Wilber: Influence of Apalachicola River flows on Callinectes sapidus 



185 



month average) flow and land- 

 ings data with autocorrelations 

 removed. The timing of peak 

 monthly harvests was not re- 

 lated to the magnitude of the 

 annual harvests. 



Regional analysis 



Given the close geographical 

 proximity of the five rivers ( Fig. 

 1) used in the multiple regres- 

 sion analyses, significant corre- 

 lations between annual flow pa- 

 rameters may be expected 

 among the rivers. Apalachicola River an- 

 nual mean flows, although significantly 

 correlated with other river flows (except 

 the St. Marks), had the lowest correla- 

 tions with the other drainages (Table 2). 



Significant correlations with blue crab 

 landings were more common for 

 Apalachicola River flows than for any 

 other north Florida river tested (Table 3). 

 Franklin County landings were correlated 

 only with Apalachicola flows, whereas 

 Wakulla County and west coast landings 

 were also correlated with Suwannee and 

 Ochlockonee flows, respectively (Table 3). 

 These significant univariate correlations 

 incorporated a one-year time lag. 



The Franklin County multivariate re- 

 gression model included Apalachicola and 

 Ochlockonee minimum flows of the previ- 

 ous year (r 2 =0.45, P<0.001; Table 4). The 

 Wakulla multivariate model accounted for the most 

 variation in blue crab landings (r 2 =0.64; Table 4) 

 and included Apalachicola mean and Ochlockonee 

 minimum flows of the previous year. The west coast 

 multivariate model with a one-year time lag in- 

 cluded Apalachicola maximum and Ochlockonee 

 minimum and mean flows (r 2 =0.53; Table 4). 



The only significant multivariate model that in- 

 cluded parameters with and without time lags was for 

 west coast landings, which used both no-lag Suwannee 

 minimum flows and Apalachicola maximum flows of 

 the previous year (r 2 =0.49). Analyses that examined 

 associations between Apalachicola River flow and 

 west coast landings with Franklin and Wakulla 

 County landings removed were not significant. 



Discussion 



Several consistent results appeared in the correla- 

 tions of annual blue crab landings with Apalachicola 



Table 2 



Pearson correlation matrix of annual mean river flows for all possible 

 combinations of five north Florida rivers. 



Apalachicola Ochlockonee St. Marks Econfina Suwannee 



1.00 

 0.77* 

 0.76* 

 0.93* 



1.00 

 0.64** 



0.77** 



1.00 

 0.79* 



1.00 



Table 4 



Multiple regression results for Franklin, Wakulla, 

 and west coast landings of blue crabs (Callinectes 

 sapidus) with a one-year time lag incorporated 

 into the analyses. The independent variables are 

 the five river drainages listed in Table 3. Listed 

 below are the signs of the correlations in paren- 

 theses, Student's ^-statistics, and associated P- 

 values. 



Region 



Variable 



Franklin 



Wakulla 



West Coast 



Apal. min ( + ) 

 Och. min. (-) 



Apal. mean ( + ) 

 Och. min. (-) 



Apal. max. ( + ) 

 Och. mean ( + ) 

 Och. min. (-) 



4.38 

 -2.68 



4.57 

 -3.05 



2.99 

 3.12 

 -2.61 



<0.001 

 0.012 



0.001 

 0.009 



0.006 

 0.004 

 0.015 



0.45 



(I 64 



0.53 



