migrated at least 150 miles before recovery on the 

 offshore grounds. 



3. The recovery patterns show that shrimp 

 disperse considerably between release and re- 

 covery, suggesting broad migration routes. De- 

 spite such dispersion, shrimp emanating from each 

 nursery area indicated a distinct pattern of 

 distribution on the offshore grounds. 



4. Shrimp leaving the estuaries and moving 

 across the offshore grounds tend to move into 

 deeper water. Although limited movement into 

 shallower water was noted on the offshore grounds, 

 such movement is apparently only temporary, 

 because recoveries after long free periods were 

 almost always from deeper water. 



5. Mark-recovery data reveal that the length of 

 time spent in the estuaries by shrimp may vary 

 from about 2 to at least 6 months. 



6. Between release in an estuary and recovery 

 on an offshore trawling ground the minimum free 

 time of any marked shrimp was 35 days, the 

 maximum 331 days. 



7. Shrimp available for capture on the Tortugas 

 trawling grounds emanate from shallower waters 

 to the north, northeast, and east of the grounds. 

 In these directions, the Tortugas stock recruit- 

 ment range extends at least as far as the south 

 Sanibel grounds, Indian Key, Shark River, 

 Flamingo, Bottle Key, Peterson Keys, and that 

 portion of Hawk Channel south of Bahia Honda 

 Key. Thus, a large portion of the estuarine 

 nursery grounds is located within Everglades 

 National Park. Shallows within the Tortugas 

 grounds may also be a source of recruits to this 

 fishery. The affinity to the Tortugas stocks of 

 pink shrimp occurring in deep water east and south 

 of -the Florida Keys, and south, west, and north- 

 west of the Tortugas grounds has not been 

 established. 



8. Shrimp available for capture on the south 

 Sanibel trawling grounds emanate from shallower 

 waters along the adjacent coast. Coastally, 

 minimum limits of the recruitment area range 

 from Pine Island Sound, to the north, to Indian 

 Key, southeast of the grounds. Offshore, pink 

 shrimp of the south Sanibel stocks occur on the 

 northwest Sanibel grounds and on the northwestern 

 portion of t lie Tortugas grounds. The relationship 

 of the south Sanibel pink shrimp to those in- 

 habiting deeper water west of the grounds is not 

 known. 



9. The Sanibel and Tortugas stocks overlap 

 along the southwest coast of Florida and in the 

 offshore water between the two trawling grounds. 

 There is evidence that young shrimp recruited 

 from nursery grounds as remote as northeastern 

 Florida Bay and Pine Island Sound associate, as 

 adults, in the area intervening between the 

 Sanibel and Tortugas grounds. Apparently Tor- 

 tugas shrimp do not migrate to the Sanibel 

 trawling grounds, and south Sanibel shrimp seldom 

 migrate to the Tortugas trawling grounds, or 

 to the northwest Sanibel grounds. 



10. The geographic distribution of the Tor- 

 tugas and Sanibel shrimp stocks as presented here 

 constitutes a minimum range. The absence of 

 fishing effort in certain contiguous regions pre- 

 cluded recoveries and, therefore, identification of 

 these regions as part of the range. In addition, 

 insufficient knowledge of the migrations of larval 

 and postlarval shrimp precludes determination of 

 their origin, which may be beyond the region 

 known to be frequented by the Tortugas and 

 Sanibel shrimp stocks as juveniles and adults. 



LITERATURE CITED 



Broad, Carter. 



1950. The shrimp fishery of the Florida Keys. 

 University of North Carolina Institute of Fisheries 

 Research, Morehead City, N.C., March 15, 1950. 

 [Mimeographed Report, 13 pp.] 



Bureau of Commercial Fisheries. 



1961. Extensive survey made off Florida east coast 

 for stocks of shrimp and scallops: M/V Silver Bay 

 Cruise 26. U.S. Fish and Wildlife Service, Com- 

 mercial Fisheries Review, vol. 23, No. 1, pp. 32-34. 



1962. Exploratory fishing for shrimp, scallops, and 

 small snappers in south Atlantic: M/V Silver Bay 

 Cruise 34. U.S. Fish and Wildlife Service, Com- 

 mercial Fisheries Review, vol. 24, No. 1, pp. 29-31. 



Burkenroad, Martin D. 



1939. Further observations on Penaeidae of the 

 northern Gulf of Mexico. Bingham Oceanographic 

 Collection, Bulletin, vol. 6. art. 6, 62 pp. 



COSTELLO, T. J. 



1964. Field techniques for staining-recapture experi- 

 ments with commercial shrimp. U.S. Fish and 

 Wildlife Service, Special Scientific Report — Fish- 

 eries No. 484, 15 pp. 



COSTELLO, T. J., AND DONALD M. AlLKN. 



1960. Notes on the migration and growth of pink 

 shrimp (Penacus rfttorarum). Gulf and Caribbean 

 Fisheries Institute Proceedings. 12th Annual Ses- 

 sion, pp. 5-9. 



458 



U.S. FISH AND WILDLIFE SERVICE 



