Abstract

We report a new case of parental care in a Chiromantis species from Northeast Thailand. This is the first report of parental care in this genus. Our observations indicate that C. hansenae adults sit on the clutches approximately 72% of the time, both day and night. This clutch attendance may protect eggs from desiccation, parasitic flies, or fungal infection, but we were unable to conduct removal experiments to test these hypotheses. In no cases did we observe adults actively guarding against known predators such as skinks. This species is unusual among arboreal breeders with parental care in having a high rate of egg attendance, relatively large clutch sizes (235.75 ± 19.78, n  =  4), and a short period before hatching (4–6 d).

Abstract

Infection by fungal spores and hyphae is an acute problem that may cause damage or loss of specimens in natural history collections. Most ichthyology and herpetology collections are fluid-preserved whole animals, stored in glass jars, but collections frequently also maintain dried specimens of skin or bones, which are vulnerable to fungus. An infection of Aspergillus fungus was discovered in the ichthyology and herpetology skeletal collections at the Natural History Museum of Los Angeles County (LACM) in October of 2003. Within our collections, 12% of fish and 4% of herpetological skeletons were visibly infected. We elected to use 70% ethanol as a fungicide because it is non-toxic, effective, inexpensive, and produces minimal damage. A total of 688 infected specimens were cleaned, and all 7,987 specimens were rehoused between June 2005 and May 2007. Treatments were carried out by a commercial fungus remediation firm, and the process was monitored by an environmental consultant. Treated specimens were stored in new plastic boxes, housed in one of four ways: sealed bags; sealed bags with desiccant; desiccant only; or no bag or desiccant. Skeletons not visibly contaminated were brushed clean, catalogued, and rehoused in sealed plastic bags and plastic boxes. Periodic agar plate sampling showed no fungal growth in a subset of the four rehousing groups over the course of two years. Among all disinfected specimens, only one displayed a recurrence of fungal growth two years after treatment. We recommend treatment of fungus-infested natural history collections with 70% ethanol, and storage in polyethylene boxes and polystyrene or polypropylene bags, to prevent infection and to contain the spread of infection if it does occur.

Abstract

We used five years of recapture data and Bayesian estimation to assess seasonal survival, movement, and growth of Oregon Spotted Frogs (Rana pretiosa) relocated into created ponds at Dilman Meadow in Oregon, USA. We evaluate hypotheses specific to the relocation and elucidate aspects of R. pretiosa life history that are poorly known. The odds of survival of relocated individuals during the first year following relocation were 0.36 times the survival odds of relocated and non-relocated frogs after one year since the relocation. Survival rate was higher for large frogs. After accounting for frog size, we found little variation in survival between ponds at Dilman Meadow. Survival was lowest for males during the breeding/post-breeding redistribution period, suggesting a high cost of breeding for males. The highest survival rates occurred during winter for both genders, and one small spring was used heavily during winter but was used rarely during the rest of the year. Individual growth was higher in ponds that were not used for breeding, and increased with increasing pond age. Our study supports other evidence that R. pretiosa use different habitats seasonally and are specific in their overwintering habitat requirements. Because frogs were concentrated during winter, predator-free overwintering springs are likely to be of particular value for R. pretiosa populations.

Abstract

Fifty Nerodia sipedon living along two kilometers of an urban stream in northeastern Pennsylvania were radio-tracked over three activity seasons, yielding more than 2520 relocations. Half the stream length is urbanized, flowing through a city park at the head of the study area and an industrial area at the downstream end; the half between is relatively natural, flowing through a conservation corridor. Individual snakes exhibited high site fidelity. For 82% of relocations, snakes were within a one-meter radius of places they had previously occupied, most often using exactly the same hole, rock, branch, or cover object. Snakes were found to have moved to a different site at 27% of relocations. When snakes moved, they returned to previously occupied places 56% of the time. Females exhibited significantly greater site fidelity than males, and snakes occupying the urban half of the study site exhibited significantly greater site fidelity than snakes found in the natural half. Individuals varied greatly in the amount of space they utilized. Snakes had a mean minimum convex polygon (MCP) activity area of 1.13 ha. Snakes appeared to use the stream to travel between locations separated by more than 100 meters. Original MCPs overestimated space use by including large terrestrial areas that were never occupied by and were unsuitable to snakes. Fixed kernel methods underestimated space use by producing multiple small, disjunct contours. Both methods often largely or completely excluded the stream. To address these problems, we provide additional estimates of space use that sum the MCPs encompassing all of a snake's locations within 100 meters of each other and add the area of stream connecting the most upstream and downstream locations.

