Stanley and Wilson: Fish abundance near oil and gas platforms 



153 



number of legs x number of wells, and whether the 

 structure was in production; and coefficients were 

 positive for the number of legs, water depth x sub- 

 merged surface area, and water depth x volume of 

 water enclosed. Since the regression coefficients were 

 negative for water depth, fishing method, quadratic 

 date, boat horsepower, and the presence of LORAN 

 and echosounder, catch rates of spotted seatrout were 

 highest while bottom-fishing by relatively small vessels 

 without sophisticated electronics. Based on the plot of 

 the sum of the linear and quadratic components of 

 month, spotted seatrout were most abundant in the late 

 spring and early summer (Fig. 1). 



Multiple-regression analysis suggested reef fish were 

 most abundant near large complex structures at inter- 

 mediate water depths (Fig. 2). Ten significant predic- 

 tor variables accounted for 35.2% of the variance in 

 the reef fish factor (Table 5). The regression coeffi- 

 cients of water depth, volume of water enclosed, and 

 the interactions of submerged surface area x volume 

 of water enclosed, and the number of legs x number 

 of crossmembers were positive, while negative regres- 

 sion coefficients were observed of the interactions of 

 water depth x volume of water enclosed, and water 



