POLLUTION-ASSOCIATED DISEASES AND ABNORMALITIES 

 OF FISH AND SHELLFISH: A REVIEW 



Carl J. Sindermann' 



ABSTRACT 



The relationship of disease and environmental stress is becoming increasingly well established with 

 time. Human activities — particularly those that result in chemical additions to the coastal/estuarine 

 environment — have increased the potential stresses on fish and shellfish inhabiting those areas. 

 Circumstantial evidence for associations of pollutants with certain fish and shellfish diseases and 

 abnormalities is accumulating. 



This paper attempts to review and evaluate existing information about associations of diseases and 

 marine environmental degradation. Emphasis has been placed on: diseases caused by contaminant 

 stress and related facultative pathogens; stress-provoked latent infections; environmentally induced 

 abnormalities; genetic abnormalities associated with mutagenic and other properties of contaminants; 

 experimentally induced lesions; contaminant effects on resistance and immune responses; and 

 pollutant-parasite interactions. 



There are several diseases, particularly fin erosion and ulcers in fish and shell disease in crustaceans, 

 for which a relationship with pollution seems evident, and there are a number of other diseases or 

 abnormalities (such as certain neoplasms and skeletal anomalies) for which a relationship with 

 pollution is indicated. Furthermore, there is some evidence that certain latent viral infections may be 

 provoked into patency by environmental stress. 



Disease is a constant concomitant of life for any 

 species, normally removing individuals from the 

 population continuously. Marine animals are, of 

 course, subject to a wide spectrum of diseases of 

 infectious or noninfectious etiology ("disease" can 

 be defined in the broad sense as "any departure 

 from normal structure or function of an animal" or 

 as "the end result of interaction between a noxious 

 stimulus and a biological system"). 



Disfunction and death due to the activity of in- 

 fectious agents constitute the narrower, but often 

 predominant concept of disease. Infectious 

 diseases — caused by viruses, bacteria, fungi, pro- 

 tozoa, and other pathogenic organisms — are usu- 

 ally prime suspects in searches for causes of mor- 

 talities, often to the exclusion of other possible 

 causes. Noninfectious diseases include such 

 phenomena as environmentally induced skeletal 

 anomalies, genetic abnormalities, physiological 

 malfunctions caused by chemical environmental 

 factors, metabolic disorders resulting from nutri- 

 tional deficiencies, many forms of neoplasia, and a 

 host of others (Sparks 1972). In many instances, it 

 is probably the combination of an infectious agent 



'Northeast Fisheries Center Sandy Hook Laboratory, Na- 

 tional Marine Fisheries Service, NOAA, Highlands, NJ 07732. 



and environmental stress that eventually causes 

 mortality. 



The distinction between "infection" and "dis- 

 ease" must be kept in mind. Most organisms are 

 constantly hosts to potentially pathogenic micro- 

 organisms, but disease results from imbalance of 

 the interactive system which includes virulence of 

 the pathogen, resistance of the host, and effects of 

 environmental stresses. 



Infectious disease usually exists in an enzootic 

 form, weakening or disabling individuals and 

 rendering them more susceptible to predators or 

 other environmental stresses. Occasionally, 

 though, epizootics and mortalities comparable to 

 the great plagues of the Middle Ages may sweep 

 through animal populations. In marine species we 

 have seen such massive epizootics result in the 

 great herring mortalities of the mid-1950's in the 

 Gulf of Saint Lawrence (Sindermann 1958), and 

 the extensive oyster mortalities of the 1960's in 

 the Middle Atlantic states (Sindermann 1968). 

 These epizootics are triggered by a complex 

 interplay of pathogen, environment, and host pop- 

 ulation. Considering only the environmental as- 

 pects of such outbreaks, any departure from nor- 

 mal conditions produces a degree of stress on the 

 population, and may contribute to an increase in 

 prevalence of a pathogen, or of facultative invad- 



Manuscript accepted Mav 1978. 



FISHERY BULLETIN; VOL. 76, NO. 4, 1979. 



717 



