Marked shrimp from the Bottle Key release (9), 

 made in November 1960, were recovered in Florida 

 Bay up to 80 days after release. One marked 

 shrimp was recovered in the Bay after two other 

 Bottle Key shrimp had already been caught on 

 the Tortugas grounds. These recoveries show 

 clearly that not all members of a given group of 

 shrimp depart the estuaries at the same time. 

 Bottle Key shrimp were recovered on the Tortugas 

 grounds from January through May 1961 (fig. 5). 

 The majority, however, were taken between Jan- 

 uary 16 and March 31, indicating that most of 

 the marked Bottle Key shrimp that reached the 

 Tortugas grounds were available for recapture 

 within 75 to 149 days after release. The straight 

 line distance between Bottle Key and 'C con- 

 servation buoy, located near the center of fishing 

 effort on the Tortugas grounds, is about 100 miles. 

 Stained shrimp released in September 1961 (12) 

 and December 1962 (15), near 'C buoy on the 

 Tortugas grounds, were recovered up to 85 and 106 

 days after release, respectively. During these 

 periods, many had moved west or northwest into 

 deeper water, some as far as 35 miles. Although 

 several shrimp from release site 15 were taken just 

 south of the northern border of the Tortugas 

 grounds, none was recovered off the Tortugas 

 grounds (fig. 6). 



Marked shrimp released in Pine Island Sound 

 (10) in November and December 1960, were re- 



/\ RECOVERY LIMITS 

 ^s aftfh infi nfl« 



AFTER 106 DATS 



Figure 6. — Dispersal of marked pink shrimp on the 

 Tortugas grounds, December 1962 through March 1963. 



covered on the Sanibel grounds from January 

 through November 1961 . The center of the south 

 Sanibel grounds is about 22 miles from the release 

 site. The greatest numbers are recovered between 

 February 1 and May 15. Part of the increase 

 during this period, however, may be a reflection 

 of increased fishing effort. One shrimp was re- 

 covered on the Sanibel grounds about 11 months 

 after release. Since the smallest shrimp released 

 was estimated to have been at least 1 month old, 

 the recovered shrimp must have been at least a 

 year old. 



Marked pink shrimp released on the south Sani- 

 bel grounds (13) in March 1962 were caught there 

 up to 146 days after release. The recovery posi- 

 tions indicated gradual movement into deeper 

 water to the west and southwest. After 115 days 

 two marked shrimp were caught on the north- 

 western Tortugas grounds, about 80 miles distant. 



GEOGRAPHIC RANGE OF THE TORTUGAS AND 

 SANIBEL PINK SHRIMP 



The range and relationship of pink shrimp stocks 

 of the Tortugas and Sanibel grounds were demon- 

 strated by mark-recovery experiments. The Tor- 

 tugas stocks of pink shrimp are defined as those 

 pink shrimp that are available for capture on the 

 Tortugas shrimp trawling grounds during some 

 portion of their life. The Sanibel stocks may be 

 similarly defined by appropriate word substitu- 

 tion. The sources of pink shrimp eggs and larvae 

 that perpetuate these fisheries have not been 

 positively established. Much of the area fre- 

 quented by Tortugas (or Sanibel) pink shrimp as 

 juveniles and adults, however, can be determined 

 by inspection of marked shrimp release-recovery 

 information (fig. 2 and table 1), Figure 7 is pro- 

 visional and probably depicts only the minimum 

 ranges of the Tortugas and Sanibel pink shrimp 

 stocks. 



Tortugas Stocks 



The Tortugas trawling grounds, located north- 

 west, west, and southwest of Key West, have a 

 maximum depth of about 33 fathoms. The 

 "boundary" is rather indefinite and encloses 

 about 3,100 square miles. In much of the area 

 trawling is restricted by rough bottom or extreme 

 shallowness. 



North, northeast, and east of the Tortugas 

 grounds, the Tortugas stocks of pink shrimp 



MIGRATIONS OF FLORIDA PINK SHRIMP 



455 