Abstract

Mitochondrial DNA sequence data from a segment of the cytochrome b (cytb) gene were used to infer geographic distributions of two unnamed putative species of eastern Pacific bonefishes, Albula sp. A and Albula sp. C, both members of the A. vulpes complex. The molecular data revealed that Albula sp. C, a lineage originally identified from Panama, is distributed north to the coastal waters of central Mexico and the southern Gulf of California (Sea of Cortez). Albula sp. A, originally identified from the central Gulf of California and distributed to California, USA, is shown here to range to Mazatlán, Sinaloa, in the southern gulf where it occurs sympatrically with Albula sp. C. The distributions of the two putative species inferred from the molecular data suggest that the single available name for eastern Pacific bonefishes, Albula esuncula (Garman, 1899), originally described from larvae (leptocephali) collected off Acapulco, Guerrero, should be assigned to Albula sp. C. Morphometric and meristic analyses of adults of A. esuncula and Albula sp. A revealed no external characters that could be used reliably to distinguish between the two species.

Se utilizaron datos de secuencias de ADN mitocondrial obtenidos de un segmento del gen citocromo b (cytb) para elucidar las distribuciones geográficas de dos especies putativas no nombradas de macabí del océano Pacifico Oriental, Albula sp. A y Albula sp. C, que son miembros del complejo de A. vulpes. Los datos moleculares demostraron que Albula sp. C, una línea genética identificada originalmente de Panamá, se distribuye hacia el norte hasta las aguas costeras de México central y sur del golfo de California (mar de Cortés). Se demuestra que Albula sp. A, encontrada originalmente en el golfo de California central y aguas costeras del estado de California, EUA, se distribuye hasta Mazatlán, Sinaloa, en el sur del golfo donde coincide con Albula sp. C. Con base en las distribuciones de las dos especies putativas de Albula se establece que Albula sp. C debe nombrarse A. esuncula, especie descrita originalmente de larvas leptocéfalas recolectadas en la región de Acapulco, Guerrero por Garman (1899) y único nombre disponible para los macabí del Pacifico Oriental. En relación a los análisis morfométricos y merísticos de adultos de A. esuncula y Albula sp. A, no se encontraron caracteres externos que podían ser utilizados para distinguir entre las dos especies.

Abstract

Conspecific turtle populations typically exhibit variation in demographic and reproductive traits such as adult size, growth rate, sex ratio, and clutch size. Variation in these traits has been previously correlated to variation in local environmental conditions, latitude, and habitats. Given that some turtle species have large geographic ranges and occur in a variety of habitats, it is imperative to determine how traits differ throughout the species' range. Towards this end, we examined demographic and reproductive traits of Blanding's Turtles (Emydoidea blandingii) in Grant County, Nebraska over the span of six years. The population's sex ratio was female biased (0.7∶1.0, M∶F) and skewed towards large, adult turtles (5∶1, adult∶juvenile). The analysis of adult survivorship suggests that female turtles (59% annual survivorship) may be experiencing greater mortality rates compared to males (90% annual survivorship), possibly due to road mortality. Unlike all previous reports, analyses of reproductive parameters indicate that turtles in the western Nebraska population do not increase clutch size with body size. Rather, egg size increases as body size increases, which may help reduce desiccation rates of the eggs in an arid environment. Optimal egg size may not be reached due to pelvic width constraints of females. Comparisons of our findings with those of other Blanding's Turtle studies are discussed.

Abstract

The opisthoproctid fish Macropinna microstoma occupies lower mesopelagic depths in Monterey Bay and elsewhere in the subarctic and temperate North Pacific. Like several other species in the family, Macropinna has upward-directed tubular eyes and a tiny, terminal mouth. This arrangement is such that in their upright position, the visual field of these highly specialized eyes does not include the mouth, which makes it difficult to understand how feeding takes place. In situ observations and laboratory studies reveal that the eyes of Macropinna can change position from dorsally-directed to rostrally-directed, which resolves the apparent paradox. The eyes are contained within a transparent shield that covers the top of the head and may provide protection for the eyes from the tentacles of cnidarians, one of the apparent sources of the food of Macropinna.

