Fundulus Notatus Research Articles

Hatch success and temperature-dependent development time in two broadly distributed topminnows (Fundulidae)

Metabolic scaling laws predict a variety of emergent properties of biological systems based on relationships among temperature, body size, and rates of physiological processes. These models have been criticized as being overly simplistic and not accounting for directional variability arising from evolutionary tradeoffs. I measured hatch success and egg development time at six temperatures for 12 populations throughout the latitudinal range of two broadly distributed topminnows (Fundulus). I asked if hatch success and development time differed between the species and northern and southern populations. Hatch success reaction norms suggested that the more broadly (and northern) distributed Fundulus notatus was more eurythermic with a lower optima and broader performance breadth than Fundulus olivaceus. Temperature explained most variability in mass-corrected development time. Development time differed between the species, but not northern and southern populations. Deviations from predictions of universal scaling laws were most pronounced away from specie's thermal optima.

Coupling Fish Community Structure with Instream Flow and Habitat Connectivity between Two Hydrologically Extreme Years

AbstractHydrologic variability and instream habitat connectivity play fundamental roles in structuring fish communities in lotic ecosystems. We collected fish assemblage and physical habitat data from 28 central Texas streams during the summers of 2006 (a drought year with minimal summer precipitation and low stream flow) and 2007 (an exceptionally wet year with periodic flooding in spring and sustained high flows throughout summer). We evaluated the correspondence between the magnitude of physical habitat and fish community composition change in stream reaches sampled in these two contrasting years using ordination, successional vector analysis, and indicator species analysis. In 2006, streams characterized by disconnected pools had different fish community structure and habitat characteristics than streams that had habitats connected by flowing water. The amount of interannual change in both fish community structure and habitat characteristics was greatest between streams that had disconnected pools in 2006 and their paired samples in 2007. Indicator species analysis identified species that had affinities to disconnected habitats during 2006, which included opportunistic life history strategists typical of temporary waters (western mosquitofish Gambusia affinis and blackstripe topminnow Fundulus notatus) and equilibrium strategists that rely on stable pool habitats for nesting (longear sunfish Lepomis megalotis and largemouth bass Micropterus salmoides). Conversely, indicator species of connected riffle–pool habitat included fluvial specialists (central stoneroller Campostoma anomalum, spotted bass Micropterus punctulatus, and bullhead minnow Pimephales vigilax). In summer 2007, the numbers of most species of fish declined markedly compared with 2006. Community structure between previously disconnected and connected stream types was also highly variable in 2007. However, strong recruitment of juveniles following spring flooding and sustained high summer flow significantly increased the frequency and abundance of two periodical strategists, channel catfish Ictalurus punctatus and flathead catfish Pylodictus olivaris in both types of streams in 2007. These findings provide important insights into how individual species’ life history strategies influence the response of fish community structure to extreme hydrologic events, which are likely to increase in frequency in many parts of the world due to climate change.

Phylogenetic Position of Creptotrema funduli in the Allocreadiidae Based on Partial 28S rDNA Sequences

The infrequently reported allocreadiid digenean Creptotrema funduli Mueller, 1934 is documented from the blackstripe topminnow, Fundulus notatus (Cyprinodontiformes: Fundulidae), in the headwaters of the Biloxi River, Harrison County, Mississippi. Specimens from Mississippi were compared with the type material from Fundulus diaphanus menona from Oneida Lake, New York, and no substantial difference was found. A fragment of ribosomal DNA, comprising a short portion of the 3' end of 18S nuclear rDNA gene, internal transcribed spacer (ITS) genes (including ITS1, 5.8S, and ITS2), and the 5' end of the 28S gene including variable domains D1-D3 was sequenced for the species. A portion of the 28S rDNA gene from C. funduli, plus similar fragments from 8 other allocreadiids and the callodistomatid Prosthenhystera sp., were aligned and subjected to maximum likelihood and Bayesian inference analyses. Resulting phylogenetic trees were derived from the analyses and used to estimate the relationship of Creptotrema Travassos, Artigas, and Pereira, 1928 with other allocreadiids. Creptotrema was found to be closely related to Megalogonia Surber, 1928 and 3 Neotropical genera, i.e., Wallinia Pearse, 1920, Creptotrematina Yamaguti, 1954, and Auriculostoma Scholz, Aguirre-Macedo, and Choudhury, 2004. No molecular data were available for species in Creptotrema prior to this study, so the ITS1, 5.8S, and ITS2 genes have been made available for comparative studies involving neotropical species in the genus.

