Etheostoma Olmstedi Research Articles

ERECTION OF BOTHRIOCESTUS N. GEN. (CESTODA: BOTHRIOCEPHALIDEA) AND REDESCRIPTION OF BOTHRIOCESTUS CUSPIDATUS (COOPER, 1917) (SYN. BOTHRIOCEPHALUS CUSPIDATUS) FROM WALLEYE, SANDER VITREUS, (PERCIFORMES: PERCIDAE) IN NORTH AMERICA.

Based on previous molecular phylogenetic analyses, Bothriocestus n. gen. is erected to accommodate bothriocephalid tapeworms that have an elongate scolex, a well-developed apical disc, and a narrow neck region, parasitize freshwater fishes in the Holarctic, and were previously placed in the polyphyletic genus Bothriocephalus Rudolphi, 1808 (Cestoda: Bothriocephalidea). Bothriocestus claviceps (Goeze, 1782) n. comb., a parasite of eels (Anguilla spp.) in the Holarctic region, is designated as the type species. Another species of the new genus, Bothriocestus cuspidatus (Cooper, 1917) (syn. Bothriocephalus cuspidatusCooper, 1917) is redescribed from type and voucher specimens, and new material from the type host, the walleye, Sander vitreus (Mitchill, 1818) (Perciformes: Percidae), in Manitoba and Ontario (where the type locality is located) (Canada) and in New York state and Wisconsin. Bothriocestus cuspidatus of S. vitreus is characterized primarily by the possession of a narrow, long strobila (total length up to 18 cm) composed of distinctly craspedote, trapezoidal proglottids, with primary, secondary, and tertiary proglottids differing in size, and by an arrow-shaped (=cuspidatus) scolex that is distinctly broader than the first proglottids, widest near the base in lateral view and gradually becoming broader toward the anterior end in dorsoventral view. A "dwarf" form of B. cuspidatus (total length of 9-27 mm) from Johnny darter, Etheostoma nigrum Rafinesque, 1820, and tessellated darter, Etheostoma olmstedi Storer, 1842 (both Percidae: Etheostominae), is also characterized morphologically in the present paper.

Geographic variation in host fish use and larval metamorphosis for the endangered dwarf wedgemussel

Abstract Host fishes play a crucial role in survival and dispersal of freshwater mussels (Unionoida), particularly rare unionids at conservation risk. Intraspecific variation in host use is not well understood for many mussels, including the endangered dwarf wedgemussel (Alasmidonta heterodon) in the USA. Host suitability of 33 fish species for dwarf wedgemussel glochidia (larvae) from the Delaware and Connecticut river basins was tested in laboratory experiments over 9 years. Relative suitability of three different populations of a single host fish, the tessellated darter (Etheostoma olmstedi), from locations in the Connecticut, Delaware, and Susquehanna river basins, was also tested. Connecticut River basin A. heterodon metamorphosed into juvenile mussels on tessellated darter, slimy sculpin (Cottus cognatus), and Atlantic salmon (Salmo salar) parr. Delaware River basin mussels metamorphosed using these three species, as well as brown trout (Salmo trutta), banded killifish (Fundulus diaphanus), mottled sculpin (Cottus bairdii), striped bass (Morone saxatilis), and shield darter (Percina peltata). Atlantic salmon, striped bass, and sculpins were highly effective hosts, frequently generating 5+ juveniles per fish (JPF) and metamorphosis success (MS; proportion of attaching larvae that successfully metamorphose) ≥ 0.4, and producing juveniles in repeated trials. In experiments on tessellated darters, mean JPF and MS values decreased as isolation between the mussel source (Connecticut River) and each fish source increased; mean JPF = 10.45, 6.85, 4.14, and mean MS = 0.50, 0.41, and 0.34 in Connecticut, Delaware, and Susquehanna river darters, respectively. Host suitability of individual darters was highly variable (JPF = 2–11; MS = 0.20–1.0). The results show that mussel–host fish compatibility in A. heterodon differs among Atlantic coastal rivers, and suggest that hosts including anadromous Atlantic salmon and striped bass may help sustain A. heterodon in parts of its range. Continued examination of host use variation, migratory host roles, and mussel–fish interactions in the wild is critical in conservation of A. heterodon and other vulnerable mussel species.

