NOTE Markaida et al.: Tagging studies on Dosidicus gigas 



221 



9 I 



Sta. Rosalia, 9-16 October 2001 



Ml Sta. Rosalia n=71 

 Guaymas n=9 



ii i mi 



L 



 (     i  



10 

 October 



20 30 40 50 60 70 80 90 100 110 



I 



November 



I December 



January 



Guaymas, 3-7 April 2002 



^^™ Guaymas n=61 



Sta. Rosalia n=19 



nil , i 



JU 



10 

 April 



vrHk 

 20 30 40 50 60 70 80 90 100 110 120 130 140 210 220 



May June July August Oct [ Nov 



June 



Days after tagging 



I 



Figure 3 



Time course for recapture data for squid tagged off Santa Rosalia (A) and off Guaymas 

 (B). In both sections, black bars represent squid recaptured from the same coast where 

 tagging was done, and gray bars represent squid recaptured from the opposite coast. 

 Note that a gap exists between August and October in panel B. 



Results 



Timing of tag returns 



A total of 80 tags (8.03%) were recovered for the squid 

 tagged off Sta. Rosalia. Of these, 71 were recovered in 

 the general vicinity of this port. More than a third of 

 these tags (25) were discovered at commercial squid 

 processing plants, where the mantles are manually 

 cleaned before final processing. Squid were captured 

 generally shortly after tagging; most of the tags (52) 

 were recovered during the first 15 days (Fig. 3A). The 

 shortest recapture period was only several hours. In this 

 case, a squid tagged by the crew of one of our boats was 

 caught about one km away by our second boat. 



In addition to the Sta. Rosalia returns, another nine 

 squid (0.9%) were recaptured off Guaymas, from 39 to 

 108 days after tagging (Fig. 3A). The temporal overlap 

 in returns from the two localities (days 39-55) and the 

 total lack of any subsequent Sta. Rosalia returns would 

 indicate that a significant number, if not most, of the 

 squid migrated from Sta. Rosalia to Guaymas and po- 

 tentially elsewhere during this period (17 Nov-4 Dec). 



In the second experiment, conducted off Guaymas, 80 

 tags (8%) were also recovered. Sixty-one were recovered 



in the Guaymas area over an extended period from 2 to 

 224 days after tagging (Fig. 3B). In this case, the squid 

 were recaptured more or less constantly at a low rate 

 over the first 60 days. Surprisingly, only one tag was 

 recovered at a processing plant during this period. Spo- 

 radic returns then continued in Guaymas over the next 

 three months. It should be noted that there was little 

 squid fishing activity in the area during September 

 because of the beginning of the commercial shrimp sea- 

 son. The final three tags were recovered after 219-224 

 days (8-13 Nov). These squid were tagged on the same 

 night and location seven months earlier. 



Of the tags deployed in Guaymas, 19 (1.9%) were 

 recovered in the Sta. Rosalia area in summer 2002 

 (28 May-29 August) from 54 to 207 days after tagging 

 (Fig. 3B). Seven of these tags were recovered at squid 

 factories. A period of overlapping returns occurred over 

 days 54-72, and we interpreted this overlap in returns 

 as being consistent with a seasonal mass migration 

 form Guaymas to Sta. Rosalia. A second period of over- 

 lapping returns of similar duration occurred in July. 

 However, in this case, returns from Guaymas continued 

 throughout the entire summer and into the fall. It thus 

 appears that some squid remained in the Guaymas area 

 during this period. 



