Max A. Nickerson

Harvesting as a factor in population decline of a long-lived salamander; the Ozark hellbender, Cryptobranchus alleganiensis bishopi Grobman

We documented the harvesting of 558 Ozark hellbenders, Cryptobranchus alleganiensis bishopi, between 1969 and 1989, from the North Fork of the White River (NFWR), Ozark County, Missouri. Scientific studies accounted for 272 individuals. More than 256 Ozark hellbenders were taken for the pet trade for suppliers in Michigan, New Jersey, and Japan by collectors from Nebraska and Alabama. During the first weekend of September 1980, 171 were collected illegally. Estimates indicate that approximately 50% of the females were removed from the most significant hellbender habitat in the NFWR (riffle 2-3) that weekend. Between 1969 and 1980, coordination with the Missouri Department of Conservation helped insure that C. a. bishopi, used for scientific research, were not removed from a 2.67 km (NFWR 1) research section. Population estimates from 1970 and 1978 studies indicate stability in the most densely populated habitat. In the 1970s, larger samples of individuals collected for research were not removed from a single site, but a few individuals were collected from multiple sites within a 10 km reach of the NFWR. During 1982-1984 more than 100 individuals were removed from the same section as in 1980 by commercial collectors. This evidence supports harvesting of C. a. bishopi, especially illegal harvesting, as a contributing factor in the decline of this population and documents that the decline had begun by 1980.

Diel Activity Rhythms in the Hellbender, Cryptobranchus alleganiensis (Caudata: Cryptobranchidae)

DAILY rhythms of locomotor activity have been found in many animals including salamanders (Ralph, 1957; Bennett and Stanley, 1960; Adler, 1969). We were interested in determining the activity rhythms in hellbenders, Cryptobranchus alleganiensis, to aid in the interpretation of field observations and proposed laboratory work. Field observations indicate that C. alleganiensis is primarily nocturnal (for references see: Nickerson and Mays, 1973). However, there have been reports of diurnal activity at certain times of year, particularly during the breeding season (Smith, 1907; Bishop, 1941). Therefore, we determined the activity rhythm in the laboratory at two times of year, prior to and during the breeding season.

Evaluation of Microorganisms Cultured from Injured and Repressed Tissue Regeneration Sites in Endangered Giant Aquatic Ozark Hellbender Salamanders

Investigation into the causes underlying the rapid, global amphibian decline provides critical insight into the effects of changing ecosystems. Hypothesized and confirmed links between amphibian declines, disease, and environmental changes are increasingly represented in published literature. However, there are few long-term amphibian studies that include data on population size, abnormality/injury rates, disease, and habitat variables to adequately assess changes through time. We cultured and identified microorganisms isolated from abnormal/injured and repressed tissue regeneration sites of the endangered Ozark Hellbender, Cryptobranchus alleganiensis bishopi, to discover potential causative agents responsible for their significant decline in health and population. This organism and our study site were chosen because the population and habitat of C. a. bishopi have been intensively studied from 1969–2009, and the abnormality/injury rate and apparent lack of regeneration were established. Although many bacterial and fungal isolates recovered were common environmental organisms, several opportunistic pathogens were identified in association with only the injured tissues of C.a. bishopi. Bacterial isolates included Aeromonas hydrophila, a known amphibian pathogen, Granulicetella adiacens, Gordonai terrae, Stenotrophomonas maltophilia, Aerococcus viridans, Streptococcus pneumoniae and a variety of Pseudomonads, including Pseudomonas aeruginosa, P. stutzeri, and P. alcaligenes. Fungal isolates included species in the genera Penicillium, Acremonium, Cladosporium, Curvularia, Fusarium, Streptomycetes, and the Class Hyphomycetes. Many of the opportunistic pathogens identified are known to form biofilms. Lack of isolation of the same organism from all wounds suggests that the etiological agent responsible for the damage to C. a. bishopi may not be a single organism. To our knowledge, this is the first study to profile the external microbial consortia cultured from a Cryptobranchid salamander. The incidence of abnormalities/injury and retarded regeneration in C. a. bishopi may have many contributing factors including disease and habitat degradation. Results from this study may provide insight into other amphibian population declines.

