EMMETT and JAMIESON: TRANSPLANT OF NORTHERN ABALONE 



Removal, Tagging, and Transplanting 



Prior to transplanting any northern abalone, 

 divers searched for and removed indigenous abalone 

 from the transplant sites. The divers then collected 

 the abalone from the source area using a dull knife 

 or the arm of the sea star, Pycnopodia heliantJuyides. 

 The arms elicit an escape response, which allows the 

 abalone to be hand-picked without damaging the 

 foot. Tagging and transplanting were conducted 

 from mid-June to July 1984. Approximately 20% of 

 the northern abalone, selected haphazardly, were 

 tagged with individually numbered, stainless steel 

 washers immediately after capture. A loop of stain- 

 less steel wire was inserted through the last two 

 respiratory pores of the abalone shell, a washer tag 

 was added to one end of the loop, and the wire was 

 then twisted with a pair of pliers to anchor the tag 

 against the abalone shell. Length, width, and sex 

 of all tagged northern abalone were recorded. Shell 

 lengths of a subsample (10%) of untagged abalone 

 were measured for comparison with the tagged 

 samples. Tagged abalone were placed between 

 layers of moist kelp so that the tag wires did not 

 damage overlying abalone. Abalone were then trans- 

 ported to transplant sites within 3-4 hours of har- 

 vest and placed by divers in or immediately below 

 the Macroeystis zone, the preferred habitat for adult 

 abalone in sheltered locations (Breen 1986). A total 

 of 502 tagged abalone were placed at site A and 506 

 at site B. Abalone (w = 438) were also removed from 

 the control site (C), tagged and replaced onto the 

 site within 2-3 hours. 



Divers searched the transplant sites within 48 

 hours of completing the transplant, and monthly 

 from August 1984 to February 1985. All tagged and 

 untagged abalone shells found in the study sites 

 were collected. 



Recovery of Transplanted Abalone 



In March 1985, divers harvested tagged and un- 

 tagged northern abalone at the transplant sites and 

 tagged abalone at the control site. To maximize 

 recovery, divers divided each site into a series of 5 

 m sections using cinder blocks and cord. The area 

 of each section was measured and divers then 

 searched repetitively for abalone within each sec- 

 tion. Harvesting was terminated when repetitive 

 searches in each area recovered less than 5% of the 

 abalone harvested in the initial search. Divers also 

 searched areas adjacent to the study site for tagged 

 abalone to establish the magnitude and distance of 

 emigration. Length, width, and sex of recovered. 



tagged abalone were recorded, along with the 

 lengths of all tagged abalone. 



RESULTS 



Abalone Transplants 



A total of 2,737 northern abalone were trans- 

 planted to site A and 2,677 abalone were trans- 

 planted to site B (Table 1). The mean length of 

 tagged abalone transplanted to site A was 88.7 mm 

 and to site B, 90.2 mm. The mean length of abalone 

 tagged at the control site (site C) was 78.7 mm. The 

 differences in mean length between sites were all 

 significant (P < 0.05). The mean length (±SD) of 

 subsamples of untagged abalone transplanted to 

 sites A and B were 84.6 -i- 12.8 mm (n = 204) and 

 8.8 + 11.5 mm (w = 257), respectively. 



Table 1— Summary of number and mean length of abalone at 

 eacfi site. Density for site C is estimated from random quadrat 

 surveys conducted prior to tagging (±SD). 



Although divers carefully placed each trans- 

 planted northern abalone foot down in suitable rock 

 crevices or loose rock within the study areas, many 

 abalone subsequently moved outside the lower 

 boundary of the sites to depths of 7-10 m. This 

 movement made the effective area of the transplant 

 sites about three times larger than the original 60 

 m X 8 m dimensions. Little lateral movement of 

 northern abalone beyond the boundaries of the study 

 sites was observed. 



At sites B and C, the recovery of tagged shells 

 by monthly diving inspections was highest in Aug- 

 ust, one month after the transplant (Fig. 2). Recov- 

 ery of both tagged and untagged shells at all sites 

 in early July suggests that mortality one week after 

 transplanting was less than 2%. The relatively high 

 recovery of tagged shells in March 1985 was prob- 

 ably a consequence of the more intensive searching 

 effort during the final harvest. Cumulative recover- 

 ies of tagged shells were 10.5% at site A, 18.0% at 



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