The Influence of Turbidity on Prey Consumption in the Tessellated Darter

AbstractIncreased turbidity and the resulting decreases in water clarity have been shown to alter fish foraging behaviors in potentially detrimental ways. Given the ecological importance of darters of the genus Etheostoma and their dependence on visual cues, we examined the impact of a range of turbidity levels (3.5, 6, 10, 20, 22, and 25 nephelometric turbidity units [NTU]) on the number of prey consumed by the Tessellated Darter Etheostoma olmstedi. While a study of the Fountain Darter E. fonticola found that turbidity affected prey consumption at slightly elevated levels (≥8.7 NTU), we found no significant differences in consumption by the Tessellated Darter across turbidity levels. While there may be intragenus variation in the use of olfactory cues, another and perhaps more likely explanation is the difference in long‐term exposure to a range of turbidities. The Fountain Darter is endemic to clear, primarily spring‐fed rivers, whereas the Tessellated Darter is, comparatively speaking, a generalist that inhabits a variety of water‐clarity conditions. These data contribute to a growing body of literature highlighting the complex influences of turbidity on aquatic communities and speak to the conservation challenges associated with this ubiquitous environmental issue.Received April 26, 2016; accepted January 9, 2017 Published online March 30, 2017

Treatment of textile effluent in a developed phytoreactor with immobilized bacterial augmentation and subsequent toxicity studies on Etheostoma olmstedi fish

A static hydroponic bioreactor using nursery grown plants of Pogonatherum crinitum along with immobilized Bacillus pumilus cells was developed for the treatment of textile wastewater. Independent reactors with plants and immobilized cells were also kept for performance and efficacy evaluation. The effluent samples characterized before and after their treatment showed that the plant–bacterial consortium reactor was more efficient than those of individual plant and bacterium reactors. COD, BOD, ADMI, conductivity, turbidity, TDS and TSS of the textile effluent was found to be reduced by 78, 70, 93, 4, 90, 13 and 70% respectively within 12 d by the consortial set. HPTLC analysis revealed the transformation of the textile effluent to new products. The phytotoxicity study on Phaeseolus mungo and Sorghum vulgare seeds showed reduced toxicity of treated effluents. The animal toxicity study performed on Etheostoma olmstedi fishes showed the toxic nature of untreated effluent giving extreme stress to fishes leading to death. Histology of fish gills exposed to treated effluent was found to be less affected. The oxidative stress related enzymes like superoxide dismutase and catalase were found to show decreased activities and less lipid peroxidation in fishes exposed to treated effluent.

Short‐term dynamics of nest occupancy in an allopaternal species, the tessellated darter Etheostoma olmstedi

To inquire how male size interacts with alloparental behaviour and mating success in the tessellated darter Etheostoma olmstedi, males were given a choice of nests with or without eggs; subsequent nest occupancy, takeovers and egg deposits were monitored. Subordinate males readily occupied available nests with eggs but were often evicted by dominant males, suggesting that males of all sizes compete for the opportunity to provide allopaternal care in this species.

Sharing of potential nest sites by Etheostoma olmstedi males suggests mutual tolerance in an alloparental species.

When reproductive competitors tolerate or cooperate with one another, they may gain particular benefits, such as collectively guarding resources or attracting mates. Shared resources may be those essential to reproduction, such as a breeding site or nest. Using the tessellated darter, a species where males but not females compete over potential nest sites, we examined site use and sharing under controlled conditions of differing competitor density. Sharing was observed even when competitor density was low and individuals could have each occupied a potential nest site without same-sex sharing. Males were more likely to share a nest site with one other when the difference in size between them was larger rather than smaller. There was no evidence that female sharing was dependent on their relative size. Fish were generally more likely to use and share larger sites, in accordance with the greater relative surface area they offered. We discuss how one or both sharing males may potentially benefit, and how male sharing of potential nest sites could relate to female mating preferences. Tessellated darter males are known to provide alloparental care for eggs but this occurs without any social contact between the alloparent and the genetic father of the young. Thus, the suggestion that they may also share sites and maintain social contact with reproductive competitors highlights the importance of increased focus on the potential complexity of reproductive systems.

