BEARDSLEY and CONSER: AN ANALYSIS OF CATCH AND EFFORT DATA 



Table 3. — Number of fishing hours recorded from tournament 

 (toum.) and dock sampling at three major fishing areas for bill- 

 fishes in the Gulf of Mexico, 1971-78. See Figure 3 for location of 

 areas. 



Panhandle 



New Orleans 



Texas 



Table 4. — Japanese catch (in numbers offish) and effort (in 

 numbers of hooks) from the two 5° areas ( longline areas II and IV 

 in Figure 3) in the northern Gulf of Mexico which coincide with 

 recreational fishing areas, 1971-78. BM = blue marlin, WM = 

 white marlin, and SF = sailfish. 



region of the effort distribution where moderate 

 changes in the minimum effort criterion would 

 have Httle effect on the number of months used. 

 The resulting CPUE values by area and type of 

 fishing are displayed in Figure 4 for blue marlin, 

 Figure 5 for white marlin, and Figure 6 for 

 sailfish. 



Monthly catch and effort statistics by 5° area for 

 the Japanese longline fleet are reported by the 

 Fisheries Agency of Japan in the Annual Report of 

 Effort and Catch Statistics by Area on Japanese 

 Tuna Longline Fisheries for the period 1962-77. 

 Japanese longliners fish all four of the 5° areas 

 that compose the northern Gulf of Mexico (Areas I 

 through ly Figure 3). However, 52% of their fish- 

 ing effort in the northern gulf during 1971-77 oc- 

 curred in area II and 39% in area III. Only 1% 

 occurred in area I and 8% in area IV Since nearly 

 all recreational fishing for billfishes in the north- 

 ern gulf occurs in areas II and ly only longline 

 data from these two areas were used in this com- 

 parative analysis. Although no data on the dis- 

 tribution of longline effort within 5° areas are 

 given in the Japanese annual reports, data 

 supplied by Honma^ on the distribution of catch 

 and effort during 1971-75 show that most longline 

 effort in areas II and IV occurred in the more 

 coastal regions which coincides fairly well with 

 the location of recreational fishing grounds as dis- 

 played in Figure 3. Catch and effort statistics by 

 species for areas II and IV were compiled from the 

 Japanese annual reports for 1971-77 (Table 4). 

 Comparable statistics for 1978 were compiled from 

 the quarterly reports submitted to the Southeast 

 Fisheries Center by Japanese longliners fishing in 

 the U.S. Fishery Conservation Zone. CPUE was 

 then computed for those months in which 2,000 

 hooks or more of fishing effort occurred. As with 



^Misao Honma, Far Seas Fisheries Research Laboratory, 

 Shimizu, Japan, pars, commun, July 1977. 



the recreational data, using a minimum effort 

 criterion produced more reliable statistics and the 

 number of months accepted was not sensitive to 

 moderate changes in the threshold level. The 

 Japanese longline CPUE values by species and 

 comparable recreational fishing area are also 

 shown in Figures 4-6. 



Murphy (1960), Rothschild (1977), and others 

 have discussed some of the important aspects in- 

 volved in using longline statistics to estimate 

 changes in abundance. One of the demonstrated 

 functional relationships, which may be pertinent 

 in this analysis, is that the average amount of 

 effective effort per hook is a function of the.amount 

 of "soaking time" the gear is in the water. Al- 

 though the Japanese annual reports do not pro- 

 vide time in the water data, NMFS observers 

 aboard Japanese vessels in the northern gulf re- 

 port a consistency in the time the gear is in the 

 water during recent years (Lopez et al. 1979). Al- 

 though no data are available from earlier years of 

 the analysis period, soaking times tend to remain 

 more or less constant in most tuna longline 

 fisheries and consequently, fishing time can be 

 measured by the number of hooks set (Food and 

 Agriculture Organization 1976). The lack of data 

 on time in the water should, therefore, not con- 

 tribute significantly to any bias in the estimates of 

 relative abundance. Another aspect of the longline 

 data which is also pertinent to this analysis is that 

 sailfish and spearfish catches are combined in the 

 Japanese annual reports. This problem may be 

 minimal in coastal areas, however, since Ueyanagi 

 et al. (1970) demonstrated that sailfish are found 

 primarily in coastal areas and spearfish tend to 

 inhabit more oceanic waters. In this analysis all 

 catches from areas II and IV that were reported as 

 sailfish/spearfish in the annual reports were as- 

 sumed to be sailfish. 



55 



