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The respiratory requirements of Macrobrachium acanthurus (Weigman) at different temperatures and salinities
Aquaculture, 93 (1991) 191-197 Elsevier Science Publishers B.V., Amsterdam
191
The respiratory requirements of Macrobrachium acanthurus (Weigman) at different temperatures and salinities J.F.E. Gasca-Leyva”, C.A. Martinez-Palacios” and L.G. Rossb “CINVESTAV-IPN, Unidad Merida, Merida. Yucatan, Mexico bInstituteofrlquaculture, Universityof Stirling, Stirling FK9 4L.A, UK (Accepted 28 June 1990)
ABSTRACT Gasca-Leyva, J.F.E., Martinez-Palacios, CA. and Ross, L.C., 199 1. The respiratory requirements of Macrobrachium acanthums ( Weigman) at different temperatures and salinities. Aquaculture. 93: 191-197. The oxygen consumption rate of the freshwater prawn, Macrobrachium acanthurus ( Weigman ), was determined using closed-circuit respirometry at temperatures of 20, 25, 30 and 35°C and salinities of 0, 10 and 20%0, over a weight range of 0.33 to 34.0 g. Oxygen consumption rates ranged from 100 to 9500 mg/kg per h, increased proportionally with temperature and were inversely proportional to body weight. Respiratory rates decreased with increasing salinity, this effect being more marked at lower temperatures and virtually absent at 35°C. The data suggest that M. acanthurus has the ability to osmoregulate. Experiments in which the prawns were allowed to deplete the oxygen concentration showed that this species is an oxygen conformer, with a very limited ability to withstand anoxia.
INTRODUCTION
Although there are about 100 species of the freshwater prawn, Macrubtachium (Goodwin and Hanson, 1975), very few of these have characteristics appropriate for aquaculture and the principal efforts to date have been with Mucrobruchium rosenbergii. In 1974, Boschi listed 14 American species of Palaemonidae of probable economic value, and Cabrera-Jimenez et al. ( 1979) indicated that M. tenellum and A4. americanurn were suitable species for culture on the Pacific coasts of Mexico and Central and South America, and that M. ucunthurus and M. curcinus had a similar potential on the eastern coasts of the continent. Although M. acanthus is a smaller prawn than ikf. curcinus, it nevertheless has attractive attributes for aquaculture, in that it is tolerant of a range of salinities, has a high fecundity, is relatively resistant to diseases and handling, and has a good market acceptance. It has been successfully grown to market
0044-8486/91
jSO3.50
0 199 1 -
Elsevier Science Publishers
B.V.
192
J.F.E. GASCA-LEYVA ET AL.
size within 6 months in various parts of Mexico and has also been used in polyculture with carp (Cabrera-Jimenez et al., 1979; Martinez-Palacios et al., 1980). A knowledge of the oxygen requirements of aquatic animals is of great importance for aquaculture at all levels of intensity. Such data are critical for the design of systems (Wheaton, 1977) and are also useful in the transportation of live organisms. Respiratory data provide a good basis for the calculation of carrying capacities, particularly of semi-intensive culture systems. The major factors affecting the oxygen requirements of aquatic organisms are body weight, environmental temperature and salinity, and diet. In general, prawns with high tolerances and wide resistance to temperature and salinity variation will have a greater potential for culture in a wider range of conditions. This paper describes experiments to determine the effects of body weight, temperature, salinity and acute hypoxia on the resting oxygen consumption of juvenile and adult M. acanthurus. MATERIALS AND METHODS
Stocks of A4. acanthurus were collected from Laguna de1 Espino, Tabasco, Mexico, using traps and transported to the laboratory where they were maintained in freshwater in circular 70-l libreglass aquaria. These animals were used as broodstock to provide the juveniles and adults for the experiments. Experimental animals were maintained at 25°C and were fed ad libitum on a pelleted 22% protein diet. For the measurement of oxygen consumption rate, a simple closed-circuit respirometer was used, as described by Ross and Ross ( 1983 ) and using the same chambers and experimental protocol as described by Martinez-Palacios and Ross ( 1986). The respirometer chambers