University of Kansas Publications MUSEUM OF NATURAL HISTORY The University of Kansas Publications, Museum of Natural History, beginning with volume 1 in 1946, was discontinued with volume 20 in 1971. Shorter research papers formerly pub- lished in the above series are now published as Occasional Papers, Museum of Natural History. The Miscellaneous Pub- lications, Museum of Natural History, began with number 1 in 1946. Longer research papers are published in that series. Monographs of the Museum of Natural History were initiated in 1970. Institutional libraries interested in exchanging publications may obtain the Occasional Papers and Miscellaneous Publica- tions by addressing the Exchange Librarian, University of Kan- sas Library, Lawrence, Kansas 66044. Individuals may pur- chase separate numbers of all series. Prices may be obtained upon request addressed to Publications Secretary, Museum of Natural History, University of Kansas, Lawrence, Kansas 66044. Editor: Linda Trxieb Managing Editor: William E. Duellman PRINTED BY tJNIVERSITY OF KANSAS PRINTING SERVICE LAWRENCE, KANSAS OOl- OCCASIONAL PAPERS ^ .^-o m 2W73 of the MUSEUM OF NATURALuWISTORY The University of Kansas Lawrence, Kansas NUMBER 12, PAGES 1-28 FEBRUARY 20, 1973 MORPHOMETRIC VARIATION AND LIFE HISTORY OF THE CYPRINID FISH NOTROPIS STRAMINEUS (COPE) By JtJLIDE TaNYOLAC^ The sand shiner, Notropis stramineus (Cope) is a common in- habitant of shallow, sandy streams from Quebec and New York westward to Saskatchewan and Montana, and southward to Mexico. Sand shiners occupy streams of diverse sizes, from springs discharg- ing only a few cubic feet per second to the largest rivers in the Mississippi system. As its vernacular name implies, N. stramineus is usually associated with sandy stream bottoms; the species has rarely been found in upland areas (Ouachita, Ozark, Cumberland, and Appalachian regions) within its otherwise extensive range. The purposes of this paper are: 1) to indicate the extent and degree of geographic correlation of variation in several morpho- logical features of N. stramineus, and 2) to describe some aspects of its life history, with primary reference to populations in the Kansas River at Lawrence, Kansas. Problems relating to the nomenclature of the sand shiner have been resolved by Suttkus (1958) and Bailey and Allum (1962:64- 68). Suttkus demonstrated that the name Moniana (= Notropis) deliciosa (Girard, 1856) is applicable not to the sand shiner but instead to the weed shiner, Notropis texanus (Girard, 1856). Suttkus concluded that tlie oldest name available for the sand shiner is 1 Department of Zoology, University of Ankara, Ankara, Turkey. This paper is based on research accomplished while the author was a Research Associate at the Museum of Natural History at the University of Kansas, supported by a Fellowship from the American Association of Uni\'ersity Women and a grant from the University of Ankara. 2 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Hyhoiinathus stramineus Cope, 1864; he considered Minnilus micro- stomus Rafinesque, 1820, and Alhurmis Uneolatus Agassiz, 1863, to be nomina dubia. The following names were listed as chronological synonyms of stramineus by Suttkus (type localities in parentheses) : Hybopsis missuriensis Cope ( Missouri River at St. Joseph, Missouri); H. scylla Cope (Red Cloud Creek, tributary to Platte River); Cliola Mora Jordan (upper Missouri region); Notropis phenacobius Forbes ( Peoria, Illinois ) ; and N. reticulatus Eigenmann and Eigen- mann (Qu'Appelle, Assiniboia [Assiniboine River in Saskatchewan, Canada] ). Bailey and Allum (1962:64-68) reported that sand shiners in South Dakota "fall into two sharply defined morphotypes" that they recognized as subspecies (N. s. stramineus and N. s. missuriensis), distinguished by differences in number of circumference scale-rows. Bailey and Allum allocated H. scylla, C. chlora, and Hybopsis mon- tana Meek, 1884, to the synonymy of N. s. missuriensis. Metcalf (1966:124-131) supported the opinion of Bailey and Allum, on the basis of his counts of circumferential and predorsal scale-rows. Pre- viously, Hubbs and Lagler (1958:37, 43) and several other authors had indicated the existence of a third subspecies, southwestern in occurrence. The southwestern populations are those with which the name deliciosa was improperly associated. GEOGRAPHIC VARIATION Methods In my analysis of geographic variation in the sand shiner, nine characters were examined on 896 specimens from 61 localities, fol- lowing procedures defined by Hubbs and Lagler (1958:19-26). Meristic characters used were number of lateral-line scales, pre- dorsal-scale rows, and circumference scale-rows. Morphometric characters