SPECIES KEPRESEIfriMG THE COIIMERCIAL CATCH 



The nuriiber of cpccies of dirimp identified in watci's fichcd 

 by the domestic fishing fleet runa into dozens, but the specien talcen 

 by corranorcial fishermen probably do not exceed 20. At least 90 per- 

 cent of the total catch consists of only three species. These are 

 white shrijnp Penaeus setiferus , pinlc shrimp Penaeus duorar um, and 

 brovjn shrimp jPonaeus a2;tccus . (see figures I - 5a, 5b and ^c") The last 

 txjo are soinetiLvs referHcTTo as grooved shrimp. Of lesser importance 

 is the sea bob Xiphopencus lo-oy eri . 



Among the species contributing to the coiamercial catch, thera 

 are distinct differences in size, variations in color, and anatomical 

 sti-ucture. The species of sea shrirnp listed above have the first three 

 pairs of thoracic (walking) legs of which there are fiva pairs in all, 

 fitted with chelae (pincers). The white shrimp and the grooved slirliqj 

 have teeth above and below on the rostrum (hea'd spine), whereas the sea 

 bob has rostral teeth only on the upper surface. The grooved shrimp can 

 be distinguished from the white shrimp (which it closely rosombles at 

 first glance) by the presence on the former of grooves on either side of 

 the rostrum which extend to the back laargin of the carapace (head shell) 

 and grooves on the last segment of the tail. 



In the sea bob the last two pairs of walking legs are slender 

 and much elongated. It was from those four elongated legs and the two 

 antennae or feelers that the designation sea bob was derived. The naine 

 is a corruption of the French "sis barbes" which maans six beards - the 

 naiTiQ given to this shrimp by Louisiana fishermen of French extraction. 



Broadly spealcing, the larger slurimp come from the vrarmer waters 

 of the south Atlantic and Gulf area. In Alaska and in the Pacific Coast 

 States large shi-imp constitute relatively smjai proportions of the catch. 



In the North Atlantic Coast States pink shrimp Pandalns borealis 

 was the only specios talcen in Maine and Massacliusetts, whou tliese ITatos 

 had a commercial shrirup fishery. In New York and New Jersey, where the 

 fishery is almost entirely for bait shriiup, sand shriiap Cran-ion vul<7aris 

 and grass shrimp Palac-iuonetes yuljrar is and Palaomonetes caroiinu s con'-^ 

 stitute the entire catch. " 



The coiiunercial catch of shriiip in Alaska and in the Pacific 

 Coast States consists of the genera, Crago and Pandalus. The former, 

 coiraaonly called Bay shriii.p, are taken only in San Francisco Bay. The 

 specios landed there are for the most part Craj?o franciscorum , Crar^o 

 nigricauda, and Crago ni groiiiaculata , the first naiaad being the mosF" 

 ir.iportant. Up to 19?ky Bay slirimp account for about 75 percent of the 

 total California catch of shriaap. In 1956, hoiraver, the catch from the 

 new shrimping grounds off the northern coast of California exceeded the 

 Bay stiriiap catch. 



