FISHERY BULLETIN: VOL. 71, NO. 3 



Table 5. — Number of salmon marked and observed in 



time by mesh size and 



multifilament gill nets over varying periods of 

 area, 1966. 



Nets and 

 area 



(long.) 



Vessel 



1 14- and 133-mm mesh: 

 176°W MV Paranon 



167°W 



158°W 



Percentage loss 

 RV George B. Kelez 



Percentage loss 

 MV Si. Michael 



Percentage loss 

 Total 



Percentage loss and 

 95% confidence interval 



64- and 83-mm mesh: 



176°W MV Paragon 



167°W 



158°W 



Percentage loss 

 RV George B. Kelez 



Percentage loss 

 MV St. Michael 



Percentage loss 

 Total 



Percentage loss and 

 95°''o confidence interval 



Grand total 



(both mesh sizes) 

 Percentage loss and 



95°o confidence interval 



No. fish 

 marked 

 during 

 patrols 



Number of fish observed after marking' 



Up to 1 h 

 later 



78 



13 



58 



149 



101 



10 



47 



307 



30 



(31) 



3.2±6.4 



Up to 21/2 h 

 later 



52 



(54) 



3.7±5.1 



46 

 (50) 



..0±7.7 



Up to 11 h 

 later 



80 



(94) 



14.9±7.9 



80 

 (145) 



44.8±8.2 



173 



(301) 



42.5 ±5.6 



1 



' Number of possible observations (figures in parentheses) for the time periods; difference from the number 

 marked is because some observations vjere not made during rough weather. 



1967. — Studies of loss from gill nets fished 

 on the high seas were continued in 1967 in the 

 same manner as in 1966. Because of inclement 

 weather, only five gill net sets were observed 

 for dropouts; however, the number of patrols 

 during each set was increased over 1966. 



Observations were made from one research 

 vessel operating south of Adak Island (long. 

 176°W) in June-August. Eleven nets were 

 patrolled: two each of 133-mm monofilament 

 and 133-mm multifilament nets, two each of 

 114-mm monofilament and 114-mm multifila- 

 ment nets, two 83-mm multifilament nets, and 

 one 64-mm multifilament net. This combination 

 of mesh sizes and net materials allowed compari- 

 sons of loss rates of small and large fish and 

 comparisons between large mesh multifilament 



and monofilament gill nets. Not all of the 14 

 nets were patrolled during each set because of 

 weather or mechanical problems. The large 

 mesh multifilament nets were patrolled five 

 times as opposed to three times for the small 

 mesh nets. 



Results of the dropout experiments in 1967 

 are listed in Table 6. Overall loss rates were 

 nearly 11% (± 6.8) for periods up to 1 h, 17% 

 (±10.1) for up to 21/2 h, 58% (±18.0) for up to 

 5 h, and 64% (±9.7) for up to 10 h. The loss 

 rates for large mesh nets (multi- and mono- 

 filament combined) were nearly 58% (for up to 

 10 h) as opposed to 83% for small mesh nets 

 (although sample sizes for the latter were 

 small). 



The dropout rates of monofilament and multi- 



856 