used were predorsal length, length of caudal peduncle, head length, head width, length of orbit, and postorbital length of head, all measured to the nearest 0.1 mm and expressed as thou- sandths of standard length. Values obtained for each character were compared, among lo- calities, by application of a program entitled Sum of Squares Simul- taneous Test Procedures (SS-STP), adapted to an IBM 7090/94 computer. The analysis indicates which of the locality means, for each character, fail to differ from one another at the 95 percent confidence level. On the distribution maps that accompany the dis- cussion of each character, the results have been coded as follows: VARIATION AND LIFE HISTORY OF NOTROITS STRAMINEUS 3 solid circles indicate localities where mean values are iKJt signif- icantly different from the lowest mean obtained at any locality; solid triangles indicate localities where means are not significantly differ- ent from the highest mean value obtained at any locality; and open circles designate the remaining localities ( those having intermediate values significantly different from means of the extreme groups). The 61 localities include three in the Great Lakes drainage, 58 in the Mississippi basin, one in the Guadalupe River in Texas, and one in the Rio Grande system. All are within the presumed native range of the species. In the Mississippi basin, seven series are from the Ohio River system; 13 are from upper Mississippi system (upstream from the mouth of the Missouri River, excepting one collection from the Meramec River immediately south of the Missouri River); 26 are from the Missouri River system; six are from the Arkansas River system; and two are from the upper Red River system. Results Circumference scale-rows (Fig. 1). — The SS-STP results indicate that the distinctive sets of sample means fall into eastern and west- ern groups that correspond to the two subspecies {strcimineus and missuriensis, respectively) recognized by Bailey and Allum (1962:64- 68), Metcalf (1966:124-131), and others; their interpretations were based primarily on this character. In my samples, the range of non- significant low mean numbers of circumference scales is 22.2-24.6, the range of non-significant high mean numbers 27.7-30.0. These two sets include 72 percent of the localities. Intermediate numbers of scale-rows around the bodv were found at 17 localities, in the Platte River system, in the Missouri River and its smaller tributaries from the mouth of the Platte eastward to the Chariton River in northern Missouri, in the upper Neosho River (Arkansas River drain- age), and in the Red River system in western Oklahoma. Postorhital length of head (Fig. 2).— This character differenti- ates approximately the same samples that were separated by circum- ference scale-counts (Fig. 1). Low mean values (0.1101-0.1202, as a proportion of standard length) are mainly eastern, and high mean values (0.1316-0.1401) mainly western. The two sets include 57 percent of the 56 samples in which data are available for this char- acter. Intermediate lengths of the postorbital part of the head are found mainly in the Platte and lower Missouri rivers, the upper Neosho River in Kansas, and the upper Red River. Intermediate values in the Rio Grande and in the Osage, Meramec, and Gasconade rivers of the Missouri system in Missouri are discordant with results OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Fig. 1. Geographic trends in numbers of circumference scale-rows in Notropis straminetis. Triangles represent sample-means not significantly differ- ent from tlie highest mean value at any locality (.05 level); solid circles indi- cate means not significantly different from the lowest mean value of any locality; open circles represent locality means intermediate between those ex- treme sets. based on circumference scales, in which these localities were a part of the eastern group. Length of orbit (Fig. 3). — Geographic variation in the orbital diameter of sand shiners is great, but individual variation within local populations is small. Therefore, the SS-STP discriminated numerous (31) combinations of localities having means not signif- icantly different — a greater number of small sets of localities than emerged for any other character. As a result, few localities are in- cluded in either the "low" or the "high" groups, whose ranges of values were 0.6210-0.6980 and 0.9088-1.0030, respectively. The mean orbital diameters at most localities lie between these extreme sets, in the group designated by open circles as "intermediate" in VARIATION AND LIFE HISTORY OF NOTROPIS STRAMINEUS 5 Fig. 2. Geographic trends in postorbital length of head in Notropis stramineus. Symbols as in figure 1. figure 3. The orbit is smallest in the westernmost populations, and largest (relative to standard length) in populations near the center of the range of the species (eastern Missouri and Iowa). The large- eyed populations fall within the "eastern" set as defined by scale counts. In terms of absolute values, most "intermediates" located northeastward from Iowa and Missouri have relatively large eyes, as do specimens from the Rio Grande and Guadalupe in Texas. It is noteworthy that the results using orbital diameter and postorbital length of head are not entirely complementary; populations having the largest orbits do not have minimal postorbital lengths. PredorsaJ scale-wics (Fig. 4).