Shape variability in topminnows (Fundulus notatus species complex) along the river continuum

We examined intra- and interspecific variability in shape of three topminnow species (Funduluidae: Fundulus notatus, F. olivaceus, and F. euryzonus) across ten drainages. Within each drainage, five or more adult male topminnows were digitized at multiple sites (83 total sites) along the river continuum representing a range of stream sizes (cumulative drainage area) and hydrological conditions. Nine of the ten drainages contained two Fundulus species that were longitudinally separated along the river continuum with narrow areas of coexistence. Upstream–downstream distribution patterns were variable by drainage, allowing us to examine patterns repeated across ecologically similar species. More variability in shape was explained by drainage (19.7%) than by species (7.4%) differences. Populations of F. notatus from headwaters (three drainages) converged on a deep-bodied form similar to F. olivaceus which was typically sampled in headwaters. Fundulus notatus shape was more closely related to stream size than in the other two species. Headwater populations of F. notatus and F. olivaceus had fineness ratios near the hydrodynamic optima of 4.5 whereas downstream populations of F. notatus had shallower bodies. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 612–621.

Metabolic cold adaptation and developmental plasticity in metabolic rates among species in the Fundulus notatus species complex

Summary 1. In ectotherms, temperature and body size are the most influential and well studied variables affecting metabolic rate. Understanding mechanisms driving the evolution of metabolic rates is crucial to broader ecological theory. The metabolic cold adaptation hypothesis (MCA) makes predictions about the evolution of ectotherm metabolic rates and temperature‐metabolic rate reaction norms. 2. We examined intra and interspecific patterns in metabolic rate among populations in the Fundulus notatus species group (F. notatus, F. olivaceus and F. euryzonus). We ask if patterns of intra and interspecific variability in metabolic rate are consistent with the MCA and if metabolic rates in general are developmentally plastic. 3. Support for the MCA was mixed among intra and interspecific tests. The northern population of F. olivaceus had increased metabolic rate and no difference in temperature sensitivity (slope of temperature‐metabolic rate reaction norm). Northern populations of F. notatus had lower temperature sensitivity and no difference in overall metabolic rate. The southern coastal drainage endemic (F. euryzonus) had intermediate metabolic rates compared to southern populations of the other two more broadly distributed species. Metabolic rates were also developmentally plastic. Adults reared at warmer temperatures had lower metabolic rates after accounting for body size and temperature. 4. Differences in thermal regimes explain some variability in metabolic rates among populations consistent with MCA. However, interspecific comparisons are not consistent with MCA and are likely influenced by species differences in ecology and life history strategies.

Tests of reproductive isolation among species in the Fundulus notatus (Cyprinodontiformes: Fundulidae) species complex

We assessed prezygotic (probability of spawning) and postzygotic (hatching success) reproductive isolation among the three ecologically and morphologically similar species in the Fundulus notatus species complex. We employed a multi-generation breeding experiment to test the hypotheses that karyotypic differences, body size differences, or geographic isolation among populations will increase pre or postzygotic reproductive barriers. Overall, prezygotic barriers were strong and postzygotic barriers weak in crosses of non-hybrid heterospecifics (F1 hybrid crosses) while prezygotic barriers were weaker and postzygotic barriers stronger in crosses involving hybrid individuals (F2 hybrid crosses and backcrosses). Prezygotic barriers among the two smaller species (Fundulus notatus and F. euryzonus) broke down rapidly; first generation hybrids spawned (F2 hybrid crosses and backcrosses) as frequently as parental forms in intraspecific crosses. There was no increase in postzygotic barriers among species with cytogenetic differences. There were increased prezygotic, but not postzygotic, barriers among geographically isolated populations of one species. While pure males and females were just as likely to spawn with hybrids, some types of hybrid females suffered from increased sterility, but not inviability, over hybrid males. Female sterility was only seen in hybrids with a Fundulus euryzonus parent, while other female hybrids produced viable eggs.

Hybridization and reproductive isolation among syntopic populations of the topminnows Fundulus notatus and F. olivaceus

Fundulus notatus and Fundulus olivaceus are two closely related topminnow species that exhibit similar ecological niches and broad, largely overlapping, North American ranges extending throughout much of the Mississippi River drainage as well as the coastal drainages of the Gulf of Mexico. Previous studies have suggested that these two species are reproductively compatible despite cytogenetic differences and will hybridize when syntopic. We used nuclear and mtDNA loci to assess levels of hybridization and test for introgression in syntopic populations of these two species in four drainages in southern Illinois. Although hybridization was detected in all syntopic populations, an assessment of the proportion of hybrid individuals indicated a deficiency of hybrids relative to expectations under random mating. We determined that, although mtDNA introgression was prevalent and extended beyond the zones of contact, evidence of nuclear introgression was limited to the zone of sympatry.