were contained in, and supplied from, a water bath and so environmental temperature and salinity could be altered easily by changing the medium in the bath. The oxygen content of the water was measured using a YSI model 57 oxygen meter and probe, and the output was recorded on a Cole-Palmer flat-bed chart recorder. Two brief experiments were conducted in order to define the conditions for the respirometry. Groups of ten animals were placed in 200-l fibreglass tanks at salinities of 0, 10, 20 and 30%0 at a temperature of 25 “C. Mortalities were recorded at hourly intervals over a period of 48 h. Prawns were removed from their stock tanks, starved for 24 h, and placed in the respirometer system under the given environmental conditions. A preliminary series of four experiments, using animals of between 3 and 5 g, was conducted to determine the time required to reach a steady rate of oxygen consumption. The respiratory rate of animals in a weight range from 0.33 to 34.0 g was measured at temperatures of 20, 25, 30 and 35°C and at salinities of 0, 10, and 20%0, these conditions reflecting those likely to be experienced both in
RESPIRATORY REQUIREMENTS OF MACROBRACHIUM
193
ACANTHCJRUS
culture and in the natural environment. Measurements were made approximately 15 h after individual prawns had been introduced to the system, at which time the respirometer was closed and the decrease in dissolved oxygen was recorded over a period of no more than 15 min to avoid any hypoxic effects. For each combination of temperature and salinity, the oxygen consumption of between 35 and 45 animals was recorded and naive prawns were used for each experiment. Eleven prawns in the weight range 4 to 22 g were allowed to slowly deplete the oxygen in the chambers at 25 “C in freshwater. The oxygen content of the system was monitored continuously and the trials were terminated when the animals lost equilibrium and became moribund. RESULTS
All animals survived within the 48-h experimental periods at salinities of 0, 10 and 20%0. At 30%0 there was a 75% mortality after 3 h and 100% after 4 h; before death the animals became blanched and highly stressed. From these results it was decided to conduct experiments at salinities up to 20%. The respiratory rate of animals during the first 24 h after introduction to the respirometers is shown in Fig. 1; the data are shown as a percentage of the mean stable level. Following the initial handling stress, respiratory rate settled to an approximately constant value after 16 h. Based on this information, all further measurements were made after a 16 h acclimation period.
I, 0
8
I6
24
Time
t hours1
32
40
48
Fig. l_ Decrease in respiratory rate of Mucrobrachium acanthurus following introduction respirometers. Vertical bars show standard deviation.
to the
J.F.E. GASCA-LEYVA ETAL.
194
There was an inverse linear relationship between log,O body weight and log,,, respiration rate under all environmental conditions tested. The regression equations for these relationships are summarised in Table 1. As may be expected, oxygen consumption rate increased notably with temperature. The effects of hypoxia on respiratory rate are shown in Fig. 2. As prawns of different body weights were used in these experiments, the data were expressed as percent decrease in rate against dissolved oxygen concentration. It was clear that M. acanthurus is an oxygen conformer and that no attempt is made to regulate oxygen consumption. In general, the effect of these acute TABLE 1 Regression equations of log,, respiratory rate ( Y) on logI body weight ( W) Salinity (960)
Temperature ( “C)
Regression equations
n
ra
20 25 30 35
Y=5.761 I -0.8529W Y=5.4369-0.6935 W Y=5.2043-0.5299W
44 34 44 44
0.9400 0.9373 0.9735 0.8687
10
20 25 30 35
Y=5.1787-0.8019W Y= 5.4598 -0.7683 W Y=5.1078-0.6028W Y=5.1576-0.5798W
41 36 36 45
0.8323 0.9468 0.9592 0.8691
20
20 25 30 35
Y=5.1132-0.7036W
42 44 39 45
0.9520 0.8528 0.8899 0.9658
0
Y=5.5985-0.6752
W
Y=5.1654-0.6735W Y=4.8176-0.5522W Y=5.8550-0.7452W
“All correlation coefficients were significantly different from zero (P-z 0.001).
ok-
-
2
3 Dissolved
4
5 oxygen
7
6 (mg/l
8
I
Fig. 2. The percentage reduction in respiratory rate of Macrobrachium acanthurus under acute hypoxic conditions at 25°C and 0% salinity. The dotted curve was fitted by eye.
