vv Seer She antec aes Ren = + Sh RAN # neatly WARAIRG iweb ee Se ¥ Th A, PLT prdangs lag bpm mae rigors pees Aare Ae ate PEL Lola ere bby 9s" ations egy Operates Yee Le wale geceet yore refi ie” rates Ott rer?) Tf nent od Age + “ rag rest ay Lelie See ee eee te ee ay ay LIBRARY OF THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN no.66 - 99 4 i | THE LIFE HISTORY OF THE SPOTTAIL DARTER, ETHEOSTOMA SQUAMICEPS, IN BIG CREEK, ILLINOIS, AND FERGUSON CREEK, KENTUCKY Lawrence M. Page aoht hs | , — MMly ASE f ane / 4s "bby fe ~~ Bd Me / 4 'f 7 4 ed ea 7 ig “ ye L2= 3 A LT A A io ewe Ne ads CRORE, NAAR ee OME: ie £ Oe SH AR < ‘eat: YY Diy» SRA ee Sy be \ Jaw ee Say Ni bys ae ii yay fe AR OC NNAE AA ot nat = — LE I SII YON OY ys Af YD al MAY ys = Sa = | a 7 oie Way ry oA WARTS a iA ROD. ye csp an 1 ee wee HO9)s Sa sien Oh hAeN ee eR! C44 = ZL C= i ahi 2 yy) GY Mase NES TRE BOY, ale =.=: = Pal y ee UN\ 9) SW BOLE Ee SEO Se Za = Fe ead )),)"\ Pe) eR alle ha ° 3 FSF — 7 Ay) | Pale iy “Ss so = ILLINOIS NATURAL HISTORY SURVEY Biological Notes No. 89 /Urbana, Illinois e May, 1974 jState of Illinois | ‘Department of Registration and Education ‘NATURAL HISTORY SURVEY DIVISION / / | 1 | y ‘popeys oie svase Apnys OA) OUT, “CQURPL) vULFpUy puB AYONJUOY JUOOL[pe pUv syOUTTI] UF Sopoeds ON} JO UOLINqIAys1p EY} puY sdaovmMNds DUOJsoaYI i JO (4J2[) eAUB. [e}O} OY L—T “ALA UID |0\s009 jo As0pun[g=—= $8Q07] |DIIDjIQ SNOjAGIg 40 SWI $@q07 [0190/9 uoUISUODSIM JO Sy] tt ae OS ee oe THE LIFE HISTORY OF THE SPOTTAIL DARTER, ETHEOSTOMA SQUAMICEPS, IN BIG CREEK, ILLINOIS, AND FERGUSON CREEK, KENTUCKY | : WITH THE DESCRIPTION of Etheostoma barbouri Kuehne and Small (1971) the number of described species of the subgenus Catonotus was raised to six. Other species are known but undescribed. All Catonotus species except the wide-ranging E. flabel- _lare have relatively small ranges, and published eco- logical information on Catonotus species is limited ‘to brief notes in state ichthyofaunal reports and species descriptions and to studies on the reproduc- tion and diet of E. flabellare (Lake 1936; Daiber 1956; Winn 1958@ and 1958b; Karr 1964). The paucity of ecological information on Catonotus and the occurrence of four species of the subgenus in a small area encompassing southeastern Illinois and adjacent Kentucky prompted life-history studies of E. squamiceps, E. kennicotti, and E. obeyense. This report on E. squamiceps will be followed by similar accounts on E. kennicotti and E. obeyense. Etheostoma squamiceps was described by Jordan (1877:11) from specimens collected at Russellville, Logan County, Kentucky. The range of the species (Fig. 1) includes southern Illinois, southwestern Indi- “ana, western Kentucky, west-central Tennessee, and the Tennessee River drainage of Alabama (Smith- Vaniz 1968:106) and Mississippi (Cook 1959:207). Morphological descriptions of E. squamiceps are given by Jordan (1877:11-12), Jordan & Evermann (1896:1096), Forbes & Richardson (1908:312-313), Fowler (1922:26), Cook (1959:207), Moore (1968: 150), and Collette & Knapp (1966:39). I am indebted to Brooks M. Burr, Emest L. List, George W. Lewis, William Raino, Douglas W. Schemske, Philip W. Smith, Richard L. Smith, Lewis J. Stannard, Jr., John A. Tranquilli, and John D. Unzicker for aid in collecting specimens; to Dr. Smith, Mr. Burr, and Mr. Schemske for counsel on numerous matters; to Mr. Schemske for identifying most of the stomach contents; to Drs. David A. Etnier and Vincent H. Resh for information on the distribution of E. squamiceps; and to Dr. Francis J. Kruidenier for identification of the acanthocephalan parasite. The cover illustration was done by Mrs. Alice This paper is published by authority of the State of Illinois, TRS Ch. 127, Par. 58.12, and is a contribution from the Section of Faunistic Surveys and Insect Identification of the Illinois Natural History Survey, where Dr. Page is an Assistant Taxonomist. Lawrence M. Page Ann Prickett, University of Illinois School of Life Sciences Artist. Assistance in preparing the other illustrations was provided by Illinois Natural History Survey Illustrator Lloyd LeMere and Survey Photog- rapher Wilmer D. Zehr. The manuscript was edited for publication by Robert M. Zewadski, Associate Technical Editor of the Survey, and Dr. Howard E. Winn, University of Rhode Island, served as guest reviewer. THE STUDY AREAS Big Creek in Hardin County, Illinois, supports large populations of both E. squamiceps and E. ken- nicotti, and for this reason was selected as one of two streams to be used as study areas. Big Creek is a spring-fed, direct tributary of the Ohio River and lies in limestone formations of the Shawnee Hills. The upstream substrate is predominantly a mixture of slab rocks and gravel, the middle stream bed is mostly coarse gravel, and the downstream substrate is mostly sand. The stream system is forested throughout, and the water is usually quite clear. General characteristics and fish populations of Big Creek were discussed by Lewis (1957), who found the most abundant fishes to be Campostoma anoma- lum, Pimephales notatus, Notropis chrysocephalus, and Etheostoma caeruleum. Other darters present in his collections were Etheostoma kennicotti, E. squamiceps, E. nigrum, and Percina caprodes; old records (Forbes & Richardson 1908) exist for E. chlorosomum and E. asprigene. The second study area, Ferguson Creek in Living- ston County, Kentucky, is a short, direct tributary of the lower Cumberland River and supports large populations of E. squamiceps and E. obeyense. The stream extends only about 3 miles, under normal conditions consists almost entirely of shailow slab- rock pools and slab riffles, and has a few deepér sand-bottomed pools. The most abundant fishes are Pimephales notatus, Notropis umbratilis, Etheostoma obeyense, E. squamiceps, and Erimyzon oblongus. Other species of darters in Ferguson Creek are Etheostoma gracile, E. chlorosomum, E. asprigene, Percina maculata, and P. caprodes, all of which’ are uncommon. Most observations and collections., in COVER ILLUSTRATION: Etheostoma squamiceps collected in Gibbons Creek in Pope County, Illinois. From a drawing by Mrs. Alice Ann Prickett. 