Abstract

Anniella is a clade within Anguidae including small-bodied serpentiform lizards, previously hypothesized to be miniaturized relative to other parts of Anguidae. Ancestrally, Anguidae displays an extensive armor of dermal ossifications, but the presence or absence of osteoderms in Anniella was a source of some confusion in the past. We confirm that Anniella possesses osteoderms in the dermis deep to nearly every epidermal body scale, as well as remnant ossifications deep to the head scales. The body osteoderms display three basic components: an anterior plate bearing apparent growth ridges, a usually constricted neck portion with a distinct microstructure, and a branching portion divided into a variable number of processes. Under high magnification, collagen bundles similar to those on other lizard osteoderms are visible. The osteoderms of Anniella are reduced in their ossification relative to those of other Anguidae; they are thinner, occupy only the middle regions of the dermal scale component, and their posterior portions appear only as a series of fingerlike processes. Reduction in the osteoderms of Anniella constrasts with reinforced solidity of many of the skull elements, supporting the idea that modularity was involved in the evolution of miniaturization in this clade.

Abstract

A key element in understanding hybridization in fishes is to determine the relative influences of endogenous and exogenous selection on hybrid zone structure. To date, such studies have been limited. To help fill this gap, we conducted reciprocal transplant experiments with two pupfish species, Cyprinodon atrorus and C. bifasciatus, to assess the importance of environmental factors in their hybridization dynamics. Results from our experiments show that C. atrorus survives well when environmental variability is low or high, whereas C. bifasciatus only survives well when environmental variability is low. This corroborates the hypothesis that C. atrorus is euryplastic and C. bifasciatus stenoplastic, and also provides evidence that differential environmental tolerance may be important in regulating the distribution of genetic variation in hybrid zones between these species. However, these differences do not explain why C. atrorus is absent from C. bifasciatus habitats. This absence is likely determined at least in part by other exogenous selection factors, such as disproportionate predator susceptibility and/or inferior competitive ability of C. atrorus. Although the relative role of endogenous selection in this system remains unknown, this study provides insight into the potential complexity of exogenous selection in fish hybrid zones.

Abstract

Studies of snake movement frequently report home range sizes, and these data are key to our understanding of snake ecology. However, despite the fact that many snakes occupy landscapes with topographic relief, snake home range sizes are consistently reported as planimetric (two-dimensional) estimates. We investigate the capacity for planimetric area measurements to underestimate snake home range sizes, and we explore how this may confound understanding of snake ecology. We use radiotracking data to estimate home ranges for Crotalus mitchellii and C. ruber in a topographically-variable landscape, model surface terrain in the estimated home ranges using digital elevation data and widely-available GIS software, and compare planimetric and topographic (three-dimensional) area measurements for these home ranges. The topographic measurements exceeded planimetric ones, on average, by 14% for C. mitchellii (8% for females, 19% for males) and 9% for C. ruber (10% for females, 8% for males); this suggests that terrain modeling can provide considerably truer estimates of snake home range sizes. We discuss how such increased precision might benefit snake ecology research, and we discuss recent papers that might have concluded differently had topographic home range measurements been used. Terrain modeling has become relatively simple with the advent of modern GIS software, and snake ecologists could begin using it routinely.

Abstract

Juvenile survival is an important life history feature, because recent modeling efforts suggest that modest changes in juvenile survival rates due to habitat change may greatly affect population growth rates. We compared water loss and survival rates of recently metamorphosed American Toad (Anaxyrus americanus), Green Frog (Lithobates clamitans), and Wood Frog (Lithobates sylvaticus) juveniles contained within four microhabitats, two of which occur in uncut control forest (i.e., forest ridgetop, forest drainage) and two within recently harvested forest (i.e., clearcut open, clearcut brushpile). Survival was higher in forest drainage than forest ridgetop, indicating that microhabitats within continuous forest are not equally suitable. Brushpiles of coarse woody debris reduced desiccation risks in clearcuts as indicated by survival differences between clearcut open and clearcut brushpile and survival in clearcut open was very low for all species in both years. We found species differences in survival as well as a species by microhabitat interaction in water loss rates. These results are best explained by observed behavioral differences as opposed to physiological differences among species. We conclude that desiccation can be a major source of mortality for juveniles entering terrestrial habitats, especially habitat altered by anthropogenic land-use. Desiccation risks are greatest in areas with low soil moisture conditions, which for our study included microhabitats within clearcuts without coarse woody debris, forested ridgetops, and years with below average rainfall.

