Effects of Potassium on Adult Asiatic Clams, Corbicula manilensis 



Kevin B. Anderson 



Carl M. Thompson 



Richard E. Sparks 



Anthony A. Paparo 



Since its introduction into North America in 1938, 

 the ecological and economic impacts of the Asiatic clam, 

 Corbicula manilensis, have become increasingly impor- 

 tant. Although the ecological consequences of the Asiatic 

 clam have not yet been fully evaluated, Sinclair & Isom 

 (1963: 15) suggested the possibility that the Asiatic clam 

 could displace the native sphaeriid fauna. The clams 

 have also become important by entering food chains. At 

 Lake Sangchris, Sangamon County, Illinois, diving and 

 dabbling ducks ingest Asiatic clams in the wild (Personal 

 communication, William L. Anderson, Associate Wildlife 

 Specialist, Illinois Natural History Survey, October 

 1975). Fish species known to feed on Corbicula m. in- 

 clude the blue catfish (Ictalurus furcatus) , channel catfish 

 (/. punctatus), carp (Cyprinus carpio), redear sunfish 

 {Lepomis microlophus) , freshwater dioun [Aplodinotus 

 grunniens) (Sinclair & Isom 1963:16), and sturgeon 

 (Ingram 1959:369). 



The economic impact of the clams is serious. Sinclair 

 (1971:11) stated that the Asiatic clam was the most 

 costly liability of all exotic mollusca in North America. In 

 the Midwest, the biggest problem caused by these clams 

 is their accumulation in resenoirs, condenser pipes, and 

 water intake structures. In some cases, buildups have be- 

 come so great as to necessitate costly plant shutdowns 

 for cleaning operations. Ingram (1959:364—366) re- 

 viewed a number of problems associated with this alien 

 mollusk. 



An uninvestigated area of study concerns the effects 

 of metal ions on the Asiatic clam and whether metals 

 could affect the distribution of the clams or be used for 

 purposes of control. The objectixe of this research was 

 to measure the sublethal and lethal effects of jjotassium 

 on Corbicula m. 



ACKNOWLEDGMENTS 



We are grateful to Mr. Hubert W. Bell, Supervisor, 

 Illinois Department of Conservation Field Headquarters, 

 Havana, Illinois, for laboratory' space; Mr. Heniy J. 

 Hellrich, Superintendent of Utilities, Granite City Steel 

 Company, Granite City, Illinois, for assistance in obtain- 

 ing Asiatic clams: and to Drs. Kenneth E. Smith, .Asso- 

 ciate Chemist, and Allison Brigham, Assistant Aquatic 



This paper is published by auth 

 127, Par. 58.12, and is a contribulio 

 Illinois Natural History Survey, wher 

 Carl M. Thompson 



.rily of the Stale of Illinois, IRS Ch. 

 from the Section of Aquatic Biology. 

 Mr. Kevin I). Anderson is a Research 

 Junior Professional Scientist, and 



,rd E. Sparks is an A-ssistant Aciuatic Biologist. Mr. Anderson is also 

 c student at Western Illinois University, Macomb. Dr. Anthony A. 

 i an Associate Professor, Department of Zoology and School of 

 Southern Illinois University, Carbondale, 



Biologist, Illinois Natural History Survey, for chemical 

 analyses. We also wish to thank Mr. Robert M. Zewadski, 

 Technical Editor, Illinois Natural History .Survey, for his 

 assistance in preparing this report for publication. The 

 research was paid for, in part, by a grant from the Illi- 

 nois Institute for Environmental Quality. Mr. Kevin B. 

 Anderson's work was supported by funds provided by the 

 U.S. Office of Water Research and Technology and ad- 

 ministered by the Water Resources Center, University of 

 Illinois, Urbana-Champaign, as Project B-097-ILL. 



METHODS AND MATERIALS 

 Clams 



The mature Corbicula manilensis u.sed in this experi- 

 ment were collected on 23 October 1975 at the Granite 

 City Steel Company, Granite City, Illinois. The organisms 

 had accumulated in a reservoir containing water used for 

 cooling purposes. They were transported to the Illinois 

 Department of Conservation Field Headquarters at 

 Havana, Illinois, where they were acclimated in well 

 water for 6 weeks in a 600-liter tank. Water temperature 

 in the holding tank was maintained at 17° zb 1° C. The 

 clams were fed once a week with Gordon's formula 

 (Innes:33), which was finely ground by mixing with 

 water in a Waring blender, 



Asiatic clams used in the bioassay averaged 12.6 mm 

 in shell length (range, 11-14 mm) and 565 mg in vveight. 



Testing Apparatus 



A proportional diluter (Mount & Brungs 1967) was 

 used to deliver a continuous flow of well water or well 

 water plus potassium to the test chambei"s. The test 

 chambers were 19-liter gla.ss jars immersed in a circulat- 

 ing water bath to minimize temperature fluctuations dur- 

 ing tests. Groups of clams were placed in "clam cages," 

 each consisting of a Petri dish (100-mm diameter) cov- 

 ered with a plastic lid, A 50-mm diameter hole was cut in 

 the center of the lid. This design allowed water to circu- 

 late in the clam cages and kept the clams from crawling 

 out. The cages could be removed and placed under a 

 dissecting microscope without greatly disturbing the 

 clams. 



The flow rate of the diluter was adjusted to 3.57 

 litere per hour, allowing 90-percent replacement of the 

 test solution in 1 1 hours. 



Duplicate test chambers were used for each of the 

 five test concentrations and the controls — 12 chambers 

 in all. 