4 Ferguson Creek were made near the Route 70 bridge 2 miles east of Smithland, a locality approximately 30 miles (48 km) from the Big Creek study area (Higa): Both study streams have three predominant habi- tats: riffles, slab pools, and non-slab pools. Riffles in Big Creek are mostly of coarse gravel, non-slab pools are only moderately deep (seldom over 1 m) and usually have a sand and gravel bottom, and slab pools are shallow with a substrate of gravel laden with slab rocks ranging from 100 to 400 mm across. In Ferguson Creek, slab pools have essentially the same physical characteristics as those of Big Creek, non-slab pools are generally deeper and al- most exclusively sandbottomed, and riffles are of larger stones, mainly small slab rocks up to 150 mm across. METHODS Observations and minnow-seine collections were made at approximately monthly intervals except dur- ing spawning periods, when more frequent observa- tions were made. Studies were begun in Big Creek on 6 October 1970 and in Ferguson Creek on 22 April 1971 and were terminated in both streams on 19 June 1973. Specimens collected for laboratory examination were preserved and stored in 10-percent formalin. From Big Creek 601 E. squamiceps and from Ferguson Creek 430 E. squamiceps were pre- served and examined. Beginning in August 1971, collections were ma by habitat in the two streams, and numbers specimens were recorded by month as having beer taken from riffles, slab pools, or non-slab pools. What was considered to be approximately the same sampling effort was expended on each of the three habitats Potential predators captured during seining operation¢ were preserved in formalin for later examination ¢ stomach contents. Field notes on ambient conditions and darter behavior were routinely taken. | By repeatedly seining a measured area until ne more darters were collected, quantitative sample: were taken in each of the three habitats in J 1972, October 1972, January 1973, and April 1973 In the laboratory, all darters were sexed, measured and aged. Large specimens were sexed by examining the genital papillae; small ones were sexed by examin ing the gonads. In addition to the standard length$ (SL) of all specimens, the lengths of the anz pectoral, pelvic, and soft-dorsal fins and the depths ¢ the caudal peduncles of 40 males and 40 female: of more than 30 mm SL from Ferguson Creel were measured as potential expressions of se dimorphism. Unless stated otherwise, measurements in the text are standard lengths. Aging to year class was done by counting the annuli on scales removed from the dorsum near the TABLE 1.— Habitat distribution by percentages of Etheostoma squamiceps collected in Big and Ferguson Creeks b tween 25 August 1971 and 19 June 1973. Big Creek Sample Ferguson Creek Sample Percentage of EH. squamiceps in Percentage of E. squamiceps in Number. Slab Gravel Non-slab Noe Slab Slab Non-s a - -| ad Monks Collseted Pools Riffles Pools Gelleetet Pools Riffles Pools Adults ; January 3 100 0 0 15 7 93 0 February 9 100 0 0 9 33 67 0 March 4 100 0 0 5 0 100 0 April 4 100 0 0 3 100 0 0 May 37 57 0 43 16 19 81 0 June 8 100 0 0 8 0 100 0 July 6 100 0 0 S 0 100 0 August 22 100 0 0 8 0 100 0 September 30 100 0 0 13 30 70 0 October 21 86 9 5 1 0 100 0 November 11 100 0 0 9 11 89 0 December 5 80 20 0 4 0 75 25 Young January 8 100 0 0 27 26 41 33 February 14 93 0 7 28 57 43 0 March 19 100 0 0 4 0 100 0 April 11 100 0 0 19 63 37 0 June 0 sre ri nie 1 0 0 100 July 10 30 70 0 64 ll 73 16 August 21 100 0 0 15 0 100 0 September 26 56 44 0 43 2 96 2 October 19 32 68 0 30 0 100 0 November 47 94 4 2 38 21 76 3 December 13 92 8 0 9 0 100 0 junction of the spinous and soft-dorsal fins. Aging to month was done by using April, the month of the jgreatest breeding activity in the study areas, as month zero. Thus, a darter collected in September ‘and having two scale annuli was estimated to have ‘lived 2 years and 5 months. For certain comparisons 5 darters were divided into young (through 12 months) and adult (over 12 months) age groups. A representative sample of each collection was dissected to identify stomach contents and endo- parasites and to note the conditions of the gonads. Weights of the ovaries of 87 females were obtained and recorded as a proportion of the adjusted body weight (the specimen minus the ovaries, stomach, intestine, and liver) of the female; the weight after the removal of the digestive system was used to eliminate variations resulting from the weight of re- cently ingested food. Mature ova from 18 preserved breeding females were counted. In addition to specimens collected from the study areas during the study period, all E. squamiceps in the Illinois Natural History Survey collection were ex- amined to ascertain probable spawning periods in other localities and other years. Indicators used were that males were in extreme breeding coloration and that females were heavy with mature ova. The relative survival of each year class of the two populations was calculated by expressing the number of individuals in that year class as a propor- tion of the number of individuals in a younger year class. The breeding behavior and territoriality of darters in laboratory aquaria were observed. Stream observa- tions had indicated that territories centered naturally about large slab stones, and one or more slab stones (elevated slightly on small stones) were placed in each aquarium. HABITAT Adults of the Big Creek E. squamiceps population showed a distinct difference in their preference in habitat (as defined) from the preference of the Fergu- son Creek adult population (Table 1). In Big Creek Fig. 2.