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ZOOLOGY I 9:00 AM SATURDAY, MARCH 31, 2001 KOLENBRANDER-HARTER ROOM 201 TED CAVENDER-PRESIDING.

09:00 LAKE-LEVEL REDUCTIONS AND STRANDING OF AQUATIC SNAILS IN NESTS OF CENTRARCHID FISHES. Jack Kovach, jkovach@muskingum.edu, Muskingum College, Geology Dept., New Concord OH 43762.

Drought-induced lowering of the water-level of the New Concord Reservoir in eastern Muskingum County, Ohio, during the summers of 1994 and 1999 resulted in the stranding and eventual demise of large numbers of aquatic gastropods which became trapped in nearshore, lake-floor depressions excavated by nesting centrarchid fishes. Species affected included Cipangopaludina sp. (a non-native species that is by far the most abundant snail in the reservoir with up to 228/[m.sup.2] counted in October 1994), Physa sp. (0-3/[m.sup.2]) and Helisoma sp. (17-55/[m.sup.2]). As lake-levels drop, these snails typically remain immersed by migrating with the declining water level. Those whose path of migration leads them into the more or less circular depressions excavated by centrarchid fishes, however, become trapped there as levels of the lake continue to drop and these temporary "ponds" eventually dry up. Collection and disaggregation of the upper 3.8 cm of sun-baked substrate from an exposed centrarchid nest collected 15 Oct. 1994 and one collected 27 Oct. 1999, each measuring 48.3 cm in diameter, yielded the following numbers of shells of dead snails. The 1994 nest yielded 93 shells of Cipangopaludina sp. which had opercula in place, indicating that these animals had died recently in situ by desiccation, 47 shells of Cipangopaludina sp. lacking opercula, 11 opercula, 27 shells of Physa sp. and 22 shells of Helisoma sp. Corresponding numbers for the 1999 nest were 80, 141, 49, 34 and 25, respectively. Areas between and away from centrarchid nests were practically devoid of shells. Stranding in fish nests could account for some patchy distributions of fossil and subfossil remains of snails and other biota in lacustrine sediments.

09:15 INTERACTION BETWEEN A NATIVE AND EXOTIC CRAYFISH OF THE HUDSON RIVER VALLEY: FORAGING EFFECTS ON NATIVE BIVALVES. Carolyn A. Klocker, klockerca@hiram.edu, (David Strayer, strayerd@ecostudies.org, and Prudence Hall, hallpj@hiram.edu) Hiram College, Hiram OH 44234.

The rusty crayfish, Orconectes rusticus, has been known to displace native crayfish and reshape the populations of macroinvertebrates in benthic ecosystems where it has been introduced. The purpose of this study was to investigate aggressive interactions and competition for shelter between the introduced species, O. rusticus, and a native crayfish species to the Hudson River Valley, O. limosus, under laboratory conditions. Crayfish were collected from 3 rivers in the Hudson River Valley. All trials took place in 10-gallon aquariums and the number of aggressive contacts were recorded. Shelters were then placed in the aquariums and 20 hrs later recordings were made of which crayfish was found in the shelter. Chi-square analysis revealed that O. rusticus did not significantly dominate O. limosus in the aggression trials and dominance did not significantly affect which crayfish obtained shelter. This lack of significance may be explained by the small sample size of only 15 trials used for this study. Feeding trials revealed that both species of crayfish consumed native mussels and fingernail clams, preferring prey of smaller size classes. These findings may still provide evidence to suggest that previous and future introductions of O. rusticus into the Hudson River Valley may have an effect on native crayfish and bivalves. Further study should focus on the potential effects of this exotic species on native benthic communities using larger samples.

09:30 PATTERNS OF MACROALGAL AND PERIPHYTIC ASSEMBLAGES FROM COAL MINE IMPACTED LOTIC SYSTEMS WITHIN THE UNGLACIATED WESTERN ALLEGHENY PLATEAU. R.G. Verb(1), J.B. Keiper(2), and M.L. Vis(1). (1) Ohio University, Dept. of Environmental and Plant Biology, Athens OH 45701. (2) Cleveland Museum of Natural History.

