COUCH: DISEASES AND PARASITES OF PENAEID SHRIMPS 



i. 



Figure 46. — Pink shrimp from mortality related to salinity drop and cold-water temperatures; note dorsal region between third and 

 fourth pleural plates where muscle is protruding. Middle shrimp was still alive when photo was taken; note beginning break in dorsal 

 cuticle (arrow). Top and bottom shrimp died just prior to photograph. 



little is known of the toxic responses of penaeids to 

 such environmentally abundant pollutants as oil, 

 oil products, pesticides, heavy metals, industrial 

 chemicals, and domestic sewage. The question of 

 acquisition of resistance to infectious disease or 

 toxicants in penaeid shrimps is unanswered. 

 There is a pressing need to begin detailed studies 

 of pathogenesis of disease and mechanisms of 

 pathogenesis. 



With the knowledge that penaeid shrimps have 

 cosmopolitan distribution comes the realization 

 that the disease problems of so narrow an area as 

 encompassed in the review merely hint at the 

 vastness of the potential problems of shrimp dis- 



eases worldwide. This is not the case for many 

 other decapod Crustacea which have relatively 

 restricted ranges (i.e., Homarus americanus, Cal- 

 linectes sapidus) and which do not assume the 

 worldwide commercial value of penaeid shrimps. 



The old truisms concerning crowding of large 

 numbers of penaeid shrimps in mariculture at- 

 tempts and rapid spread of infectious diseases still 

 apply as future problems to be studied. Along with 

 this, continual need for better chemotherapeutic 

 agents and an understanding of their effects on 

 penaeid shrimps is apparent. 



Because penaeid shrimps are components in the 

 human food chain (wherein man is the final con- 



41 



