Movements of transplanted lingcod, 

 Ophiodon elongatus, determined 

 by ultrasonic telemetry 



K. Lynne Yamanaka 



Laura J. Richards 



Department of Fisheries and Oceans, Biological Sciences Branch 

 Pacific Biological Station. Nanaimo. B.C.. Canada V9R 5K6 



Lingcod, Ophiodon elongatus, have 

 formed an important component of 

 commercial and recreational 

 fisheries from Alaska to California. 

 In the center of their range, how- 

 ever, in Puget Sound, Washington, 

 and in the Strait of Georgia, Brit- 

 ish Columbia, Canada, lingcod 

 stocks are currently depressed. For 

 example, annual commercial 

 catches in the Strait of Georgia de- 

 clined from a high of 3300 metric 

 tons (t) in 1944 to 80 1 in 1989, prob- 

 ably owing to overfishing (Ketchen 

 et al., 1983; Richards and 

 Yamanaka, 1992). In 1990, the com- 

 mercial fishery was closed; however, 

 a restrictive recreational catch is 

 still permitted. Similar declines in 

 central Puget Sound led to a com- 

 plete fishery closure between 1978 

 and 1982, followed by a small rec- 

 reational fishery (Buckley et al., 

 1984). 



Because of the value of the ling- 

 cod fishery, there is considerable in- 

 terest in rebuilding these stocks. 

 This paper describes a feasibility ex- 

 periment for one approach to en- 

 hance natural stock rebuilding. 

 Abundance is currently average or 

 above average for lingcod stocks in 

 offshore areas of the British Colum- 

 bia coast (Richards and Yamanaka, 

 1992). Lingcod could be trans- 

 planted from these areas into the 

 Strait of Georgia. Such an experi- 

 ment was conducted by Buckley et 

 al. (1984) in Puget Sound. They 

 found that transplanted young-of- 

 the-year lingcod (10-20 cm) were 

 582 



caught in the area 2 and 3 years 

 after release. However, most trans- 

 planted adult lingcod left the area 

 and migrated towards their capture 

 site. Our experiment involved trans- 

 planting juvenile lingcod (age 2- 

 3yr) and tracking their movement 

 in the new area through ultrasonic 

 telemetry. 



Ultrasonic telemetry has been 

 used successfully on a number of 

 marine fish species (Holland et al., 

 1985, 1990; Quinn et al., 1989; 

 Clark and Green, 1990; Ruggerone 

 et al., 1990; Matthews et al, 1990). 

 Unlike conventional tags, ultrasonic 

 tags allow continuous monitoring of 

 fish movements. They are usually 

 limited, however, to small sample 

 sizes and short time periods because 

 of cost and labour constraints. Ul- 

 trasonic telemetry was useful for 

 this study because precise positions 

 could be obtained for individual fish. 



Matthews ( 1992) conducted a pre- 

 vious ultrasonic telemetry study on 

 lingcod. In addition to tracking six 

 stationary lingcod, she displaced 

 five adult male lingcod a short dis- 

 tance (maximum 2.8 km) from their 

 capture site. Four of these lingcod 

 returned to their exact capture sites 

 within 60 hours. Thus, she demon- 

 strated that adult male lingcod were 

 capable of homing over short dis- 

 tances. She concluded that trans- 

 plants of adult male lingcod would 

 likely be unsuccessful, given this 

 tendency to home. 



We addressed two issues left un- 

 answered bv Matthews (1992). In 



particular, we designed an experi- 

 ment with juvenile rather than 

 adult lingcod and we displaced 

 these fish a relatively long distance 

 (250km). We determined whether 

 lingcod remained at the transplant 

 site over a period of approximately 

 one month. Based on previous stud- 

 ies, we hypothesized that homing 

 lingcod would leave the transplant 

 area within a few days and exhibit 

 directional movements towards the 

 capture site. We compared the 

 movements of transplanted lingcod 

 with similar-size control lingcod 

 caught, tagged, and released in the 

 study area. 



Methods 



The experiment was conducted off 

 the east coast of Vancouver Island, 

 British Columbia (Fig. 1). The 12 X 

 4 km study area was chosen because 

 it contained shallow reefs typical of 

 lingcod habitat (Ketchen et al., 

 1983). The area was conveniently 

 marked by navigational aids and 

 separated from small islands to the 

 north and east by a 300-m deep 

 channel. A commercial fishery ex- 

 isted here historically, and recent 

 SCUBA and recreational fishing ac- 

 tivities confirmed the presence of a 

 small resident lingcod population. 



Experimental lingcod were col- 

 lected at the end of September 1991 

 from Queen Charlotte Strait, about 

 250 km northwest of the study area 

 (Fig. 1). They were held for 5-34 

 days before being tagged and re- 

 leased. Prior to tagging, lingcod 

 were immobilized in an anaesthetic 

 bath (MS222, tricaine methane 

 sulphonate). Tags were then an- 

 chored through the dorsal muscu- 

 lature adjacent to the dorsal fin by 

 means of two self-locking nylon ties 

 (Holland et al., 1985). Tagged ling- 

 cod were held overnight to assess 

 condition; only healthy-appearing 



Manuscript accepted 17 Fehruary 1993. 

 Fishery Bulletin: 91:582-587 1 1993). 



