DISEASES, PARASITES, AND TOXIC RESPONSES OF 



COMMERCIAL PENAEID SHRIMPS OF THE GULF OF MEXICO 



AND SOUTH ATLANTIC COASTS OF NORTH AMERICA^ 



John A. Couch* 



ABSTRACT 



A reference work and review of both infectious and noninfectious diseases of commercial penaeid 

 shrimps of the Gulf and South Atlantic region of the United States is presented. Disease is second only 

 to predation and periodic physical catastrophes in limiting numbers of penaeid shrimps in nature and 

 second only to nutritional and reproductive requirements in limiting aquacultural successes with 

 p>enaeid shrimps. 



Infectious agents causing disease in penaeid shrimps are a virus, bacteria, fungi, protozoa, hel- 

 minthes, and nematodes. A well-described Baculovirus infects larval and adult shrimp and is as- 

 sociated with mortality, particularly in larval shrimp. Bacteria of the genera Vibrio, Beneckea, and 

 Leucothrix are associated with disease in penaeid shrimps, but bacterial roles in mortality are unclear. 

 The same is largely true for fungi with members of the genera Lagenidium and Fusarium causing 

 pathogenesis in cultured shrimp. Lagenidium causes severe destruction of larval shrimp tissues. Of 

 the many protozoan groups represented in and on penaeid shrimps as tissue parasites and commensals, 

 the MicrospKjrida of the genera Nosema, Thelohania, and Pleistophora are the most destructive. The 

 ciliate protozoa Zoo^/iamratum sp., Lagenophrys sp., and Parauronema sp. may cause dysfunction in 

 shrimp. An undescribed apostome ciliate is associated with black gill disease. A suctorian, Ephelota sp., 

 is an ectocommensal of larval shrimp, attaching to the cuticle. The six species of gregarines reported 

 cause little or no pathogenesis, and a single reported flagellate si)ecies role in shrimp health is 

 uncertain. 



Flatworms found in penaeid shrimps are metacerceu"iae of a species o{ Microphallus in muscles and 

 viscera, metacercariae of Opecoeloides fimbriatus in viscera, plerocercoid larvae of Prochristianella 

 hispida in the hepatopancreas and hemocoel, and four other cestode developmental stages. Nematodes 

 found are Thynnascaris sp., Spirocamallanus pereirai, Leptolaimus sp., and Croconema sp. 



Noninfectious disease agents in penaeid shrimps are chemical pollutants, heavy metals, and en- 

 vironmental stresses. Organochlorine, organophosphate, and carbamate pesticides all have adverse 

 eflfects in penaeids. Fractions of petroleum, particularly the naphthalenes, are very toxic to shrimp. 

 Little other work has been done on the effects of petroleum on penaeid shrimps. Cadmium causes black 

 gills in shrimp by killing gill cells. Mercury is accumulated by penaeids and may interfere with their 

 osmoregulatory abilities. Many chemotheropeutic chemicals used routinely in treatment offish dis- 

 eases are toxic to shrimp at certain determined concentrations. 



Spontaneous pathoses found are a benign tumor, muscle necrosis, and gas bubble disease. "Shell 

 disease" is discussed from points of view of possible causes. A syndrome of "broken backs" is reported in 

 jienaeid shrimps for the first time. An overview is presented for general needs in penaeid shrimp health 

 research. 



Recent attempts to culture penaeid shrimps in 

 large quantities have stimulated renewed interest 

 in the pathobiology of crustacean species. Patho- 

 gens and disease, in general, have been indicted as 

 causes for many failures in maintaining various 

 life-cycle stages of Crustacea. Therefore, consid- 



'Contribution No. 283 from the Gulf Breeze Environmental 

 Research Laboratory. 



^U.S. Environmental Protection Agency, Environmental Re- 

 search Laboratory, Gulf Breeze, PL 32561. 



Manuscript accepted May 1977. 



FISHERY BULLETIN: VOL. 76, NO. 1, 1978. 



erable amounts of new information and data on 

 known and recently discovered diseases of penaeid 

 shrimps have been published or reported in the 

 last decade. This recent information, along with 

 an older but equally valuable series of publica- 

 tions, presents a substantial body of knowledge 

 which describes and defines problems of disease 

 encountered in the biology, management, and 

 massive culture of penaeid shrimps. 



Major contributions to the study of shrimp dis- 

 eases in North America have been made by sev- 



1- 