An Evaluation of Fish Assemblages of the Saw Mill River, New York: An Urban Stream

Presence/absence data of 11 species of fish collected during 2008, 2009, and 2010 from five selected stations along the freshwater reach of the Saw Mill River, Westchester County, NY were examined using correspondence and parsimony analysis. The length of the river sampled extended from its northern source in Chappaqua (river km 36.9) south to Executive Boulevard (river km 6.4) in Yonkers, a distance of approximately 30.5 km. Correspondence analysis showed the distribution of stations in “species space” and indicated that two stations (Chappaqua and Hawthorne Cinema) aligned to the left of the origin of Axis #1 but in different quadrants, while the other three stations (Rumbrook, Lawrence Street, and Executive Boulevard) aligned to the right of the origin of Axis #1, with Rumbrook in a different quadrant than the Lawrence Street and Executive Boulevard stations. However, the analysis does not indicate specifically which fish assemblages are associated with each station. Parsimony analysis, which treats each collection site as if it were a “taxon” and the presence/absence of the fish as “character states” of those “taxa”, addressed this problem and aggregated the stations into two main groups, one containing two stations (Lawrence Street and Rumbrook) united by the presence of Rhinichthys cataractae (Longnose Dace) and the other consisting of three stations (Chappaqua, Hawthorne Cinema, and Executive Boulevard) united by the presence of Micropterus salmoides (Largemouth Bass). Within this larger group is a sub-group consisting of two stations (Chappaqua and Hawthorne Cinema) united by the presence of Lepomis gibbosus (Pumpkinseed). In addition, the analysis allows one to readily visualize aspects of the fish distributions along the length of the river. For example, Catostomus commersonii (White Sucker), Lepomis auritus (Redbreast Sunfish), and Rhinichthys atratulus (Blacknose Dace) were found at all sites, while Semotilus atromaculatus (Creek Chub) was found at both Chappaqua, the northernmost station, and also at Rumbrook, the approximate mid-point station of the section of the river sampled. The Longnose Dace was only found in the southern reaches of the river from Rumbrook south to Lawrence Street, and Etheostoma olmstedi (Tessellated Darter) was found at Executive Boulevard and Lawrence Street, our two southernmost stations. The analysis also readily identifies species that are endemic to a particular section of the river: Ambloplites rupestris (Rock Bass) at the Lawrence Street station, Salmo trutta (Brown Trout) at the Hawthorne Cinema site, and Pimephales promelas (Fathead Minnow) at Chappaqua.

Adoption and cuckoldry lead to alloparental care in the tessellated darter (Etheostoma olmstedi), a non-group-living species with no evidence of nest site limitation

While extensive empirical and theoretical work has focused on the evolution of costly cooperation (particularly in group-living species), less attention has been paid to more low-risk or immediately beneficial forms of cooperation. In some non-group-living darters, alloparental care (or allocare) by subordinates has been noted to result from by-product benefits as small territorial (subordinate) males adopt and provide care to the abandoned eggs of large territorial (dominant) males. In the tessellated darter (Etheostoma olmstedi), allocare also results from sneak fertilization. However, information on the rate of allocare by tessellated darters is contradictory: prior behavioral work suggested that it is very common, while a genetic examination showed males to primarily care for their own young. We found behavioral and genetic evidence of very high levels of allocare at our study location. The relative size of the assigned fathers of young to the alloparental male is consistent with the idea that initial allocare primarily results from sneak fertilization (“cuckoldry-based allocare”), but later allocare results from subordinate males caring at previously abandoned nests (“adoption-based allocare”). Larger males appeared to breed more frequently at different nests, but did not father more individual offspring than smaller males. Finally, low relatedness between abandoning and alloparenting males suggests that kin selection does not contribute to alloparental care. We discuss how variation in nest availability may explain the inconsistent findings of the rate of alloparental care in the tessellated darter, and how increased research in this and similar systems can expand our understanding of the evolution of cooperation.

