SHERIDAN ET AL.: RECAPTURE PATTERNS OF TAGGED PENAEID SHRIMP 



leased off Tamaulipas averaged significantly greater 

 distances than brown shrimp released off Texas 

 (23.7 and 25.6 km versus 11.1 and 13.0 km, respec- 

 tively). The distributions of recaptures by distance 

 travelled indicated that most Texas recaptures 

 (70%) occurred within 20 km of release sites, while 

 only 40% of the Tamaulipas recaptures were made 

 at close range (Fig. 2). In all but one case, percent- 

 ages of total Tamaulipas recaptures in any given 

 distance category exceeded those of Texas recap- 

 tures. 



Days at large were significantly affected only by 

 the main effects of species, sex, and state (Table 4). 

 Mean days at large were greater for shrimp released 

 off Tamaulipas (16.4-20.2 days) than for shrimp 

 released off Texas (11.8-14.4 days), and within each 

 state brown shrimp tended to be at large longer than 

 pink shrimp. Within each species-state group, 

 female shrimp remained at large longer than male 

 shrimp. The distributions of recaptures by days at 



large indicated that 65-85% of all Texas recaptures 

 were made 1-19 days after release, whereas only 

 45-50% of Tamaulipas recaptures occurred during 

 this time period (Fig. 3). Proportions of brown 

 shrimp recaptures in the 40-79 days at large cate- 

 gories were also greater than those of pink shrimp. 

 Movement speeds of recaptured shrimp were af- 

 fected by the interaction of species and state (Table 

 5). This was reflected both in the significant main 

 effect of state (shrimp released off Tamaulipas 

 moved faster than those released off Texas, 1.67- 

 2.34 km/d versus 1.04-1.25 km/d) and in the species 

 X state interaction (pink shrimp released off Tamau- 

 lipas had significantly greater speeds than pink 

 shrimp released off Texas, and the same trend was 

 found for brown shrimp). The majority of all shrimp 

 recaptured exhibited speeds of less than 1 km/d (Fig. 

 4). However, recaptures of shrimp released off 

 Tamaulipas usually had proportionally more shrimp 

 with speeds exceeding 4 km/d. 



BROWN SHRIMP 



n MALES, TA N = 80 

  MALES, TX N = 181 



0-19 20-39 40-59 60-79 80-99 100-119 120+ 

 KILOMETERS 





■/ 



I 



0-19 20-39 40-59 60-79 80-99 100-119 120+ 

 KILOMETERS 



F1 



0-19 20-39 40-59 60-79 80-99 100-119 120+ 

 KILOMETERS 



0-19 20-39 40-59 60-79 80-99 100-119 120+ 

 KILOMETERS 



Figure 2.— Comparison of distances travelled by recaptured shrimp after release off Tamaulipas (TA) or Texas (TX). 



301 