We examined if there were particular groups of macroalgae and periphyton assemblages specific to abandoned coal mines and/or reclaimed sites within the unglaciated Western Allegheny Plateau. Fifty-six streams were visited from May to June 1999. Stream sites were placed into one of nine categories based upon catchment mining/ reclamation history and other land use within the stream site's watershed. At each stream site the periphyton and macroinvertebrates (to ascertain herbivory influence) from riffles, macroalgae from a 20-meter stream segment, 29 environmental parameters (e.g. pH, metal concentrations, current velocity), and habitat were examined to assess the impacts coal mining had on the lotic system. A total of 594 infrageneric algal taxa and 40 macroinvertebrate taxa were recorded from these stream sites. Diatoms were the most abundant and diverse algal organisms (359 taxa), followed by chlorophytes (121), Cyanobacteria (42), euglenophytes (31), xanthophytes (14), chrysophytes (12), rhodophytes (6), dinophytes (6), and cryptophytes (3). Based on canonical correspondence analyses (CCA), the first and second axes were highly correlated with pH (r=-0.96) and specific conductance (r=0.59) respectively. A wide range of pH values (2.47-7.93) was found at these stream sites, primarily due to the influence of acid mine drainage from abandoned and reclaimed coal mines. Highly acidic sites were characterized by a dominant flora of Eunotia exigua, Frustulia rhomboides, Klebsormidium rivulare, and Microspora tumidula. Predictable relationships were observed between the water quality from abandoned and reclaimed mines and the biotic assemblages present, which may prove useful in the assessment and management of reclamation efforts.

09:45 GENETIC DELINEATION OF HIGHER TAXA IN FRESHWATER BRYOZOANS. Michael B Lore, lore.3@wright.edu, Tim Wood, tim.wood@wright.edu, Wright State University, Department of Biological Sciences, Dayton OH 45435.

This study addresses the systematic relationship among the five known families of freshwater bryozoans (Ectoprocta: Class Phylactolaemata). The group lends itself particularly well to genetic work because it is relatively small yet still includes a remarkable diversity of species. Bryozoans have been previously classified only by their external morphology, leaving certain phylogenetic and evolutionary relationships somewhat speculative. The approach used here is to focus on the sequences coding for the ribsomal RNA, specifically the 18s and ITS-1 regions. Much of the material examined was collected during a survey of the British phylactolaemate bryozoans by Okamura, Wood, and Lore in the summer of 2000. Additional material, such as the lophopodid species, came from Europe and North America. Results still being analyzed reveal strongly conserved genomes within the 18s region. The family status of Hyalinella punctata is expected to be clarified, along with the structure of the Genus Plumatella and relations among the nontubular taxa.

10:00 THE ORIGIN OF SIMULTANEOUS HERMAPHRODITISM IN THE FRESHWATER MUSSEL GENUS UTTERBACKIA (BIVALVIA: ANODONTINAE) AS INFERRED FROM PHYLOGENETIC ANALYSIS OF DNA SEQUENCES. Elizabeth A. Knazek, eknazek@kent.edu, (Walter R. Hoeh), Kent State University, Dept. of Biological Sciences, Kent OH 44242.

The freshwater mussel genus Utterbackia contains species which utilize either gonochoric (=dioecious) or hermaphroditic reproductive systems. U. peggyae and U. peninsularis both possess gonochoric reproductive systems while U. imbecillis and "U. imbecillis", an undescribed species, exhibit simultaneous hermaphrodism (SH). This implies an evolutionary transition if the genus is in fact a monophyletic group and, therefore, a question regarding the evolution of mating systems. A phylogenetic analysis of DNA sequence data from the four species would enable an evaluation of the number and directionality of mating system transitions in the genus. Goals of the project include: testing the monophyly of the genus Utterbackia, estimating the evolutionary relationships among the four species, and estimating the number of reproductive system transitions that occurred in the Utterbackia lineage. A previous phylogenetic analysis of Utterbackia, using allozyme data, suggested that SH arose a single time within the genus and this hypothesis will also be tested. Total DNA was extracted, and a 710 bp fragment was PCR amplified. The PCR products were then purified and cycle sequencing reactions performed. The sequencing reactions were run on a LI-COR 4200S sequencer. Thus far, both strands of a 710 bp fragment of the Cytochrome c oxidase subunit I gene have been cycle sequenced for 44 individuals representing 19 populations.

10:15 FLOTATION OF SHELLS OF DEAD ASIATIC CLAMS (CORBICULA FLUMINEA), SALT FORK LAKE, GUERNSEY COUNTY, OHIO. Jack Kovach, jkovach@muskingum.edu. Muskingum College, Geology Dept., New Concord OH 43762.