Fish abundances in shoreline habitats and submerged aquatic vegetation in a tidal freshwater embayment of the Potomac River

Submerged aquatic vegetation (SAV) is considered an important habitat for juvenile and small forage fish species, but many long-term recruitment surveys do not effectively monitor fish communities in SAV. To better understand the impact of recent large increases of SAV on the fish community in tidal freshwater reaches of the Potomac River, we compared traditional seine sampling from shore with drop ring sampling of SAV beds (primarily Hydrilla) in a shallow water (depths, <1.5m) embayment, Gunston Cove. To accomplish this, we developed species-specific catch efficiency values for the seine gear and calculated area-based density in both shoreline and SAV habitats in late summer of three different years (2007, 2008, and 2009). For the dominant species (Fundulus diaphanus, Lepomis macrochirus, Etheostoma olmstedi, Morone americana, Lepomis gibbosus, and Fundulus heteroclitus), density was nearly always higher in SAV, but overall, species richness was highest in shoreline habitats sampled with seines. Although historical monitoring of fish in Gunston Cove (and throughout Chesapeake Bay) is based upon seine sampling (and trawl sampling in deeper areas), the high densities of fish and larger areal extent of SAV indicated that complementary sampling of SAV habitats would produce more accurate trends in abundances of common species. Because drop ring samples cover much less area than seines and may miss rare species, a combination of methods that includes seine sampling is needed for biodiversity assessment. The resurgence of SAV in tidal freshwater signifies improving water quality, and methods we evaluated here support improved inferences about population trends and fish community structure as indicators of ecosystem condition.

Large males have a mating advantage in a species of darter with smaller, allopaternal males Etheostoma olmstedi

Abstract Theory suggests that males that are larger than their competitors may have increased mating success, due to both greater competitive ability and increased attractiveness to females. We examined how male mating success varies with male size in the tessellated darter Etheostoma olmstedi. Previous work has shown that large males tend to move around and breed in vacant breeding sites, and consequently provide less care for their eggs, while smaller individuals can be allopaternal, caring for the eggs of other males as well as for their own. We studied female egg deposition in a natural breeding population using artificial breeding sites and in the laboratory, where female choice of spawning site was restricted to two breeding sites tended by two males of different sizes. In both the field and the laboratory, nests tended by larger males were more likely to receive new eggs. Additionally, the mean size of males associated with a nest was positively correlated with both the maximum coverage of eggs at the nest and the number of times new eggs were deposited. We discuss how the increased mating success of larger males, despite their decreased parental care, may help explain allopaternal care in this species.

Morphological Change in the Tessellated Darter (Etheostoma olmstedi) Following the Introduction of the Banded Darter (E. zonale) to the Susquehanna River Drainage

Abstract The strong connection between ecology and morphology in fishes predicts that ecologically relevant morphological features will change in concert with changes in habitat use and feeding ecology even over relatively short timescales following species introduction. Here, this hypothesis is tested by examining the trophic morphology of specimens of the native Tessellated Darter, Etheostoma olmstedi, collected at Catatonk Creek, Candor, Tioga Co., NY, USA, between 1961 and 2002. The collections of E. olmstedi bracket a 1980 range expansion by the non-native Banded Darter, E. zonale. Examination of the E. olmstedi specimens revealed that the length of the buccal cavity relative to body size increased following the invasion of Catatonk Creek by E. zonale. An increase in buccal cavity length (BCL) is expected to result in higher suction feeding performance measured as volumetric flow rate of water through the mouth. Such an increase in BCL may enable E. olmstedi to exert greater suction forces on prey an...

