Caillouet et al : Relationship between sea turtle stranding rates and shrimp fishing intensities 



245 



The statistical relationship between stranding 

 rates and fishing intensities persisted despite our 

 using more stringent criteria than did Caillouet et 

 al. ( 1991) to exclude from the analyses strandings to 

 which possible causes had been assigned. In the ab- 

 sence of significant heterogeneity among the signifi- 

 cant positive correlation coefficients, the null hypoth- 

 esis could not be rejected. Therefore, there was no 

 significant change in the degree of statistical asso- 

 ciation between sea turtle stranding rates and fish- 

 ing intensities for some offshore depth intervals 

 within to 20 fm, despite TED regulations, nor was 

 there a significant difference in the degree of this 

 association between the upper and lower coasts. 



In 1990-93, as in 1986-89, there was a significant 

 positive correlation between ln(S + 1) and \n(E + 1) 



within 0-5 fm on the upper coast, but not on the lower 

 coast. Depth increases more rapidly with distance 

 from shore on the lower than on the upper coast (Fig. 

 1 ). In addition, shrimp move to deeper waters as they 

 migrate southward along the Texas coast each year, 

 accompanied by a corresponding concentration of the 

 shrimping fleet in areas of shrimp abundance. A 

 smaller percentage of fishing effort occurred in the 

 0-5 fm depth interval on the lower coast than on the 

 upper coast (Table 2). 



The significant negative correlations detected be- 

 tween ln(S + 1) and ln(£ + 1) for some depth inter- 

 vals seaward of 20 fm probably resulted from a ten- 

 dency for fishing effort to be concentrated season- 

 ally within certain depth intervals. The pattern of 

 correlations involving fishing intensities in various 



