664 



Fishery Bulletin 100(4) 



Vancouver Island 



Oaas 



Island 



Strail of Juan de Fuca 



Washinmon 



Figure 2 



(Upper left ) The commercial hai-vesting districts for sea urchins in Washington (after Lai and Bradbury. 1998). Harvest district numbers 

 are shown in the upper left corner of each district. (Right) Enlargement of San Juan Channel, showing locations of study sites. Sites 1-3 

 are complete harvest sites, sites 4—6 are selective harvest sites, and sites 7-9 are control sites. Dashed lines represent the boundary of 

 the areas on the west coast of San Juan Island and in San Juan Channel closed to commercial sea urchin harvest through fall 1998 The 

 dotted line represents the modified southern boundary of the reserve area in San Juan Channel established in fall 1998. (Lower left) 

 Enlargement of the Strait of Juan de Fuca sampling area. Black circles indicate locations of randomly chosen sampling sites. 



term effects of harvest; whereas large-scale sampling 

 better indicated how treatments affected the entire bed 

 of sea urchins. We identify the scale of sampling (sites vs. 

 circular areas within sites) for all results. 



Size distribution 



In SJC, we measured all sea urchins removed during the 

 initial harvest of complete and selective hai^est sites 

 in March 1997, and all sea urchins removed during the 

 second annual harvest of selective harvest sites in March 

 1998. In September of 1997 and 1998, we measured a min- 

 imum of 100 sea urchins in situ in all sites in randomly 

 chosen 5 m x 5 m quadrats. We also measured sea urchins 

 in the circular areas within sampling sites in situ in all 

 sites five times per year: early March, mid March, April, 



June, and September. The sampling periods represented 

 preharvest and 5, 30, 90, and 180 days after harvesting in 

 each year for the selective harvest treatment. 



Nineteen randomly chosen sites in the western SJDF 

 were sampled in August and September 1997 (Fig. 2). All 

 sites were 7-8 m below mean lower low water. At each site, 

 we measured sea urchins (/) situ on 1-3 transects parallel 

 to shore, each >30 m-. 



Lower and upper size limits for commercial sea urchin 

 hai^est are 102 and 140 mm test diameter in SJC, and 83 

 and 114 mm in SJDF (Pfister and Bradbury, 1996). Sea ur- 

 chin measurements in SJC and SJDF were recorded to the 

 nearest 5 mm (e.g. 130 mm=test diameters 130-134 mm), 

 except during the initial sampling periods (March- June 

 1997), when sea urchins measured in situ only were re- 

 corded to the nearest 10 mm (e.g. 130 mm=test diameters 