Competition for territories does not explain allopaternal care in the tessellated darter

Extensive research has focused on understanding the evolution of parental care, with fishes providing important model systems for understanding patterns of variation within and between species. Classic theory predicts that individuals will care for offspring when the fitness benefits through increased offspring survival and growth outweigh the cost to the parents through decreased future reproductive opportunities. Yet, a puzzling observation not explained by this basic theory is the fact that in some species individuals defend and provision unrelated offspring and thus exhibit alloparental care. The tessellated darter, Etheostoma olmstedi, represents one of the first known examples of allopaternal care in fishes. In this species, males often clean and guard eggs fertilized but deserted by other males. Allopaternal care has been argued to occur in the tessellated darter because of competition for a limited number of mating sites where less dominant males accept territories with eggs when other breeding sites are not available. Here, we test this hypothesis using male territory choice experiments. When allowed to choose between two otherwise identical territories either containing eggs fertilized by another male or with no eggs, males spent significantly more time at territories with eggs. This demonstrates that competition for mating territories is not the primary factor explaining the existence of allopaternal care in the tessellated darter. Instead, males of this species may exhibit allopaternal care to dilute predator pressure on their own eggs or because females prefer to mate with males whose territories contain eggs.

Microhabitat use by blackbanded (Percina nigrofasciata), turquoise (Etheostoma inscriptum), and tessellated (E. olmstedi) darters during drought in a Georgia piedmont stream

We used underwater observations to quantify microhabitat use for blackbanded,Percina nigrofaciata, turquoise, Etheostoma inscriptum, and tessellated, E. olmsteadi, darters in a 116 m reach of a Piedmont stream during 2001-2002. The sampling period and the previous 12 months were the first and second driest years on record, respectively. Spring 2002 had the greatest amount of available habitat, and principal component analysis indicated that only one of three species pairs displayed significant differences in microhabitat use during this season. Conversely, in fall 2001 (intermediate microhabitat availability), all three species used significantly different microhabitats. In general, turquoise darters used areas with greater amounts of erosional substrata, tessellated darters occurred over more depositional substrata, and black- banded darters utilized intermediate microhabitats. During fall 2001, large blackbanded darters (≥55 mm SL) occupied faster microhabitats with more erosional substrata, and used a greater variety of depths than smaller conspecifics (40-55 mm). In fall 2001, large turquoise darters (≥40 mm) used deeper microhabitats with higher velocities and more erosional substrata than smaller individuals, whereas the opposite was true (≤50 mm in faster, more erosional, than >50 mm) in fall 2002. In general, darters did not occur in micro- habitats with significantly higher invertebrate abundan- ces, however both blackbanded and tessellated darters occupied microhabitats with higher percentages of Diptera in a single season. The inconsistent responses of darters to microhabitat prey abundance may have been influenced by extreme drought conditions.

Quantification of native muskellunge nursery habitat: influence of body size, fish community composition, and vegetation structure

Habitat utilization of native young-of-the-year (YOY) muskellunge, Esox masquinongy, was quantified by the type and density of vegetation present, water depth, and fish communities associated with their presence and abundance in nursery bays of the Upper St. Lawrence River. We completed 441 seine hauls and captured 400 YOY muskellunge in 11 bays that were sampled each July and August over a 3-year period (2002–2004). We hypothesized a change in habitat utilization related to increasing body size, as YOY muskellunge doubled in total length from July to August. Fine-leafed submerged and emergent macrophytes and prey availability (cyprinids, Notropis sp., banded killifish, Fundulus diaphanous and tessellated darter, Etheostoma olmstedi), were positively related to muskellunge use in July, while in August coverage of broad-leafed submerged macrophytes and increased overall vegetation density were the best habitat descriptor. In both months, muskellunge were associated with moderate (20–60%) vegetation coverage and density, however, captures were in areas of significantly greater vegetation coverage and density than was generally available. A negative relation of muskellunge occurrence with water depth, yellow perch, Perca flavescens, and stonewort, Chara vulgaris, was observed in both months. The negative relationship between muskellunge and depth, plus their strong linkages to nearshore submerged vegetation and forage fish that inhabit the nearshore areas, highlights the importance of protecting the ecological integrity of nearshore habitats. Our findings should assist managers in protecting native stocks, planning restoration and enhancement initiatives, and in regulating riparian and nearshore development.

