Tuna aerobic swimming performance: Physiological and environmental limits based on oxygen supply and demand (original) (raw)
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The aerobic capacity of tunas: Adaptation for multiple metabolic demands
Comparative Biochemistry and Physiology Part A: Physiology, 1996
Tunas are pelagic, continuous swimmers, with numerous specializations for achieving a high aerobic scope. Tunas must maintain a high rate of energy turnover, and therefore require elevated levels of aerobic performance in multiple physiological functions simultaneously. Based on a model of oxygen demand and delivery to the swimming musculature, the yellowfin's total oxygen consumption at the predicted maximum sustainable (aerobic) swimming velocity is well below estimates of its maximum oxygen consumption. This suggests that the high aerobic scope of tunas may be a specialization that permits continuous swimming in addition to supplying oxygen to other metabolic functions. Estimates of the metabolic costs of oxygen-debt repayment, growth, and specific dynamic action have been combined with this model of aerobic swimming performance to evaluate the total energy budget in relation to the aerobic scope of the yellowfin tuna. Repay ment of the oxygen debt incurred during burst swimming is potentially a large component of tuna respiratory metabolism and the relatively high aerobic capacity of tuna white muscle may be a specialization for rapid lactate clearance.
Studies of Tropical Tuna Swimming Performance in a Large Water Tunnel - Energetics
Journal of Experimental Biology, 1994
The metabolic rates (V(dot)O2) of three tropical tunas [yellowfin tuna (Thunnus albacares), kawakawa (Euthynnus affinis) and skipjack (Katsuwonus pelamis)] were estimated using a large water-tunnel respirometer. Experiments lasting up to 31 h were used to determine the effects of velocity (U) on tuna V(dot)O2 over a range of U (17-150 cm s-1) and temperatures (1830°C). Replicate tests were carried out on several fish. The swimming V(dot)O2 of yellowfin is temperature-dependent (Q10=1.67, determined over intervals of 35°C). For yellowfin and skipjack, it was also possible to partition metabolic costs between maintenance and locomotion. The standard metabolic rate (SV(dot)O2) was estimated by extrapolation of the U/V(dot)O2 function to U=0. Comparisons of SV(dot)O2 for different size groups of yellowfin show that the mass-specific scaling exponent for V(dot)O2 is -0.40. The SV(dot)O2 of tuna is comparable to values determined previously by stasis respirometry and is approximately th...
Studies of Tropical Tuna Swimming Performance in a Large Water Tunnel:I. Energetics
Journal of Experimental Biology, 1994
The metabolic rates of three tropical tunas [yellowfin tuna (Thunnus albacares), kawakawa (Euthynnus affinis) and skipjack (Katsuwonus pelamis)] were estimated using a large water-tunnel respirometer. Experiments lasting up to 31 h were used to determine the effects of velocity (U) on tuna over a range of U (17–150 cm s−1) and temperatures (18–30°C). Replicate tests were carried out on several fish. The swimming of yellowfin is temperature-dependent (Q10=1.67, determined over intervals of 3–5°C). For yellowfin and skipjack, it was also possible to partition metabolic costs between maintenance and locomotion. The standard metabolic rate was estimated by extrapolation of the function to U=0. Comparisons of for different size groups of yellowfin show that the mass-specific scaling exponent for is −0.40. The of tuna is comparable to values determined previously by stasis respirometry and is approximately three times higher than that of salmonids. Further comparisons with salmonids show ...
Environmental Biology of Fishes, 2010
Of the few measurements of the behavioural and physiological responses of tuna to hypoxia, most are restricted to shallow diving tropical species. Furthermore, when wild tuna experience low dissolved oxygen, they are likely to have an increased oxygen demand associated with the metabolic cost of food digestion and assimilation (specific dynamic action). However the response of postprandial tuna to hypoxia has never been examined. This study focuses on the metabolic and behavioural responses of both fasted and postprandial southern bluefin tuna (Thunnus maccoyii) to low dissolved oxygen. Fasted T. maccoyii were exposed to dissolved oxygen levels of 4.44, 3.23, 2.49 and 1.57 mg·l −1 for 20-21 h. In moderate hypoxia (4.44 and 3.23 mg·l −1 ), swimming speed was enhanced (1.5 and 1.3 times normoxic speed, respectively) presumably to increase ventilation volume. Routine metabolic rate (R r ) was similarly elevated (1.3 and 1.2 times normoxic R r , respectively), most likely due to increased metabolic demand of faster swimming. At 2.49 mg·l −1 , swimming speed increased to over double the normoxic speed, possibly as an escape response. At 1.57 mg·l −1 , both swimming speed and R r were reduced (0.8 and 0.9 times normoxic level, respectively), and tuna failed to survive the entire 20 h exposure period. This reveals that the critical oxygen level of T. maccoyii is between 1.57 and 2.49 mg·l −1 , demonstrating that they are remarkably well adapted to low dissolved oxygen. Feeding did not greatly influence their hypoxia tolerance with tuna surviving exposure to dissolved oxygen levels of 2.96 and 1.81 mg·l −1 for 21 h, after ingesting a ration of 6.7% body weight of sardines (Sardinops sagax). In a subsequent experiment to determine the effects of hypoxia on digestion rate, T. maccoyii were fed to satiation and exposed to a dissolved oxygen level of 2.84 mg·l −1 for 6.5-8 h. There was no significant difference in swimming speed, R r and gastric evacuation rates of tuna in hypoxia compared to those in normoxia. This demonstrates that in moderate to severe hypoxia, T. maccoyii are still capable of aerobically supporting maintenance metabolism, routine swimming and specific dynamic action. It is hypothesized that adaptations which support the large metabolic scope of tuna are also likely to be beneficial for oxygen extraction and delivery in conditions of hypoxia.
