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The Unionid Mussel Fauna of Northeastern Ohio's Grand River

2005; Ohio State University Libraries; Volume: 105; Issue: 3 Linguagem: Inglês

2471-9390

Martin K. Huehner, Robert A. Krebs, Gregory M. Zimmerman, Melissa Mejia,

Water Quality and Resources Studies

Unionid mussel distribution, numbers, and species were examined in the Grand River to provide a recent and comprehensive study of mussels from northeast Ohio’s longest river. The entire length of the Grand was canoed and examined for unionid mussel beds, with the exception of upstream areas where the river was small; SCUBA was used to survey just upstream of Fairport Harbor. The lower river, designated Grand River’s Wild and Scenic section, was studied in 1995, the middle reaches, called the Scenic section, were surveyed in 1996, and completion of the headwater region followed in 1998. Finally, a survey near the mouth of the river was made in 2002. A total of 95 sites were examined visually, by hand, with bottom sieves, dip nets, or by diving, as conditions demanded; riverbanks were searched for dead shells. A total of 11,625 living mussels and 4,514 dead shells comprising 27 species were identified. All species found were represented by living specimens. Comparisons to earlier collections indicated that the unionid fauna is changing, especially in downstream areas, but the diversity of these threatened macroinvertebrates in the Grand River has been much less affected than in the neighboring Ohio rivers to the west. OHIO J SCI 105 (3):57–62, 2005 Manuscript received 15 April 2004 and in revised form 26 April 2005 (#04-13). INTRODUCTION The first extensive reports of the unionid fauna of the Grand River, OH, were published by Ortmann (1924), who identified 17 species despite surveying only a small proportion of the river. Since this time, periodic collections of mussels has continued, with most collections dating to the 1960s by Professor David Stansbery. Although unpublished, the records of these collections, which include shells from 24 different species, are available in a database from the Ohio State Museum of Biological Diversity. The Grand River is the largest stream in NE Ohio and it drains portions of Lake, Ashtabula, Trumbull, and Geauga counties (Fig. 1). Although it is in the St. Lawrence basin, the Grand River is adjacent to Mississippi drainage, with Pymatuning Creek to the east and the Mahoning River to the southeast. On its western and southwestern edges, the Grand River adjoins the Chagrin and Cuyahoga river watersheds, respectively. Like the Cuyahoga, the Grand River has had a complex history that joined it with the Mississippi drainage during glacial times. In 1974, the Ohio Department of Natural Resources designated about 55 km of the Grand River as Scenic, from US Route 322 in southern Ashtabula County downstream to the Harpersfield Dam (Fig. 1). Another 39 km of the river, from the Harpersfield Dam down to the Norfolk and Western railroad bridge in Painesville, was designated as Wild and Scenic. The main channel of the Grand River’s headwaters extends upstream from US Route 322 for another 37 km through Trumbull and Geauga counties, providing in total, over 120 km of potentially high quality mussel habitat. Many tributaries join the Grand River as it flows through woodlands, fields, and wetlands and eventually empties into Lake Erie at Painesville. FIGURE 1. The watershed of the Grand River, OH, which encompasses parts of Lake, Ashtabula, Trumbull, and Geauga counties. Indicated by rectangles are the locations where the river changes classification, from headwater to Scenic at Route 322, to Wild and Scenic at Harpersfield dam, and functionally ending at the railroad bridge south of Painesville. Collections at the mouth of the river were made just above the dredging region of Fairport Harbor. The present study was conducted to satisfy a pressing need for recent and comprehensive information of the Grand River’s unionid mussel fauna, and it presents the results in two parts. Part I supplies detailed information about unionid populations and their distribution in the 58 VOL. 105 UNIONIDS OF OHIO’S GRAND RIVER river as categorized by these four primary divisions: river mouth, Wild and Scenic, Scenic, and headwaters. Part II contrasts changes in the mussel fauna over the past half century plus. Further details are available from the Ohio Department of Natural Resources as final project reports for each of these sections of the river (Huehner 1996, 1997, 1999), and from EnviroScience, Inc. (2002). Names of the species described here follow Turgeon and others (1998). MATERIALS AND METHODS Field collections were performed in the Grand River’s Wild and Scenic section (River Mile 30.9 to RM 9.0) during July of 1995, in the Scenic portion (from Route 322 to Harpersfield Dam, RM 64.7 to RM 30.9) during July of 1996, in the headwaters section (Parkman to Route 322, RM 99.0 to 64.7) during August and September of 1998, and in the city of Fairport Harbor (RM 0.5-1.75) in 2002. The river was accessed at road crossings, by private