894 



Fishery Bulletin 101(4) 



gence sample revealed that blood pH, Pcog, and lactate 

 recovered completely for all experimental turtles (Figs. 1 

 and 2). Minimal changes in blood pH, PcOj and lactate were 

 detected in laboratory and field control turtles during col- 

 lection of the 5-7 serial blood samples (Figs. 1 and 2). 



Ions, glucose, and osmotic pressure 



Postsubmergence blood samples from laboratory turtles 

 revealed elevations in plasma Na*, K+, and osmotic pres- 

 sure when compared to the corresponding presubmergence 

 values (Table 1). Significant increases in the plasma Na*, 

 K+, and osmotic pressure were observed more frequently 

 in turtles with a longer in-water rest interval between suc- 

 cessive submergences (Table 1). In contrast, the plasma ion 

 concentrations and osmotic pressure of control turtles did 

 not substantially change (P>0.05, n=9) during serial blood 

 sample collection. In addition, no significant differences 

 in plasma glucose and CI" (P>0.05, n = 10) were measured 

 in any of the experimental turtles. Although most of the 

 postsubmergence changes in the blood parameters in 

 experimental turtles were not significant (Table 1), and 

 minimal alterations in blood chemistry were observed 

 in control turtles, the results suggested that there was a 

 relationship between blood acid-base status and plasma 

 osmolality and ion concentration. Therefore, correlation 

 analyses were used to determine the interdependence of 

 these variables. 



Figure 3 shows the results of the correlation analyses, 

 where pH is plotted versus ion concentration (i.e. Na*, 

 K*, and CI" concentration), osmolality, or hematocrit. 

 Nonsubmerged control turtles had a significant correla- 

 tion between blood pH and plasma chloride, and pH and 

 hematocrit (Fig. 3). As pH declined, there were slight, yet 

 significant, increases in the [CI"] and hematocrit. How- 

 ever, no correlation was detected between pH and plasma 



[Na*], [K+], or osmolality in these animals. In contrast, 

 a significant correlation was detected between blood pH 

 and plasma [Na*], [K+], [CI"], osmolality, and hematocrit 

 in experimentally submerged turtles (Fig. 3). In each case, 

 a decrease in blood pH led to an increase in the correlated 

 variable. These data are consistent with significant water 

 movement into and out of the red blood cells during and 

 after forced submersion. 



Brief forced submergence of loggerhead turtles in trawl- 

 equipped fishing nets had a profound effect on the plasma 

 ionic status (Table 2). Plasma [K*] increased significantly 

 immediately following submergence in all experimen- 

 tal turtles. Significant increases were also observed in 

 the plasma [Na*] and osmotic pressure, although these 

 changes did not occur in turtles from all of the experimen- 

 tal treatments (Table 2). Turtles partially to completely 

 recovered from the ionic imbalances, although subsequent 

 submergences caused significant increases in plasma K"^ 

 and nonsignificant increases in plasma Na* and osmolality 

 in most experimental turtles (Table 2). Ionic homeostasis 

 in forcibly submerged turtles was achieved within 180 min 

 of the final submergence, whereby plasma ion concentra- 

 tions were comparable to the initial presubmergence val- 

 ues (Table 2). The plasma ion concentrations and osmotic 

 pressure in nonsubmerged control turtles were unaffected 

 by serial blood sampling. Thus, ionic changes in experimen- 

 tal turtles resulted from the forced submergence and not 

 from handling and repetitive blood sampling. 



Discussion 



Acid-Base status 



Multiple submergences of 2-year-old loggerhead sea tur- 

 tles under laboratory and field conditions produced sig- 



