incurs 



31 



• ' . iiiimiiiii 



Figure 8. — Lateral view of the commercial shrimp, M. vollenhovenii, with black-spot disease on the carapace, 



abdomen, and walking legs. 



caught countless numbers of young shrimp 

 and larval fishes. The catch, molded into cakes 

 and placed between banana leaves, was smoked 

 and eaten by the fishermen. 



When I examined the catch made by the 

 women on November 15, 1953, I found that the 

 young shrimp averaged 5 to 10 mm. long. Be- 

 fore November juvenile shrimp were not 

 abundant, an indication that the group caught 

 in November was from the peak spawning in 

 September. The early development of M. vol- 

 lenhovenii appears to be nearly identical to 

 that of M. rosenbergii reported by Ling 

 (1967a). Ling (1967a) found embryonic de- 

 velopment was 19 to 20 days, larval develop- 

 ment (planktonic) 30 to 45 days, or a total of 

 50 to 65 days until the shrimp settled as 4.5- 

 to 5.0-mm. juveniles. 



Disease 



A black-spot microbial infection was found 

 around scratches on the body or legs of shrimp 

 (fig. 8). Anderson and Conroy (1968) have 

 reported similar diseases in Crustacea. The 

 infection not only ate through the carapace 

 or abdomen but also attacked underlying tis- 

 sues such as the gill filaments or the abdominal 

 muscles; the telson and walking legs also were 

 heavily infected. At times, the infection 

 formed a ring around the middle portion of a 



walking leg and caused part of the leg to fall 

 off. Identification of the disease was not pos- 

 sible because laboratory facilities were lacking. 

 A sample of 150 shrimp examined on May 30, 

 1953, had 137 infected. Though not confined 

 to shrimp of any size range, the infection ap- 

 peared to be most severe on large individuals. 

 The palatability of the shrimp did not appear 

 to be affected by the infection. A substantial 

 mortality of M. vollenhovenii may occur at 

 times from the disease. 



BIOLOGY OF M. macrobrachion 



The biology of M. macrobrachion, in this 

 report, will include only a description of the 

 small noncommercial species, and its contri- 

 bution in numbers and size in the culls from 

 the commercial catch. 



Description 



M. macrobrachion, a small species, is usually 

 less than 75 mm. long. The body is a light 

 blue-gray mottled with dark spots. The ros- 

 trum is long and slender, and arches slightly 

 upward at the tip; 8 to 10 dorsal spines extend 

 from the carapace onto the rostrum, and a 

 short space separates them from 2 spines at 

 the tip of the rostrum; 4 to 6 spines are present 

 on the ventral surface. The carpus of the 



11 



