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Fishery Bulletin 101(4) 



nificant blood metabolic and respiratory disturbances. 

 The most dramatic changes in blood pH, Pco.^, and lactate 

 occurred following the first of the three forced submer- 

 gences in all of the experimental turtles (Table 3). Under 

 laboratory conditions, the turtles exhibited an average pH 

 change of 0.54 U following the first submergence, whereas 

 initial submergence of 2-year-old loggerhead sea turtles 

 in TED-equipped commercial fishing nets induced a pH 

 decrease of 0.63 U. The initial acid-base disturbances mea- 

 sured in our study were comparable in magnitude to those 

 measured in Kemp's ridley and loggerhead sea turtles in 

 standard TED certification trials (Table 3). 



The second and third submergences of 2-year-old log- 

 gerheads sea turtles did not result in similar changes in 

 blood pH, PcOj, and lactate, as was measured following the 

 initial submergence (Table 3). To our knowledge, no infor- 

 mation is available in the literature on the physiological 

 effects of multiple submergences in sea turtles for compari- 

 son. Obviously, the interval between the submergence epi- 

 sodes directly influenced the magnitude of the blood acid- 

 base imbalance during successive submergences. A longer 

 time interval at the surface led to enhanced recovery of 

 blood pH, Pcog, and lactate. Lutz and Dunbar-Cooper ( 1987) 

 reported that loggerhead sea turtles captured during trawl- 

 ing at Cape Canaveral, Florida, exhibited a 16.8% decline 

 in lactate 180 min following submergence. Those authors 

 proposed that the rate of lactate decline was dependent on 

 the magnitude of the lactate concentration, so that 10 mM 

 of lactate would decline at a rate of 1.25 niM lactate/h. 

 However, in the present study, the rate of lactate decline 

 was considerably higher than that suggested by Lutz and 

 Dunbar-Cooper (1987). Lactate declined 70.0% and 79.6% 

 within 180 min of the submergence episodes in treatment 

 3 turtles, whereas no decline was measured in treatment 

 1 turtles (10 min interval) between submergences. In fact, 

 it was apparent that lactate continued to washout into the 



bloodstream during the 10-min recovery phases in these 

 turtles (Fig. 1, Table 3). Thus, turtles with a brief period 

 between the submergence episodes would have a limited 

 ability to release the CO2 retained during submersion or 

 to break down lactic acid produced during the course of 

 the forced dive. Lactate declined 15.2%- and 18.7% during 

 the 42-min interval between submergences in treatment-2 

 turtles. Blood lactate declined 80.9%, 76.0%, and 82.5% in 

 treatment-1, -2, and -3 turtles, respectively, during the final 

 180-min recovery period. Thus, the overall rate of lactate 

 decline in the final 180 minutes of the laboratory study was 

 2.6 ±0.2 mM/h. Finally, the elevated lactate concentration 

 in sea turtles during the 180-min postsubmergence recov- 

 ery time interval suggests that the samples were collected 

 too soon to permit complete recovery of blood lactate. 



Comparable rates of lactate clearance measured in the 

 laboratory submergence study were detected following 

 forced submergences of loggerhead sea turtles in TED- 

 equipped fishing nets. Substantial retention of CO, and 

 additional washout of lactate occurred during the 10-min 

 postsubmergence recovery interval in treatment-4 turtles. 

 Treatment-5 turtles exhibited a 6% drop in the blood 

 lactate concentration during the first 42-min postsubmer- 

 gence recovery interval and a 17.5% decrease in the blood 

 lactate during the second recovery interval. Thus, the 42- 

 min postsubmersion recovery interval permitted recovery 

 of blood gases, but was inadequate to clear the blood lactate 

 (Fig. 2, Table 3). Lactate declined 80.4% and 83.8%, respec- 

 tively, during the first two 180-min postsubmergence re- 

 covery intervals in treatment-6 turtles. As was the case for 

 laboratory submerged sea turtles, a longer surface interval 

 ultimately resulted in an increased ability to recover from 

 the submersion episodes. In fact, lactate declined 82.7%, 

 82.8%, and 87.9%, respectively, in treatment-4, -5, and -6 

 turtles 180 minutes after the final submersion episode 

 (Fig. 2, Table 3). 