STUDIES OF TROPICAL TUNA SWIMMING PERFORMANCE IN A LARGE WATER TUNNEL
1994
Yellowfin tuna (Thunnus albacares) swimming kinematics was studied in a large water tunnel at controlled swimming velocities (U). Quantified kinematic variables included the tail-beat frequency, stride length (l), caudal amplitude, yaw, the propulsive wavelength, the speed of the propulsive wave (C) and the sweepback angle of the pectoral fins. In general, all variables, except the propulsive wavelength and consequently C, are comparable to values determined for other teleosts. The propulsive wavelength for the tunas (1.23-1.29L, where L is fork length) is 30-60 % longer than in other cruise-adapted teleosts such as salmonids. The resulting thunniform swimming mode and the morphological and anatomical adaptations associated with the long propulsive wavelength (e.g. fusiform body shape, rigid vertebral column) act to minimize anterior resistance and maximize caudal thrust. The long propulsive wavelength also increases the maximum l which, in concert with the elevated muscle temperatures of tunas, increases their maximum swimming velocity.
Aerobic and anaerobic swimming performance of individual Atlantic cod
The Journal of experimental biology, 2000
Individual Atlantic cod (Gadus morhua) were exercised using three different measures of swimming performance. (1) An endurance test (critical swimming speed, U(crit), protocol) designed to assess predominantly aerobic endurance swimming (duration hours). (2) An acceleration test (U(burst)), in which the fish were required to swim against a rapidly increasing current until exhausted (duration minutes). This test was designed to assess predominantly glycolytic-based swimming capacity. (3) A sprint test that examined the animals' ability to swim away from a sudden stimulus (duration seconds). Rates of oxygen consumption ( mdot (O2)) during the endurance test and various morphological variables of the individual fish were also measured. Both aerobic and anaerobic swimming performance of individual cod were found to be significantly repeatable over a 3 month period. mdot (O2) during the U(crit) protocol was also significantly repeatable at intermediate to high swimming speeds, but no...
Modelling energetic costs of fish swimming
2005
The oxygen consumption rates of two cyprinid fishes, carp (Cyprinus carpio L.) and roach (Rutilus rutilus (L.)), were analysed for a wide range of body mass and swimming speed by computerized intermittent-flow respirometry. Bioenergetic models were derived, based on fish mass (M) and swimming speed (U), to predict the minimal speed and mass-specific active metabolic rate (AMR) in these fishes (AMR 5 aM b U c). Mass and speed together explained more than 90% of the variance in total swimming costs in both cases. The derived models show that carp consume far more oxygen at a specific speed and body mass, thus being less efficient in energy use during swimming than roach. It was further found that in carp (AMR 5 0.02M 0.8 U 0.95) the metabolic increment during swimming is more strongly effected by speed, whereas in roach (AMR 5 0.02M 0.93 U 0.6) it is more strongly effected by body mass. The different swimming traits of carp and roach are suitable for their respective lifestyles and ecological demands.
Journal of Fish Biology, 2020
Oxygen uptake, heart rate, and contraction frequencies of slow oxidative (SO) and fast glycolytic (FG) muscle, were measured simultaneously in gilthead seabream Sparus aurata submitted to stepwise increases in current speed in a swimming respirometer. Variation in oxygen uptake was closely related to variation in heart rate, over initial steps these rose in concert with an increase in contraction frequency of SO muscle. There was an asymptote in oxygen uptake and heart rate at high speeds, that reflected a transition from exclusive use of aerobic SO muscle to a combination of SO and anaerobic FG muscle, and which preceded fatigue.