Responses of Swimming Skipjack (Katsuwonus pelamis) and Yellowfin (Thunnus albacares) Tunas to Acute Hypoxia, and a Model of Their Cardiorespiratory Function

Heart rate and swimming-speed responses to acute hypoxia were measured in skipjack (Katsuwonus pelamis) and yellowfin tunas (Thunnus albacares). Swimming speeds began to increase in both species when O2 tension (Po2) reached approximately 124 mmHg. Bradycardia became significant in both species when Po2 reached approximately 130 mmHg. Heart rate fell with Po2 in yellowfin tuna, but, in skipjack tuna, it increased at the lowest O2 levels reached (89–70 mmHg). Bradycardia occurred in both species despite concomitant increases in swimming speed. A continuous infusion dye dilution system was used to monitor changes in ventilation volume (V̇g) during hypoxia in yellowfin tuna. As Po2 fell, V̇g increased. At the lowest O2 levels (109–90 mmHg), V̇g was 45% higher than during normoxia. Ventilation volume increased despite no concomitant increases in swimming speed. Data from these experiments were used to develop a model capable of predicting O2 demand and delivery, maximum sustainable (i.e., aerobic) swimming speeds, and minimum survivable O2 levels for yellowfin and skipjack tunas. Results from the model indicate that the cardiorespiratory system of tunas is capable of maximum rates of O2 delivery, even at low swimming speeds, that are approximately three times those of other active teleosts. We believe that, because the pelagic environment provides no place to hide and rest following exhaustive activity, the ability of the cardiorespiratory system of tunas to deliver O2 to the tissues at high rates evolved for the rapid repayment of O2 debts rather than to permit exceptionally high sustained swimming speeds.

[1]  R. Saunders.  THE IRRIGATION OF THE GILLS IN FISHES: II. EFFICIENCY OF OXYGEN UPTAKE IN RELATION TO RESPIRATORY FLOW ACTIVITY AND CONCENTRATIONS OF OXYGEN AND CARBON DIOXIDE , 1962 .

[2]  E. Nakamura.  Development and Uses of Facilities for Studying Tuna Behavior , 1972 .

[3]  S. Nilsson.  Control of Gill Blood Flow , 1986 .

[4]  Richard W. Brill,et al.  Cardiorespiratory responses of skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares), and bigeye tuna (Thunnus obesus) to acute reductions of ambient oxygen , 1990 .

[5]  P. Butler,et al.  Changes in activity and ventilation in response to hypoxia in unrestrained, unoperated dogfish (Scyliorhinus canicula L.). , 1984, The Journal of experimental biology.

[6]  K. Holland,et al.  HORIZONTAL AND VERTICAL MOVEMENTS OF YELLOWFIN AND BIGEYE TUNA ASSOCIATED WITH FISH AGGREGATING DEVICES , 1990 .

[7]  D. R. Jones,et al.  The influence of blood gas properties on gas tensions and pH of ventral and dorsal aortic blood in free-swimming tuna, Euthynnus affinis , 1986 .

[8]  David Hanson,et al.  Relationship of Gill Ventilation and Perfusion in Pacific Dogfish, Squalus suckleyi , 1970 .

[9]  P. Butler,et al.  Response of the dogfish (Scyliorhinus canicula L.) to slowly induced and rapidly induced hypoxia , 1971 .

[10]  G. Sharp,et al.  I. – BEHAVIORAL AND PHYSIOLOGICAL PROPERTIES OF TUNAS AND THEIR EFFECTS ON VULNERABILITY TO FISHING GEAR , 1978 .

[11]  Stefan Nilsson,et al.  The Circulatory System , 1983 .

[12]  E. Stevens.  Some Aspects of Gas Exchange in Tuna , 1972 .

[13]  J. Bernards.  Principles of comparative respiratory physiology , 1976 .

[14]  J. Magnuson.  COMPARATIVE STUDY OF ADAPTATIONS FOR CONTINUOUS SWIMMING AND HYDROSTATIC EQUILIBRIUM OF SCOMBROID AND XIPHOID FISHES , 1973 .

[15]  J. L. Roberts.  II. – RAM GILL VENTILATION IN FISH , 1978 .

[16]  M. Ingham,et al.  Oxycline characteristics and skipjack tuna distribution in the southeastern tropical atlantic , 1977 .

[17]  Heeny S. H. Yuen.  Behavior of Skipjack Tuna, Katsuwonus pelamis, as Determined by Tracking with Ultrasonic Devices , 1970 .

[18]  Pingguo He,et al.  Tilting behaviour of the Atlantic mackerel, Scomber scombrus, at low swimming speeds , 1986 .

[19]  J. Magnuson.  Digestion and Food Consumption by Skipjack Tuna (Katsuwonus pelamis) , 1969 .

[20]  Robert J. Olson,et al.  Apex Predation by Yellowfïn Tuna (Thunnus albacares): Independent Estimates from Gastric Evacuation and Stomach Contents, Bioenergetics, and Cesium Concentrations , 1986 .

[21]  Andrew E. Dizon,et al.  III. – CORRELATIONS BETWEEN ENVIRONMENT, PHYSIOLOGY, AND ACTIVITY AND THE EFFECTS ON THERMOREGULATION IN SKIPJACK TUNA , 1978 .

[22]  E. Hanamoto.  Effect of oceanographic environment on bigeye tuna [Thunnus obesus] distribution , 1987 .

[23]  Kenneth D. Lawson,et al.  ACOUSTIC TELEMETRY FROM FISH , 1974 .

[24]  W. H. Neill,et al.  Respiration rates and low-oxygen tolerance limits in skipjack tuna , 2013 .

[25]  A. R. Connor,et al.  Muscle glycogen and blood lactate in yellowfin tuna, Thunnus albacares, and skipjack, Katsuwonus pelamis, following capture and tagging , 1964 .

[26]  J. R. Brett.  The metabolic demand for oxygen in fish, particularly salmonids, and a comparison with other vertebrates. , 1972, Respiration physiology.

[27]  W. H. Neill,et al.  RESPIRATION RATES AND LOW-OXYGENTOLERANCE LIMITS IN SKIPJACK TUNA, KATSUWONUSPELAMIS , 1981 .

[28]  P. W. Hochachka,et al.  I. – THE TUNA POWER PLANT AND FURNACE , 1978 .

[29]  P. W. Hochachka,et al.  L-(+)-Lactate translocation into the red blood cells of the skipjack tuna (Katsuwonus pelamis) , 1987 .

[30]  S. Perry,et al.  Effects of Exhausting Exercise on Acid-Base Regulation in Skipjack Tuna (Katsuwonus pelamis) Blood , 1985, Physiological Zoology.