Abstract

Bullsnakes (Pituophis catenifer sayi) have been the subject of few rigorous scientific investigations despite suspected declines. Because relatively little ecological information exists for this species, sound conservation or management decisions regarding them are difficult to make. This is particularly true in the upper Midwest, which represents the northern periphery of the snake's geographic range. Using radio-telemetry, we studied aspects of the ecology of Bullsnakes (15 males, 12 females) in Sauk County, Wisconsin, which included determining habitat preferences and movement patterns. Male and female Bullsnakes exhibited a preference for open bluff sides over habitats traditionally reported as favored by this species (i.e., sand prairies or grasslands), and avoided areas of agriculture and closed canopy bluff side forest. Nested ANOVA analysis of home ranges measured as 100% minimum convex polygons (23 ha females, 41 ha males) and 95% kernels (53 ha females, 83 ha males) were larger in males than females. Average daily movement rates were larger in males (31.7 m females, 36.7 m males). Evidence of site fidelity was also found. Based on these results, the conservation of this snake can be substantially influenced by preservation and maintenance of large sites containing open bluffs and oak savannas.

Abstract

The Gillbacker Sea Catfish is a valid species of ariid catfish from the northeastern coast of South America. There are many synonyms in the literature for the Gillbacker Sea Catfish and even recent classifications have used different scientific names. Examination of a wide range of sizes of individuals from different localities and examination of types and original species descriptions of Silurus parkeri, Bagrus flavescens, B. emphysetus, Arius physacanthus, A. bonneti, A. clavispinosus, and A. despaxi has lead us to the conclusion that all these names refer to the Gillbacker Sea Catfish and the valid name for the species is Sciades parkeri. The species is distinguished from all other ariid species by the following combination of features: body coloration yellow; swim bladder divided into three chambers, posterior chamber moderately sized; nuchal plate shield-shaped, usually larger than supraocciptal process; anterior notch of nuchal plate absent; head shield exposed and granulated in orbital and postorbital regions; lateral edge of accessory patches not emarginated or shallowly notched; fleshy furrow connecting posterior nares absent; and mesial gill rakers absent from first two gill arches. Striking intraspecific and/or ontogenetic variation in eye size, maxillary-barbel length, supraoccipital-process size, nuchal-plate size and shape, and dorsal-spine thickness contributed to the numerous synonyms and misidentifications for Sciades parkeri. Bagrus albicans, described from French Guiana, has at times been listed as a synonym of Sciades parkeri. Our examination of the holotype of B. albicans, however, led us to conclude that it is a synonym of Sciades proops.

Abstract

Habituation is ubiquitous throughout the animal kingdom. Nonetheless, there are no studies that report habituation of the rattling behavior in rattlesnakes. Ten Western Diamondback Rattlesnakes (Crotalus atrox) were stimulated to rattle in an automated apparatus at five-minute intervals until they failed to rattle for ten consecutive trials over four consecutive days. Group data are reported for the occurrence of rattling, latency to rattle, and duration of rattling. Both long-term and short-term habituation were documented, though there was notable variation within and between individuals. Differences within and among individuals over the four testing days were found. We recommend that future studies focus on proximate factors (e.g., sex, body temperature) that may influence the course of habituation of the rattle response.