— The total extent of variation in number of predorsal scale-rows is small, relative to local (individual) variation in sand shiners. Therefore, the SS-STP did not yield dis- crete sets of localities having distinctively "low" and "high" mean values; the range of "low" means, not significantly different from OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Fig. 3. Geographic trends in length of orbit in Notropis stramineus. Sym- bols as in figure 1. one another, extended from 13. S6 to 15.13 scales, and the range of "high" means from 14.93 to 16.53 scales. Therefore, in figure 4, the localities plotted as having "intermediate" values (open circles) are ones that are a part of both sets, rather than ones excluded from both sets. These five localities are scattered across the range of the species, at about the same latitude. Values at other localities are geographically correlated, forming a pattern generally like that shown by the characters previously discussed. Two departures are notable: 1) greater westward extent of the "eastern" group into areas that yielded intermediate values for other characters; and 2) exceptionally high numbers of predorsal scales at the northernmost localities, causing their populations to be associated with the west- ern rather than the eastern group in this character. The mean num- bers of predorsal scale-rows at the three northeastern localities in question (Ohio, Michigan, and Minnesota) are 15.14, 15.80, and 15.20, respectively. VARIATION AND LIFE HISTORY OF NOTROPIS STRAMINEUS 7 Fig. 4. Geographic trends in number of predorsal scale-rows in Notropis stramineus. Symbols as in figure 1. Predorsal length (Fig. 5). — Western populations of sand shiners have the shortest predorsal lengths, in relation to their standard lengths. However, the geographic pattern shown by this character does not conform well to an east-west clinal trend, because "high" and "low" values are found at adjacent localities in several parts of the range: upper Red River, Kansas River, lower Missouri River, upper Illinois River, and upper Ohio River. Predorsal length and the number of predorsal scale-rows are not positively correlated. Rather, the opposite tendency exists; those populations having the shortest bodies anterior to the dorsal fin usu- ally have the largest number of scales along the nape. Most such populations are western or northern. As in predorsal scale-counts, local variation is so great compared to inter-locality variation that no wholly distinctive sets of localities emerged from the SS-STP analysis. The "low" (0.5077-0.5201) and "high" (0.5201-0.5480) OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Fig. 5. Geographic trends in predorsal length in Notropis stramincus. S> hols as in figure I. m- sets overlapped by one locality. That locality, in the Rio Grande drainage, is therefore the only one shown as "intermediate" by an open circle in figure 5. Head length (Fig. 6). — Altliough variation in head length has only limited relation to geographic region, most northern and east- ern populations have shorter heads than do southwestern popula- tions. The analysis separated localities into numerous (27) sets for this character; hence, the "high" and "low" sets contain only 23 localities, 41 percent of the total from which data were taken. The ranges of mean values within these two sets are well separated (low=0.2494-0.2596; high =0.271 1-0.2857). All localities belonging to the low group lie along or east of tlie Mississippi River or in the Platte River system, with the exception of one locality in the Kansas River basin. All localities having high mean values lie west of the VARIATION AND LIFE HISTORY OF NOTROPIS STRAMINELS 9 Fig. 6. Geograi^hic xariation in head length in Notropis stramineus. Sym- bols as in figure 1. Mississippi, except for one localit)' in the upper Ohio basin. Inter- mediate head-lengths are found at widely scattered localities. Head width (Fig. 7). — In general, northeastern sand shiners have relatively