—(Upper Photo) Slab pool in the headwaters of Big Creek, Hardin County, Illinois. (Lower Photo) Slab riffles in Ferguson Creek, Livingston Coun- ty, Kentucky. 6 they strongly preferred slab pools (Fig. 2) during all seasons and were seldom taken in riffles or in non-slab pools. In contrast, in Ferguson Creek adults were almost exclusively taken in slab riffles (Fig. 2) during the nonspawning seasons. During the height of the spawning season (April), adults of both populations were most common in the slab pools. Comparative collections made at localities other than the study streams revealed that E. squamiceps adults are most commonly found in slab riffles, ice., among and under small slab rocks (100-200 mm) characteristically forming the substrate of riffles in upper elevation streams. The seemingly dichotomous habitat preference found in the two study areas re- sults from the strong association of the species with slab rocks. In Ferguson Creek both the riffles and the shallow pools have substrates composed of slab rocks, and E. squamiceps prefers the riffles. “How- ever, in Big Creek the riffles are of coarse gravel, or if of slab are very shallow, and E. squamiceps is forced to occupy the slab pools. The occupation of slab pools in Big Creek indi- cates that slab rocks are more important to the species than other physical factors such as temperature and current. The slab pools of Big Creek are shallow and often become hot and stagnant in late summer, contrasting strongly with the cool, swift-flowing riffles of Ferguson Creek. The importance of slab rocks is further demonstrated by the absence of the species in Coastal Plain streams in extreme southern Illinois and elsewhere (Fig. 1), which typically lack a slab substrate. Young E. squamiceps were somewhat more scat- tered throughout the stream systems than were the adults but still showed a rather strong preference for slab riffles in Ferguson Creek and for slab pools in Big Creek (Table 1). In Big Creek the young moved downstream from the spawning areas and were found generally distributed in slab pools and riffles throughout the stream system. The occupation of gravel riffles in Big Creek by a greater proportion of young than adults may reflect the capacity of young darters, in contrast to the larger adults, to hide among the coarse gravel. Winn (1958b:161) observed a similar lack of restriction of young E. flabellare to the large-rock riffles occupied by adults. REPRODUCTION Reproductive Cycle of the Male The testes of the male E. squamiceps enlarged, as did the genital papilla (Fig. 3), as the spawning season approached. In breeding males testes were large, white, and spongy; following the spawning season the testes diminished in size and returned to the translucency characteristic of nonbreeding males. Breeding tubercles did not develop on E. squamiceps and are not thought to develop on any species of Catonotus (Collette 1965:603). Fig. 3—Genital papillae of Etheostoma squamiceps. A, nonbreeding male; B, breeding male; C, nonbreeding fe male; and D, breeding female. The nonbreeding specimens were 1+-year-old darters collected on 21 July; the breeding specimens were 2+-year-olds collected on 24 March. All papillae are shown 12 times actual size. In early spring large males became very dark and could be sexed on sight. The darkening of the male prior to spawning is a phenomenon observed in several other species of darters, including the closely related E. flabellare (Lake 1936:818; Winn 1958b:172), E. nigrum (Winn 1958b:172), and sey- eral species of Percina (Winn 1958b:172; Page & Smith 1970:6 and 1971:6). The most extreme breeding pigmentation was ob- served on males in aquaria spawning (Fig. 7) and nestguarding. In contrast to the female and the nonbreeding male, the breeding male was without the typical mottled pattern. The entire head to the posterior margin of the opercle was black and swollen, - From the head to below the junction of the dorsal fins the body was nearly white. The posterior half _ of the body was boldly marked with 7 or 8 vertical bars. The three caudal spots were coalesced into a vertical bar. The flesh over the anal spines was thickened. All fins except the pectorals blackened, but the caudal and _ soft-dorsal fins retained their characteristic clear banding. The membranes of the spinous-dorsal fin were black except for a proximal zone without pigment. The spines of the spinous- dorsal fin were tipped with small, white knobs, each knob being preceded by a small but prominent black spot. The rays of the soft-dorsal fin were tipped with small knobs, white in some individuals and black in others. Males of E. squamiceps selected cavities under slab rocks as future nesting sites (Fig. 4) a few i ee we SN Santer 2, aaa days or weeks before spawning and vigorously de- fended them against intruders. Such a cavity was always cleaned of silt and debris; in contrast, lifting a stone which did not harbor a Catonotus male be- neath it always released a flurry of small debris. The requirement noted for E. flabellare (Winn 1958a:208 ), that to be used as a nest site a stone must be between 1.5 and 2.5 cm above the substrate, was not found for E. squamiceps. Aquarium-held males were observed to shake their tails repeatedly and vigorously under stones selected as nest sites, forcing out silt and small gravel and enlarging the cavity. One male was observed to shake the posterior half of his body with the soft-dorsal fin against the bottom of the nest stone, apparently cleaning the area to be used for egg deposition. In both Ferguson and Big creeks