FISHERY BULLETIN: VOL. 79, NO. 1 



TABLE 2.— Data on effort and catch for billfishes recorded by 

 tournament and dock sampling, 1971-78, in the western North 

 Atlantic and Gulf of Mexico. 



period of the year, Japanese longliners fish in the 

 same area for yellowfin and bluefin tunas but fre- 

 quently catch billfishes as well. Detailed and con- 

 sistent catch and effort data are available from 

 both the recreational and longline fisheries in this 

 area over the period 1971-78. These attributes 

 make the northern Gulf of Mexico fishery unique 

 when compared with other billfish fisheries in that 

 more than one type of gear is operating at signifi- 

 cant effort levels in the same time and place, and 

 consistent catch and effort statistics are available 

 from both types of fishing operations for a reason- 

 ably long time series. In this analysis we attempt 

 to: 1) determine the utility and consistency of catch 

 and effort data from the recreational and longline 

 fisheries for indexing changes in abundance of 

 billfish populations, 2) obtain species- and area- 



specific indices of abundance that incorporate both 

 recreational and longline data, and 3) gain a bet- 

 ter understanding of the dynamics of the fishery 

 by modeling the general characteristics of recre- 

 ational and longline fishing for billfishes. 



The northern Gulf of Mexico was divided into 

 three areas based on the general distribution of 

 recreational fishing (shaded areas in Figure 3). 

 The easternmost. Panhandle, groups fishing effort 

 from Panama City, Destin, and Pensacola, Fla., 

 and Orange Beach and Mobile, Ala. The center. 

 New Orleans, combines effort from South Pass and 

 Grand Isle, La., and the westernmost, Texas, en- 

 compasses all fishing from Texas. Recreational 

 catch and effort data are acquired in each of these 

 areas by sampling both daily, noncompetitive rec- 

 reational fishing as well as fishing conducted dur- 

 ing organized big-game fishing tournaments. 

 From 1971 through 1978 over 136,000 h of tourna- 

 ment and nontournament fishing for billfishes in 

 these three areas were recorded (Table 3). Tour- 

 nament and dock data were processed and 

 monthly total catch and total effort were compiled 

 by species, area, and type of fishing. CPUE was 

 computed for those months in which 60 h or more 

 of fishing effort had been sampled. The 60-h min- 

 imum effort criterion was chosen by making two 

 series of calculations of the variance of monthly 

 CPUE using various minimum effort criteria, and 

 then subjectively selecting a minimum effort level 

 which provided a balance between the variance 

 and sample size considerations. Using the 60-h 

 minimum effort criterion produced more reliable 

 statistics without causing the sample size to be- 

 come unacceptably small. It represents approxi- 



100' 



30- 



25 



Galveston Qi' 



TEXAS 



85" 



PANHANDLE 



i< inn 



-30" 



«c:i==^ 



> 



JSLm 



25" 



Figure 3. — The shaded areas, Panhandle, New Orleans, and Texas, are major recreational fishing areas for billfishes. The larger areas, 

 I, II, III, and IV, are 5° squares from which Japanese longline catch and effort data are available. 



54 