narrow heads, whereas southwestern sand shiners have broad heads. The distribution of high and low mean values for this character resembles that for head length, demonstrating that the total size of the head increases westward, and especially south- westward. At the IS localities included in the "low" group in figure 7, mean head-widths varied from 0.1293 to 0.1439; mean head- widths at the 13 localities in the "high" group varied from 0.1556 to 0.1698. Length of caudal peduncle (Fig. 8). — Geographic pattern is scarcely evident in the distribution of distincti\'ely high and low mean values for this character. The longest caudal peduncles tend to occur at high latitudes and high elevations, hence at peripheral localities. Caudal peduncles are usually shortest in the central, and iO OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Fig. 7. Geographic variation in head width in Notwpis stramineus. Sym- bols as in figure 1. especially the west-central, part of the range of the sand shiner. Individual (local) variation accounts for a large part of the total variation in length of the caudal peduncle. The group of low means (0.2152-0.2348) includes 27 localities, and the group of high means (0.2360-0.2512) 21 localities; only seven localities (13%) fall into the intermediate group. Lateral-line scales (Fig. 9). — Low numbers of lateral-line scales characterize sand shiners in the central and southern parts of the range of the species. Lateral scale-rows are more numerous at peripheral localities in the east, north, and west. Therefore, lateral- line scales vary independently of circumference scales and predorsal scales, and tend to be most numerous at high latitudes or high ele- vations. The group of low mean values (32.61-34.00) includes 25 localities, and the group of high values (34.53-36.25) includes 17 localities, leaving 18 localities (30%) in the intermediate group. VARIATION AND LIFE HISTORY OF NOTROPIS STRAMINEUS II Fig. 8. Geographic variation in length of caudal peduncle in Notropis stramineus. Symbols as in figure 1. Character Summary and Taxonomic Conclusions The SS-STP analysis disclosed similar geographic trends in three of the nine characters. Circumference scale-rows, predorsal scale- rows, and postorbital length of head have extreme values in essen- tially the same sets of eastern and western populations. The popu- lations are segregated somewhat differently by the SS-STP results in the remaining six characters. Orbital size is smallest in the western- most populations, but largest near the center of the range of the species; populations having the largest orbits are among the eastern set distinguished by the three characters mentioned above. Predorsal length diminishes from cast to west, but local variation in this char- acter is great and members of the two extreme sets are intermixed broadly through the central part of the range. Head width sorts, principally, southwestern populations from those elsewhere. Head length, caudal peduncle length, and the number of lateral line scales 12 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Fig. 9. Geographic variation in lateral-line scales in Notropis stramineus. Symbols as in figure 1. vary without clear geographic pattern, althougli the highest values for the last two characters tend to occur at peripheral localities. In view of nonconformities in the variational patterns of these characters, recognition of subspecies may seem to be unwarranted in Notropis stramineus. However, I believe the results are suffi- ciently in accord with one another, in five traits having well-defined geographic patterns, to justify continued recognition of two taxa. Their distinguishing features, synonymies, and ranges are stated below. Notropis stramineus stramineus (Cope) Diagnosis. — Circumference scales 22-25; postorbital length of head 11-12 percent of standard length; orbital diameter more than 8 percent of standard length; head width less than 15 percent of standard length; predorsal scale-rows usually 13-15. VARIATION AND LIFE HISTORY OF NOTROPIS STRAMINEUS 13 Range. — Southern Saskatchewan to Quebec ( Slastenenko, 1958), southward through Great Lakes drainage and Ohio River basin; upper Mississippi basin westward to eastern Iowa, southern Missouri and southeastern Kansas ( including Osage River system ) ; Red River in eastern Okhihoma and Texas; southwestward in Gulf-coastal streams to Rio Grande. Remarks. — On geographic grounds, the names N. phenaculnns Forbes, 1885, and A^ reticulatus Eigenmann and Eigenmann, 1893, apply to this subspecies. Notropis stramineus missuriensis (Cope) Diagnosis. — Circumference scales usually 27-30; postorbital length of head 13-14 percent of standard length; orbital