OYSTER PRODUCTION 

 DELAWARE BAY 



iMIiii 



950 1955 I960 1965 

 YEAR 



Figure 4. — Oyster production in New Jersey waters ol Delaware Bay, 1950-65. 



talities in Louisiana. SpraKuc and Orr (1953, 

 1955) demonstrated that .V. ostrcannii as de- 

 .scribed by Prytherch, was actually two species, 

 which they designated .V. ufitrcanifn (emended) 

 .nui .V. piiitherchi. Spores of A^ pnjtherchi are 

 larjJTcr and more elongate, localize in the jr'"^ 

 rather than in the mantle, and have vegetative 

 stages only in the crab Menippe mercenaria 

 (Say). The life cycle of N. OHtrcanmi includes 

 a mud crab host — Panopeus herbstii Milne-Ed- 

 wards, Eurypanopeus depressus (Smith), or 

 Eiinjtiiim Umosuni (Say). In many oyster- 

 growing areas most oysters are infected, al- 

 though infections are rarely heavy. Mackin 

 (1962) has pointed out the lack of tissue reac- 

 tion to the parasite and the lack of e idence 



for existence of lysins or toxins. Feng (1958) 

 found that a dynamic equilibrium existed be- 

 tween acquisition by the oyster of new parasites 

 .ind elimination of spores. 



Netnatopsis was found to be widely distrib- 

 uted on the Atlantic and Gulf coasts of the 

 United States by Landau and Galtsoff (1951). 

 They found heavy infections in oysters from 

 certain localities, such as the mouth of Chesa- 

 peake Bay, but relations with other ecological 

 factors such as abundance of crabs were not 

 apparent. The intensity of infection was cumu- 

 lative and increased with age of the host. No 

 evidence was obtained to indicate that Nema- 

 topsi.-^ infection caused poor meats or mortality 

 of oysters. 



342 



U.S. FISH AND WILDLIFE SERVICE 



