas darterpopulations. Southwest. Nat. 13:301-323., AND K. STRAWN. 1957a. The effects of lightand temperature on the fecundity of the green-throat darter, Etheostomalepidum. Ecology 38:596-602.

,AND . 1957b. Survival of Fl hybridsbetween fishes of the sub-family Etheostomatinae.J. Expt. Zool. 134:31-60.KUEHNE,R. A., AND R. W. BARBOUR. 1983. TheAmerican darters. Univ. Press of Kentucky.LACHNER,. A., E. E. WESTLAKENDP. S. HANDWERK.1950. Studies on the biology of some percid fishesfrom western Pennsylvania. Amer. Midi. Nat. 43:92-111.LAGLER, K. F.,J. F. BARDACH, R. R. MILLER ND D.R. M. PASSINO. 1977. Ichthyology.John Wiley andSons.MARSH,E. 1980. The effects of temperature andphotoperiod on the termination of spawning in theorangethroat darter (Etheostomapectabile)n centralTexas. Tex.J. Sci. 32:129-142.MATHUR, D. 1973. Food habits and feeding chro-nology of the black-banded darter, Percina nigro-fasciata (Agassiz), in Halawalee Creek, Alabama.Trans. Amer. Fish. Soc. 102:48-55.MILLER, R.J., AND H. W. ROBISON. 1973. The fishesof Oklahoma. Oklahoma State University Press.MORRIS, M. A., AND L. M. PAGE. 1981. Variation inwestern logperches (Pisces: Percidae), with descrip-tion of a new subspecies from the Ozarks. Copeia1981:95-108.MOYLE,P. B. 1976. Inland fishes of California. Univ.Calif. Press.NIKOLSKI, G. V. 1963. The ecology of fishes. Aca-demic Press.NOAA. 1974. Climates of the states. Vols. 1 and 2.NOAA.PAGE, L. M. 1983. Handbook of darters. TFH Pub-lications.

, AND P. W. SMITH. 1970. The life history ofthe dusky darter, Percina sciera, in the EmbarrasRiver, Illinois. Ill. Nat. Hist. Surv. Biol. Notes 69., AND . 1971. The life history of theslenderhead darter, Percinaphoxocephala, n the Em-barras River, Illinois. Ill. Nat. Hist. Surv. Biol. Notes74.

PFLIEGER, W. L. 1975. The fishes of Missouri. Mis-souri Department of Conservation.

SCALET, C. G. 1973. Reproduction of the orange-belly darter, Etheostoma adiosumcyanorum Osteich-thyes, Percidae). Amer. Midi. Nat. 89:159-165.SCOTT, W. B., AND E.J.CROSSMAN.973. Freshwaterfishes of Canada. Bull. Fish. Res. Bd. Canada 184.SCHENCK, J. R., AND B. G. WHITESIDES. 1977. Re-production, fecundity, sexual dimorphism and sexratio of Etheostomafonticola (Osteichthyes, Perci-dae). Amer. Midi. Nat. 98:365-375.SMITH,P. W. 1979. The fishes of Illinois. Univ. Ill.Press, Urbana.SMITHSONIANNSTITUTION. 1896. Meteorologicaltables. Smith. Misc. Coll.STARNES, W. C. 1977. The ecology and life historyof the endangered snail darter, Percina (Imostoma)tanasi Etnier. Tenn. Wildl. Res. Agency Tech. Rep.77-52.STRAWN, K. 1956. A method of breeding and raisingthree Texas darters. Part II. Aquarium J. 27:11,13, 14, 17, 31, 32.. 1961. A comparison of meristic means andvariances of wild and laboratory-raised samples offishes, Etheostomagrahamiand E. lepidum(Percidae).TexasJ. Sci. 13:127-159.

, ANDC. HUBBS. 1956. Observations on strip-ping small fishes for experimental purposes. Copeia1956:114-116.STEVENSON,M. M. 1971. Percina macrolepida Pisces,Percidae, Etheostomatinae), new percid fish of thesubgenus Percina from Texas. Southwest. Nat. 16:

65-83.THOMAS, D. L. 1970. An ecological study of fourdarters of the genus Percina (Percidae) in the Kas-kaskia River, Illinois. Ill. Nat. Hist. Surv. Biol. Notes70.THOMPSON, B. A. 1978. Logperches of southeasternUnited States (Etheostomatini, Percina). ASB Bull.25:27.WILLIAMS,J. . 1975. Systematics of the percid fishesof the subgenus Ammocrypta,enus Ammocrypta,withdescriptions of two new species. Bull. Ala. Mus. Nat.Hist. 1.WINN, H. E. 1958. Comparative reproductive be-havior and ecology of fourteen species of darters(Pisces-Percidae). Ecol. Monogr. 28:155-191.

DEPARTMENT OF ZOOLOGY, THE UNIVERSITY OFTEXAS AT AUSTIN, AUSTIN, TEXAS 78712.Accepted 27 April 1984.

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