diameter less than 8 percent of standard length; head width more than 14 per- cent of standard length; predorsal scale rows 15-17. Range. — Missouri and Arkansas River systems; intergrades with N. s. stramineus in eastern South Dakota and Nebraska (including Platte River system), small tributaries of Missouri River in north- eastern Kansas and northwestern Missouri, Neosho River in Kansas and upper Red River system in western Oklahoma. Remarks. — On geographic grounds, the names Hijhopsis scijUa Cope, 1870, Cliola chlora Jordan, 1878, and (according to Bailey and Allum, 1962:68) Hijhopsis montanus Meek, 1884, apply to the subspecies missuriensis. LIFE HISTORY A study of some aspects of the life history of the sand shiner in the Kansas River at Lawrence was based on 3632 specimens, col- lected biweekly or monthly in 1967 (March 24, May 2, June 8 and 24, July 6, 13, and 24, August 9, September 1, and October 18). The study area extended along the north shore of the Kansas River for a distance of several hundred yards downstream from a low-flow dam in Lawrence. The Kansas River is a turbid stream having variable flow. At the gauging station nearest to my study area, discharge has \aried from 185 cubic feet per second (cfs) to 483,000 cfs within the 30-year period of record. In 1967, minimum and maximum rates of dis- charge were 220 and 88,900 cfs. Flow on dates when sand shiners were collected increased from 468 cfs ( March 24) to 41,700 cfs (June 24), and diminished to approximately 2,000 cfs in September. Sand shiners were collected by means of seines 6 to 15 feet long, 14 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY having 1/8 to 3/16-inch woven nylon mesh. The fish were preserved in 10 percent formahn for three or more days, washed in water, and transferred to 70 percent ethyl alcohol, where they remained for at least one week before data were taken from them. The accounts of age- and size-composition and of reproduction that follow are based mainly on the collections from the Kansas River at Lawrence; observations on other populations are appended to these accounts. The latter observations are based on series of specimens deposited in the University of Kansas Museum of Natural History. The series selected are representative of the western sub- species, commonly recorded as N. s. misstiriensis (from South Da- kota, Wyoming, Colorado, Nebraska, Kansas, and New Mexico), and eastern subspecies, commonly recorded as N. .s. stromineus (from Kentucky, Wisconsin, Minnesota, Illinois, Iowa, Missouri, Kansas, Oklahoma [Red River], Texas, and Mexico). Series of "in- tergrades" from eastern Kansas, southeastern Nebraska, southwest- em Iowa, and Missouri were examined also. These collections were obtained in spring or summer in various years. Age- and Size-composition Most samples of sand shiners from the Kansas River consisted of three age-groups, based on evidence obtained from opercles, scales, and length-frequency distributions. For 233 sand shiners of selected sizes, opercles and scales were removed, cleaned, and examined under magnification using transmitted light. Annuli were discernible on both structures, but usually were most obvious on the opercle, where they appeared as fine opaque lines parallel to the posterior margin of the bone. The 1967-annulus had not formed on fish taken March 24, and only a few yearlings caught on May 2 had completed that annulus. All age-I fish had an annulus by June 8, but the 1967 year-mark was not apparent on all age-II and age-Ill specimens until mid-July. Thus, prior to July 24, ages of individual fish were inferred from the positions of annuli ( extent of growth beyond the outermost annulus), as well as the number of annuli observed on their opercles and scales. The age- and size-distributions of the 10 samples of sand shiners obtained from March 24 to October 18 are shown in figure 10. The number of fish in the samples varies greatly; on figure 10, differences in the numerical scale (vertical scale) on various dates should be noted. Age-Ill fish were present, but in diminisliing numbers, from March 24 through July 6; none was found thereafter. Age-II fish were numerous on March 24 and May 2, but diminished in abun- VARIATION AND LIFE HISTORY OF NOTROPIS STRAMINEUS 15 200 100 0 80 40 X 0 [1400 _i < Q300 > Q -200 u_ o ^ 100 0 20 0 80 40 I / I \ H ^— .. — ..