RELATION BETWEEN TAIL LENGTH AND TOTAL LENGTH FOR THREE 

 COMMERCIALLY IMPORTANT SPECIES OF PENAEID SHRIMP' 



By Clark T. Fontaine and Richard A. Neal, Fishery Biologists 



Bureau of Commercial Fisherie.s Biological Laboratory 



Galveston, Texas 77550 



Length measurements of shrimp from commer- 

 cial landings are an important source of biological 

 information. Total length (tip of telson to tip of 

 rostrum) is the measurement most commonly used, 

 but it cannot be determined directly when fisher- 

 men separate shrimp "heads" (cephalothorax) and 

 "tails" (abdomen) before they reach the docks. 

 We determined the relations between tail length 

 (anterior margin of first abdominal segment to tip 

 of telson) and total length so that measurements 

 obtained from headless shrimp could be converted 

 to total lengths. 



The relations were based on data from 1,581 

 brown shi'imp, Penaeus a. asteciis Ives (86-225 

 mm., total length) ; 2,460 white shrimp, P. sefiferus 

 (Linnaeus) (74-213 mm.); and 1,909 pink shrimp, 

 P. d. duomrum Burkenroad (82-194 mm.). The 

 brown and wliite shrimp were caught off the Texas 

 coast, and the pink shrimp were from the Tortugas 

 grounds off Florida. Measurements were made to 

 the nearest millimeter, and, when possible, equal 



1 Contribution No. 262, Bureau of Commercial Fisheries Biological Laljora- 

 tory, Galveston. Texas 77550. 

 Puljlisherl August 1968. 



luunbers of shrimp were measured in each 5-mm. 

 total length group. 



The relation between tail length and total length 

 appeared to be linear for the range of sizes ex- 

 amined; a straight line was fitted to data for each 

 sex of each species by the method of least squares 

 (figs. 1 and 2) . Formulas for the lines are presented 

 in table 1. 



T.\BLE 1. — Equations describing the relations between tail 

 length and total length of pink, brown, and white shrimp 



[Y = total length. X = tail length] 



FISHERY BULLETIN: VOL. 67, NO. 1 



126 



