182 



Fishery Bulletin 92(1), 1994 



. . A .Jl A .£ A _M_A_ 



A- Apalachicola R. 

 O Ocklockonee R. 

 SM- St. Marks R. 



E- Econfina R. 



S- Suwannee R. 



" EST ^..-•'^•° °° 



Figure 1 



Percentage of total Florida west coast blue crab (Callinectes sapidus) landings 

 caught by area (Steele, 1982). The five rivers used in the multivariate regres- 

 sion analyses (Apalachicola, Ochlockonee, St. Marks, Econfina, and Suwannee) 

 are depicted. 



Autoregressive order 1 (ARIMA) models were con- 

 ducted on the Franklin and Wakulla County blue 

 crab annual data and the residuals from these 

 analyses were correlated with flow. This approach 

 provided statistically rigorous estimates of P-values 

 for the flow/landings relationships that were inde- 

 pendent of any effects resulting from the one-year 

 autocorrelations in landings. Analyses that used the 

 ARIMA residuals and those that used unadjusted 

 blue crab landings data were reported because both 

 methods impart useful information. Correlations 

 that used unadjusted annual blue crab data, i.e., 

 significant autocorrelations were not removed, were 

 biologically relevant because feedback mechanisms 

 inherent to these autocorrelations (such as reproduc- 

 tion and recruitment) may also be associated with 

 flow. Results of analyses that used unadjusted data 

 are also more readily compared to results of other 

 studies. Use of ARIMA models statistically validated 



the significant relations between blue crab landings 

 and flow data, but may have removed some biologi- 

 cally relevant information. This paper primarily 

 refers to unadjusted regression results. 



Regression analyses incorporating a one-year time 

 lag between flows and landings were conducted to 

 examine the effects of flow on early blue crab life 

 history stages. Contemporaneous analyses were con- 

 ducted to assess the effect of flow on adults. 



Univariate and stepwise multivariate regression 

 analyses were conducted to estimate the amount of 

 variability in blue crab landings accounted for by 

 five major rivers on Florida's northern gulf coast. 

 The criterion for admitting a flow variable into the 

 stepwise regression models was an F-statistic 

 greater than 4.0 for its partial correlation with land- 

 ings. Data on blue crab landings for the west coast 

 of Florida were used as a dependent variable in 

 some analyses. To more specifically examine 