the largest con- centrations of nests were found in the shallow (to 300 mm) slab pools in the uppermost portions of the stream systems, where the stream beds were ‘typically 1-3 m wide and the current slight but observable. A few nests were found in slab riffles in Ferguson Creek and in spring runs in Big Creek. Deep water (over 400 mm) was usually avoided; however, during the prolonged 1973 spring floods E. squamiceps was found spawning in water as deep as 600 mm. Only large males developed the breeding pattern, underwent gross enlargement of the testes, and were found guarding nests. These large males probably did most or all of the spawning. Young males that had not reached a standard length of 40 mm by the end of the spawning season did not have enlarged testes and presumably were not sexually mature. All males of 40 mm or more appeared to be sexually mature; Fig. 4——A typical nesting site of Etheostoma squamiceps photographed in Big Creek on 22 April 1971. The male was guarding his nest beneath a slab rock. however, there was no evidence that 1-year-old males actually spawned. Reproductive Cycle of the Female Generally, the largest E. squamiceps females of all age-classes spawned the earliest in the season al- though a few l-year-old females as small as 40 mm spawned as early as 24 March. A few females as small as 35 mm spawned in late April and early May. TABLE 2.— Relationship between size, age, and ovary weight of Htheostoma squamiceps females and the number of mature ova produced. An age of 1 year — 11-13 months, 2 years — 23-25 months, 3 years — 35-36 months. Number of Mature Standard Adjusted Age Ovary (Orange or Length Body Weight in Weight in Translucent) inmm inGrams* Years Grams Ova 32 0.57 1 0.07 54 35 0.59 1 0.06 44 37 0.74 1 0.21 80 40 0.93 1 0.17 40 41 0.85 2 0.15 56 42 itilat 2 0.25 70 43 1.05 1 0.23 50 44 1.18 2 0.20 64 48 1.27 2 0.12 28 48 ney ¢!) 2 0.37 140 48 1.64 2 0.32 110 49 uel 2 0.33 132 51 2.27 2 0.60 91 51 2.16 2 0.33 116 55 2.56 2 0.21 80 55 2.77 3 0.72 234 57 3.32 3 0.78 227 58 3.22 3 0.79 357 * Adjusted body weight is the specimen’s weight after the re- moval of the ovaries, stomach, intestine, and liver. In contrast to males, females did not undergo a color and pattern change with the approach of the spawning season. The most evident morphologi- cal changes associated with spring were a marked distention of the belly, accompanying the presence of maturing ova, and an enlargement of the genital papilla (Fig. 3). Enlargement of the papilla in most females was evident by February; gross distention of the belly preceded spawning by only a few days or weeks. Small white ova were present in most females by October, but in very small females ova did not appear until December. Larger yellow ova began appearing in December and were present in most females by February. Large, maturing orange ova appeared in March and April. Just prior to spawning the mature ova lost their orange opacity and became translucent. The oldest and largest females produced the largest numbers of mature ova; the youngest and smallest generally produced the fewest. The number of mature ova counted in 18 females ranged from 28 to 357 (Table 2). For these females the relationship between the number of mature ova (F) and the adjusted body weight (W) was F — -27.12 + 83.88W, with r — 0.845, and between the number of mature ova and the standard length (L) was log F = -2.589 + 2.729 log L, with r — 0.691. Estimates of the number of eggs laid in aquaria by individual females were 50 (by a 57-mm, 3-year- old), 50 (by a 62-mm, 3-year-old), 20 (by a 41-mm, l-year-old), and 120 (by a 54-mm, 2-year-old). Ma- 500 e=BIG CREEK o=FERGUSON CREEK St = 24804 ae = Ol+ 28! A $ agit Is6 e2 ~ 8 Hor oe 8 100 2B! elt $ a ar = 50 n +814 48it v el + 2 i437 as ees $2 8 ite see 2 set Oh, ps eit w git o2+ ol 02+ ac I+ oi4t2 | < WO%o4 +B tt oi 3 a tet uw olt eft+t!So4 [e) 5 e2t Ret elt = 2+ get e+ = 2+ elt 2 o+ SPAWNING JULY SEPT, NOV. JAN. MAR. MAY Fig. 5.—Monthly variations in ovarian weight relative to adjusted body weight of Etheostoma squamiceps. The vertical axis is a logarithmic scale. The number beside each dot is the age of the female. The lower five dots for May represent postspawning females. ture ova averaged 1.6 mm in diameter, were trans- lucent, and contained a single oil droplet. Spawning and the subsequent absorption of re- maining immature ova resulted in a rapid decrease in the size of the ovaries. Ovaries of postspawning females collected in April and May contained only small, white ova and were very small in comparison to ovaries of prespawning females collected in March and April (Fig. 5). Ovaries increased markedly in size between the recovery period and the spawning period in the following spring (Fig. 5). The pro- portionally largest ovaries (equalling 26.4 percent and 28.7 percent, respectively, of the adjusted body weights of the females) were found in a 22-year-old, 5l-mm female collected in Big Creek on 9 April 1971 and in a 1-year-old, 37-mm female collected in Big Creek on 31 March 1973. Ovary-weight-to-ad- justed-weight ratios ranged from 0.091 to 0.287 and — averaged 0.189 in the 18 females represented in Table © 2. Spawning i E. squamiceps spawned at the study areas from — late March through May on the undersides of the slab rocks (Fig. 6) selected as nesting sites by the males. Temperatures at which spottail darters were — found spawning ranged from 14° to 19° C. These temperatures usually prevailed from late March to late May, warming from temperatures ranging from 3° to 10° C in January, February, and early March. Nests of E. squamiceps were found in Trousdale County, Tennessee, on 21 April 1973 and in Todd County, Kentucky, on 22 April 1973. Late March was the most probable time of spawning for E. squamiceps collected at other localities (Table 3). of which were observed. Four of the spawnings oc curred in the morning hours, one in the afternoon, and three during the night or early morning. Aquarium temperatures ranged from 19° to 25° C. ' : 7 : Eight spawnings occurred in the laboratory, five Fig. 6—Eggs of Etheostoma squamiceps on the under- side of a stone removed from a slab pool in the headwaters of Big Creek on 22 April 1971. TABLE 3.