FISHERY BULLETIN: VOL. 71, NO. 2 



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Figure 13. — Sea-surface temperatures and lilbacore 

 catches, 16 September 1970. Numbers encircled indicate 

 the daily catch of individual bait boats. 



On 16 September bait boats were again con- 

 centrated near the mouth of the Columbia 

 River where a finger of 14 °C water extended 

 toward shore. Judging from our data, this 

 distribution of bait boats near the Columbia 

 River was a common pattern, indicating favor- 

 able conditions for concentration of albacore 

 in this area. 



Cruise — 27 July-2 August 



A cruise was conducted in the general area 

 of the early albacore fishery to compare oceanog- 

 raphic conditions in areas of high and low 

 catch rates and to obtain albacore for a study 

 of their food habits. The ship operated in the 

 region of the jig fishery during the major 

 decline in fishing success, 27 July to 2 August 

 (Figure 1). 



Oceanographic Conditions 



Sea-surface temperatures measured during 



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SURFACE TEMPERATURE (°C) 



^(6-~. l5/.f. X^COLUUBIi _ 



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Figure 14. — Sea-surface temperatures recorded on the 

 27 July-2 August cruise. Dots indicate stations. (Cayusc 

 7007D) 



the week of the cruise show two regions of 

 warm (16°C or greater) water separated by 

 a tongue of cooler 15°-15.5°C water (Figure 14). 

 This pattern corroborates that found on 30 

 July by infrared radiometry from an aircraft 

 (Figure 9), when 16°C water was also located 

 in two areas off the northern coast. The 

 temperature section along the outbound cruise 

 track extending offshore in a northwesterly 

 direction (Depoe Bay stations) shows these 

 two areas of warm (16°C) surface water (Figure 

 15). The slope of the isotherms towards the 

 coast is indicative of upwelling, but nearshore 

 surface temperatures were above 13 °C, implying 

 little upwelling during this period of weak 

 winds (Figure 3). The thermocline was located 

 between 20 and 50 m, generally deepening 

 farther offshore. 



Figure 15. — Temperature section along the stations 

 extending northwest of Depoe Bay on the outbound 

 leg, 27-29 July. 



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