788 



Fishery Bulletin 90(4). 1992 



2 8 km displacement 



R S-20 30-24 00 



S-05 00-0630 

 & 19 00-03 00 



Maximum 33 hours to return 



C 05 45 until 4/27 



Voldes Island 



Figure 5 



Positions of Ophiodon elongatus fish no. 1 1 (69.5 cm male) cap- 

 tiored from site C, moved 2.8km north to release site R. and 

 monitored 25-27 April. S = stationary. 



Figure 6 



Positions of Ophiodon elongatus fish no. 8 (57.0 cm male) cap- 

 tured from site C, moved 2.2 km south to release site R, and 

 monitored 16-27 April. 



reconvened at 16:30, the fish was in the same position 

 where it remained until 03:15. It then moved from 

 03:15 to 04:47 when the signal was temporarily lost. 

 When relocated at 05:30, it was followed back to the 

 capture site (05:30-05:45). It was at this site 4 days 

 later that tracking stopped. The 2.8km return trip took 

 about 35 h. 



Fish no. 11, a 69.5cm male, was captured in 15m of 

 water, tagged and displaced 2.8km to the north, and 

 released in 12 m of water (Fig. 5). The fish remained 

 stationary from release (20:30) until 24:00, when it 

 moved to the west and south until 05:00. It remained 

 at this position until tracking ended at 06:30. Later that 

 day, the fish was relocated in the same location where 

 it remained until 03:00. At this time the fish moved 

 southeast and southwest and reached its original cap- 

 ture site at 05:45. It remained there until 27 April when 

 tracking ended. The 2.8km return trip took ~33h. 



One fish did not return from displacement. Fish no. 

 8, a 57.0cm male was caught, tagged, and transplanted 

 2.2km (Fig. 6) to the release site. Tracking continued 

 for 12 d, during which time the fish apparently re- 

 mained at the release site and no movement was 

 detected. Because I was unable to make scuba obser- 

 vations at this site, it is possible that the tag was shed, 

 which would also result in a stationary signal. 



Lingcod took 33-60h to return from their 1.0-2.8 

 km displacements for an average homing speed of 

 59.5 m/h (Table 1). Actually, their movement rate was 

 faster since they moved only at night. If averaged over 

 the total period when movement was documented 

 (6h, 24:00-06:00) for two consecutive nights (total of 

 12h) then the rates are 83.3-233m/h (x 195.8m/h or 

 1 175.0 m/d). 



Discussion 



Similar to intertidal fishes (Williams 1957) and several 

 species of rockfishes (Carlson and Haight 1972, 

 Matthews 1990), lingcod are another rocky reef fish 

 capable of homing. Ultrasonic tracking is limited by low 

 sample sizes due to tag cost and labor-intensive track- 

 ing. This study represents the first attempt to use ultra- 

 sonic telemetry to research lingcod movement 

 behavior, but this was limited to displaced males soon 

 after their nesting season. Additional work is necessary 

 to determine whether males behave differently (e.g., 

 do not home) at other times of the year. Telemetry 

 would also be valuable to determine whether females 

 make inshore-offshore movements to relocate previous- 

 ly used areas. 



Lingcod movement occurred at night (24:00-06:00, 

 Figs. 3-5) sometimes under dark, moonless skies. Little 

 work has been done on fish vision in cold-temperate 

 water systems (see review in Loew and McFarland 

 1990). Nevertheless, water at night is darker and has 

 lower visibility than during the day, and as Ebeling and 

 Bray (1976) point out, "...the relatively turbid, 

 temperate waters are often a dark and gloomy place 

 at night." Moreover, during our April tracking study, 

 most nights were overcast and rainy, further reduc- 

 ing the water's visibility. The low visibility at night 

 presumably precludes lingcod from using visual land- 

 marks which usually requires precise recognition of 

 specific features such as coral heads or rocks (Hasler 

 1966, Reese 1989). Still, an important question re- 

 mains: Why should lingcod move at night when visibil- 

 ity is better during the day? Perhaps their nocturnal 

 movement is to avoid predation since lingcod some- 



