Length-Weight Relation and Conversion of "Whole" and "Headless" 

 Weights of Royal-Red Shrimp, Hymenopenaeus robustus (Smith) 



By 

 EDWARD F. KLIMA, Fishery Biologist 



Bureau of Commercial Fisheries 



Exploratory Fishing and Gear Research Base 



Pascagoula, Miss. 39567 



ABSTRACT 



Differences in the length-weight regression coefficient (b) between sexes are 

 noted for shrimp in one of three areas, and differences among areas are apparent. 



Equations for converting whole weight to headless weight and vice versa are 

 given for three areas. The estimating equations differ between the areas. Estimating 

 equations for each area are adequate for describing the relation between whole and 

 headless weights and headless and whole weights. 



INTRODUCTION 



Exploratory research vessels of the Bureau 

 of Commercial Fisheries have found royal- 

 red shrimp, Hymenopenaeus robustus (Smith), 

 along the upper Continental Slope in the west- 

 ern North Atlantic from Cape Hatteras, N.C., 

 to Brazil (Bullis, 1956; Bullis and Cummins, 

 1963). Population density varies widely 

 throughout the species range, however, and 

 only three areas with commercial potential 

 have been delineated. One lies off the east 

 coast of Florida, from St. Augustine to Fort 

 Pierce; another lies south-southwest of the 

 Dry Tortugas; and the third is off the Mis- 

 sissippi River Delta from southeast of the 

 Mississippi Passes to off Mobile, Ala. 



Commercial harvesting of the royal-red 

 shrimp has increased since the discovery 

 of these areas. During 1967, over 70,000 

 pounds of headless (or "heads off") royal-red 

 shrimp, valued at more than $55,000, were 

 landed. Roe 1 estimated that the three areas 

 could produce annually 1.6 million pounds of 

 20 -count whole shrimp. 



With the development of a royal-red shrimp 

 fishery, there is need for biological studies. 

 Information on the length-weight relation of 



1 Unpublished manuscript. The distribution of royal-red 

 shrimp, Hymenopenaeus robustus (Smith), on three poten- 

 tial commercial grounds off southeastern United States by 

 Richard B. Roe, 1967, Bureau of Commercial Fisheries 

 Exploratory Fishing and Gear Research Base, Pascagoula, 

 Miss. 39567, 24 pp. 



this species is required for studies of con- 

 dition, growth, sexual maturity, and equi- 

 librium yield in terms of weight. This paper 

 describes the length-weight relation of royal - 

 red shrimp for each of the three commercial 

 fishing areas off the southern United States. 



Statistics on commercial shrimp fisheries 

 of the South Atlantic and Gulf States are col- 

 lected and published by the Bureau of Com- 

 mercial Fisheries. Shrimp landings are tabu- 

 lated in units of "headless" (or "heads off") 

 weight. Because fishery biologists and in- 

 dustry personnel need information on both 

 total and tail weight of shrimp, an appropriate 

 conversion factor is required. Estimates of 

 headless weight when whole weight is given 

 and whole weight when headless weight is 

 given also are presented in this paper. 



MATERIAL AND METHODS 



Length-weight and total weight -tail weight 

 equations were computed from measurements 

 of 1,978 shrimp caught by exploratory re- 

 search vessels during October and November 

 1965. Of these, 1,547 were taken from the 

 St. Augustine area, 227 from the Dry Tortugas 

 area, and 204 from the Mississippi Delta 

 grounds. 



Standardized handling procedures were used 

 to decrease variation due to handling and 

 processing of specimens. The specimens were 

 frozen immediately after capture. Prior to 

 measurement, the samples were thawed and 

 excess moisture was removed by blotting with 



