NOTE Yamanaka and Richards Movements of transplanted Ophiodon elongatus 



585 



leased at the north side of Amelia Island, moved in a 

 westerly direction for 5 days, turned east, and then 

 remained within a 0.3 km 2 area for 17 days, after which 

 the tag battery expired. All four control fish remained 

 within 0.4 km- of their capture-release site over the 

 entire tracking period. 



Transient lingcod were apparently more active than 

 resident lingcod, and control lingcod moved little. An 

 analysis of variance on the ranked movement rate data 

 for the experimental lingcod indicated that rates dif- 

 fered significantly among fish within a group (P<0.001) 

 and, furthermore, that rates differed significantly be- 

 tween fish in transient and resident groups (P<0.001). 

 Similarly, movement rates differed significantly be- 

 tween experimental and control groups of lingcod 

 (P<0.001). Mean (±SE) movement rates were 4.9±0.5m/ 

 min, 1.8±0.2m/min, and 0.3±0.2 m/min, respectively, for 

 transient, resident, and control groups of lingcod. Move- 

 ment rate was also related to fish size. For the experi- 

 mental lingcod, rank correlation coefficients between 

 mean movement rate and fish length (0.69) and weight 

 (0.60) were significant (P<0.05). Thus, fish size may 

 determine movement patterns, which in turn deter- 

 mine the tendency of experimental lingcod to leave or 

 remain in the study area. 



We calculated the total (horizontal) distance trav- 

 elled by each lingcod (Table 1) as the sum of the dis- 

 tances between sequential observations of fish posi- 

 tion. This measurement obviously depends on the 

 number of positions recorded for a fish during each 

 tracking period. Furthermore, the number of positions 

 recorded was highly variable, because of continuous 

 observations for some fish. We computed daily move- 

 ment rates (km/d) to ensure meaningful com- 

 parisons among fish. These rates were calcu- 

 lated from distances between estimated 

 positions at 24-hour intervals for fish with 

 three or more sequential daily position obser- 

 vations. As demonstrated for the raw move- 

 ment data, daily movement rates were signifi- 

 cantly greater for transient fish than for 

 resident fish (Wilcoxon rank sum test, P<0.05), 

 and for resident fish than for control fish 

 (Wilcoxon rank sum test, P<0.001). Mean (±SE) 

 daily movement rates were 1.42+0.24 km/d 

 U = 19), 0.80±0.13km/d (rc=51), and 

 0.05±0.01km/d (n=21) for transient, resident, 

 and control groups of lingcod, respectively. 



Continuous observations for four experimen- 

 tal fish were sufficiently long to examine diel 

 activity patterns. We determined the distance 

 travelled between estimated positions at se- 

 quential 2-hour periods (Fig. 2). By late-Octo- 

 ber, the study area was experiencing only 8 



hours of daylight. Lingcod travelled the greatest dis- 

 tances at night (Fig. 2). Movement rates for these fish 

 averaged 2.1±0.3m/min (n=58> during the night (1600- 

 0800 hours) and 0.7±0.1 m/min (ra=26) during the day 

 (0800-1600 hours). 



Discussion 



Movements of lingcod transplanted 250 km from their 

 normal habitat were related to fish size. The larger 

 fish tended to disperse from the study site within a 

 few days of release. These results corroborate the 

 findings of Buckley et al. (1984); when lingcod are 

 transplanted over large distances, the smaller fish are 

 more likely to remain in the new area. 



The tendency for larger experimental lingcod to leave 

 the study area may be related to the onset of sexual 

 maturity. Lingcod spawn in the Strait of Georgia be- 

 tween December and March (Low and Beamish, 1978). 

 Lingcod selected for the transplant were all smaller 

 than the size at 50% maturity. However, sexual matu- 

 rity in lingcod can occur over a wide size range 

 (Richards et al., 1990). For example, all experimental 

 male lingcod and one transient female lingcod were 

 larger than the size at 20% maturity. Thus, some of 

 the recorded movements could be associated with se- 

 lection of spawning (nest guarding) sites. 



Ultrasonic tags provide short-term information on 

 fish behaviour. Experimental lingcod could be followed 

 for at most 28 days (Table 1) and we can not discount 

 the possibility that resident lingcod left the study area 

 after the end of the experiment. Furthermore, tran- 



~i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — 



8 12 16 20 24 4 8 12 16 20 24 4 8 12 16 20 

 Hour of day 



Figure 2 



Distances travelled over 2-hour intervals by four lingcod observed con- 

 tinuously for 48-60 hours. Distances are shown corresponding to the 

 interval midpoint. The shaded rectangles indicate periods of darkness. 



