which indicates that Ungcod in the study region are 

 an international resource. 



The time between tagging and recapture averaged 

 18 mo (Table 4) and did not differ significantly by 

 the distance traveled (^2,128 = 1-32; 0.25 < P < 

 0.50). 



The majority of the nonmigratory recaptures were 

 caught in May-July, but the migratory fish were 

 caught mostly in August-October. This difference 

 could not be attributed to any seasonal pattern of 

 migration and was probably a sampling artifact. 

 Fishing effort by commercial troUers and sport 

 fishermen in the tagging areas peaked during May- 

 July, while the fishing effort of the trawl fleet on 

 Constance Bank, from which many of the migratory 

 recaptures came, peaked in late summer and fall 

 (Smith 1981; Leaman 1982, 1983, 1984). 



We found that migratory tendency apparently did 

 not depend on individual size. Figure 2 shows a com- 

 parison of the release length-frequency distributions 

 of lingcod recaptured <8.1 km (Graph IV) and more 

 than 8.1 km (Graph V) from release location. The 

 null hypothesis that migratory and nonmigratory 

 lingcod have the same length distribution was ac- 

 cepted ix- = 13.09 with 10 df; 0.10 <P < 0.25). 



The release-length distribution of all recaptured 

 lingcod was significantly different from that of all 

 tagged lingcod (x^ = 25.42 with 10 df; P < 0.01); 

 release lengths of recaptured lingcod averaged 

 slightly larger than those of all tagged lingcod (Fig. 

 2, Graphs III, IV, and V). 



Recaptured lingcod offered no evidence that males 

 and females differ in migratory behavior. Recapture 



Table 4.— Time span between date of tagging 

 and date of recapture for tagged lingcod re- 

 coveries with known month of recapture. 



Table 5.— Distributions by sex of the lingcod recaptured <8.1 km 

 from the tagging location and of those recaptured >8.1 km from 

 the tagging location. 



rates were virtually the same for the two sexes. The 

 null hypothesis that male and female tagged re- 

 coveries represent two populations with equal pro- 

 portions of nonmigratory and migratory individuals 

 was accepted (x" = 3.14 with 1 df; 0.05 <P< 0.10) 

 (Table 5). However, numbers of females tagged and 

 recaptured were so low that any conclusion from this 

 comparison should obviously be drawn with caution. 



Discussion 



The highly imbalanced sex ratio of the tagged fish 

 can be explained by different depth distributions of 

 the two sexes. Others have found, as we did on our 

 tagging cruises, that female lingcod tend to reside 

 deeper than males (Chatwin 1956; Miller and Geibel 

 1973; Cass et al. 1984). Most of our tagging effort 

 was at depths of 25-30 m where the abundance of 

 lingcod regardless of sex was the greatest. We 

 fished in depths down to 100 m and found that rela- 

 tive abundance of females increased with depth. 



The reason that the small tagged individuals 

 tended to be recaptured at a lesser rate than the 

 larger ones could be the higher natural mortality of 

 small lingcod within the size range of our tagged 

 sample. Lingcod are renowned for their cannibal- 

 ism (Chatwin 1956; Phillips 1959), which could be 

 a likely source of size-dependent mortality. 



Our results show more lingcod migratory behavior 

 than most previous studies. Hart (1943) reviewed 

 recovery information from 1,993 lingcod tagged dur- 

 ing 1939-43 throughout the Strait of Georgia, BC, 

 Canada, and stated that "some but not more than 

 5% of lingcod are more or less migratory." Chat- 

 win (1956) summarized Hart's data together with 

 information from additional tagging in the Strait of 

 Georgia through 1954 and found that of 342 total 

 recaptures, 41 (12%) moved more than 1 mi (1.6 km) 

 but <5 mi (8.1 km) from the point of tagging, and 

 32 (9.3%) moved farther than 5 mi. Chatwin there- 

 fore concluded that lingcod was a relatively seden- 

 tary species with no well-defined migration pattern. 

 Phillips (1959) reviewed the above two papers and 

 concluded from these and other tag recovery obser- 

 vations in the literature that lingcod is a nonmigra- 

 tory species, particularly after reaching maturity. 



Reeves (1966) reported on results from tagging 

 437 lingcod on 40-Mile Bank, which is about 50 km 

 west of Cape Flattery, WA. The overall recapture 

 rate was very high because of an intensive trawl 

 fishery for lingcod in the vicinity of tagging; 53.3% 

 of all tagged fish were recaptured within 6 wk of 

 release. Only 5% of the recaptures were farther than 

 5 mi (8.1 km) from the tagging site. However, the 



157 