—.2 May ^-i 8 June H (4) I *~~* 24 June 0^1 — I — r- 12 18 80 ~ 40 0 (2) 0 • 40 0 80 40 0 80 40 40 20 T I I I 1 1 1 1 r 1 1 1 r- *-^ ^^ * * '' 24 Ju {2)-» 1 September ^ 12 16 24 n 1 — 30 "T 1 \ \ 36 42 48 STANDARD LENGTH IN MM Fig. 10. Length-frequency distribution in samples of Notropis stramineus from the Kansas River at Lawrence, obtained on various dates in 1967. Roman numerals indicate the age-groups represented in the samples, arabic numerals the number of individuals assigned to each age-group. dance later. Age-I fish dominated all samples from June through October. Nearly all growth in length by age-groups I and II was accom- plished before July 13. From that date onward, the size-range and average size of the fish in my samples remained almost constant, except for the sample obtained September 1 (Fig. 10). That sample consisted of surprisingly small fish judged to be age-I by examina- tion of opercles and scales. One possible reason for the disparate size-range in the September sample can be suggested. Deep, s\\'ift flow at the study-site made seining unusually difficult, and all speci- mens were caught from one small pool, only a few inches deep, that extended into a slight depression on a large sandbar. On other dates samples were taken from more extensive areas, and greater range of depths, in the mainstream as well as in pools along sandbars. 16 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY The size-ranges of different age-groups overlapped in all sam- ples. The smallest age-Ill fish found was 38 mm in standard length (March 24), the largest 47 mm (July 6). The size-range in age-II was 21 mm (March 24) to 45 mm (October 18), and of age-I fish 15 mm (March 24) to 43 mm (October 18). Young-of-the-year first appeared in my collections on July 13, following disappearance of age-Ill fish from the samples. Special efforts to obtain young, using 1/8 inch-mesh netting as well as 3/16 inch-mesh seines, were made only on July 24 and October 18. Young as small as 12 mm in standard length following preservation were present on both of these dates. Populations of N. s. missuriensis and N. s. stramineus from other localities in Kansas and Missouri consisted of age-Ill and younger fish. Three-year-old sand shiners occurred as late as August, but no four-year-old fish were found among specimens from these states. The largest specimen of N. s. missuriensis in collections from 30 localities is 64.2 mm in standard length, and was obtained in the Cache la Poudre River, Colorado, in September. The largest N. s. stramineus in collections from 52 localities is 61.5 mm long; it was obtained in Black Earth Creek, Wisconsin, in June. No differences in age-composition, average size, or maximum size distinguish the two subspecies. In both, northern popula- tions seem larger in average size (standard length) than southern populations. Reproduction Sex-ratio. — Male and female gonads are distinguishable by gross inspection in sand shiners more than 25 mm in standard length. For this and later analyses, the fish in each sample were grouped by 3- mm intervals of length; my discussion concerns specimens larger than 26 mm (groups 27-30 mm and longer). Sex was ascertained for 2101 sand shiners from the Kansas River, of which 1128 (53%) were males (Table 1). Males were more numerous than females in all samples except those on July 13 and 24— dates on which I think spawning was in progress. On some other dates, females out- numbered males in the smaller size-groups (Table 1), indicating that the average size attained by males slightly exceeded that of females. Nevertheless, the maximum size attained by females (46.0 mm on July 13) was as great as that of males (46.6 mm on August 9) in my samples from the Kansas River. In N. s. missuriensis from 22 other localities, males were more numerous than females in 13 cases. Males outnumbered females in 17 of 26 collections of N. s. stramineus for which sexes were deter- VARIATION AND LIFE HISTORY OF NOTROPIS STRAMLNEUS 17 0) u a l-l J3 2, o> " 00" *^ r- I 2 'a c ■4-< OS I OJ a < c O Or o 00 I— I 'O jj ot (U g 0+ b£ 3 05 c^-- -^ ot "3 CO >. ^ CH- 3 C Ot 3 (M CH- 00 ^o in «M CD CO O oq *o 00 r}< -^ 00 00 t~- rp Tf CM 1— I O CO o I- K5 O (M 01 ^ in 00 o o (M ^ (M ^ &-» °°S • ° •8 June o24June - • o - '• • - • • 0 o • • • o» , o - •6 July °l3July o - - • • • o • o« • 0 • - o o o° o • o •, • • ° • 0 o8 • o • o o - •24 July . - • - • . . . .