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Due to concerns that wildlife may be attracted to Stormwater detention ponds and would be exposed to contaminants accumulating in these ponds, a field study of 15 Stormwater ponds and one natural wetland in Guelph and the Greater Toronto Area, Ontario, was performed in 1997 and 1998. At 9 of 16 sites, copper levels in water exceeded the Canadian Water Quality Guidelines (CWQGs) for the protection of aquatic life. Canadian Water Quality Guidelines were also exceeded by average water concentrations for lead at four sites, for zinc at three sites, for chromium at seven sites, and turbidity at ten sites. At the natural wetland, only turbidity levels exceeded the CWQGs. Sediments from all ponds contained concentrations of at least one contaminant that exceeded the “lowest effects level” (LED of the Guidelines for the Protection and Management of Aquatic Sediment in Ontario. Stormwater pond sediments contained concentrations exceeding provincial sediment quality guidelines at the LEL for polychlorinated biphenyls (PCBs), gamma-hexachlorocyclohexane (g-bhc), total Kjeldahl nitrogen (TKN) and total phosphorus (TP), turbidity, oil and grease, total PAHs, chromium, zinc, cadmium, copper, lead, nickel and arsenic. Concentrations of g-bhc, TKN, TP, cadmium, copper, lead, zinc and arsenic in the sediment of the natural wetland also exceeded the LEL. Sediments at one site exceeded the provincial guideline at the severe effect level for chromium. Concentrations of lead, zinc, cadmium and total PAHs in sediments were correlated with the age of the ponds. Concentrations of organochlorine pesticides and PCBs were low (<0.08 µg/g wet weight) in pump-kinseed (Lepomis gibbosus) collected from two ponds in Guelph. Red-winged blackbird [Agelaius phoeniceus) eggs from two ponds in Toronto contained up to 1130 ng/g pp’DDE and up to 670 ng/g total PCBs. Those concentrations were much higher than in a reference site, but an order of magnitude below concentrations associated with health effects in songbirds. Among four Stormwater ponds and one natural wetland in Guelph, there was statistically lower hatching success of northern leopard frogs (Rana pipiens) eggs, and larvae took longer to metamorphose into frogs at two Stormwater ponds. Statistically fewer tadpoles survived to metamorphosis at one Stormwater pond. We conclude that Stormwater ponds do not offer clean ecosystems for wildlife and the monitoring of contamination and its effects within Stormwater ponds is necessary.

Emerging infectious diseases (EIDs) are typically characterized by novelty (recent detection) and by increasing incidence, distribution, and/or pathogenicity. Ophidiomycosis, also called snake fungal disease, is caused by the fungus Ophidiomyces ophidiicola (formerly “ophiodiicola”). Ophidiomycosis has been characterized as an EID and as a potential threat to populations of Nearctic snakes, sparking over a decade of targeted research. However, the severity of this threat is unclear. We reviewed the available literature to quantify incidence and effects of ophidiomycosis in Nearctic snakes, and to evaluate whether the evidence supports the ongoing characterization of ophidiomycosis as an EID. Data from Canada remain scarce, so we supplemented the literature review with surveys for O. ophidiicola in the Canadian Great Lakes region. Peer-reviewed reports of clinical signs consistent with ophidiomycosis in free-ranging, Nearctic snakes date back to at least 1998, and retrospective molecular testing of samples extend the earliest confirmed record to 1986. Diagnostic criteria varied among publications (n = 33), confounding quantitative comparisons. Ophidiomycosis was diagnosed or suspected in 36/121 captive snakes and was fatal in over half of cases (66.7%). This result may implicate captivity-related stress as a risk factor for mortality from ophidiomycosis, but could also reflect reporting bias (i.e., infections are more likely to be detected in captive snakes, and severe cases are more likely to be reported). In contrast, ophidiomycosis was diagnosed or suspected in 441/2,384 free-ranging snakes, with mortality observed in 43 (9.8 %). Ophidiomycosis was only speculatively linked to population declines, and we found no evidence that the prevalence of the pathogen or disease increased over the past decade of targeted research. Supplemental surveys and molecular (qPCR) testing in Ontario, Canada detected O. ophidiicola on 76 of 657 free-ranging snakes sampled across ~136,000 km2. The pathogen was detected at most sites despite limited and haphazard sampling. No large-scale mortality was observed. Current evidence supports previous suggestions that the pathogen is a widespread, previously unrecognized endemic, rather than a novel pathogen. Ophidiomycosis may not pose an imminent threat to Nearctic snakes, but further research should investigate potential sublethal effects of ophidiomycosis such as altered reproductive success that could impact population growth, and explore whether shifting environmental conditions may alter host susceptibility.

Ophidiomycosis (snake fungal disease) is caused by the fungus Ophidiomyces ophiodiicola. As ophidiomycosis is difficult to study in free-ranging snakes, a reliable experimental model is needed to investigate transmission, pathogenesis, morbidity, and mortality, and the effects of brumation and temperature on disease development. Our objective was to develop such a model via subcutaneous injection of O. ophiodiicola conidia in red cornsnakes ( Pantherophis guttatus). The model was used to evaluate transmission and the effects of brumation and temperature in co-housed inoculated and noninoculated snakes. All 23 inoculated snakes developed lesions consistent with ophidiomycosis, including heterophilic and granulomatous dermatitis, cellulitis, and myositis, and embolic fungal granulomas throughout the liver and the coelomic connective tissue in 21/23 (91%). In the inoculated snakes, 21% of skin swabs, 37% of exuvia, and all liver samples tested positive by qPCR (quantitative polymerase chain reaction) for O. ophiodiicola. A post brumation skin swab from 1/12 noninoculated snakes that brumated in contact with inoculated snakes tested positive by qPCR, suggesting possible contact transmission. That snake had microscopic skin lesions consistent with ophidiomycosis, but no visible fungal elements. Of the 23 inoculated snakes, 20 (87%) died over the 70-day experiment, with ophidiomycosis considered the primary cause of death; 12 (52%) of the inoculated snakes died during brumation. Overall, this experimental model of ophidiomycosis reproduced skin lesions analogous to those of many natural cases, and internal lesions similar to the most severe natural cases. The study provides tentative experimental evidence for horizontal transmission in brumation, and offers a tool for future studies of this widespread snake disease.

