Abstract:SUMMARY:We characterised the effect of seasonal fluctuations in water temperature (T w ) on the nonventilatory period (NVP) of Mediterranean loggerhead turtles, Caretta caretta. Ten captive turtles, that were subject to the natural variations in T w found in the Gulf of Naples, dived significantly longer when T w decreased. More than 50% of summer and winter dives lasted between 2 and 10 min; the maximum dive duration (120 min) occurred in winter at a T w of 13°C. The longest NVP coincided with a low level of … Show more
“…The lack of a capacity to compensate dive behaviour for seasonal thermal variability in A. arafurae is consistent with similar findings in freshwater crocodiles (Campbell et al 2010a, b) and some turtle species (e.g. Clark et al 2008b;Gordos et al 2003a;Bentivegna et al 2003) and suggests that in air-breathing diving ectotherms, dive behaviour especially in warm environments is not subject to thermal acclimation. Therefore, for air-breathing diving ectotherms like A. arafurae, future environmental warming could have substantial consequences for behaviour and in turn could result in reduced survivorship.…”
The presumption that organisms benefit from thermal acclimation has been widely debated in the literature. The ability to thermally acclimate to offset temperature effects on physiological function is prevalent in ectotherms that are unable to thermoregulate year-round to maintain performance. In this study we examined the physiological and behavioural consequences of long-term exposure to different water temperatures in the aquatic snake Acrochordus arafurae. We hypothesised that long dives would benefit this species by reducing the likelihood of avian predation. To achieve longer dives at high temperatures, we predicted that thermal acclimation of A. arafurae would reduce metabolic rate and increase use of aquatic respiration. Acrochordus arafurae were held at 24 or 32°C for 3 months before dive duration and physiological factors were assessed (at both 24 and 32°C). Although filesnakes demonstrated thermal acclimation of metabolic rate, use of aquatic respiration was thermally independent and did not acclimate. Mean dive duration did not differ between the acclimation groups at either temperature; however, warm-acclimated animals increased maximum and modal dive duration, demonstrating a longer dive duration capacity. Our study established that A. arafurae is capable of thermal acclimation and this confers a benefit to the diving abilities of this snake.
“…The lack of a capacity to compensate dive behaviour for seasonal thermal variability in A. arafurae is consistent with similar findings in freshwater crocodiles (Campbell et al 2010a, b) and some turtle species (e.g. Clark et al 2008b;Gordos et al 2003a;Bentivegna et al 2003) and suggests that in air-breathing diving ectotherms, dive behaviour especially in warm environments is not subject to thermal acclimation. Therefore, for air-breathing diving ectotherms like A. arafurae, future environmental warming could have substantial consequences for behaviour and in turn could result in reduced survivorship.…”
The presumption that organisms benefit from thermal acclimation has been widely debated in the literature. The ability to thermally acclimate to offset temperature effects on physiological function is prevalent in ectotherms that are unable to thermoregulate year-round to maintain performance. In this study we examined the physiological and behavioural consequences of long-term exposure to different water temperatures in the aquatic snake Acrochordus arafurae. We hypothesised that long dives would benefit this species by reducing the likelihood of avian predation. To achieve longer dives at high temperatures, we predicted that thermal acclimation of A. arafurae would reduce metabolic rate and increase use of aquatic respiration. Acrochordus arafurae were held at 24 or 32°C for 3 months before dive duration and physiological factors were assessed (at both 24 and 32°C). Although filesnakes demonstrated thermal acclimation of metabolic rate, use of aquatic respiration was thermally independent and did not acclimate. Mean dive duration did not differ between the acclimation groups at either temperature; however, warm-acclimated animals increased maximum and modal dive duration, demonstrating a longer dive duration capacity. Our study established that A. arafurae is capable of thermal acclimation and this confers a benefit to the diving abilities of this snake.
“…Marine pollution caused by persistent organic pollutants (POPs), and resultant diseases, human activities such as the development of tourism, coastal urbanization, and naval traffic, and particularly incidental fisheries capture are potential threats to the survival of Caretta caretta in the Mediterranean Sea (Laurent et al 1996, Bentivegna et al 2002.…”
We detected concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) in the liver, muscle, and fat of 11 loggerhead sea turtles Caretta caretta from the central and southern Adriatic Sea. All samples contained PCBs at various concentrations, with Congener 138 (28%), 153 (27%), and 180 (32%) dominating the congener composition of the tissues. The dioxin-like congener (118, 13%) was detected in all tissues analyzed. The lower-chlorinated PCBs were not detected. The average of the total PCB concentrations, expressed in nanograms per gram wet weight, was 459.6 ng g -1 in fat, 82.9 ng g -1 in liver, and 5.8 ng g -1 in muscle. Among 13 organochlorine pesticides for which analyses were conducted, 4 were detected: p,p '-DDE (57%); p,p '-DDD (16%); and p,p '-DDT and o,p '-DDT (27%). Spatial differences were found among OC concentrations in loggerheads from the central and southern Adriatic Sea. The only samples containing detectable concentrations of p,p '-DDT and o,p '-DDT were from the southern area.
“…This turtle began to breathe regularly 5 min after the start of the fat biopsy. Although this period of apnea appears prolonged, it was still well within the maximum dive durations of up to 2 hr (Bentivegna et al, 2003) and 7 hr (Hochscheid et al, 2005) reported for loggerheads in winter, and it is comparable to routine dive durations of subadult loggerheads of 19-30 min (Lutcavage and Lutz, 1997). The fact that all treatment turtles experienced apnea may be attributable to the method of i.v.…”
ABSTRACT:Rapid, safe, and effective methods of anesthetic induction and recovery are needed for sea turtles, especially in cases eligible for immediate release. This study demonstrates that intravenous propofol provides a rapid induction of anesthesia in loggerhead (Caretta caretta) sea turtles and results in rapid recovery, allowing safe return to water shortly after the procedure. Forty-nine loggerhead sea turtles were recovered as local fishery by-catch in pound nets and transported to a surgical suite for laparoscopic sex determination. Treatment animals (n532) received 5 mg/kg propofol intravenously (i.v.) as a rapid bolus, whereas control animals (n517) received no propofol. For analgesia, all animals received a 4 ml infusion of 1% lidocaine, locally, as well as 2 mg/kg ketoprofen intramuscularly (i.m.). Physiologic data included heart and respiratory rate, temperature, and a single blood gas sample collected upon termination of the laparoscopy. Subjective data included jaw tone and ocular reflex: 3 (vigorous) to 0 (none detected). Anesthetic depth was scored from 1, no anesthesia, to 3, surgical anesthesia. Turtles receiving propofol became apneic for a minimum of 5 min with a mean time of 13.7 6 8.3 min to the first respiration. Limb movement returned at a mean time of 21.1 6 16.8 min. The treatment animals were judged to be sedated for ,30 min (mean anesthetic depth score $ 1.5) when compared to controls. Median respiratory rates for treatment animals were slower compared to controls for the first 15 min, then after 35 min, they became significantly faster than the controls. Median heart rates of control animals became significantly slower than treatment animals between 40 and 45 min. Physiologic differences between groups persisted a minimum of 55 min. Possible explanations for heart rate and respiratory rate differences later in the monitoring period include a compensatory recovery of treatment animals from anesthesia-induced hypoxia and hypercapnia or, alternatively, an induced response of the nonsedated control animals. The animals induced with propofol were easier to secure to the restraint device and moved less during laparoscopy. In conclusion, propofol is a safe and effective injectable anesthetic for use in free-ranging loggerhead sea turtles that provides rapid induction and recovery.
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