Spatial and Temporal Species Associations with the Topeka Shiner (Notropis topeka) in Missouri

ABSTRACT Causes for the decline of the federally endangered Topeka shiner (Notropis topeka) are unclear. I used a database of fish community samples in Missouri, dating from 1938 to the present, to investigate spatial and temporal patterns of species occurring within the range of N. topeka. I used what is known about other species associated with N. topeka to provide falsifying evidence for the alternative hypotheses for the decline of N. topeka. Seven species showed a strong decline and four showed a strong expansion over time. Strongly declined species were Ameiurus melas, Carpiodes carpio, Hybognathus placitus, Lepomis humilis, N. topeka, Phenacobius mirabilis, and Pimephales promelas. Strongly expanded species were Fundulus notatus, Lepomis macrochirus, Micropterus salmoides, and Semotilus atromaculatus. Notropis topeka retreated to small, high-gradient streams over time, but this was not a general pattern among other species. In the 1990s, declined species were generally less abundant than expanded species. Declined species were negatively associated with three of the expanded species: F. notatus, L. macrochirus, and M. salmoides. Declined species were not associated in general, but the same three expanded species were positively associated. Information from the literature showed declined species to be generally tolerant of physical/chemical stress but intolerant of species interactions. Information from this longterm data set and current knowledge of these species generally contradicted the physical/chemical hypotheses but not the species interaction hypotheses for the decline of N. topeka.

Effects of metal contamination from mine tailings on allozyme distributions of populations of great plains fishes

This study was conducted to assess the effects of zinc and lead on genetic variability of minnow populations (Gambusia affinis, Pimephales notatus, and Fundulus notatus) sampled from two creeks, one receiving mine drainage (Willow Creek) and one reference (Brush Creek), in the Tri-State Mining district in Kansas. Zinc and lead concentrations were greater in water samples taken from sites in Willow Creek compared to sites sampled in Brush Creek. While total numbers of fish captured from Willow Creek were smaller than numbers taken from Brush Creek, there were no differences in these fish communities for estimates of species diversity, richness and evenness. Genetic differentiation within creeks was rare. However, there was significant differentiation between creeks for allozymes of the enzymes glucose phosphate isomerase (GPI) in F. notatus and P. notatus, malate dehydrogenase (MDH) in G. affinis, and phosphogluconate dehydrogenase (PGDH) in F. notatus. Proportions of heterozygous genotypes of P. notatus and G. affinis were higher in Willow Creek compared to Brush Creek. In vitro experiments were conducted to assess the effects of zinc and lead on sensitivity of enzyme staining during electrophoresis. Results indicated allozyme sensitivity to zinc for GPI and PGDH loci. Other studies suggest that zinc competitively competesmore » with magnesium as a cofactor for these enzymes. Allozymes did not exhibit differential sensitivity to lead. The significant differentiation between creek populations and the results of the in vitro tests indicate a selective effect of zinc on allozymic distributions of these fishes. These results demonstrate the potential use of genetic variability as a bioindicator of heavy metal contamination.« less

Changes in the abundance of small littoral-zone fishes in Lake Mendota, Wisconsin

Since 1900, major changes have occurred in the assemblage of small littoral-zone fishes (maximum total length < 150 mm; usually encountered in the nearshore area) that inhabits Lake Mendota, Wisconsin. A diverse assemblage that included several environmentally sensitive species has been replaced by an assemblage dominated by a single species, the brook silverside (Labidesthes sicculus), whose abundance fluctuates dramatically from year to year. Between 1900 and 1981, eight species, the pugnose shiner (Notropis anogenus), common shiner (Notropis cornutus), blackchin shiner (Notropis heterodon), blacknose shiner (Notropis heterolepis), tadpole madtom (Noturus gyrinus), banded killifish (Fundulus diaphanus), blackstripe topminnow (Fundulus notatus), and fantail darter (Etheostoma flabellare), disappeared from the lake. The blackchin shiner and banded killifish were the most abundant small littoral-zone species in 1914–1916, and remained common until the late 1960's. Their decline was associated with the invasion and explosive increase in abundance of an exotic macrophyte, the Eurasian water milfoil (Myriophyllum spicatum), in the mid-1960's. The decline and disappearance of the blackchin shiner and banded killifish in three other Wisconsin lakes was also associated with the invasion of Eurasian water milfoil. Changes in the assemblage of small littoral-zone fishes in Lake Mendota indicate environmental degradation in the nearshore area, and may have important implications for the entire fish community of the lake.

