FISHERY BULLETIN: VOL 



METHODS 



Artificial Tagging 



Between 26 October 1973 and 17 October 1976, 

 1,847 olive rockfish (19-43 cm total length, TL) 

 were tagged and released upon capture at 18 sites 

 off southern California (Figure 1, Table 1). Gener- 

 ally, sites were selected either on the basis that 

 they were reefs regularly fished by partyboats or 

 private vessels, which maximized the opportunity 

 to recapture tagged animals; or that sites had to be 

 within 2 km of another regularly fished reef that 

 harbored olive rockfish, which maximized the op- 

 portunity to recover fish that move short dis- 

 tances. The exception was Naples Reef, which had 

 no other suitable site within 2 km. Naples Reef 

 was included because its fish fauna was being 

 studied intensively by other scientists. Only a few 

 fish were tagged at some sites, such as Anacapa 

 Island, Platform Holly, and Avila, either because 

 olive rockfish were infrequent there or because 

 the sites were relatively remote from Santa 

 Barbara. 



The tags (yellow Floy^ anchor type FD-67c) con- 

 sisted of a plastic tube 42 mm long with a 15 mm 

 nylon stem and a 10 mm cross b£ir attached to the 

 stem and were inserted with a Floy tagging gun, 

 FDM 68, with a heavy-duty needle 2 cm long. My 

 name. Department of Biology, UCSB, and a 

 number were printed on each tag. The anchor was 

 injected into the dorsal musculature between the 

 second and third dorsal spines, leaving the 

 brightly colored end free. Even though bryozoan 

 growth completely obscured the legend within a 

 few months, this growth was easily rubbed off by a 

 person's finger when the tag was read. 



Fish were caught by hook and line aboard re- 

 seeu^ch vessels and sportfishing partyboats, then 

 measured, tagged, and returned to the water. Be- 

 cause of expanded gas in their swim bladders, fish 

 taken at depths greater than about 20 m had to be 

 deflated before they could return to depth. Perhaps 

 10% of all fish tagged required deflation, using a 

 technique modified slightly from Gotshall (1964). 

 A 3.8 cm, 18 gage hypodermic needle was inserted 

 through the body wall into the swim bladder. 

 However, instead of placing both fish and needle 

 underwater, then waiting for the gas bubbles to 

 stop emanating from the needle, gas was sucked 



Table l. — Descriptions and locations of tagging sites for olive 

 rockfish near Santa Barbara, Calif. For locations of sites see 

 Figure 1 also. 



Site and description 



Diablo Canyon, Avila — 1 1 km west of Avila Harbor. 9 m reef in 33 m, 0-3 km 



offshore 

 Naples Reef— 24 km west of Santa Barbara, 16 km offshore, in 8-10 m, 



surrounded by 16-20 m deep sand flats 

 Oil Platform Holly — 18 km southwest of Santa Barbara, in 60 m, about 3-2 km 



offshore 

 1 Mile Reef — 2 km southeast of Santa Barbara, 2-6 m reef in 30-35 m 

 Horseshoe Reef — 10 km east of Santa Barbara, Average depth 8- 10 m, sur- 

 rounded by 12-13 m 

 Oil Platform Hilda — 8 7 km east of Santa Barbara. 3 1 km offshore in 34 m 

 4 Mile Reef — 6 4 km southeast of Santa Barbara. 6-8 m pinnacle in 40 m 

 Oil Platform Hillhouse — 10 4 km southeastot Santa Barbara, 8 9 km offshore in 



58 m 

 Oil Platforms Houchin, Hogan, Hope — About 14 km southeast of Santa 



Barbara, about 7 km offshore in 50 m 

 Talcott Shoals, Santa Rosa Island — 64,0 km southwest of Santa Barbara, 2-15 



m pinnacles in 4-45 m 

 Fraser Pt , Santa Cruz Island — 46 km south of Santa Barbara, 2-6 m reefs in 



12-15m 

 Smugglers Cove. Santa Cruz Island — 40 km southeast of Santa Barbara 

 Anacapa Island — 43 km southeast of Santa Barbara 

 Rincon Oil Island — 19 km east of Santa Barbara (not figured) 

 Deephole Reef — 68 km east of Santa Barbara, 2-6 m reefs in 24-28 m, about 



18 km offshore (not figured) 



from the bladders to speed the process, and if 

 needed, the fish's everted stomach was pushed 

 back into place. About 20% of the inflated fishes 

 died either before or immediately after being re- 

 turned to the water. Undoubtedly others that 

 swam downward also died; of six fish placed in a 

 tank after deflation, two died within 1 day and the 

 rest survived for 2 wk, to the end of the test. Elimi- 

 nated were all fish whose eyes were everted by gas 

 expansion in the choroid plexa. Experience with S. 

 caurinus, S. paucispinis, and S. serranoides indi- 

 cates that this condition frequently leads to blind- 

 ness and/or death, whether or not pressure is re- 

 leased. 



Tagging mortality in fish that did not have to be 

 deflated was probably low. Ten of 12 tagged olive 

 rockfish lived for 2 mo in an aquarium, two dying 

 after about 1 mo, apparently of a fungal infection. I 

 saw none of the extensive hemorrhaging previ- 

 ously observed in Floy-tagged Pacific mackerel. 

 Scomber japonicus (Gregory''). 



Biological Tagging 



I analyzed the parasite mix of olive rockfish to 

 determine the feasibility of using parasites as 

 "biological tags." Differences in parasite infection 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



'Gregory, P, A, 1977, Results of tagging mortality experi- 

 ments on Pacific mackerel, Pneumatophorus japonicus . Calif. 

 Dep Fish Game. Mar Res, Tech. Rep. 40. 21 p. 



976 



