Metabolism is a physiological process reflecting the energy expenditure of living organisms and hence their food requirements (in heterotrophs). The metabolic rate of fish is usually measured by their rate of respiration, i.e., their rate of oxygen consumption (see Fig. 51). Information on oxygen consumption is not only useful in comparative physiology, but in fish culture and fishery management as well. It provides insights in solving the problems associated with rearing fish or transporting live fish, among others (Froese 1988; see also Box 33).
The OXYGEN table documents the oxygen consumption of fishes based on experiments reported in the published literature, together with factors known or likely to affect metabolic rate, notably body weight; temperature; salinity; oxygen concentrations; activity level; swimming speed; and major applied stress factor. Additional experimental details, such as the number of fish, and other information may be in the Comment field. The following fields provide details on the above-listed factors.
Oxygen consumption: Pertains to the amount of oxygen used by fish in mgkg-1h-1. If the consumption was reported in other units, these were transformed to mg oxygen per kilogram fish per hour. In addition, a computed field was included in which the oxygen consumption at temperatures between 5 and 30°C was re-expressed as the corresponding consumption values at 20°C, based on the multipliers in Table 3.3 in Winberg (1971).
Sex: A multiple-choice field consisting of: fry; juveniles; female; male; mixed (for both male and female); unsexed (for unknown sex).
Weight: Refers to the weight in g of the test organism. If there was more than one fish in an experiment, the mean weight in g was recorded.
Number: The total number of individual fish used in the experiment.
Temperature: The mean water temperature, in °C, during the experiment.
Salinity: The mean salinity in ppt during the experiment. If the salinity was not stated, 35 ppt was assumed for marine species and 0 ppt for freshwater species. For diadromous fishes, such assumption was pointed out in the Comment field. Erroneous assumptions will affect the calculated oxygen saturation only slightly.
Fig. 51. Relative oxygen consumption of Oreochromis niloticus niloticus compared with miscellaneous species. Note the relatively straight descending line of standard/routine metabolism vs. body weight and the vertical series of values caused by stresses applied.
Oxygen (mmHg):
Refers to the average partial pressure of oxygen in mmHg in the test water. As stated by Thurston and Gehrke (1993), this value was estimated through assumptions based on the description of the test method when not given in the original paper. These assumptions included corrections for test temperature and water salinity.
Oxygen (mg/l): This field pertains to the oxygen concentration of the test water in mg/l. If there is an entry in the oxygen (in mmHg) field, the values in mg/l were not extracted from the literature but calculated from the mmHg values, using the following transformation:
where b
is the Bunsen coefficient for oxygen at the given temperature and salinity (Colt 1984).
100% oxygen saturation: This field states, for reference purposes, the calculated maximum oxygen content, in mg/l of the water at the given temperature and salinity.
Saturation%: This field expresses the actual oxygen content of the test water as percent of the maximum possible oxygen content. Typical saturation levels were around 90%. Values below 70% were classified as ‘hypoxia’, values above 105% were classified as supersaturation (see Applied Stress).
Activity level: A choice field that allows accounting for the effect of activity on metabolic rate. The available choices for this field are: standard metabolism (resting fish); routine metabolism (spontaneously active fish); active metabolism (swimming fish).
Swimming speed: Refers to the swimming speed of the fish as another index of activity. Speed was either reported as or converted to body length per second (BL/s) with ‘BL’ usually corresponding to total or fork length.
Applied stress: This is a choice field that pertains to stress applied before or during an experiment. The choices include: none specified; temperature (changes or extreme values); photoperiod (unusual duration or timing of light exposure); feeding (during or right before the experiment); starvation (no food offered for more than 24 h); toxins; hypoxia (insufficient oxygen); hypercapnia (excessive amount of carbon dioxide in the blood resulting from their being forced to swim rapidly); (changes in) salinity; high pH; low pH; sedative; transport; other stress. If the choice is ‘other’, the stress should be specified in the Comment field.
The OXYGEN table can be used to test hypotheses on the relationships among different activities and stresses to which fish are exposed, to estimate energy (food) consumption for trophic modeling and to connect growth, morphology and metabolic rate, among other things.
The OXYGEN table contains the largest collection of data on fish metabolism
The OXYGEN table probably contains the largest collection of data on oxygen consumption of fish, with close to 7,000 records for about 300 species. The information was obtained from over 400 references such as Winberg (1960), Congleton (1974), Gorelova (1977), Marais (1978), Subrahamanyam (1980) and Neumann et al. (1981). Of these records, 6,400 stem from the database ‘OXYREF’ compiled by Thurston and Gehrke (1993). The remainder have been added by FishBase staff.
Verification was done by going back to the original literature and checking the values and other relevant information reported. However, this has been done, for few of the entries to date. FishBase staff will continue to add new records and to verify the information entered so far.
You get to the OXYGEN table by clicking on the Biology button in the SPECIES window, the Morphology and physiology button in the BIOLOGY window, and the Metabolism button in the next window.
In the Internet, you get to the OXYGEN table by clicking on the Metabolism link in the ‘More information’ section of the ‘Species Summary’ page. You can create a list of all species with available data by selecting the Metabolism radio button in the ‘Information by Topic’ section of the ‘Search FishBase’ page. If you select the Graphs radio button in the ‘Information by Family’ section of that page, you can create Relative oxygen consumption graphs for different families.
We are grateful to R.V. Thurston and P.C. Gehrke for offering the database OXYREF for distribution through FishBase.
Colt, J. 1984. Computation of dissolved gas concentrations in water as functions of temperature, salinity and pressure. Am. Fish. Soc. Spec. Publ. 14, 154 p.
Congleton, J.L. 1974. The respiratory response to asphyxia of Typhlogobius californiensis (Teleostei: Gobiidae) and some related gobies. Biol. Bull. 146:186-205.
Froese, R. 1988. Relationship between body weight and loading densities in fish transport using the plastic bag method. Aquacult. Fish. Manage. 19:275-281.
Gorelova, T.A. 1977. Respiration rate of the fry of some tropical fishes. Polskie Archiwum Hydrogiologii 24(Suppl.):447-453.
Marais, J.F.K. 1978. Routine oxygen consumption of Mugil cephalus, Liza dumerii and L. richardsoni at different temperatures and salinities. Mar. Biol. 50:9-16.
Neumann, D.A., J.M. O’Connor and J.A. Sherk, Jr. 1981. Oxygen consumption of white perch (Morone americana), striped bass (M. saxatilis) and spot (Leiostomus xanthurus). Comp. Biochem. Physiol. 69A:467-478.
Subrahamanyam, C.B. 1980. Oxygen consumption of estuarine fish in relation to external tension. Comp. Biochem. Physiol. 67A:129-133.
Thurston, R.V. and P.C. Gehrke. 1993. Respiratory oxygen requirements of fishes: description of OXYREF, a data file based on test results reported in the published literature, p. 95-108. In R.C. Russo and R.V. Thurston (eds.) Fish physiology, toxicology, and water quality management. Proceedings of an International Symposium, Sacramento, California, USA, 18-19 September 1990. EPA/600AR-93/157.
Winberg, G.G. 1960. Rate of metabolism and food requirements of fishes. Minsk, USSR. Transl. Ser. Fish. Res. Board Can. 194, 1960.
Winberg, G.G. 1971. Methods for the estimation of production of aquatic animals. Academic Press, London. 175 p.