Bremen, Univ., Diss., 2001. / Computerdatei im Fernzugriff.

Bremen, Univ., Diss., 2001. / Computerdatei im Fernzugriff.

Thesis (M.Sc.)--Acadia University, 1999. / Includes bibliographical references (leaves 89-96). Also available on the Internet via the World Wide Web.

Thesis (M.Sc.)--Acadia University, 1999. / Includes bibliographical references (leaves 89-96). Also available on the Internet via the World Wide Web.

Thesis (M.S.)--Youngstown State University, 1995. / Includes bibliographical references (leaves 28-30).

Thesis (M.S.)--Bowling Green State University, 2009. / Document formatted into pages; contains vii, 57 p. : col. ill., maps. Includes bibliographical references.

Thesis (M.S. in zoology)--Washington State University, May 2009. / Title from PDF title page (viewed on May 22, 2009). "School of Biological Sciences." Includes bibliographical references (p. 18-25).

Mudpuppy (Necturus maculosus) populations are apparently declining throughout the Great Lakes region, yet little is known about their natural history. Using minnow traps, I captured 120 individual mudpuppies in Wolf Lake, Chicago, Illinois, and recaptured 34 of those individuals. Trapping periods of ≥ 3 consecutive nights occurred at intervals during January to May 2015, and October 2015 to March 2016. I also caught 25 mudpuppies using hand nets, including 1 recapture, during ice-free periods. Overall trapping success differed among trapping periods (p = 0.01). Relatively high trapping success during trapping periods from early November through early April suggests that there is a fairly large window in which mudpuppies may be successfully captured. The number of captures was negatively correlated with water temperature and was marginally significant (r = - 0.23, p = 0.09). However, daily capture success declined precipitously above 14.1° C, as indicated by a nonparametric two-dimensional Kolomogorov-Smirnov (2DKS) test (p < 0.001). Analyses of size classes indicated potential gear biases, with mudpuppies in traps (mean 26.9 ± 0.5 cm) larger than those caught using hand nets (mean 14.7 ± 0.8 cm, p < 0.0001). These results suggest multiple capture methods may be necessary to accurately assess demographic profiles and levels of recruitment. Stomach contents obtained through gastric lavage, a non-lethal stomach flushing method, included mollusks, leeches, insects, isopods, amphipods, crayfish, fish, a frog, and a juvenile mudpuppy. Invasive species were present in guts, including rusty crayfish (Orconectes rusticus), round gobies (Neogobius melanostomus), and zebra/quagga mussels (Dreissena spp.), suggesting that mudpuppies may forage on invasives in changing aquatic communities. Small juvenile mudpuppies (< 20 cm) consumed fewer fish and no crayfish, but more leeches and amphipods, than adult size classes (p < 0.0167). Nonmetric multidimensional scaling ordinations showed overall different communities of prey among size classes. ANOSIM results confirmed observed differences in composition among size classes (Global R = 0.253 for abundance, 0.258 for volume, and 0.267 for % volume of gut contents, p = 0.001 for all). These results suggest that mudpuppies in lake ecosystems occupy a broad niche that changes over their development.

Metagonimoides oregonensis is a digenetic trematode that infects raccoons as definitive hosts, the snail Elimia proxima as a first intermediate host and in the southern Appalachians, encysts in the muscle tissue of a variety of second intermediate salamander hosts. My first study examined 289 individual salamanders representing six species from 23 streams in North Carolina to determine which species of salamanders are naturally infected.  I found that five of the six species examined had natural infections, but that there was variation in infection intensity and prevalence among the species. Of the six species, Desmognathus quadramaculatus may be most important in transmission, as they had the highest prevalence and intensity of infection. This may be due to their long larval period, which results in a longer trematode accrual period.  My second study explored the role of host and parasite behavior in driving infection dynamics in this system. I examined both parasite response to host chemical cues and host response to parasite presence and chemical cues. I did not see a behavioral response by either the parasite or the host, indicating behavior is probably less important in determining variable infection among hosts in this system, than are environmental and ecological factors. My final study examined the effect of cercariae exposure (n=0, 20, 60) on locomotor performance of D. quadramaculatus, Eurycea wilderae and Hyla versicolor. I did not see any effect on locomotor performance for any of the species. / Master of Science

Amphibians are key health indicator species and important sentinels for ecosystem health. With 32% of amphibians threatened with extinction, and an additional 25% without enough data on record to fully understand their status, amphibians are facing what is being called the Amphibian Extinction Crisis. Of caudate amphibians (salamanders/newts), 49.8% are threatened or endangered, making them currently the most threatened vertebrate taxa. As a result of the Amphibian Extinction Crisis, it is imperative that captive breeding facilities be established as a hedge against future amphibian extinctions. Unfortunately, captive assurance colonies face frequent failure due to lack of natural stimuli, which are necessary for amphibian breeding. Therefore, assisted reproductive technologies (ART) have been employed to reproduce endangered amphibians, increasing the success of captive assurance colonies worldwide. Over the last decade, a great deal of attention has been given to restoring anuran (frog/toad) populations through captive breeding, but little attention has been given to preservation of caudate species. Caudate amphibians are notoriously difficult to breed in captivity, thus it is crucial that ART be developed to help preserve endangered caudates sooner, rather than later. The following studies highlight some of the first attempts at developing ART protocols in caudate amphibians. Protocols were developed for: hormone induction of gamete production; cryopreservation of salamander sperm; and in vitro fertilization. These protocols were developed for the common, model species Ambystoma tigrinum in order to assure safety and efficiency for later application in endangered species.