The Nests and Nest Site Selection by Ozark Hellbenders, Cryptobranchus alleganiensis bishopi Grobman

Two Ozark hellbender, Cryptobranchus alleganiensis bishopi, nests were discovered by the authors in early October 1980 within crevices between dolomitic limestone bedrock in the North Fork of the White River, Ozark County, Missouri. Although we were unable to pry into the crevices with steel bars we assume they were nests because of the presence of egg strands (Figs. 1-3) and social activity. Since the nests of Ozark hellbenders have not been described, and because our observations seem to vary from Cryptobranchus nests described by Alexander (1927) and Bishop (1941), we herein include a brief description of the two nests. Nest One was discovered at 13:30 h CSDST on 2 October along the eastern margin of a riffle. Water temperature was 170C and there was no noticeable current. A single strand of eggs was protruding (Figs. 1-3) from a crevice. The top portion of bedrock was almost 2 m in length, 35 to 40 cm thick and rested in a huge slab of bedrock. The opening extended for more than a meter in length and to 4.0 cm in height, was mostly perpendicular to the stream bed, and faced upsteam. At least one C. a. bishopi was in the nest, and within fifteen minutes an adult female, which appeared to be spent, walked to the nest rock and slid under its margin (Fig. 3). Nest Two was found 8 October at 13:20 h CSDST within 4 m of the east

Potential recovery of a declined turtle population diminished by a community shift towards more generalist species

Models suggest that a declined turtle population may rebound if the cause of decline is remedied and adult mortality is reduced, but recovery time will likely be slow. In 2005-2007, we reexamined a river turtle community which included a population of Northern Map Turtles (Graptemys geographica) that had been reduced by approximately 50% between 1969 and 1980 likely as a result of harvesting, and had failed to rebound by 2004 despite no evidence of continued harvesting. Comparisons of population estimates for G. geographica showed no significant differences between 2005 and 2006 (z = 1.79, P = 0.073) or between 2006 and 2007 (z = 1.07, P = 0.284). However, the population estimate for 2007 was not significantly different from the population estimate for 1969 (z = 0.48, P = 0.629) but was significantly higher than the population estimate for 1980 (z = 2.96, P = 0.003), suggesting the population had returned to its pre- decline (1969) size. While the recovery of the G. geographica population demonstrates that a previously harvested river turtle population may rebound if no further harvesting occurs, the recovery period will be extensive, thus confirming model predictions. Furthermore, the turtle community composition was shifting towards a higher relative abundance of generalist species and a lower relative abundance of specialist species - a pattern that can be expected with habitat degradation, another threat which may present new challenges to G. geographica, a dietary specialist.

Reassessment of the Turtle Community in the North Fork of White River, Ozark County, Missouri

In an effort to identify long-term changes in a river turtle community and its habitat, we reexamined the turtle community in a 4.6 km section of the North Fork of White River (NFWR), Ozark County, Missouri, that was previously studied between 1969 and 1980. We compared data collected in 2004 to data from 1969 and 1980 to determine if alterations in the habitat, community composition, or Northern Map Turtle (Graptemys geographica) population size and structure had occurred. Previous studies showed that the population of G. geographica declined between 1969 and 1980. Our results indicate that the population of G. geographica failed to rebound by 2004. The population of Red-eared Sliders (Trachemys scripta elegans) that established in the research section between 1971 and 1980 expanded their distribution between 1980 and 2004. Threats to the population of G. geographica included lack of basking sites, increased human recreational use of the stream, and water quality degradation.

Effect of light and temperature on growth and conidial discharge in basidiobolus.

