in the Atlantic, a species that is similar in many 

 respects to the striped marlin. The catch-per-unit- 

 effort for sailfish in the eastern Pacific has averaged 

 about four times the catch rate for the same species 

 in the Atlantic. 



These wide variations in catch rates between the 

 Atlantic and eastern Pacific indicate a possibility of 

 a lower density level or of a much smaller white 

 marlin population, or both, in the Atlantic when 

 compared with striped marlin in the eastern Pacific 

 and sailfish in both oceans. If this is true, given 

 approximately the same fishing effort, a greater 

 percentage of tag recoveries of these species could 

 be expected in the Atlantic. 



The recovery rate of striped marlin tagged in the 

 eastern Pacific using the FM-67 plastic tag was 

 slightly less than for the metal tip tags used by the 

 Woods Hole Oceanographic Institution Atlantic 

 program for white marlin (1.06% eastern Pacific, 

 1.229f Atlantic). The plastic FT-1 tag gave near 

 equal recovery rate results for sailfish in the Atlan- 

 tic and the eastern Pacific (0.86% eastern Pacific. 

 0.80% Atlantic). The recovery rate for striped mar- 

 lin tagged with metal tip "H"" tags in the eastern 

 Pacific has been 0.40%. 



From the limited amount of data available, no 

 definite conclusions can be reached. However, it 

 appears that the plastic dart tag is as satisfactory as 

 the metal tip dart tag. When the possible differences 

 in population levels and projected recovery rates 

 are considered, the plastic dart tag actually may 

 prove to be superior. 



In the northeastern Pacific there have been 

 enough striped marlin tag recoveries to make some 

 observations regarding their migration. Striped mar- 

 lin usually are available during the first 3 months of 

 the year off Mazatlan, Mexico. Movements of tag- 

 ged fish from this area are toward the southwest and 

 west, to and beyond the tip of Baja California. In 

 late spring the principal component of the fishery 

 changes to sailfish dominance. 



Striped marlin are usually available about the tip 

 of Baja California from late spring through fall. Mi- 

 grations of tagged fish to the south and some to the 

 west and northwest have been recorded. During 

 late spring and early summer the reproductive activ- 

 ity of striped marlin increases in this area (M. El- 

 dridge and P. Wares. '^ pers. comm.; Kume and 

 Joseph, 1969). Thus the migrations away from the 



'M. Eldridge and P. Wares, National Marine Fisheries Ser- 

 vice. Tiburon Fisheries Lahoratorv. P.O. Box 98, Tiburon. CA 

 94920. 



tip of Baja California in a southerly direction may 

 be related to spawning activity of striped marlin in 

 the general vicinity of the Revillagigedo Islands. 

 Some spawning activity has been reported in this 

 area by the Japanese longline fleet during the period 

 late June through October (G. Adachi.*" pers. 

 comm.). Gonad indices for striped marlin collected 

 in areas of reported spawning have been several 

 times higher than the index found about the tip of 

 Baja California (M. Eldridge.* pers. comm.). 



Since the amount of longline fishing becomes less 

 as one proceeds north of Magdalena Bay, Baja 

 California, Mexico, the number of returns of 

 striped marlin tagged about the tip and migrating 

 northwest of the Magdalena Bay area would be re- 

 duced in proportion to the amount of fishing effort. 

 However, some recoveries have been recorded 

 northwest from the tip of Baja California toward 

 southern California, immediately prior to the 

 movement of striped marlin into the southern 

 California fishery. An increase in catch per effort is 

 noted in this area during the second and third quar- 

 ters of the year. The southern California sport- 

 fishery takes only a small number of striped marlin 

 during late August through October (usually less 

 than 500); the Japanese longline fleet does not oper- 

 ate in this area. Therefore the chance of recovering 

 a striped marlin off southern California is remote. 

 However, from the limited number of striped marlin 

 tagged off southern California and recovered a 

 short time later near the tip of Baja California, indi- 

 cations are that a southerly migration from southern 

 California exists in the fall. 



The rates of migration for striped marlin about 

 the tip of Baja California-Mazatlan-Revillagigedo 

 Island area was 1.9 nautical miles per day. Two 

 westward records of long distance migrations from 

 the coast of North America toward Hawaii show 

 rates of 12.3 and 26.0 nautical miles per day. From 

 southern California to near the tip of Baja Califor- 

 nia, four records show an average migration of 12.3 

 nautical miles per day. A southward migration from 

 the tip of Baja California to near Clipperton Island 

 was recorded at 16.3 nautical miles per day. 



Distant water migrations from southern Califor- 

 nia and about the tip of Baja California show a 

 much higher migration rate in nautical miles per day 

 when compared with those recaptured near the tip 

 of Baja California, Mexico. 



Sailfish recoveries indicate little movement, the 



"G. .Adachi, P.O. Box 240. Manzanillo. CoHma, Mexico. 



236 