— Collections of breeding Etheostoma squamiceps. Preceding spawning, males periodically left the -nest stone to court females. When attempting to lure 4a female back to the stone, a male would swim near ya female, display his bold pattern and spread fins, »and wag his tail at or against the female. After joining a male under his nest stone, a female / usually remained passive while the male courted her. 'The male was extremely active at this time, con- stantly darting about, nudging the female with his snout, and occasionally bobbing his spinous dorsal fin up and down, the contrasting dark and clear areas of which created a blinking effect. Eventually the female began moving about, arch- ing her head upward, and holding her snout near the underside of the stone, apparently selecting a ; site for egg deposition. Both male and female assumed an inverted posi- ‘tion when laying and fertilizing eggs. After nosing about the rock for a time, the female rolled to one ‘side and simultaneously rose to press her venter ) against the underside of the nest stone. Usually almost | immediately after the female had inverted, the male rolled to one side and positioned himself tightly along- side and slightly overlapping the female, with a } pelvic fin across her nape, in an inverted head-to-head | position (Fig. 7). Pressed against the stone, the ‘female began quivering slightly, barely moving for- ' ward as she did so, and laying a series of two to five eggs on the stone. As she laid the eggs, the male trembled and released sperm. Then both fish immediately returned to a right-side-up position be- neath the stone for a short time before courting by the male began the sequence again. Fifteen seconds to several minutes elapsed be- tween inversions. Each inversion lasted less than 5 seconds. The eggs were concentrated in a con- stricted area but never were laid on top of other eggs. Eggs were deposited as high as 35 mm above the substrate. The presence of a second female with a spawning | pair was tolerated, and in fact, both females were | courted by the male. No instances of more than one of the females spawning at a time were observed, | however. At least three females spawned with one male _ in an aquarium, two with another. In one instance the | spawnings with different females occurred within 2 Locality Collection Date Remarks _ Ferguson Creek, Livingston Co., Ky. 24 March 1972 Spawning when collected. Ferguson Creek, Livingston Co., Ky. 23 March-20 May 1973 Spawning when collected. Big Creek, Hardin Co., Ill. 15 April-3 May 1971 Spawning when collected. Big Creek, Hardin Co., Ill. 31 March-20 May 1973 Spawning when collected. Hickory Creek, Livingston Co., Ky. 27 March 1964 Female in extreme breeding condition. ' Duck River, Coffee Co., Tenn. 28 March 1965 Male in extreme breeding coloration. Rush Creek, Posey Co., Ind. 29 March 1963 Males and females in extreme breeding condition. hours of one another; in another instance the spawn- ings were 5 days apart. Eggs laid by a second or third female were added to those already in the nest, enlarging the concentrated egg mass. Counts and estimates of the numbers of eggs in 20 nests of E. squamiceps found in Big and Ferguson creeks were 8, 90, 125, 125, 160, 200, 200, 200, 200, 250, 275, 300, 450, 475, 475, 500, 850, 1100, 1500, and 1500, the mean being 449. Several nests contained many more eggs than the largest number of mature ova (357) found in preserved females and, as in aquarium nests, contained eggs from more than one female. Eggs in nests averaged 1.8 mm in diameter. Males vigorously guarded the eggs. Whenever a nest stone in a stream was lifted for observation, a male was found undermeath and usually swam away only when provoked. When a male did dart away, he usually returned soon after the rock was replaced. In all nests which were re-examined on a later date, the male had returned and was again guarding the nest. Aquarium-held males were constantly active while guarding eggs, darting back and forth and continu- ously brushing the eggs with their dorsal fins. The knobs on the tips of the dorsal spines of E. squamiceps males may be an adaptation to reduce the sharpness of the spines, thereby reducing the probability of rupturing eggs, during the nest-guarding time. Peri- odic nipping at the eggs presumably removed invad- ing organisms. The breeding pattern of the male was retained during the egg-guarding period. Nests were guarded against potential egg preda- tors, including crayfishes. Large crayfishes introduced into aquaria were driven from the nest stone by the male E. squamiceps as he repeatedly charged the crayfishes and bit them or hit them on the abdomen. A 63-mm male E. squamiceps succeeded in driving from his nest a 75-mm total length Orconectes ken- tuckiensis but not a 90-mm Cambarus laevis, both common crayfishes in Big Creek. Nests were never tended by females. Lake (1936: 823) believed that only E. flabellare males provide parental care to their eggs. Some areas used as breeding grounds contained large numbers of nests. Separate nest stones of E. squamiceps were found as close as 200 mm from one another. Two large stones with two Catonotus nests Fig. 7—Etheostoma squamiceps spawning in aquaria. A nest of eggs is on the underside of the stone above each pair of darters. ‘under each were located; one had two nests of E. “squamiceps (approximately 200 mm apart); the other had one nest of E. squamiceps and one of E. _kennicotti. In both instances of double occupancy of a nest stone, the two nests were completely sep- ‘arated from one another by substrate material when the rock was in place in the stream. Similar sharing \of one nest stone was described by Lake (1936:823) ‘for E. flabellare. The spawning behavior of E. squamiceps is similar ‘to that of E. flabellare, described by Lake (1936) and Winn (1958a and 1958b). Differences in the spawning behavior of E. flabellare from that of E. \squamiceps are the head-to-tail egg-laying position, \the fact that females may remain inverted for as ‘long as 2 hours, the habit of the female of usually laying only one egg at a time, and the intolerance by the male of the presence of a right-side-up female under the nest stone. / Sexual Dimorphism Winn (1958b:172) listed among the sexually dimorphic characters of E. flabellare the larger anal, pectoral, and pelvic fins of the male. In addition ‘to behavioral (territorial) and morphological (colora- ition and size) differences between the sexes of E. isquamiceps, the anal, soft-dorsal, pelvic (P<0.01), and pectoral fins (P<0.10) were significantly longer tin males. The depth of the caudal peduncle was also ‘greater in males (P<0.01). DEVELOPMENT AND GROWTH | Eggs incubated in aquaria at temperatures vary- ing from 18° to 22°C (64°-72°F) hatched in 270-275 hours (11.3-11.5 days), and eggs incubated at 22°- 6°C (72°-79°F) hatched in 125-130 hours (5.2-5.4 fdays). Three nests of E. squamiceps eggs were found to be hatching in Big Creek on 3 May 1971, including one nest first discovered and marked on 17 April. This nest had been observed periodically between 17 April and 3 May, during which time water tem- peratures varied from 14° to 18°C (57°-64°F). No eggs were added during this time; thus, a minimum of 16 days of incubation is required at this tempera- ture range. Lake (1936:826) found eggs of E. flabel- are to have much longer incubation periods: 14-16 days at an average temperature of 74°F, 21 days at 0°-71°F, and 30-35 days at 63°-68°F. E. squamiceps hatchlings (Fig. 8) were 6.5 mm in TM RESSSS KX SSS Be Fig. 8—Etheostoma squamiceps hatchling. 1] total length and mostly translucent, but they had red blood, black melanophores over most of the body, and metallic gold eyes. Melanophores were especially prominent on top of the head and on the lower one-third of the yolk sac. Pectoral fins and the lower jaw were well developed, as they are in E. flabellare hatchlings (Lake 1936:826-827), making these two species more precocious at hatching than are Etheostoma gracile (Braasch & Smith 1967:9) and Percina sciera (Page & Smith 1970:9). In aquaria, fry left the nest stone soon after hatching and sought refuge among the gravel sub- strate. Propulsion was accomplished by rapid move- ments of the caudal fin. The smallest specimens examined from the study areas were two 12-mm females collected 20 July 1971 in Big Creek. Several specimens from 13 to 20 mm were collected in a number of habitats in both study areas between 23 June and 25 August of 1971 and 1972. At 12 mm juveniles had essentially the morphology of adults but were without scales on the nape, breast, and belly, and were without a lateral-line canal. In 75 A o a STANDARD LENGTH, mm w a i) n = MALE ————= FEMALE ) 10 20 30 40 42 MONTHS OF AGE 75 B e e 65 2 € € ~ 55 oad = Co) & 45 a [ay < < 35 ma 60 e221 21-80 31-40 41-50 651-60 > 60 mm mm mm mm mm mm mm mm mm mm mm mm (10) (41) (43) (57) (16) (6) (7) (10) (17) (14) (14) (5) Nematoda 2.4 Oligochaeta 2.4 4.7 1.8 _ Gastropoda 2.4 7.3 8.8 12.5 Tal 20.0 Arachnida Araneae oie ws ais 20.0 ai tha Acarina 10.0 4.8 2.3 10.0 Crustacea Cladocera 30.0 22.0 4.7 1.8 a 42.9 Ostracoda 50.0 17.1 2.3 3.5 12.5 28.6 Copepoda 30.0 43.9 20.9 7.0 12.5 71.4 Isopoda Asellidae Bo 10-83 9.8 8.8 37.5 16.7 14.3 me 17.6 14.3 14.3 20.0 Amphipoda 10.0 1-83 20.9 17.5 37.5 50.0 14.3 10.0 23.5 3D.t Decapoda Astacidae 1.8 12.5 16.7 _ Insecta : Plecoptera 1G 17.1 1lec3 1.8 i Py oH Ae ¥ oe Theil Ephemeroptera 30.0 29.3 27.9 45.6 31.3 16.7 28.6 10.0 11.8 28.6 28.6 Odonata Zygoptera 6 2.4 a 30 3 ie a0 30 Trichoptera 12.2 2.3 5.3 10.0 58.8 14.3 42.9 _ Coleoptera : Dytiscidae Dt es 58 1.8 Hydrophilidae ar ae 23 oe Psephenidae oe 7.3 2.3 1.8 Be Elmidae ae 4.8 ae 1.8 14.3 Diptera Tipulidae ie ae T1 Simulidae 50 se ae or ae ae Ae 20.0 11.8 a A us Chironomidae 70.0 56.1 72.1 36.8 43.8 50.0 100.0 90.0 82.4 64.3 50.0 40.0 Ceratopogonidae ae Bf 4.7 O6 Others 10.0 7.3 4.7 3.5 _ Miscellaneous aa 2.4 4.7 16.7 ae os 5.9 7.1 7.1 amined. A large variety of food organisms was found (Tables 8 and 9). The predominant components of | the diet of the Big Creek population were chironomid larvae, mayfly naiads, copepods, amphipods, isopods, _ostracods, and cladocerans, and of the Ferguson Creek population were chironomids, caddisflies, mayflies, amphipods, and isopods. Little seasonal variation in the diet was found (Table 8). The use of cladocera, ostracods, and acarina by juvenile E. squamiceps accounts for their | presence in the diet during summer and early autumn and their absence in the rest of the year. The large | populations of small crayfishes in spring correlates 'with their appearance in stomachs of May- and ' April-collected darters. The most commonly eaten organisms, chironomids, were eaten in the largest numbers in the months immediately preceding spawn- ing, presumably reflecting an increase in consump- tion associated with spawning preparedness. The smallest darters examined fed predominantly on copepods, cladocera, ostracods, and chironomids; the largest darters fed mainly on amphipods, isopods, and chironomids in Big Creek, and on amphipods, chironomids, and caddisflies in Ferguson Creek (Table 9). Aquarium-held E. squamiceps searched for food by moving over the gravel bottom in short, jerky movements. When a benthic organism was located, the darter approached closely, directed his snout toward it, and then quickly sucked it into his mouth. Nest-guarding males fed as readily as other indi- viduals. Fry were successfully raised on brine shrimp. TapLe 9.