Seventeen isolates of Basidiobolus (Entomophthorales) were obtained from 22 specimens of a salamander (Desmognathus fuscus) dissected under red light, and formation and discharge of conidia at wavelengths greater tharl 600 nm was proven. Growth of 177 isolates of Basidiobolus (including the six named species) at 25 C and 37 C was compared in the dark and with occasional exposure to light. Growth differences were measured and conidial discharge was noted after 72 hrs. Light apparently has greater effect on growth than on conidial discharge at higher temperatures. Effect of light on conidial discharge is reduced at higher temperatures. Isolates of the fllngus differ significantly in response to light at different temperatures, possibly representing four physiologically different strains. Trans. Kans. Acad. Sci., 75 (1), 1972.

Hellbender Salamanders (Cryptobranchus alleganiensis) Exhibit An Ontogenetic Shift In Microhabitat Use In A Blue Ridge Physiographic Region Stream

Organisms that experience large changes in body size during the life span often exhibit differences in resource use among life stages. Ontogenetic shifts in habitat use reduce intraspecific competition and predation and are common in lotic organisms. Although information on the immature life stages of the Hellbender (Cryptobranchus alleganiensis) is limited, this aquatic salamander exhibit’s ontogenetic shifts in habitat use in some streams, with adults sheltering under large rocks and larvae utilizing interstitial spaces of gravel beds. Due to the geomorphology of Little River, Tennessee, however, limited interstitial spaces within the gravel are filled with sand. Therefore we quantified microhabitat parameters for three life stages of Hellbenders (larvae, sub-adult, adult) to determine if an ontogenetic shift in microhabitat occurred in this location. We found no significant differences in stream substrate at capture sites among the stages, but there was a positive correlation between rock shelters underlain with very coarse gravel and overall Hellbender occupancy. Although we found no difference in water quality parameters and streambed particle size among the stage classes at the site of capture, there was a significant difference in the average shelter size among all stages, with larvae utilizing the smallest shelters. As the smaller rocks utilized by larvae in Little River could be less secure shelter than the larger rocks used by adults, mortality may be higher in young Hellbenders due to a potential increase in overall predation risk and susceptibility to flooding. Based on these results, future Hellbender research and conservation efforts should consider differences in life stage habitat use as well as specific stream particle classes.

Toad Suspect in Death of California Sea Lion (Zalophus californianus) (Lesson)

Peterson and Bartholomew (1967) make no mention of any interactions between sea lions and anurans. We have observed young sea lions actively pursue, bite and then discard anurans (Rana catesbeiand and Hyla crgrifer) which had inadvertently entered their pool. At 11:00 A.M., 2 June 1971, a female Zalophus californiangs, ca. 60 lbs., was observed floating listlessly in its pool. It failed to respond to food offerings. The symptomology was as follows: 1) signs of gastrointestinal distress, i.e., regurgitation, attempted regurgitation and apparent cramping; 2) tremors and mild convulsions; and 3) loss of equilibrium or muscular coordination. Immediately before dying, at approximately 1:00 P.M., the animal lost the ability to swim and began biting savagely at anything nearby. A gross autopsy revealed nothing unusual except an adult Buf o vmericatzvs (possibly B. vmericans X B. fouvleri), partially digested, in the cardiac portion of the stomach. The toad measured 63 mm SV and has been preserved (MAZG 1280) in the collection of Max Allens Zoological Gardens, Eldon, Missouri. The Colorado River Toad, B. dIvariGs, exudes enough poison to kill a large dog when seized in the dogs mouth (Wright, 1966). Schaaf and Garton (1970) note that few vertebrates feed heavily on toads but that raccoons do eat B. americvnus, characteristically avoiding the parotoid glands.

Additional Noteworthy Records of Missouri Amphibians and Reptiles with a Possible Addition to the Herpetofauna

Extensive held work within Missouri recently has led to the discovery of new localities for many species of amphibians and reptiles (Nickerson and Krager, 1971 ) that were not included in Reptiles of Missouri (Anderson, 1965) or other works. This report is concerned with records along the northern Ozark border. All specimens are deposited within the Milwaukee Public Museum Herpetological Collection.