There is veiy little information about the wildlife utilization of Stormwater detention ponds although such ponds often self-seed into wetland habitats. To inventory wildlife utilizing Stormwater ponds, a study was performed in 1997 and 1998 of 15 Stormwater ponds and one natural wetland varying in age from 3 to 22 years in the Guelph and the Greater Toronto Area (GTA) in Ontario, Canada. Seven of the Stormwater ponds were primarily open water with the aquatic vegetation accounting for less than 50% of the surface area. However, 90% of the surface area of four ponds was covered in aquatic vegetation. The surface area of those ponds covered with vegetation was positively correlated with total organic carbon and copper concentrations in sediment Invertebrate populations in the Stormwater ponds were often dominated by a single taxon. The most abundant benthic animals were tubificid worms or chironomidae. The number of taxa in sweep-net samples ranged from 4 to 25 and correlated positively with the age of the pond and total organic carbon in sediment The number of taxa in the benthos correlated negatively with oil and grease concentrations in sediment The range in number of amphibian species was one to seven in Guelph and zero to four in the GTA. In total, 40 species of birds were observed in the GTA ponds and 71 species were observed in the Guelph ponds during April to November 1997. A mean of 1.6 to 1.7 bird species was observed per survey at Stormwater ponds in Guelph and the GTA. The number of species of amphibians and birds did not correlate with water quality, sedimentology, contaminant concentration, percentage of surface area of the pond covered with plants, or any benthic community parameter measured. Four species of reptiles and eight species of mammals were noted at or adjacent to the Stormwater ponds and six species of fish were found in the ponds. We concluded that wildlife made use of the ponds, but species richness at almost all sites was low to moderate indicating that the ponds did not provide high quality habitat for wildlife

A population of bullfrogs (Rana catesbeiana) in Algonquin Provincial Park, Ontario, Canada, was studied from May 1985 through October 1987. Of 1187 individuals marked with tattoos, 567 were recaptured at least once. The age of each marked individual was estimated using size–frequency distributions. A negative relationship between age and sex ratio indicated lower survivorship for mature males than for mature females. The average age at maturity was estimated to be 5 years post-transformation (YPT), at 113 mm standard length (snout to urostyle) for females, and 3 YPT, at 91 mm, for males. The minimum age at maturity was 4 YPT, at 94 mm standard length, for females, and 3 YPT, at 90 mm, for males. Age at maturity was greater, and size at maturity smaller, than reported for other populations. A logistic growth model fitted to the data, and comparison of age-specific mean standard lengths, indicate an intersexual difference in the pattern of growth. The asymptotic maximum standard length, as derived from the logistic model, was 181 mm for females and 148 mm for males. The estimated growth constant, r, was greater for males than for females, indicating that males attained their maximum size at a younger age than did females.

Syntopic populations of bullfrogs (Rana catesbeiana), green frogs (Rana clamitans), and mink frogs (Rana septentrionalis) were monitored between May and October in each of 1985 through 1987 and 1991 through 1993 in Algonquin Provincial Park, Ontario, Canada. We assessed the descriptive and predictive utility of a dichotomous system for classification of anuran life histories by testing the hypothesis that large body size and large clutch size are associated with a survivorship curve in which mortality is highest for very small individuals. Ages of individuals were estimated from size-frequency and recapture data. Survivorship and longevity were estimated from standing age distributions smoothed with the log-polynomial method. Survivorship was also estimated by comparing the number of animals in an age-class in a given year with the number in the next age-class in the next year. Age distributions were unstable in all three species. The strengths and weaknesses of both methods of estimation of survivorship are discussed. RCsumC: Des populations de Ouaouarons (Rana catesbeiana), de Grenouilles vertes (Rana clamitans) et de Grenouilles du Nord (Rana septentrionalis) du meme endroit ont Ctk ktudikes de mai 2 octobre en 1986, 1986 et 1987 et de nouveau en 1991, 1992 et 1993, dans le parc provincial Algonquin, Ontario, Canada. Nous avons estimk la valeur descriptive et prkdictive d'un systkme dichotomique de classification de la dynamique des populations d'anoures en kprouvant l'hypothkse selon laquelle une grande taille et un grand nombre d'oeufs par couvke sont associks B une courbe de survie dans laquelle les trks petits individus ont le plus fort taux de mortalitC. L'ige des individus a Ct6 estimk 2 partir de donnkes rang-frkquence et de donnkes capture-recapture. La survie et la long6vitC ont Ct C estimkes d'aprks la courbe de distribution des Ages, rkgulariske par la mkthode logarithmique-polynomiale. La survie a kgalement Ct C estimke par comparaison entre le nombre d'animaux dans une classe d'ige au cours d'une annke donnCe avec le nombre d'animaux de la classe d'ige suivante au cours de l'annke suivante. La distribution en fonction de l'ige s'est avCrCe instable chez les trois espkces. Les forces et faiblesses des deux mkthodes d'estimation de la survie sont examinkes. [Traduit par la RCdaction]

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