SHRIMP FISHERY PROGRAM 

 Joseph H. Kutkuhn, Acting Program Leader 



Understanding the dynamics of pre-exploited and exploited phases 

 of any commercial fish or shellfish population is prerequisite to implement- 

 ing a management program for the fishery it supports. Studies on each of 

 three well«defined phases which characterize development in important Gulf 

 of Mexico shrimp populations, viz. , larval and postlarval (pre«exploit ed), 

 juvenile (semiexploited), and adult (fully exploited), continued during the year. 



In the east Texas coast area, a l»year survey designed to delimit 

 spawning areas and ascertain the seasons and extent of spawning activity in 

 brown and white shrimp populations was undertaken. Superimposed on this 

 survey is a continuation of a project carried out during the period March 1959»« 

 March I960 which sought to explore the feasibility of measuring the density 

 of larval shrimp during their passage from offshore spawning to inshore nurs« 

 cry grounds. Analysis of the earlier project's data is now underway. The re*» 

 suits thereof together with those of the current study will provide (1) a basis 

 for documenting mortality suffered by shrimp populations at successive devel» 

 opmental stages; (2) evidence for linking spawning populations with inshore 

 nursery areas utilized by their progeny; and (3) answers to the question of 

 what mechanisms govern the movement of larvae from spawning to so-called 

 nursery areas. 



Closely meshed with these early life history studies is a project 

 concerned with outlining procedures for distinguishing larvae and early post- 

 larvae of coexistent Penaeidae. In the 2 years since its inception, consider- 

 able progress in identifying, describing, and comparing the early life history 

 stages of these shrimp can be shown. The most successful technique for ob- 

 taining material which is validly describable has involved capturing shrimp 

 ready to spawn, allowing them to spawn in aquaria free of foreign matter, 

 nurturing the eggs and any resulting larvae, and rearing the latter through as 

 many growth stages as possible. Unfortunately, the inability to rear larvae be- 

 yond a certain critical point (Protozoea I) still limits this technique's usefulness. 



Information providing a means for evaluating juvenile (or inshore) 

 population phases continues to be secured systematically from the commercial 

 bait shrimp fishery (Galveston Bay). Bait fishery production around the Gulf 

 is still rising annually, but methods which would permit assessment of the re- 

 lationship between increasing exploitation during immature stages and each 

 species potential maximum yield have yet to be devised. 



Movement patterns, mortality, and growth in exploited (offshore) 

 population phases underwent increasingly intensive study in the south Florida 

 area. Additional mark-recapture experiments in a series started 4 years ago 

 materially supplemented our knowledge of the Tortugas pink shrimp popula- 

 tion's geographical range. A better-than-anticipated rate of mark-recovery in 

 one experiment has encouraged extension of the staining technique for marking 

 shrimp to studies of population mortality. 



A statistical analysis of Gulf shrimp stocks for the period 1956-1959 

 indicated that the more important species are generally faring well. 