Threatened Fishes of the World: Etheostoma perlongum (Hubbs and Raney 1946) (Percidae)

tion status: Threatened (Warren et al. 2000); Threatened in North Carolina (Shute 1997). Identification: Subgenus Boleosoma. Adults reaching 45–75 mm SL (Shute et al. 1982). Similar to its sister species, Etheostoma olmstedi, with the exception of having a more-slender body and higher vertebral and lateral scale counts. D1 IX– XII; D2 13–15; A II + 8–9; Vertebrae 39–42; Lateral scales 59–64. Lateral line complete. Illustration by E. F. Menhinick. Distribution: Along with Menidia extensa and Fundulus diaphanus, one of three endemic fishes in Lake Waccamaw, North Carolina, (Hubbs and Raney 1946). Specimens from the headwaters of the Waccamaw River, just below the Lake Waccamaw dam are morphological intermediates between E. perlongum and E. olmstedi. Abundance: The least common of the three Lake Waccamaw endemics; Lindquist and Yarbrough (1982) estimated the population to be approximately 125,000 individuals, –25%. Habitat and ecology: Diet consists primarily of aquatic insects, particularly chironomid larvae. Found in offshore waters in fall and winter, they migrate to shallow inshore waters in March to spawn. Reproduction: Spawning occurs from March through June beneath woody debris and rocks, typically in <1 m depth (Lindquist et al. 1981). Males guard nests where several females may spawn (Lindquist et al. 1981, 1984). An annual species; most individuals die shortly after spawning (Shute et al. 1982), perhaps due to depleted somatic lipid levels (Schultz 1999). Threats: Two primary threats to E. perlongum are degradation of water quality and destruction of habitat (Shute 1997). The Lake Waccamaw shoreline is densely developed with homes and cottages. Development is likely to increase nutrient loading in the lake (Shute 1997), causing wide-scale algal blooms. Additionally, suitable spawning habitat such as fallen trees and rocks are considered dangerous to boaters and are often removed. Because E. perlongum has an annual life cycle, reproductive failure for even a single year could lead to rapid extinction. Conservation actions: Habitat is indirectly protected because Lake Waccamaw has been designated T. J. Krabbenhoft (&) AE J. M. Quattro Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA e-mail: Krabbenhoft@biol.sc.edu

Reproduction based on local patch size of Alasmidonta heterodon and dispersal by its darter host in the Mill River, Massachusetts, USA

Abstract We studied the reproduction and shell size structure of the endangered dwarf wedgemussel (Alasmidonta heterodon) in the Mill River, Massachusetts, at sites of different mussel abundance, and assessed the dispersal capacity of its host fish, the tessellated darter (Etheostoma olmstedi). We quantified 4 phases of reproduction at 5 study sites of contrasting adult mussel abundance (3 low-abundance sites, 1 intermediate, 1 high), including gravidity, glochidial release, host infection rate, and juvenile recruitment. The ratio of gravid to nongravid individuals was higher at the high-abundance site, and comparatively lower at the intermediate- and low-abundance sites. Glochidial release, infection rates on host darters, and juvenile recruitment were directly proportional to mussel abundance. The highest glochidia density (0.12/m3) occurred at the high-abundance site. Mean infection rates during early May to late June ranged from 31% at the high-abundance site to 8% at the intermediate- and 0 to 2% at ...

Substrate Choice by Three Species of Darters (Teleostei: Percidae) in an Artificial Stream: Effects of a Nonnative Species

Etheostoma zonale, the banded darter, was introduced to the Susquehanna River basin, Pennsylvania, through an interbasin transfer. We examined the effects of darter density and the presence of E. zonale on the substrate choice of two native darter species (Etheostoma olmstedi, the tessellated darter, and Percina peltata, the shield darter) in an artificial stream. In single species trials, E. olmstedi, E. zonale, and P. peltata exhibited nonrandom substrate selection and occupied patches of large substrate significantly (P < 0.05) more often than expected. No intraspecific density effects were observed. The presence of E. zonale did not affect the substrate choice of P. peltata but did induce a shift of E. olmstedi from large to small substrate in high-density trials (P < 0.05). Etheostoma zonale was most frequently the aggressor in behavioral interactions. Neither E. olmstedi nor P. peltata directed any agonistic behavior toward E. zonale; however 40% of aggressive acts initiated by E. zonale were directed toward E. olmstedi and P. peltata. Displacement of E. olmstedi by the aggressor E. zonale suggests potential deleterious effects on the native species.

