STUDIES ON THE MARKING OF COMMERCIAL SHRIMP WITH 

 BIOLOGICAL STAINS 



INTRODUCTION 



The role of tagging- and marking as 

 aids in determining growth, migration, fishing 

 pressure, and mortality in a commercial -fish- 

 ery population has been described by many 

 authors (Rounsefell and Kask, 1945; Rounsefell 

 and Everhart, 1953). With the exception of 

 various lobster and crab investigations, tagging 

 and marking programs have been confined to 

 finfish. 



Commercial shrimp have been tagged, 

 using the Petersen disk, by the Fish and Wild- 

 life Service, by the Bureau of Fisheries, and by 

 at least one of the Gulf States . Lindner and 

 Anderson (1956) tagged a total of 46,532 shrimp 

 from 1935 through 1947 and reported a gross 

 return of 15.6 percent. Data presented show 

 that recoveries decrease with decrease in size 

 at tagging. No recoveries were obtained from 

 shrimp tagged at a length of 80 mm. or less, 

 and recovery of shrimp in the 85 to 110 mm. 

 range was less than 10 percent. The authors 

 present no details on the maximum period of 

 tag retention, but growth analysis based on re- 

 coveries was limited to a 60-day period. It 

 would appear, therefore, that few recoveries 

 were made of shrimp with more than 60 days' 

 "out-time". McRae (1952) reported a 2.01-per- 

 cent return on 1,137 shrimp tagged along the 

 Texas coast during April, May, and June, 1951. 

 Complete size data are not shown, but the small- 

 est shrimp recovered was approximately 104 

 mm. long at time of tagging. The maximum 

 period between tagging and recovery was 80 days. 



These programs have met with some 

 success, but a more suitable tagging or mark- 

 ing method is needed for shrimp under a length 



\J The term "tagging" is used to denote the 

 application of a mechanical tag or other identif- 

 ication device. "Marking" refers to the use of 

 mutilation, staining, or other means of identifica- 

 tion not requiring the attachment or insertion of 

 mechanical devices. 



of 100 mm., and for use in long-term experi- 

 ments on both juvenile and adult shrimp. 



The tagging or marking of shrimp is 

 complicated by their frailty and small size, and 

 by a high shedding frequency that precludes use 

 of the exoskeleton for either marking or tagging. 

 The massive population and a high mortality re- 

 quire that large numbers be released, preferably 

 over a short period, before a tagging or marking 

 experiment can attain statistical validity. 



Since tags may affect the normal swim- 

 ming ability of shrimp and physical damage 

 accompanying attachment may be considerable, 

 this study was directed toward investigating the 

 practicality of marking shrimp with biological 

 stains. Although tags would be superior for ob- 

 taining individual growth and migration data, it 

 is considered that field studies are directed to- 

 ward the shrimp population rather than the 

 individual . A distinctive and easily applied ab- 

 normal coloration would serve the identification 

 requirements for population studies . 



The use of biological stains for identifica- 

 tion purposes has been tried with varying degrees 

 of success on a number of marine and fresh- 

 water animals. Loosanoff (1937) was successful 

 in marking starfish, Asterias, for periods up to 

 10 months with Nile Blue Sulfate, and Vernon 

 (1937) marked Asterias with Neutral Red. Feder 

 (1955) has used these stains to mark the Pacific- 

 coast starfish, Pisaster ochraceus . Gustafson 

 (1953) and Klawe (1954) were generally unsuccess- 

 ful in their efforts to stain the marine worms 

 Glycera and Nereis although some 14 stains were 

 tested. Dunn and Cocker (1951) and Carranza 

 (1953) injected fish with a number of stains with 

 varying success. Two studies of particular in- 

 terest are those of Menzel (1955) and Racek (1955). 

 Menzel injected white shrimp, Penaeus setiferus , 

 with Fast Green and reported that staining was 

 plainly visible for over 60 days, Racek apparent- 

 ly achieved some success in marKing Australian 

 penaeid prawns by immersing them in solutions 

 of Trypan Blue and Nile Blue Sulfate . He 



