The white shrimp, Penaeus setiferus, was the first species of commercially important shrimp in the U.S., with the fishery for this species dating back to 1709 (Muncy 1984). P. setiferus is common in Florida waters and is generally found where water is less than 27 m deep (Muncy 1984). Antennae are significantly longer than body length, and may reach 2.5 - 3 times body length (Muncy 1984). Chromatophores in white shrimp are widely spaced, thus lending a lighter body color to this species than in either pink or brown shrimp. Overall body color is a bluish white, speckled with black, with pink-tinged sides. Pleopods are often marked with dark red, while the margins of the uropods of the tail are green along their margins (Williams 1984). Its carapace has a medial carina (keel-like ridge) that is continuous with the rostrum at the anterior end of the animal, and extends posteriorly approximately 2/3 the length of the carapace. The rostrum is elongate and slender, somewhat distally upcurved, with 5 - 11 (usually 9) sharp teeth on the dorsal surface, and 2 teeth on the ventral edge. Unlike its congeners P. aztecus and P. duorarum, P. setiferus has no bordering groove along the carina. The integument is thin, and appears polished and translucent.The abdomen is carinate on segments 4 - 6, with the carina of segment 6 having a narrow groove on either side. The telson has a deep medial groove along its length, and a sharp tip. The ventral margin of the pleura of the first segment is almost straight.P. setiferus is sexually dimorphic, with females growing larger than males. Additionally, the female thelycum, which lies between pereopods 3- 5, is open and has raised ridges along the anterolateral surface. The male pentasma has a diagonal ridge across the dorsolateral lobe.