Parentage and Nest Guarding in the Tessellated Darter (Etheostoma olmstedi) Assayed by Microsatellite Markers (Perciformes: Percidae)

Parental investment as manifested through extended parental care of young presumably enhances the reproductive success of the custodial parent. In the Tessellated Darter (Etheostoma olmstedi), the primary caregivers are breeding males on the nest. However, prior field observations on nesting darters seem suggestive of behaviors that are more difficult to interpret evolutionarily. These include tending clutches that may have been fertilized by other males and appropriating nests from smaller courting males. To address such possibilities genetically, we assayed six microsatellite loci in 16 nest-tending males and the embryos from their associated clutches. In most cases, a guardian male had sired nearly all of the embryos in his nest. However, in one nest, a guardian male had been cuckolded, and in two other nests, an attendant male guarded embryos that were not his own presumably resulting from nest takeovers. From direct genotypic counts, a mean of at least 3.2 mothers contributed to the progeny in a nest, and computer simulations suggest that the true maternal number may be substantially higher.

Comparison of Lipid Levels during Spawning in Annual and Perennial Darters of the Subgenus Boleosoma, Etheostoma perlongum, and Etheostoma olmstedi

Etheostoma perlongum, the Waccamaw darter, is an annual species, and most adults die soon after spawning. This study compared the body composition of the Waccamaw darter to a close relative, E. olmstedi, the tessellated darter, during the spawning season. Tessellated darters are perennial, some live three years. Lipid composition of both species was quantified as the proportion of the body that could be extracted in petroleum ether. Nonlipid composition was quantified as the residual of a regression of lean dry mass on standard length. Change in lipid and nonlipid composition was followed through the spawning season. Differences in body composition were consistent with life-history differences. Waccamaw darters had less lipid in their bodies through the spawning season and some depleted nonlipid material. Tessellated darters were more conservative of lipid and few depleted nonlipid material. At the same time that adult Waccamaw darters had highly depleted bodies, their young were in good condition. Adult Waccamaw darters appear to be actively allocating lipid and nonlipid material to reproduction rather than to maintenance or storage. Mean lipid levels in Waccamaw darters during spawning were comparable to lipid levels associated with death in other fish species. The conditions required for a semelparous annual life history and the conditions that select for an iteroparous life history are discussed relative to the habitat and biology of both species.

Comparative Microhabitat Use of Ecologically Similar Benthic Fishes

Although benthic insectivorous fishes such as darters and sculpins represent a significant component of riffle communities, few studies have compared the habitat use of these non-related but ecologically similar fishes. The objectives of this study were to examine the habitat use of Etheostoma olmstedi (tessellated darter) compared to Cottus bairdi (mottled sculpin) in Nescopeck Creek and Cottus cognatus (slimy sculpin) in Jack's Creek, Pennsylvania through underwater observation. Etheostoma olmstedi occupied habitats with significantly deeper waters than those available, whereas adult and young of the year Cottus occupied habitats with significantly faster water velocities than those available. Canonical discriminant analysis revealed microhabitat partitioning between E. olmstedi and each Cottus species. Cottus bairdi and C. cognatus occupied significantly shallower habitats with faster water velocities than E. olmstedi. Sculpin species were observed most frequently under substrate whereas E. olmstedi occurred most frequently on the top surface of the substrate. Hurlbert's standardized niche breadth values indicated that C. bairdi and C. cognatus were habitat specialists with regard to water velocity measures, but exhibited generalistic patterns of depth and substrate size use. Etheostoma olmstedi was a habitat specialist with respect to depth, but exhibited generalistic patterns of resource use for substrate size. Differential habitat use by these benthic fishes is consistent with the hypothesis that resource partitioning facilitates species coexistence among stream fishes.