FISHERY BULLETIN: VOL. 70, NO. 3 



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-I 1 I 



NORTHERN 



AREA 



SOUTHERN 

 AREA 



Figure 1. — Area of the eastern north Pacific bluefin tuna 



fishery. 



waters occurs (except for a narrow band of very 

 cold, rich upwelled water near shore south to 

 San Juanico). Red crabs (Pleuroncodes plan- 

 ipes) are abundant in this area. Winds and 

 weather are generally favorable for purse-seine 

 operations after mid-June, but in April and May 

 strong northwest winds severely restrict fishing. 



From Punta Eugenia to Point Conception, the 

 southern California offshore area typically ex- 

 hibits the warm Catalina Gyre in association 

 with cold, upwelled water centered off Ensenada 

 and to the north of Point Conception. Hydro- 

 graphic conditions in this region favor good fil- 

 ter feeding for bait fishes, and winds and weath- 

 er improve in late July through September. 

 Seldom is this district too warm for bluefin. 



The occurrence of the various school types in 

 the northern and southern areas of the fishery 

 is nonrandom (chi square 985.20, P<0.001). 

 Perhaps the most striking diflference is the al- 

 most complete lack of jumping and boiling 

 schools in the southern area and the predomi- 

 nance of breezers in this same area (Table 3). 

 These differences may reflect diflFerences in the 

 feeding behavior of T. thynnus on different prey 



918 