Observations on the flotation of shells of recently-deceased individuals of the Asiatic clam, Corbicula fluminea, in Salt Fork Lake, Guernsey County, Ohio, are reported. Lowering of the level of the lake in 1993 for the purpose of constructing a boat ramp exposed thousands of this non-native clam, together with native species, to dessication for several weeks. As the level of the lake was later slowly restored to its normal level, one to three C. fluminea shells were, on several occasions, observed floating near shore at the surface of the lake. One such shell, measuring 5.3 cm long by 4.6 cm wide with a shell weight (without soft parts) of 18.95 g, collected 10-4-93, placed in a bucket of lake water and transported to the laboratory, remained floating, ventral-side up, for more than 48 hours before settling to the bottom of the bucket. More recently, a specimen 3.4 cm by 3.1 cm with a shell weight (without soft parts) of 6.55 g, which had died recently of unknown causes, was observed floating along the shore of the lake on 9-14-00. Flotation of dead clams may be a common phenomenon and could result in the transportation and deposition of clam shells to sedimentary environments in which the clams did not actually live.

10:30 TEMPORAL CHANGES IN DARTER COMMUNITY STUCTURE SINCE 1978 IN THE LITTLE MIAMI RIVER, GREENE COUNTY, OHIO. Erin P. Grimm, grimmep@muohio.edu, Orie L. Loucks, Miami University, Oxford OH 45056.

Studies by David Wynes in 1978 afford an opportunity now to uncover how fish communities may have changed in response to changes in stream environments. The objectives of a re-sampling in 2000 were to determine whether habitat characteristics and darter species assemblages at six sites along the Little Miami River in Greene County, Ohio had changed since 1978. Fish were collected between May and September 2000 using Wynes' methods, a drag seine, and in June and August using an electroshocker. Physicochemical characteristics of the water also were measured. Since 1978, sites 5 and 6, the two sites located downstream from Beavercreek Wastewater Treatment Plant, have recovered from the discharges of the plant. Orthophosphates, total suspended solids, and biochemical oxygen demand have decreased markedly. These sites show an increase of 82% and 100% in the number of darters collected. Sites 3 and 4, above the discharge, also showed an increase in species numbers, including the addition of two species at Site 3 and an increase from 9 to 14 species at Site 4, possibly due to the abatement of degraded habitat below the wastewater ouffall. Water quality improvements also have been observed at the other sites, but darter impoverishment has occurred at all upstream sites. At Site 1, the most upstream site, only 33 individuals, representing seven species, were collected during five months and only 38 individuals were found at Site 2, representing 40.3% and 74.8% declines in the number of individuals. Decreases also were observed at sites 3 and 4 (55.1% and 49.5%) where only 66 and 53 individuals were collected. The number of species collected at sites 1 and 2 have declined by 12.5% and 38.5%. Index of Biotic Integrity scores, ranging from 33 to 41, suggest that the entire fish community has been affected.

10:45 A LOSS OF FISH SPECIES AS A RESULT OF STRESS FACTORS ACTING ON A SMALL STREAM ECOSYSTEM. Matthew J. Greene, greene.118@osu.edu, and Ted M. Cavender, The Ohio State University, Museum of Biological Diversity, 1315 Kinnear Rd., Columbus OH 43212-1192.

There were two main objectives of this research: 1) Compare historical fish records with current records to determine the extent of species decline in the headwaters of the Little Miami River. 2) Define the major stress factors that are working in the headwaters to decrease species diversity. The study area includes the drainage as it extends upstream of Clifton, Ohio. The primary land use in this area is row crop agriculture. In order to minimize flooding and maximize field perimeters streams have been modified and the riparian narrowed. The watershed above this point drains approximately 168sq.km, and has an average gradient of 2m/km. A low head dam separates the study area from the rest of the river. A total of 24 fish collection sites were made upstream of Clifton Impoundment (CI) for the purpose of determining the present status of fish populations. Additional collections were made downstream of the CI to determine if the low head dam was acting as a barrier for fish that were once upstream of it. Eleven fish collection sites upstream of the CI were selected for analysis of dissolved oxygen, turbidity, temperature, pH, nitrates, ammonium, and orthophosphates. The Index of Biotic Integrity (IBI), Shannon Index (H'), and Qualitative Habitat Evaluation Index (QHEI) were employed in order to evaluate fish collection sites. Of nearly 48 species previously recorded for the study area, only 28 were located, or about 60% of the original fauna. Dissolved oxygen reached supersaturated conditions ([is greater than] 10mg/L) during daylight hours and low levels ([is less than] 5mg/L) at night. Turbidity readings reached nearly 50 NTUs during high flow periods, which was high compared to low flow periods. Quantitative scores for the IBI, H', and QHEI were 34.4, 2.2, and 59.9. Riparian reduction, channel modification, and nutrient enrichment appear to be the major factors currently operating in the Little Miami River headwaters causing a reduction in species richness.
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Publication:The Ohio Journal of Science
Geographic Code:1USA
Date:Mar 1, 2001
Words:2264
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