lat. 38°25'N., long. 118° 15' W. (18 miles south 

 of Los Angeles Harbor, California) was recover- 

 ed south of Japan, at lat. 31°30', long. 149°40'E. 

 on June 23, 1953 (Ganssle and Clemens 1953). 

 The recovery locality was approximately 550 

 miles southeast of Tokyo. The tag was of viny- 

 lite tubing secured with nylon line . The specimen 

 was one of 215 albacore tagged in August 1952 . 

 Two other specimens of the same group had been 

 recaptured off Morro Bay, California, within 43 

 days from the time of tagging . 



Two albacore tagged off northern Baja 

 California in August 1953 were recaptured in the 

 vicinity of Midway Island in the mid-Pacific 

 (Blunt 1954) . The first recovery was obtained at 

 36°40' N, 178° 12' E on February 2, 1954. The 

 second albacore was caught on February 23, 1954 

 at 30° 10' N Lat., 178°54'W. The tags on both 

 specimens were made of vinylite tubing. The 

 two specimens were from a group of 754 albacore 

 tagged in the vicinity of Guadalupe Island. Twelve 

 other specimens from the same group were re- 

 covered off central California within 45 days of 

 release. 



A news release from the Pacific Oceanic 

 Fishery Investigations, dated February 6, 1956, 

 reports that an albacore tagged October 5, 1954 

 at a point 1,300 miles north of the Hawaiian Is- 

 lands was recaptured on January 19, 1956 about 

 75 miles northeast of the entrance to Tokyo Bay. 



The above returns offer quite definite proof 

 that albacore perform extensive migrations in 

 the north Pacific . Whether this applies to the 

 population as a whole, or only to a portion of the 

 population, is not known. Here again tagging did 

 not bear out the conclusion reached from morpho- 

 metric comparisons, that local and Japanese 

 albacore are non -intermingling. 



Pacific mackerel , Pneumatophoru s diego 



One of the interesting population studies of 

 Pacific fishes is that conducted on the Pacific 

 mackerel, Pneumatophoru s diego, reported by 

 Roedel (1952) . Meristic and morphometric com- 

 parisons were made on Pacific mackerel from a 

 number of areas, and the results were evaluated 

 in the light of tagging experiments . 



Material was examined from the following 

 geographic areas: 



Locality 



No. samples No. specimens 



British Columbia 2 



Southern California 20 



Soledad (Ensenada, northern 



Baja California) 2 



Viscaino Region, central 



Baja California 6 



Cape San Lucas Region 2 

 Gulf of California Region 4 



141 

 897 



196 



460 

 641 

 242 



Meristic counts . --Meristic counts were 

 centered on variations in positions of structures 

 of the vertebral column with respect to the num- 

 ber of the vertebra on which they first occurred. 

 Variation in total number of vertebrae was of no 

 value: total number of vertebrae is an exceedingly 

 constant character in the Pacific mackerel . Out 

 of 2,352 fish studied, only 10 specimens had other 

 than 31 vertebrae: 3 specimens had 30 vertebrae 

 and 7 had 32 vertebrae. But little more variation 

 was found in the position of the first haemal spine; 

 all but 40 individuals had the spine on the fifteenth 

 vertebra, the remainder were either one more or 

 less than this. The position of the first haemal 

 arch was somewhat more variable, about 10 per- 

 cent of the specimens had the arch on either the 

 tenth or twelfth vertebrae, with the remainder of 

 specimens having the first haemal arch on the 

 eleventh vertebra . Differences among the four 

 "northern" regions in this character were not 

 significant, nor between the two southern regions 

 (Cape and Gulf) . Differences between Viscaino 

 and the Cape San Lucas region were highly 

 significant . 



Roedel found a structure on the vertebrae, 

 which he termed the haemal brace, to be the most 

 variable meristic character. The haemal brace 

 extends from the centrum to the haemal arch; it 

 may be either paired (usually) or single on the 

 vertebra of first occurrence . Variation found in 

 die first occurrence of the haemal brace was as 

 follows: 



63 