Abstract

Etheostoma flabellare has long been recognized as a geographically variable, polytypic species that contains undescribed species-level diversity. As the first phase of a long-term study, morphological comparisons were made on one historically recognized subspecies, E. f. brevispinum, to examine variation and determine its distribution and taxonomic status within the E. flabellare complex. Examination and analyses of meristic, morphometric, and pigmentation variables from nine river drainages (Atlantic Slope and Mississippi River Basin) revealed that Etheostoma brevispinum, the Carolina Fantail Darter, is diagnosable based on a combination of characteristics and is restricted to the Savannah, Santee, and Yadkin (upper Pee Dee River) rivers of North Carolina, South Carolina, and Virginia. Data do not support recognition of New and Roanoke River populations of E. flabellare as intergrade zones between E. brevispinum and E. flabellare as previously suggested. A potential contact zone between E. brevispinum and other forms of the E. flabellare complex was identified in the Pee Dee River; however, no intermediate populations suggestive of an intergrade zone were identified.

Abstract

This study examines the role that historical events have played in the diversification of members of the genus Ambloplites by estimating divergence times of clades within the genus. DNA sequences of the mitochondrial cytochrome b gene were used to develop phylogenetic hypotheses for Ambloplites using maximum parsimony and Bayesian methods. The timing of diversification within and between species of Ambloplites was estimated using nonparametric rate-smoothing and penalized likelihood methods calibrated by fossil dates. Monophyly of three of the four species was supported. The ages of the most recent common ancestors of species of Ambloplites estimated in this study confirm earlier estimates that in most instances, their origins occurred prior to the Pleistocene. A comparison of estimated divergence times of lineages to sea level fluctuations indicates a correspondence to extremely high or low sea stands throughout the Neogene Period. Populations of Ambloplites in the Ozarks and Ouachita highlands previously assigned to A. ariommus appear to have either been introgressed by A. rupestris or were misidentified as A. ariommus. Ambloplites rupestris displays low genetic divergence throughout its range and is consistent with a re-colonization of previously glaciated areas following the Pleistocene.

Abstract

Scanning electron microscopy (SEM) is a powerful tool used in the study of lizard skin morphology and has allowed researchers to gain insight into the intricate structure of complex epidermal layers, an interesting part of which is the outer layer or oberhautchen. Methods involved in the preparation of samples for SEM are invasive and usually involve killing and preserving specimens. Here we present a new, simple, highly accurate method for the examination of living lizard epidermis using polyvinylsiloxane impression material and epoxy resin to create molds. We created molds of live Oedura castelnaui (Squamata: Diplodactylidae) using two different types of epoxy resin to compare their efficacy. Viscosity was the important factor determining whether there were artifacts in the mold, and the resin that created fewest artifacts was Epirez 123® (ITW Polymers & Fluids). We used Epirez 123® to create molds of Phyllurus ossa, P. amnicola, and Nephrurus levis (Squamata: Carphodactylidae), which all have ornate oberhautchen. We visually compared these with published images of hair sensors of congeners, and found that our method compared very favorably. Thus, this method can produce exceptional quality reproductions of complex microornamentations within the oberhautchen of living lizards.

Abstract

Cichlids of the genus Oreochromis have a duplication of the prolactin gene, and the two paralogs have diverged substantially in sequence. Cichlids as a group show elaborate patterns of obligate parental care, and Oreochromis is characterized by costly female parental behavior. Recent experiments indicate a role for prolactin in stimulating parental care behaviors in some species of fish, particularly sticklebacks. We hypothesize that the recent paralog of the prolactin gene in Oreochromis (and possibly other cichlids) plays a role in the elaborate parental care of these fish and has diverged due to selection on this function since the duplication event. We provide a preliminary test of this hypothesis by searching for a signal of positive selection on the branch leading to the recent paralog clade, and by comparing the average ratio of nonsynonymous to synonymous substitution rates in the two paralog clades. Our analysis revealed significant evidence for positive selection on the new paralog after gene duplication.

Abstract

The histology, histochemistry, and ultrastructure of the adhesive breeding glands of male Gastrophryne carolinensis are described. Adhesive glands are mutlicellular exocrine glands in the dermis of the sternum and forearm that cause the male to adhere to the female during amplexus. The epithelial cells have distinct plasma membranes, and the product consists of electron-dense secretory granules that fill the cytoplasm and are released intact by an apocrine process. We support one previous study and contradict another report by finding that adhesive glands react positively for neutral carbohydrates and negatively for glycosaminoglycans and proteins. The ultrastructural results, the first on these organs, confirm that adhesive glands are derived from mucous glands and not serous glands.