property, from County Parks, and from State Wildlife Areas. We established 12 sites near the river mouth, 18 collection sites in the Wild and Scenic section, 27 sites in the Scenic section, and 26 sites in the headwater section. The search strategy employed to locate mussel populations was to move downstream while observing conditions such as water velocity, depth, bottom composition, extent of submergent vegetation, and flood or muskrat deposited shells on the banks. Once a potential site was located, searchers examined the bottom by hand to determine its composition, extent of available habitat, and to determine whether mussels were present. If suitable habitat was limited or if no or very few mussels were found within a few minutes, another site was investigated downstream. When a preliminary search yielded a reasonable number of mussels (10-15 or more), then a full search was performed. Exact locations of collecting sites were logged on 7.5-minute USGS topographic maps in 1996 and 1998. A Garmin GPS 40 geographic positioning unit was used to fix latitude and longitude for each stop. All surveys at the river mouth followed preset transects. Mussel collection methods were determined by the physical conditions encountered at each site, and usually they consisted of hand searching through the bottom, snorkeling or SCUBA (river mouth only) as determined by water visibility and depth. The most upstream reach (RM 99.0 90.4) of the Grand River was accessed by foot, but from RM 90.4 to RM 9.0 the entire length was canoed to locate mussel populations. Banks were examined for flood-deposited shells and muskrat middens; dip nets were used to scoop fine sediments from under flat rocks and logs where salamander mussels (Simpsonaias ambigua) would be found. Buckets with 1.25 cm mesh bottoms were used to sort fine sediments for smaller mussels. The actual time spent collecting mussels was recorded for each site and varied from 1/2 to 1-1/2 hours. Living specimens encountered were maintained under water in nylon mesh bags, identified to species, and returned to the river bottom in a natural position. Dead mussel shells were similarly collected, measured, and returned to the stream. Representative specimens (no living special status species were removed) with collection site information were verified by Dr. David Stansbery and deposited in the Ohio State Museum of Biological Diversity. RESULTS The number of live individuals and shells found in each of the three regions of the Grand River are summarized in Table 1. Specific site data were recorded and submitted to the Ohio Department of Natural Resources (Huehner 1996, 1997, 1999). Live individuals of 27 species were observed. Early results for historical collections of the unionid fauna were compiled only with respect to the entire river from Ortmann (1924), and this reference provides only the presence or absence of a species (Table 2). In contrast, records from the Ohio State Museum of Biological Diversity, under the bivalve search (http://www.biosci.ohio-state.edu/ ~molluscs/OSUM2/), lists 3,555 specimens, not including those deposited for the present study (Table 2). These results also were recorded by county (Table 1), which approximates the recreational designations used here: Wild and Scenic region is predominantly Lake County, with a small section of Ashtabula; the Scenic section is entirely within Ashtabula County; and the headwater region is predominantly in Trumbull and Geauga counties, with only a short stretch penetrating into Ashtabula. Thus, for contrast, comparing county collections to these three divisions of the river enabled us to compare faunal changes along the river that have occurred over the past 30-40 years. The depth of the river near the mouth and the absence of Q. quadrula in any museum collections suggest that no previous information on this zone exists. The Headwaters Section Twenty-five sites along the headwaters section (which runs from Geauga, through Trumbull, and into Ashtabula counties) were surveyed to yield a total of 3,579 living mussels of 19 species (Table 1). The most dominant mussel species found in the headwaters of the Grand River were Elliptio dilatata (29%), Lampsilis radiata luteola (24.2%), Fusconaia flava (13.8%), and Actinonaias ligamentina (9.4%). Subdominant species included Lampsilis cardium (4.8%), Amblema plicata (3.4%), Lasmigona costata (2.9%), and Obovaria subrotunda (2.9%). The remaining 11 species were less prominent, although some occurred in significant numbers locally (that is, Pleurobema sintoxia, 8.2% at RM 78.5 and Utterbackia imbecillis, 37.4% at RM 76.6). No mussels were found in the Grand River’s three most upstream sites. The first had a bedrock bottom, while the second and third had sandy gravel sediments, which are adequate substratum environments. These two sites were extensively searched visually and by excavating the substrata, but neither living nor relic mussels were found. The first mussel community was encountered at RM 91.8, where we counted 100 living mussels of nine species. OHIO JOURNAL OF SCIENCE 59 M. K. HUEHNER AND OTHERS