CONTENTS 



Page 



Introduction 1 



The fishery 1 



Purposes of the study 2 



Acknowledgments 3 



Methods and materials 3 



Vessels and gear 3 



Observations of fleet activity 5 



Shrimp discards 6 



Treatment of data 6 



Size distribution of shrimp 6 



Sampling variation from single and double nets 6 



Effect of trawl mesh size 8 



Shrimp size isopleths 8 



Sex ratio 10 



Size of shrimp 10 



Distribution of shrimp by size and depth 10 



Fleet concentrations 16 



Shrimp discarding 16 



Summary 22 



Literature cited 23 



Appendix 24 



FIGURES 



1. Map of south Florida showing the Tortugas fishing grounds 2 



2. Important features of Tortugas grounds- Controlled area, boundary of 



fishery stations occupied 5 



3. Relationship of average carapace lengfths of male andfemale pink shrimp-- 



September, 1957-November, 1958 7 



4. Relationship of carapace length of pink shrimp caught by main nets and try 



nets 8 



5. The percentage of females by size of female shrimp 10 



6. Percentage of female pink shrimp in the catches, by months, September, 



1957-November, 1958 10 



7. Relationship of depth of water and average size of female shrimp 10 



8. Relationship of depth of water and average size of male shrimp 11 



9- Relationship of the annual average size of shrimp and depth of water 11 



10. Female shrimp size and depth (Cruises I, II, 1-6) 12 



11. Female shrimp size and depth (Cruises 7-13) 13 



12. Female 'shrimp size and depth (Cruises 14-23) 14 



13. Male shrimp size and depth (Cruises 7-8, 14-19, and 22-23) 15 



14. Numbers of shrimp caught per hour in a standard try net (Cruises I, II, 



1. 2) 17 



15. Numbers of shrimp caught per hour in a standard try net (Cruises 3-10).... 18 



16. Numbers of shrimp caught per hour in a standard try net (Cruises 11-23) .. 19 



17. Distribution of fishing effort on the Tortugas grounds (November, 1957- 



February, 1958) 20 



18. Distribution of fishing effort on the Tortugas grounds (March-July, 1958)... 20 



19. Distribution of fishing effort on the Tortugas grounds (July -November, 



1958) 21 



20. Size frequency distribution of the total catch of pink shrimp and those dis- 



carded 22 