The effects of dissolved oxygen and aquatic surface respiration on the critical thermal maxima of three intermittent-stream fishes

Critical thermal maxima (CTM) were determined for three species of fish in hypoxic (1.2 mg l-1), normoxic (7 mg l-1) and hyperoxic (12 mg l-1) oxygen tensions. All fish were acclimated to 30°C under a regulated photoperiod of 12:12. During each CTM determination, one-half of the test fish were allowed free access to the surface (to permit aquatic surface respiration) while the remaining one-half were denied access to the surface. Under hypoxic conditions, CTMs of Fundulus notatus, Notropis lutrensis and Pimephales vigilax given access to the surface were significantly higher than those of conspecifics without access to the surface. With access to the surface, all species had significantly lower CTMs under hypoxic conditions than under normoxic and hyperoxic conditions. CTMs measured under normoxic and hyperoxic conditions were not different for any of the test species. Under all comparable oxygen tensions with surface access, F. notatus had the highest CTM, N. lutrensis intermediate and P. vigilax had the lowest CTM. The critical oxygen concentration for N. lutrensis during CTM determinations occurred between 1.2 and 2 mg l-1.

Assemblage Organization of Stream Fishes: The Effect of Rivers on Adventitious Streams

Assemblage Organization of Stream Fishes: The Effect of Rivers on Adventitious Streams

Fishes of Oklahoma Springs

Fishes of Oklahoma Springs

Forage Fish Assemblages in the Brazos River Upstream and Downstream from Possum Kingdom Reservoir, Texas

ABSTRACT The forage fish assemblage of the Brazos River was sampled at one location above and four locations below Possum Kingdom Reservoir each month for one year. A total of 13,936 individuals representing 18 species, 14 genera and five families were collected. Five of these species, Notropis stramineus, Notropis atherinoides, Hybognathus placitus, Hybopsis aestivalis and Cyprinodon rubrofluviatilis were found only upstream from Possum Kingdom Reservoir. Hybognatus placitus accounted for 45% of fish captured at the upstream site. In contrast, nine species were collected exclusively in the tailwaters, including Etheostoma spectabile, Percina sciera, Campostoma anomalum, Notropis venustus, Pimephales notatus, Labidesthes sicculus and Fundulus notatus. Only four species were obtained at all five stations—Gambusia affinis, Menidia beryllina, Pimephales vigilax and Notropis lutrensis. N. lutrensis was the most common tailwater species equalling 87.9% of the total downstream catch. Median species diversity in...

The distribution, biology, and status of the fishes Campostoma anomalum, Clinostomus elongatus, Notropis photogenis (Cyprinidae), and Fundulus notatus (Cyprinodontidae) in Canada

Campostoma anomalum, Clinostomus elongatus, Notropis photogenis, and Fundulus notatus in Canada are confined to a few streams in southern Ontario and are considered rare or threatened in this country. The distribution of C. anomalum shows dramatic expansion in the Thames River drainage over the past decade. Clinostomus elongatus has a disjunct distribution and has apparently been extirpated from several watersheds owing to habitat degradation. Information on the stability of N. photogenis and F. notatus populations is lacking. Both C. anomalum and N. photogenis are rheophilic and occur in relatively high gradient streams. Clinostomus elongatus occurs mainly in cool, clear headwaters. Fundulus notatus is confined to turbid and sluggish or stagnant streams. Factors affecting the vulnerability of these species, based on habitat requirements, are described and measures to conserve their habitats are suggested. Observations on growth, reproduction, feeding, predation, and parasitism are also described.

