NOTE Renaud et al.: Activities of juvenile Chelonia mydas 



589 



day. Seven turtles remained in the general area of 

 their capture throughout the study period. Of the 

 others, T6 used three areas along both jetties and 

 T7 moved extensively along both jetties before mov- 

 ing up the channel and into South Bay. Only data 

 from the pass were used in analyses for T7. 



Daily movements of turtles along the jetties ranged 

 from less than 50 m to more than 1,000 m. Mean 

 rate of movement ranged from 8 m/h to 568 m/h 

 (Table 2). The least movement occurred at night, 

 ranging from 8-127 m/h. Seventy percent of all loca- 

 tions were within 5 m of the jetties. Only 0.3% were 

 within channel boundaries, including five channel 

 crossings. Overall areal ranges of turtles remaining 

 in the jetty area were from 2,274 to 31,168 m 2 . Over- 

 all core areas ranged from 130 to 7,374 m 2 . 



Five of the nine turtles tracked had ranges re- 

 stricted to the north side of the south jetty (Fig. 1). 

 Northerly winds, in excess of 20 knots, coincided with 

 the movement of T6 from the windward side of the 

 north jetty into protected waters near the south jetty 

 by day 14. Mean locations for three turtles (Tl, T4, 

 and T5) were within 400 m of the Barracuda Cove 

 beach. The mean location of T2 was about 650 m from 

 the beach, about halfway up the jetty. The only turtle 

 that had significantly different mean locations for 

 different time periods was Tl (P<0.05). The mean 

 dusk location of Tl was about 250 m closer to the 

 jetty tip than its mean dawn and day locations and 

 over 400 m closer than its mean night location. T3, 

 on the south side of the north jetty, also showed 

 greater westward movement at night than at any 

 other time (P<0.05). 



Submergence and surface behavior 



Tracking was conducted for a total of 108 hours at 

 dawn, 247 h during the day, 60 h at dusk, and 151 h 

 at night. Time spent submerged ranged from 80.8 to 

 97.8% and averaged 91% for all turtles (Table 1 ). Sub- 

 mergence time ranged from 0.02 to 39.8 minutes. 

 Overall mean submergence time varied from 1.9 to 

 6.1 min between turtles. Surface time ranged from 1 

 to 1,146 seconds. Overall mean surface time varied 

 from 8.5 to 26.5 seconds. 



A breakdown of submergence time by turtle re- 

 vealed that 99% of all turtle submergences were <20 

 min, 74-96% were <10 min, and 38-64% were <1 

 min (Fig. 2). Submergence patterns were significantly 

 different when data were analyzed by dawn, day, 

 dusk, and night (Table 3). The number of sub- 

 mergences >10 min was higher at night than at other 

 time periods for every turtle tracked at night. 



A breakdown of surface time by turtle revealed that 

 99% of all turtle surfacings were <120 sec, 67-92% 

 were <15 sec, and 41-77% were <5 sec (Fig. 2). Sur- 

 face patterns also were significantly different when 



