364 



Fishery Bulletin 101(2) 



Similar to the results for nonstandardized recoveries, 

 the standardized recaptures for Strait of Georgia, Puget 

 Sound, west coast of Vancouver Island, and Washington 

 State coastal waters were based on recaptured fish at 

 liberty for 5 years or less. For fish released in the Strait 

 of Georgia, the majority (86%) were recaptured in the 

 Strait of Georgia (Table 4). A further 7% were recaptured 

 off the west coast of Vancouver Island, 6% in Washington 

 State coastal waters, and only 1% in Puget Sound (Table 

 4). For fish released off the west coast of Vancouver Island, 

 the majority of standardized recoveries (73%) occurred in 

 Washington State coastal waters (Table 4). Only 20% were 

 recaptured in the area of release. 



Movement by sex and size 



In general, small-size females (<70 cm) released in the 

 Strait of Georgia and northern British Columbia were of 

 the sex-size category (Fl) of spiny dogfish that were recap- 

 tured in the highest proportion in other areas (Table 5). 

 All sex-size categories of spiny dogfish (except Ml, small 

 males <70 cm) released off the west coast of Vancouver 

 Island were recaptured in other areas in high proportions 

 (Table 5). 



Discussion 



The low recovery percentage in this study is probably 

 related to a low reporting rate. Until recently spiny dogfish 

 catches in Canadian waters were discarded without being 

 examined. However, this low recovery percentage also 

 reflects the high abundance of spiny dogfish off the west 

 coast of North America. Ketchen (1986) reported abun- 

 dance estimates of 300 000 t for the whole North American 

 coast and Saunders (1989) estimated 210,000-260,000 t 

 in Canadian waters. It is clear that spiny dogfish are 

 common and relatively abundant from northern Oregon 

 to southeastern Alaska. Knowledge of the movements of 

 spiny dogfish within eastern waters and between eastern 

 and western waters is still limited but indicates that this 

 shark is a key species in those coastal ecosystems. The use 

 of the more durable modified Petersen tag in other areas 

 would add to our knowledge of dogfish movement between 

 these ecosystems. 



Holland (1957), reporting on tagging studies conducted 

 in the 1940s, concluded that Puget Sound and the Strait 

 of Georgia supported indigenous populations. However, 

 Ketchen ( 1986) reviewing studies by Foerster ( 1942), Fujio- 

 ka ct al. ( 1974 ), and McFarlane et al. ( 1982) suggested more 

 movement between the inside populations than reported in 