—Continued Mean Number of Food Organisms Per Stomach Big Creek Ferguson Creek Food O i SSS oe aS —™ id is < 21 21-30 31-40 41-50 51-60 > 60 <2 21-30 31-40 41-50 51-60 > 60 mm mm mm mm mm mm mm mm mm mm mm mm (10) (41) (43) (57) (16) (6) (7) (10) (17) (14) (14) (5) Nematoda ae 0.02 Oligochaeta S33 0.02 0.07 0.02 -- 7 Gastropoda 0.02 «0.07 0.12 0.25 Ps i e 4 .. 0.07 0.20 ) Arachnida Araneae Be se ae are Ee ee 0 0.30 = 0.07 - Acarina 0.10 0.05 0.02 " ei gi 010 ; ) Crustacea ; Cladocera 1.70 1.39 0.14 0.02 na sha 5.43 Ostracoda 2.70 0.63 0.02 0.25 0.13 x 0.29 Copepoda 0.80 1.68 0.51 0.11 0.13 we 5.14 Isopoda Asellidae f 0.07 0.09 0.16 0.94 0.33 0.14 ois 0.18 Amphipoda 0.10 0.10 0.37 0.28 1.00 1.83 0.14 0.10 0.65 Decapoda Astacidae be hic ee 0.04 0.19 0.17 Insecta Plecoptera ae 0.22 0.07 0.02 2s or ae Ae 3m Ephemeroptera 0.30 0.37 0.30 0.68 0.44 0.33 0.71 0.30 0.12 Odonata Zygoptera ie 0.02 ae os as a Se oe oe Trichoptera ai 0.15 0.02 0.11 0.19 we oe 0.20 1.53 Coleoptera Dytiscidae as ae as 0.02 a Hydrophilidae ae oe 0.02 =e 0.06 Psephenidae no 0.32 0.02 0.02 0.06 ais oye Elmidae se 0.05 is 0.02 sic ae 0.14 Diptera Tipulidae 3° as a Se ae 0 Sie ee a Simulidae He ws Ns Me ae an ae 1.20 0.18 Chironomidae 1.10 2.29 4.07 1.44 0.75 0.83 8.14 12.00 5.82 Ceratopogonidae 2 oe 0.07 ss Others 0.10 0.07 0.05 0.04 Miscellaneous one 0.02 0.05 Be a 3.83 Sa as 0.06 INTERACTIONS WITH OTHER ORGANISMS and seemed nearly to account for all available sit Competition Competition for these sites was somewhat redu by the partial staggering of spawning periods. E. squamiceps occurs syntopically with all other sequence of spawning by the species known dere species of eaonon ema ae a lack spawn on the undersides of slab rocks in the stud of total competitive exclusion between E. squamiceps areas was, from earliest to latest: Eurycea bisline and any closely related (and described) species. (Amphibia), Etheostoma squamiceps, Etheostor At the study areas, interspecific competition for — kennicotti, Etheostoma obeyense, and Pimepha habitat space seemed unlikely except possibly be- notatus. No nests of Etheostoma nigrum were foun tween E. squamiceps and E. kennicotti in the slab although the species is known to spawn on the under. pools of Big Creek. In Ferguson Creek no other sides of stones (Winn 1958a:205-206 and 1958D:17 riffle-inhabiting darters occurred. In both Ferguson 180). and Big creeks the slab pools generally had a small variety of fishes, and the species of Catonotus were Predation almost always the most commonly occurring fishes. As potential predators nine Esox americanus a The number of nesting sites of E. squamiceps and 12 Lepomis cyanellus collected with E. .squamice other slab-rock users in a given area was often great from Big and Ferguson creeks were preserved a later examined for ingested Catonotus. One 121-mm E. americanus contained a recently ingested 44-mm E. squamiceps. No other evidence of predation was found. £ Parasitism _ Both study populations of E. squamiceps were heavily parasitized by a spiny-headed worm, Acantho- 19 cephalus jacksoni. A total of 194 of these worms was removed from the intestines of 240 darters. The infestation was more severe in Big Creek (0.91 worms per darter) than in Ferguson Creek (0.53), and more severe in large darters (as many as 19 worms in a 69-mm male) than in small. In Ferguson Creek these worms were found only in darters collected from February through May and in August, but in t Taste 10.—Characteristics of Etheostoma squamiceps (24 specimens), FE. kennicotti (24 specimens) and a hybrid BE. squamiceps x E. kennicotti, all from southern Illinois. es E. squamiceps BE. kennicotti Characteristic Standard Hybrid Standard Range Mean Deviation Range Mean Deviation ‘Number of lateral-line scales 48-54 50.5 2.0 46 39-46 42.6 1.8 Number of pored lateral-line scales 25-40 33.8 3.4 30 14-25 ile) 7/ 3.0 Yumber of scales around caudal peduncle 17-21 19.6 1.2 20 17-20 18.3 0.8 Number of vertical bands on caudal fin 6-9 7.6 0.8 Ul 8-11 9.3 0.8 Number of dorsal spines 7-9 8.3 0.6 8 6-8 7.2 0.5 umber of dorsal rays 12-14 13.0 0.4 13 11-13 12.1 0.5 umber of pectoral rays 10-12 ital 0.4 12 11-13 12.0 0.2 ‘Pectoral fin length/standard length 0.21-0.25 0.23 0.01 0.26 0.23-0.28 0.25 0.01 ‘Spinous dorsal fin base length/ standard length 0.21—-0.24 0.23 0.01 0.23 0.23-0.28 0.26 0.01 ‘Spinous dorsal fin base length/ soft dorsal fin base length 0.87-1.04 0.94 0.06 1.00 0.73-0.91 0.81 0.06 {Spinous dorsal fin height/ soft dorsal fin height 0.50-0.86 0.62 0.08 0.54 0.44-0.55 0.47 0.03 Spinous dorsal fin height/body depth 0.35-0.52 0.46 0.05 0.39 0.35-0.43 0.39 0.02 ‘Nape squamation Fully sealed Partially scaled Naked “Belly squamation Fully scaled Fully scaled Variable naked strip Dorsal fin pigmentation Without marginal band Light marginal Distinct marginal band it band ‘Caudal spots Three black spots Three black spots No black spots 7 | | TABLE 1i1—Summary of life-history information on Big Creek and Ferguson Creek populations of Etheostoma squamiceps. Characteristic Life-History Data Principal habitat of adults Principal habitat of young »Age at reaching sexual maturity )Age at first spawning Size at reaching sexual maturity »Sexual dimorphism 1 year Females 1 year; Slab rifles in Ferguson Creek; Slab riffes in Ferguson Creek; slab pools in Big Creek slab pools in Big Creek males 2 years Females about 35 mm; males about 40 mm Males are larger, have longer fins