CONTRIBUTIONS TO THE BIOLOGY OF THE ROYAL 

 RED SHRIMP, Hymenopenaeus rohnstus SMITH' 



William W. Anderson^ and Milton J. Lindner" 



ABSTRACT 



The royal red shrimp, Hymenopenaeus robustus, has been located in commercial concentrations in three 

 areas off the coast of the United States in depths from about 250 to 550 m : one area, known as the St. 

 Augustine Grounds, is off the east coast of Florida; another is off the Dry Tortugas; and the third 

 is off the Mississippi River Delta. 



Information on the biology of the species on the St. Augustine Grounds was collected intermittently 

 from 1957 to 1967. 



The reproductive systems of males and females are described and illustrated. The ovaries of ripe 

 females are dark red or maroon, and the exceedingly large spermatophores are bright yellow. We 

 observed no indication of sex reversal. 



Burrowing and swimming habits as observed from the research submarine Aluminaut are summarized. 



The early life history of H. robushis is unknown. Neither larval nor postlarval stages were en- 

 countered in the plankton collections of the M/V Theodore N. GUI. Juveniles under 50 mm total 

 length were not caught. 



Size of shrimp was not correlated with depth but appeared to be correlated with latitude. Usu- 

 ally shrimp were larger north of lat 29°39' N than between lat 29°00' and 29°39' N. 



Males mature at about 125 mm and females at about 155 mm total length. In each sex, maturity 

 is reflected by a change in the regression of carapace length on total length. 



Spawning probably occurs throughout the year, but the peak is between January and May. 



Year classes are evident in the length distributions. Recruitment on the fishing grounds begins 

 when the shrimp are approaching 1 year of age and are less than 100 mm total length. They reach 

 maturity at about 3 years, and minimum life span appears to be no less than 5 years. Recruitment 

 is probably not complete until at least 2 years. Most of the shrimp on the fishing grounds are mature. 



The royal red shrimp, Hymenopenaetis robustus 

 Smith, a large deepwater penaeid (Figure 1), 

 has a wide distribution from the east coast of 

 the United States to well down the east coast 

 of South America, principally in depths of 256 

 to 549 m (140-300 fm). 



Surveys by the Bureau of Commercial Fish- 

 eries (now the National Marine Fisheries Ser- 

 vice) have indicated three major concentrations 

 of these shrimp off the coast of the United States 

 that have commercial possibilities: (1) off St. 

 Augustine on the east coast of Florida (Figure 

 2), (2) off the Dry Tortugas in the Florida 



' Contribution No. 301, National Marine Fisheries 

 Service Biological Laboratory, Galveston, Tex. 77550. 



- State Game & Fish Commission, Coastal Fisheries 

 Division, Brunswick, Ga. 31520. 



' Formerly National Marine Fisheries Service Bio- 

 logical Laboratory, Galveston, Tex. 77550. 



Manuscript received January 1971. 



FISHERY BULLETIN: VOL. 69, NO. 2, 1971. 



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v^' 



Figure 1. — Adult female and male royal red shrimp, 

 showing great difference in size of sexes. Female (up- 

 per) 210 mm and male (lower) 160 mm total length. 



313 