Abstract

The environment sea turtle embryos experience in the nest is determined by the needs of the growing embryos and the ability of the nest substrate to transport heat, water, and respiratory gases to meet those needs. Relatively little is known of the PO₂s in natural sea turtle nests, and what is known has been obtained through methods which may alter the nest PO₂ during measurement. I describe a noninvasive means of measuring sea turtle nest PO₂ using fiber-optic O₂ sensors. I found that both the rate of nest PO₂ decline and the minimum nest PO₂ varied considerably among Loggerhead Turtle (Caretta caretta) nests. Nests exhibited rates of decline and minimum PO₂s that ranged from 0.07 to 0.19 kPa/day and 11.4 to 16.4 kPa, respectively. No difference in minimum nest PO₂ was observed between nests that were relocated and those left in situ. The mean minimum nest PO₂ in this study (13.8 ± 0.21 kPa) is in agreement with other measurements of nest PO₂, but the rate of PO₂ decline measured in this study suggests that previous work may have underestimated how quickly the developing embryos reduce the nest PO₂. The more rapid decline in nest PO₂ may mean that the developing embryos fall below their critical PO₂ and consequently experience reduced metabolic rates much earlier in incubation than previously suggested.

Abstract

Despite the importance of understanding error associated with sampling, there has been a paucity of discussion in many analyses within sea turtle biology. We investigated sampling and non-sampling errors for size measurements (straight carapace length, straight carapace width, and mass) of hatchling Flatback Turtles, Natator depressus, from two study sites in tropical Australia using a priori and post hoc methods. A priori and post hoc methods produced similar error estimates (max difference  =  0.19 g and 0.24 mm), highlighting methodologies that may be transferred for other species without requiring a census of every hatchling in a clutch. The standard practice of sampling ten hatchlings per nest resulted in reasonably low sampling error (upper 95% CI  =  0.9 g for mass, 0.7 mm for straight carapace length, and 1.0 mm for straight carapace width), but sample size may be reduced if less precise size measurements are required. Effort analysis showed that sampling error from a nesting population was minimized when sampling effort was spread over the maximum number of clutches rather than concentrating effort within fewer clutches.

Abstract

Masticophis flagellum (Coachwhip) and Coluber constrictor (Eastern Racer) are widespread North American snakes with similar foraging modes and habits. Little is known about the selection of prey by either species, and despite their apparently similar foraging habits, comparative studies of the foraging ecology of sympatric M. flagellum and C. constrictor are lacking. We examined the foraging ecology and prey selection of these actively foraging snakes in xeric, open-canopied Florida scrub habitat by defining prey availability separately for each snake to elucidate mechanisms underlying geographic, temporal, and interspecific variation in predator diets. Nineteen percent of M. flagellum and 28% of C. constrictor contained stomach contents, and most snakes contained only one prey item. Mean relative prey mass for both species was less than 10%. Larger C. constrictor consumed larger prey than small individuals, but this relationship disappeared when prey size was scaled to snake size. Masticophis flagellum was selective at the prey category level, and positively selected lizards and mammals; however, within these categories it consumed prey species in proportion to their availability. In contrast, C. constrictor preyed upon prey categories opportunistically, but was selective with regard to species. Specifically, C. constrictor positively selected Hyla femoralis (Pine Woods Treefrog) and negatively selected Bufo quercicus (Oak Toad), B. terrestris (Southern Toad), and Gastrophryne carolinensis (Eastern Narrowmouth Toad). Thus, despite their similar foraging habits, M. flagellum and C. constrictor select different prey and are selective of prey at different levels of taxonomy.

Abstract

A major challenge faced by conservation officials is determining which habitats are most vulnerable to anthropogenic perturbation and thus are in most critical need of protection. We utilized a fish with life history attributes presumably conducive to low rates of gene flow and small effective population size to gain insight into the appropriate conservation units in the Carolina Sandhills, a threatened ecosystem in the southeastern United States. We assessed variation in nuclear and mitochondrial DNA sequence data throughout the range of the Pinewoods Darter, Etheostoma mariae (Percidae), a species endemic to headwater streams of the Lumber and Little Pee Dee rivers (Pee Dee Drainage) in the Carolina Sandhills. Concordant partitions in nuclear and mitochondrial DNA loci support the designation of two Evolutionarily Significant Units (ESUs): one each from Lumber and Little Pee Dee rivers. The data suggest these populations have been historically isolated and are on distinct evolutionary trajectories. Additionally, this research underscores the potential importance of fine-scale sampling in conservation genetics studies of organisms predisposed to genetic differentiation and demonstrates that significant population structure can occur even within a single drainage.

