308 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



preserved specimens which have otherwise nearly 

 all faded. Sometimes numerous similar, white, 

 small spots are scattered over the head and body, 

 and in such specimens the longitudinal rows as 

 described above are not as saliently marked, but 

 even then the spots in the longitudinal rows stand 

 out more prominent ly than the others. Most other 

 species have white spots moi*e or less developed, 

 but they are usually most prominent in callfumi- 

 cus and also in acstimrius. 



Specimens ecaamlned. — San Diego, California 

 (22 lots in Nat. Mus., 1 to 11 specimens in a lot, 

 and one lot of 25 specimens, 18 of which are in- 

 cluded in the tables). The following localities 

 on the west coast of Lower California : San Qnen- 

 tin Bay (46561); San Bartolome Bay (47269: 

 59464) ; Puerto San Bartolome (A. M. N. H. 5460 

 and 5462) ; Ballenas Bay (A. M. N. H. 5452) ; 

 Magdalena Bay (472S6)- Total number of speci- 

 mens studied 123, 42 to 570 mm. ; 15 from the west 

 coast of Lower California; all others from San 

 Diego. 



Geographic distrihufion. — The specimens ex- 

 amined rejiresent a range from San Diego Bay. 

 Calif., to Magdalena Bay, Lower California. It 

 has previously been reported from Tomales Bay, 

 Calif., to Magdalena Bay, these two localities be- 

 ing the extremes of its range known at present. 

 Its center of abundance is at San Diego; it is 

 abundant at Monterey; at San Francisco it is not 

 abundant although taken in moderate commercial 

 quantities. 



Size. — This is the largest species of Pdralirhthys 

 in American waters. The largest fish of which 

 there is any definite record is that reported by 

 Lockington (1879), a specimen weighing 58 

 pounds. 4 feet 10 inches in length. The same author 

 (1878-79) states that he was told that the fish 

 reaches a weight of 70 pounds. Jordan and CHl- 

 bert (1881) record a fish of 55 pounds. 



Distinctive characters and relationship. — This 

 species is closely related to aestuarius and ad- 

 sjfersits. From the latter it differs chiefly in the 

 depth of body, there being no intergrading indi- 

 viduals in the many specimens examined although 

 the extremes of the two species approach closely. 

 The form of the frequency-distribution polygon 

 for the number of gill rakers is different in the 

 two species, but in this case there is considerable 

 overlapping. P. caUfomicus is most closely re- 



lated to aestiKiriu.y. differing from the latter in 

 that the scales retain their ctenoid character with 

 age and in the smaller number of dorsal and anal 

 rays, there being some intergrading in the latter 

 characters. In practice, caJiforiiic'us may be 

 readily distinguished fi'om adspersus in its more 

 slender body and also in their widely separated 

 geographical ranges. From aestuarius, large 

 specimens, those over 200 mm., may be distin- 

 guished by the character of the scales. Small 

 specimens, however, may be distinguished only by 

 the number of fin rays, and this is not reliable in 

 every case (tables 5 and 6) . Difficulty will, there- 

 fore, be experienced in identifying some isolated 

 small specimens in the localities where the two 

 species occur together. In fact this may prove 

 impossible in the case of some individual small fish. 

 If a fish has less than 74 dorsal and less than 56 

 anal rays, it is nearly always a califoniicus. The 

 probability of its being an aestuanus is remote. 

 Likewise, if a specimen has more than 77 dorsal 

 and more than 60 anal rays it is most likely an 

 aestuarius; the chance of its being a calif arnicas is 

 almost negligible. However, the identification of 

 small specimens having 74 to 77 dorsal I'aj's and 

 56 to 60 anal rays must be doubtful. 



Biology. — Although it is a common and impor- 

 tant species very little is known regarding its life 

 history. Clark (1931) states that "spawning . . . 

 occurs from February to July with its greatest 

 intensity in May." According to this author, the 

 fisliermen think that when the fish become abun- 

 dant in late winter or early spring they are mi- 

 grating from greater depths to spawn nearer the 

 coast. This would indicate a spawning migration 

 in the opposite direction from that taken by the 

 summer flounder on the east coast (p. 319) . As to 

 the rate of growth, Clai-k estimates a length of 1-5 

 inches for fish one year old ; 4—9 inches at 2 years ; 

 6-15 inches at 3 years; 10-16 inches at 4 years, and 

 11-17 inches at 5 years. 



Fixhenj and economic importance. — The Cali- 

 fornia halibut is one of the important food fishes 

 on the coast of California and Lower California. 

 The trammel net is an important gear by which 

 this species is taken and is practically the only 

 gear used around San Pedro due to legal restric- 

 tions (Clark 1931). The inner layer of the tram- 

 mel nets used there has a mesh of 8 inches, 



