Hunt et al.: Movement of Gadus morhua in the Gulf of Maine area 



853 



40 



20 







20 



40 



60 



covered there and between 15% and 

 20% of recaptures were from releases 

 in the 5Yb area. Cod tagged in unit 

 area 4Xs show more widespread dis- 

 persal than those from 4Xr. 



The small number of releases from 

 division 5Y precluded detailed inter- 

 pretation of movement. However, there 

 is an indication of association with the 

 4X area, as well as movement from the 

 Browns Bank area into 5Y. both of 

 which were not unexpected because 

 the majority of releases were near the 

 northeastern border of 5Y. Results, 

 therefore, probably do not reflect those 

 for the remainder of the 5Y area. 



The pattern observed for Georges 

 Bank is similar to that seen on Browns 

 Bank. Dispersal of postspawning cod 

 appears to be substantial in both a 

 north and south direction. Interaction 

 between the Browns Bank and inshore 

 area and Georges Bank accounted for 

 most of the movement of tagged cod. 

 The interchange was bidirectional, but 

 more cod appeared to move from 

 Georges Bank to Browns Bank (about 

 30%) compared with about 3% of 

 Browns Bank cod moving to Georges 

 Bank. Relatively small numbers of cod 

 released in the 5Zj and 5Zm area were 

 recaptured in areas further to the 

 south or west. However, Hunt and 

 Buzeta ( 1996) noted that the U.S. com- 

 mercial fishery, and therefore the prob- 

 ability of recovering tags from the 1994 

 and later releases in the area west of 

 the 1MB, has been substantially reduced with the 

 introduction of closed areas in 1995. 



Information for the Browns Bank and Georges 

 Bank areas is shown in Figure 6 for adjusted recap- 

 tures in the area and from the area. Preliminary com- 

 parison of recoveries in the first twelve months and 

 total recoveries showed little variation in the distri- 

 bution or proportions ( Table 3 ) and therefore total re- 

 coveries were used. Dispersal from the area of release 

 appears to be substantial for both the 4Xp and 5Zj ar- 

 eas. However, a high proportion of fish recaptured in 

 the two areas was released fi-om the same area. The 

 two patterns may represent postspawning dispersal 

 (top panel for each area) and summer distribution or 

 year-round residents (bottom panel for each area). 



The seasonal distribution of recaptures from the 

 Browns Bank and Georges Bank areas is shown in 

 Figure 7. Recaptures were combined by quarter and 



I 



III 



Unit area of recapture 

 for cod released In 

 4Xp 



n ° 



Unit area of release 

 for cod recaptured In 

 4Xp 



in Lo un 



60 



40 



20 







-20 



-40 



-60 



-80 



Unit area of recapture 

 for cod released in 5Zj 



-.|l-- 



I 



Unit area of release 

 for cod recaptured in 

 5Zj 



E 

 X 



Unit area 



Summary 

 Georges B 



Figure 6 



of adjusted cod tag recoveries for the Browns Bank l4Xpl and 

 ank (5Zj) areas, aggregated by unit area. 



unit area (by division for recaptures outside the di- 

 vision of release). In the Browns Bank area, seasonal 

 distribution appears to be consistent with aggrega- 

 tion in the spawning season (first quarter) and with 

 progressive dispersal to adjacent areas in the remain- 

 der of the year. This pattern may be repeated on an 

 annual basis with return of migrants during the 

 spawning season. Seasonal trends in the Georges 

 Bank area are more difficult to interpret and the in- 

 fluence of fishing season may be a factor, compared 

 with trends for Browns Bank, because closure to com- 

 mercial groundfishing in the first half of the year 

 limits potential recoveries during the spawning sea- 

 son. However, the recapture pattern for cod recov- 

 ered in division 4X suggests that the migrants do 

 not return to Georges Bank because the proportion 

 remains relatively constant over the first to third 

 quarters and increases in the fourth quarter. 



