VESSEL LENGTH (M) 

 14 16 le 



Figure 12. — Relation between fishing-power factors and vessel length for 211 shrimp vessels fishing on the Tor- 



tugas grounds in January and February 1965. 



speed. In the first 10 months we collected 2,340 

 samples, each representing the catch from 

 about 100 m.2 (1,070 ft.^) of bottom. 



Table 5 summarizes by station and month 

 the catch data for the samples collected through 

 April. Abundance trends at individual stations 

 varied somewhat, but in general, relative 

 abundance decreased during the 8-month 

 period. Exceptions to this trend were at 

 stations 5 and 6. A marked but temporary in- 

 crease in abundance occurred at these stations 

 in December and to a lesser extent at station 7. 

 Abundance declined at all but one of the re- 

 maining four stations in the eastern portion of 



the Bay, and stations 3 and 4 showed a reduc- 

 tion of more than 50 percent between Novem- 

 ber and December. 



These data suggest a movement of shrimp 

 from the inner basins of the Bay westward 

 during the fall and "winter. This movement and 

 the general decline in abundance are consistent 

 with the findings of earlier research which 

 has shown emigration of juveniles out of the 

 estuary and low rates of recruitment in the 

 winter. 



A logarithmic transformation was applied to 

 the catch data (table 5) to overcome the prob- 

 lem of unequal variances among stations. 



19 



