72 



Fishery Bulletin 89(1), 1991 



lOr 



BEACH SEINE 



Subyearling Chinook Salmon 

 n = 13,513 



0545 1200 1800 2045 2400 0500 



Sunrise Sunset 



Time 



PURSE SEINE 

 » Subyearling Chinook Salmon D 



n = 1461 



15 - 



10 - 



5 - 



0545 

 Sunrise 



1800 2045 2400 0500 



Sunset 



20 r- 



PURSE SEINE 

 Steelhead 

 n = 4673 



0545 

 Sunrise 



I i ' 1 



1200 1800 2045 2400 0500 

 Sunset 



Time 



Figure 2 



Diel catch patterns for chinook 

 salmon, coho salmon, and steel- 

 head from beach and purse seine 

 sampling at Jones Beach, 1978-80 

 (samples combined and averaged). 



13.7% of the total catch for the two 24-hour sampling 

 periods. 



Purse seine catches peaked during the interval about 

 1.5 hours after daylight (15.8% CPS) and remained 

 near 6.5% CPS throughout the daylight intervals the 

 (Fig. 2D). Catches decreased in the night intervals to 

 an average 3.7% CPS; 18.5% (4.6 SD) of the CPS was 

 obtained during darkness. 



Yearling chinook salmon 



The majority of yearling chinook salmon migrated mid- 

 river; purse seine catches totaled 2029 fish compared 

 with 113 from the beach seine. The peak catch with the 



purse seine was during the interval 0946 to 1115 hours 

 (12.3% CPS). Overall, 46% of the total catch was taken 

 in 31% of the sets (1.5 hours after sunrise to about 1330 

 hours) (Fig. 2E). Purse seine catches were smallest 

 from dusk to midnight (average 3.2% CPS), with larger 

 catches occurring during the remainder of the night 

 intervals (average 5.4% CPS). The night catch was 

 21.1% (7.0 SD) of the total purse seine catch for a 

 24-hour period. 



Sockeye salmon 



Sockeye salmon juveniles were caught only in the 

 purse seine (222 fish), with 15% (6.3 SD) captured at 