A Distinctive Chromosomal Race of the Cyprinodontid Fish, Fundulus notatus, from the Upper Tombigbee River System of Alabama and Mississippi

Fundulus notatus and F. olivaceus are sibling species which have diploid chromosome numbers of 40 and 48 respectively. However, populations of F. notatus analyzed from the Upper Tombigbee River system of Alabama and Mississippi exhibit a strikingly different karyotype. The Tombigbee population of F. notatus has a modal diploid count of 44, which is intermediate between F. olivaceus and other populations of F. notatus analyzed. Phenotypically and ecologically, the Tombigbee population is essentially identical to other populations of F. notatus. Therefore, the Tombigbee population of F. notatus is considered to represent a variant or chromosomal race of F. notatus. The karyotype of the Tombigbee race could have originated either independently, or through natural hybridization, or by a mechanism involving Robertsonian rearrangements of chromosomes. THE blackstripe topminnow, Fundulus notatus (Rafinesque), and the blackspotted topminnow, F. olivaceus (Storer), are sibling species belonging to the Cyprinodontidae. F. notatus and F. olivaceus are readily distinguished from other members of the genus Fundulus by the presence of a broad black lateral stripe which originates at the tip of the snout and terminates at the caudal fin. F. notatus may be distinguished from F. olivaceus on the basis of dorsolateral spotting. F. notatus has vague indistinct spots while F. olivaceus has distinct spots of at least the same intensity as

First Records of the Stoneroller (Campostoma anomalum) and the Blackstripe Topminnow (Fundulus notatus) from Canada

Stoneroller (Campostoma anomalum) and blackstripe topminnow (Fundulus notatus) were found, respectively, in the Thames and Sydenham rivers of southwestern Ontario. These are new records for Canada.

Food, Feeding Selectivity and Ecological Efficiencies of Fundulus notatus (Cyprinodontidae)

Terrestrial arthropods formed 41% of the diet of field- collected blackstripe top minnow, with a consistent Electivity Index (E) value of positive-one; snails, aquatic insects and microcrustaceans, re- spectively, occupied 19%, 16% and 10% of the diet. Positive E values were maintained for aquatic insects, except in stagnant pools where inter- specific fish competition probably occurred. Crustaceans assumed negative E values except in a single habitat, while snails took positive E values only in stagnant pools. Top minnows smaller than 38 mm, S.L., supple- mented terrestrial arthropods with microcrustaceans for 28% of their ration; crustaceans decreased and aquatic insects increased in relative importance as fish size increased. Algae were ingested with 41% fre- quency, but apparently not digested. Fishes in feeding experiments showed a preference for chironomid larvae but an electivity for floating, terrestrial insects, which were readily available. Physid snails, with 42% frequency of occurrence in field- collected fishes, were avoided in the presence of abundant alternative prey. Assimilation efficiency was 97% for all size classes of top minnows. Top minnows of 48 to 65 mm S. L. had a lower ecological growth effi- ciency, (5.9%) than smaller fishes (8.5%). The average daily energy expenditure for 48 to 65 mm fishes was lower, 20 cal x g of initial dry wt-1 (gWo-1), than the 55 cal x gWo-1 for fishes smaller than 48 mm, S. L..; but the net efficiency of food utilization for growth in the latter (21.6%) was not significantly higher than that in 48 to 65 mm fishes (15.0%). Fundulus notatus facilitates the entrance of allochthonous organic material into the ecosystem by digesting and defecating the remains of terrestrial arthropods, and it indirectly taps the flow of niatter and energy from allochthonous plant sources by preying upon aquatic insect detritus-feeders, getting more than one-half of its ration directly or in- directly from basically allochthonous sources. It also functions as a third- or fourth-level predator.

Morphological Adaptations of Cyprinodontoids for Inhabiting Oxygen Deficient Waters

A previously unrecognized morphological adaptation of fishes to oxygen depletion is described. Natural oxygen depletion was simulated by use of sodium sulfite. It was demonstrated that some fishes are adapted to permit use of an oxygen rich layer of water at the atmosphere-water interface. Representative cypronodontoids (Fundulus notatus, Gambusia affinis, and Poecilia reticulata) exhibited maximum adaptation and the greatest survival ability of the species tested. Notemigonus crysoleucas, Brachydanio rerio, Lepomis macrochirus, and L. cyanellus, representing other suborders, showed less adaptation to these conditions and correspondingly lower survival. Micropterus salmoides seemed unadapted for survival in oxygen depleted waters. Carassius auratus exhibited a physiological adaptation, but used the oxygen rich surface water as a supple-

An Analysis of a Natural Hybrid Swarm by Means Chromosome Morphology

Abstract The sibling species Fundulus olivaceus and Fundulus notatus have karyotypes comprised of 48 and 40 chromosomes, respectively. The karyotype of F. notatus is probably derived from one similar to that of F. olivaceus by a Robertsonian change involving centric fusion. A hybrid swarm between F. olivaceus and F. notatus was identified and analyzed using chromosome numbers to distinguish hybrid and backcross individuals.