• • - •3 August °l September . ° OO ° • • • t 1 1 1 1 1 s 1 1 • 1 1 1 1 1 .100 24 26 28 30 32 34 36 38 40 42 44 46 STANDARD LENGTH IN MM. Fig. 11. Gonosomatic index (ovary weight/total fish weight) in female Notropis stramineus obtained from the Kansas Ri\er at Lawrence in 1967, as a function of date of capture and standard length of specimens. Males of N. s. stramineus are tuberculate from April (Oklahoma and Texas) to July (Illinois and Wisconsin) and August (Iowa, Kansas, Missouri). Specimens taken on August 25 (Minnesota) and September 1 (Missouri) had no tubercles. In populations regarded as intergrades (eastern Kansas, south- eastern Nebrask.i, southwestern Iowa, and northern Missouri), tu- berculate males were found from May through August. Females of N. s. missuriensis usually had maximal ovary weights in June. However, a population from Gypsum Creek, McPherson Co., Kansas, had large gonads at the end of April; also, the smallest mature female, 24.5 mm in standard length, with large eggs was found in that collection. The largest individuals in a sample from Spring Creek, Smith Co., Kansas, seemingly had spawned by June 24; smaller fish probably had not spawned by that dat(\ In the Arkansas system in southwestern Kansas, most sand shiners may complete spawning in June, but a population from Crooked Creek, Meade Co., had ovaries heavier than 0.200 g on July 4. No females 20 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY rr— 1 — 1 — J.. I 1 1 1 1 1 I I 1 I I I I I I I I 1 r 24 March ©2 May n o„ ° • o tot o • .»„!?•- >. •8 June o24June •° •. ° •• •°. .' 0 en g.4 UJ Ll ir UJ h- 2.8 < Q •6 July ol3July o o • O CO o »24 July • • •9August 01 September • • • o o o,o o o 0 I 1 I I I I I I I I I I I I I I I I I I I I I 24 26 28 30 32 34 36 38 40 42 44 46 STANDARD LENGTH IN MM. Fig. 12. Size of c)\a in female Notropis straminctis from tlie Kansas River at Lawrence, 1967. \'ertical scale in mm. Each point plotted represents the aver- age diameter of 10 of the largest eggs found in an individual fish. had ova exceeding 0.79 mm diameter later than August 29 in Kansas. One specimen from Wyoming, 46.0 mm in standard length, 24 June, had not spawned and had the largest ovaries (0.735 g) of any fish examined in my study. In a separate study of sand shiners in the Smoky Hill River in western Kansas, Summerfelt and Minckley (1969:447) reported that "Spawning probably occurred several times between June and August, but apparently most fish spawned in late July and August in both 1965 and 1966." Those authors noted a striking year-round correlation between water temperature and egg size; mid-summer temperatures were between 20 °C and 25 °C in 1965 and 27-33' C in 1966 when eggs were largest. VARIATION AND LIFE HISTORY OF NOTROPIS STRAMINEUS 21 Females of N. s. strcunineus in series that I examined had maxi- mal ovary weights in May (Kansas and Missouri) to July (Michigan and Wisconsin). A population from Middle Creek, Miami Co., Kansas, probably had completed spawning by June 28, while one from Floyds Fork Creek, Jefferson Co., Kentucky, and one from the Loutre R., Montgomery Co., Missouri, had ovaries heavier than 0.200 g on June 2 and 6. None had ova exceeding 0.79 mm in diam- eter later than August 30 in Missouri. Ovary weight and maximum egg-size (0.95 mm) in stramineiis are about the same as in mis- suriensis. Females in series identified as intergrades had maximal ovary weights and egg-size in May, as in the case of N. s. stramineus from the same latitude. Tlie smallest female, 29.6 mm, with large eggs was found in May (North Fork Cottonwood River, Marion Co., Kansas.) Seemingly, the spawning period for N. s. stramineus varies lati- tudinally (May in South to July in North), but is mainly earlier and shorter in duration than the spawning season of N. s. misstiriemis in Kansas and Missouri. Fecundity. — Ovaries were categorized as 1) undeveloped — gray ovaries containing nucleated cells (oocytes) and small eggs (ova) with diameters not more than 0.33 mm; 2) developed— yellow ova- ries having eggs from 0.33 mm to 0.95 mm in diameter; 3) spent — gray ovaries flaccid and containing few eggs. Fecundity was determined from females that appeared to be well developed but not to have spawned. Ordinarily eggs were counted in one of the ovaries, because the two lobes appeared to be the same size; this number was doubled to determine the total egg complement. When the two lobes appeared to differ in size, the eggs were counted in both lobes. The "diameter of ova," as shown in table 2, represents the average diameter of the ten largest eggs in each fish; egg-diameters were determined by means of an ocular micrometer at constant magnification, and converted to mm by cali- bration to a stage micrometer. All contained eggs of varied sizes during the spawning season. Egg diameters of mature fish as given by Summerfelt and Minckley (1969:447) are smaller than those I report, because their measurements were taken from the total egg complement of each ovary. Females of N. s. missuriensis from the Kansas River had maximal egg counts from June S to July 6, as shown in table 2. Sev(>n females, from 32.8 mm to 43.9 mm in standard length, contained 550 to 1533 eggs. 22 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY s en a PQ > 3 o a; o "X^ ■y. 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