In the 19th century, the enormous 

 and complex Magdalena area was 

 probably the principal breeding ground 

 of the California gray whale. However, 

 because its central waters were ac- 

 cessible to sailing ships and its shal- 

 lower tributaries to whaleboats, its 

 whale population was soon exploited. 

 From 1952 through 1957, boat traffic 

 was often seen in the main bay. Gray 

 whales consorted in numbers only in 

 the more inaccessible tributaries. 



Yavaros area . --In February 1953, 

 an aerial survey of the Yavaros area 

 disclosed breeding grounds at Yavaros 

 and Bahia Refornna, on the eastern 

 side of the Gulf of California. Whales 

 had never before been found here, 

 even by early whalers. 



The Yavaros area is about 6 to 8 

 miles south of the port and bay of 

 Yavaros, Sonora. It seems to have 

 no distinctive feature which would 

 attract gray whales. The water is only 

 2 to 5 fathoms deep. The whales 

 observed were from 200 to 800 yards 

 from the beach, leaving mud trails 

 behind them as they swam in waters 

 believed to be as shallow as 2 fathonns 

 (fig. 14). 



There are perhaps 10 to 20 square 

 miles of lagoon in the northern part 

 well suited to gray whales (fig. 15). 



Figure 14.~Yavaros calving area. 



Reforma area .--Bahia Reforma is a 

 huge lagoon-like bay 120 nautical miles 

 southeast of Yavaros, in the State of 

 Sinaloa. It is about 35 miles long and 

 is navigable by whales and small boats. 



Figure 15.— Reforma calving area. 



NORTHWARD MIGRATION 



The northward migration first passes 

 San Diego in mid -February, is in full 

 swing in March and April, and tapers 

 off in early May. Gray whales going 

 north seem to veer off the coast at 

 Point Loma, passing La Jolla several 

 miles at sea, as though on direct 

 course across the great bight of the 

 coast of southern California from San 

 Diego to Palos Verdes Peninsula. 

 Because movement apparently is away 

 from the coast, it does not seem 

 possible to count the migration north 

 with the same accuracy possible for 

 the southward migration. From Palos 

 Verdes Peninsula, most whales mi- 

 grate parallel to the coast on their 

 way north. 



Vessels engaged in fur-seal research 

 for the Bureau of Commercial Fish- 

 eries, in 1958 and 1959, sighted gray 

 whales during March from 36°46'N. 

 in Monterey Bay to 41°23'N. off 

 Gold Bluffs, California. April obser- 

 vations ranged from 40°47'N. off the 

 Eel River in California to 47°54'N. 

 off James Island, Washington. On April 



14 



