SUBLETHAL EFFECTS OF SUSPENDED SEDIMENTS ON ESTUARINE FISH 



by 

 J.M. O'Connor, D.A. Neumann, and J. A. Sherk, Jr. 



I. INTRODUCTION TO SUBLETHAL EFFECTS OF 

 SUSPENDED SOLIDS ON ESTUARINE FISH 



The lethal effects of a variety of solids are documented for numerous 

 freshwater fish (Ellis, 1936, 1937; Wallen, 1951; Wilson, 1956; Cordone 

 and Kelley, 1961; Herbert, et al . , 1961; Herbert and Merkens, 1961) and 

 for some estuarine species (Rogers, 1969; Sherk and O'Connor, 1971; 

 O'Connor, Neumann, and Sherk, 1976). However, the sublethal effects are 

 only dealt with in histological studies of fish gill tissues (Southgate, 

 1962; Herbert, et al . , 1961; Herbert and Merkens, 1961; Ritchie, 1970). 

 The physiological impact of sublethal concentrations has not been studied 

 previously. This part of a 3-year laboratory study (Sherk, O'Connor, and 

 Neumann, 1976; O'Connor, Neumann, and Sherk, 1976) presents the results 

 of histological and physiological studies of the sublethal effects of 

 suspended solids on estuarine fish. 



Seven estuarine fish species .(white perch, Morone americana; striped 

 bass, Morone saxatilis ; hogchoker, Trineotes maautatus; spot, Leiostomus 

 xanthums; mummichog, Fundulus heteroatitus ; striped killifish, Fundulus 

 majalis; and oyster toadfish, Opsanus tau) were placed in fuller's earth 

 and natural sediment suspensions, and hematological changes wQre noted 

 during timed exposures. The effects of fuller's earth suspensions on gill 

 tissue in white perch and on carbohydrate metabolism in hogchoker were 

 determined at various concentrations. Oxygen consumption rates of striped 

 bass, white perch, and toadfish were measured in filtered water from the 

 Patuxent River, Maryland, and compared to consumption rates in filtered 

 river water suspensions of fuller's earth or Patuxent River sediment. 



A knowledge of the sublethal effects of suspended materials is impor- 

 tant in evaluating the effects of dredging or of disposal of dredged 

 materials. This report provides base-line data which can be combined with 

 knowledge of local conditions in preproject consideration of the effects 

 of dredging activities. 



II. SUBLETHAL EFFECTS OF SUSPENDED SOLIDS 

 ON THE HEMATOLOGY OF ESTUARINE FISH 



1. Introduction . 



This section presents an assessment of the effects of suspensions of 

 fuller's earth and natural sediments on several basic hematological param- 

 eters in fish: Microhematocrit (packed red blood cell volume) , red blood 

 cell count, hemoglobin concentration, and osmolality (ionic concentration 

 of the blood) . 