Abstract

Advent of the polymerase chain reaction (PCR) has allowed conservation biologists to use small portions of tissue to obtain genetic material for population genetic and taxonomic study. Fin clips are used extensively in large-sized fishes, but it is unclear how clipping enough fin tissue for genetic analysis will affect survival of smaller fishes such as minnows and darters, which are among the most threatened organisms in North America. We tested for effects of fin clipping on survival and swimming performance of non-threatened Brown Darters (Etheostoma edwini) in order to justify similar tissue collection in co-occurring endangered Okaloosa Darters (E. okaloosae). We collected 48 E. edwini from a small stream in northwest Florida, transported them to the laboratory, and randomly assigned them to one of three experimental groups: control, entire right pectoral fin removed, or rear half of caudal fin removed. Successful amplification of DNA indicated that our fin clips were large enough for genetic analysis using PCR. No mortality occurred during a two-month observation period. Fin regeneration was almost complete and we could not visually distinguish clipped fins from control fins after two months. We then randomly assigned fish into the same three experimental groups, clipped fins, and evaluated their ability to hold position at 20 cm/sec in an experimental flow chamber. Neither fish size nor treatment type affected position-holding behavior. Fin clipping does not adversely affect survival and swimming performance of E. edwini maintained in the laboratory. Additional research on the effects of fin clipping on small-sized fishes should be conducted in the field to evaluate survival under natural conditions.

Abstract

We quantified the importance of nest and paternal characteristics for survival of eggs of Fathead Minnow, a multiple-batch spawner in which breeding males guard and tend nests. We stocked experimental ponds three weeks apart and then intensively monitored 150 nests. Nest predation by conspecifics accounted for most of the egg mortality, and 29% of all nests failed to produce hatchlings. Although egg survival was not affected by date of stocking or nest initiation, hatching success improved in larger and longer-lasting nests. Nests where paternal care was observed during our monitoring were larger, lasted longer, and thus were more likely to produce hatchlings than nests where care-giving was not observed. Over one-third of the male caregivers displayed agonistic behaviors toward nest intruders, and this index of aggressive defense was also associated with improved nest performance. Larger males nested earlier and were more likely to be aggressive than smaller males. Post-spawning mortality of these larger, early-nesting males may facilitate a mid-summer demographic shift among breeders over the spawning season: nests of large, aggressive males are followed by those of smaller or later-maturing fish, who are more likely to survive to spawn again the following year.

Abstract

Centrarchids (sunfish and bass species) and Bullfrogs (Lithobates catesbeianus) have been introduced into aquatic systems around the world and have the potential to negatively impact native fish and anurans. We surveyed fish and anuran assemblages from 26 impoundments in the New Jersey Pinelands, USA. We excluded non-native species and used ordination analysis to generate four native-species community gradients based on native-fish and anuran presence–absence and abundance data. All four community gradients paralleled an increase in the percentage of upstream-altered land (development and upland agriculture) and an increase in either non-native-centrarchid richness or abundance. Based on presence–absence and abundance data, native-fish and native-anuran assemblages, including restricted species (those generally limited to the Pinelands region) and widespread species (those widely distributed in New Jersey), differed between impoundments with and without non-native centrarchids. Compared to widespread species, the greatest differences between impoundment types were found for restricted species. Three non-native-frog species, including Bullfrogs, were associated with degraded impoundments that supported non-native fish. Our results demonstrate that watershed conditions and native fish and anuran assemblages differ between impoundments with and without non-native centrarchids, and suggest that some restricted species may be especially vulnerable to impacts from watershed disturbance and non-native species. Our findings support the idea that the environmental resistance associated with intact water-quality conditions may help prevent the invasion of non-native fish and anurans. We recommend that land-use activities that degrade water quality and reduce invasion resistance be avoided in unaltered watersheds to conserve native-fish and native-anuran community integrity.