Migrations, Mortality, and Growth of Pink Shrimp 



Thomas J. Costello and Donald M. Allen 



Migrations Two mark- recapture experiments executed during the period 



November-May (1960-61) extended a series of similar experiments initiated 

 in 1958 to circumscribe the geographical range of stocks supporting the Tor- 

 tugas pink shrimp fishery. 



Responding to intensified publicity (and a sizeable monetary induce- 

 ment), commercial fishermen turned in 56 and 149 recaptures, respectively, 

 of shrimp stained and released as juveniles at Bottle Key (13, 309) in Novem- 

 ber, and Lower Pine Island Sound (32, 913) in December. Of the Bottle Key 

 recaptures, 10 came from Florida Bay within 6 miles of the release site, and 

 46 from the Tortugas grounds about 120 miles to the west. The last of these 

 was made early in May, 6 naonths following release, confirming the stated 

 durability of certain biological dyes as shrimp-marking agents. 



All Pine Island Sound recaptures were made on the Sanibel fishing 

 grounds within a 30-mile radius of the release site. 



The accompanying table and figure summarize the results of com- 

 pleted experiments. These results tentatively indicate that all of Florida Bay 



constitutes nursery area for 

 pre-recruit segments of the 

 Tortugas pink shrimp stock, 

 whereas Barnes Sound and 

 Biscayne Bay on the Florida 

 east coast, and estuaries 

 north of Cape Romano on the 

 west coast do not. More- 

 over, migration patterns ex- 

 hibited by these experinnental 

 populations suggest the gen- 

 eral movement of immature 

 shrimp to be , somewhat ra- 

 dially, in an east-west (on- 

 shore-offshore) rather than 

 in a north- south (coastwise) 

 direction. This relationship 

 between inshore nursery 

 areas and directly opposing 

 offshore spawning areas 



seeras to hold regardless of 

 Release sites for mark- recapture experiments, . . j-^^.^ „„„ ■ 



^ ^ the migration distances in- 



and probable routes of juvenile pink shrimp to , , ^, . . ^ ^<.-ii 



^ J i- X- volved. The questions still 



recapture area, Florida Bay and Gulf of Mexico, . , 4. /i\ 



•^ ■' rennain, however, as to (1) 



1958-1961. 



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