and a deeper caudal peduncle, and in spring are much more boldly patterned Absent 28-357 ‘Breeding tubercles Number of mature ova counted |Description of egg in nest “Spawning period ‘Spawning habitat Spawning position Nesting site Number of eggs counted in nests Egg guarding ‘Incubation periods Influence of sex on growth rate ensity pu Slab pools 8-1500 Only by the male 1.8 mm in diameter, translucent, adhesive From late March to May or early June Both male and female briefly inverted, head to head Underside of a slab stone 270-275 hours at 18°-22° C, 125-130 hours at 22°-26° C By the third year males are significantly larger than females Up to 9.6 darters/m? in slab riffles in Ferguson Creek; slab pools in Big Creek 1 male in Ferguson Creek; up to 2.0 darters/m? in 1.3 females: 1 male in Big Creek ) Sex ratio among young 1.7 females: Longevity 3+ years Maximum size 72 mm standard length ) Migrations To and from spawning grounds / Territoriality Extreme in breeding males; rincipal diet weak in females and nonbreeding males Aquatic insect immatures and crustaceans 20 Big Creek worms were found in darters collected in every month except June, July, and August. A. jacksoni has previously not been known to parasitize Etheostoma (Hoffman 1967:283). The only ectoparasites found were two piscicolid leeches attached to the caudal fins of two young E. squamiceps collected in Big Creek in October. Hybridization No accounts of hybridization involving E. squami- ceps were listed by Schwartz (1972). One E. squami- ceps x E. kennicotti hybrid male was collected in Big Creek on 1 October 1971. The specimen measured 40 mm, was 1+ years old, and shared morphological characteristics with both parent species (Table 10). SUMMARY The life-history information on E. squamiceps col- lected in Big and Ferguson creeks between 6 October 1970 and 19 June 1973 is summarized in Table 11. LITERATURE CITED Braascu, M. E., and P. W. SmirH. 1967. The life history of the slough darter, Htheostoma gracile (Pisces, Per- cidae). Illinois Natural History Survey Biological Notes 58. 12 p. Cottetrs, B. B. 1965. Systematic significance of breeding tubercles in fishes of the family Percidae. U. S. Na- tional Museum Proceedings 117(3518) :567—-614. , and L. W. Knapp. 1966. Catalog of type specimens of the darters (Pisces, Percidae, Etheostomatini). U.S. National Museum Proceedings 119 (3550) :1-88. Coox, F. A. 1959. Freshwater fishes in Mississippi. Missis- sippi Game and Fish Commission, Jackson. 239 p. Darper, F. C. 1956. A comparative analysis of the winter feeding habits of two benthic stream fishes. Copeia 1956(3):141-151. Derevey, E. S., Jr. 1947. Life tables for natural populations of animals. Quarterly Review of Biology 22:283-314. Forses, S. A., and R. E. RicHarpson. [1908.] The fishes of Illinois. Illinois State Laboratory of Natural History. exxxi + 357 p. Fowter, H. W. 1922. Records of fishes for the eastern and southern United States. Philadelphia Academy of Na- tural Sciences Proceedings 74:1-27. US ISSN 0073-490X HorrMan, G. L. 1967. Parasites of North American fresh- water fishes. University of California Press, Berkeley and Los Angeles. 486 p. JorpaNn, D. S. 1877. Contributions to North American ich- thyology based primarily on the collections of the United States National Museum. II. A.—Notes on Cottidae, Etheostomatidae, Percidae, Centrarchidae, Aphododeridae, Dorysomatidae, and Cyprinidae, with revisions of the genera and descriptions of new or little known species. U. S. National Museum Bulletin (10): 1-68. , and B. W. EverMANN. 1896. The fishes of North and Middle America. U. S. National Museum Bulletin (47) :1-1240. Karr, J. R. 1964. Age, growth, fecundity and food habits of fantail darters in Boone County, Iowa. Iowa Academy of Science Proceedings 71:274—-280. KUEHNE, R. A., and J. W. SMALi, Jr. 1971. Etheostoma barbouri, a new darter (Percidae, Etheostomatini) from the Green River with notes on the subgenus Catonotus. Copeia 1971(1) :18-26. Lake, C. T. 1936. The life history of the fan-tailed darter Catonotus flabellaris flabellaris (Rafinesque). Ameri- can Midland Naturalist 17(5) :816—-830. Lewis, W. M. 1957. The fish population of a spring-fed stream system in southern Illinois. Illinois State Acad- emy of Science Transactions 50:23-29. Moore, G. A. 1968. Fishes. Pages 21-165 in W. F. Blair, A. P. Blair, P. Brodkorb, F. R. Cagle, and G. A. Moore, Vertebrates of the United States. McGraw-Hill Book Company, New York. Pace, L. M., and P. W. SmirH. 1970. The life history of the dusky darter, Percina sciera, in the Embarras River, Illinois. Illinois Natural History Survey Biological Notes 69. 15 p. , and . 1971. The life history of the slenderhead darter, Percina phoxocephala, in the Embarras River, Illinois. Illinois Natural History Survey Biological Notes 74. 14 p. Scuwartz, F. J. 1972. World literature to fish hybrids with an analysis by family, species, and hybrid. Gulf Coast Research Laboratory, Ocean Springs, Mississippi. 328 p. SmirH-Vaniz, W. F. 1968. Freshwater fishes of Alabama. Auburn University Agricultural Experiment Station, Auburn, Alabama. 211 p. Winn, H. BE. 1958a. Observations on the reproductive habits of darters (Pisces-Percidae). American Midland Na- turalist 59(1):190-212. 1958b. Comparative reproductive behavior and ecology of fourteen species of darters (Pisces-Percidae). Ecological Monographs 28(2):155-191. (56614—4M—5-74) Hiss ws teats fol ee fet ates pen ens Naat aa Het tiv aia 4 "| PRA Faby el oy BS vant Rares ‘ ‘ an : wy es : RNa HN aC : ‘ : » rt i oI : ; ‘ . ety Rah ‘ : 2 S Vea “ ni Ln? " wee i nf) PUN SN ; tN ays AR ve AN saMe ‘ \ a“ ae \ ‘ ‘ «i's in : < : ' ‘ - Seth TMTANIE Naat Seat ay rAeaywusbcteartcact ise eh SNH HY, ’ sah ; : : OTS y . WS \ WO mately ‘ ‘ i rt $ ah ‘ De le LeNA A 4 TVS CAUT AN eugene