RESPIRATORY REQUIREMENTS OF MACROBRACHIUMACANTHURUS
195
hypoxic conditions became evident at dissolved oxygen levels of 4 to 6 mg/l. Below about 4 mg/l there was a progressive decline in oxygen consumption rate and below 1.5 mg/l there was a marked linear reduction in rate, accompanied by strong swimming and ventilatory movements. DISCUSSION
It is widely appreciated that smaller animals have a higher oxygen consumption rate ( QOz) than larger individuals of the same species (Beamish and Mookherjii, 1964; Muller-Feuga et al., 1978) and this relationship was clearly revealed in these experiments. The effects of temperature are self-evident from the regression equations derived from this work. The overall effects of salinity and temperature on QO, of a 3.5-g A4. acanthurus can be seen in Fig. 3. The respiratory costs were maximal in freshwater and were reduced at higher salinities, with the greatest reduction at 1OYoo.This strongly indicates that M. acunthurus is an osmoregulator and that the isosmotic point is close to lOo/oo.These results are in contrast to those of Moreira et al. ( 1983) who suggested that QO, was maximal at the isosmotic point. On the other hand, Nelson et al. ( 1977) showed significant changes in QO, in response to salinity and Stephenson and Knight ( 1980) showed that QOz declined with increasing salinity from freshwater to 28%0 in M. rosenbergii. It is clear that z k P
3.2
1
25 ‘C
20 lc
Salinity
( %I
Fig. 3. The respiratory rate of 3.5-g Macrobrachium acanthurus at different temperatures and salinities.
196
J.F.E. GASCA-LEYVA ET AL.
M. acanthurus is an osmoregulator and that not all Macrobruchium species have the same osmoregulatory capacity and response in QO, to salinity changes. It is also evident that many previous workers have used postlarvae or juveniles in their experiments and that there is probably a strong difference in response depending on developmental stage. The response to acute hypoxia was that of an oxygen conformer. This is in agreement with the data of Mauro and Malecha ( 1984) who showed that VOz decreased with increasing hypoxia in A4. rosenbergii. However, the same authors also showed that scaphognathite beat rate significantly increased as p0, declined suggesting an attempt to regulate oxygen intake. This increased respiratory effort was clearly seen in the present work while it was also notable that M. acunthurus was unable to withstand extreme hypoxia for more than 15 min, in contrast to the more prolonged tolerance times found in some tropical fish (Ross and Ross, 1983; Martinez-Palacios and Ross, 1986). The data derived in this work form a useful basis for the calculation of carrying capacities of semi-intensive and intensive culture systems for M. acanthurus over the range of temperatures and salinities most commonly encountered in the field. In using the data generated here, however, it will be necessary to make some allowance for routine motor activity, and the effects of social interactions which are probably density-dependent. The contribution of specific dynamic action is also very important although this was not measured in this work. Armitage and Wall ( 1982) showed a decrease in V02 during starvation in the crayfish, Oronectes nais. Similarly, Sacayanan and Hirata ( 1986 ) showed an approximate doubling of respiratory rate in Penaeus japonicus after feeding and this factor could reasonably be applied to the data reported here.
REFERENCES Armitage, K.B. and Wall, T.J., 1982. The effect of body size, starvation and temperature acclimation on oxygen consumption of the crayfish, Oronectes nais. Comp. Biochem. Physiol., 73A: 63-68. Beamish, F.W.H. and Mookherjii, P.S., 1964. Respiration of fishes with special emphasis on standard oxygen consumption. I. Influence of weight and temperature on respiration of goldfish, Carassiusauratus L. Can. J. Zool., 42: 161-175. Boschi, E.E., 1974. Biologia de 10s crustaceos cutivables en America Latina. FAO Simposio sobre Acuicultura en Carpas de America Latina. Carpas/6/74/SR 7. FAO, Rome. Cabrera-Jimenez, J.A., Chavez, C. and Martinez-Palacios, C.A., 1979. Fecundidad y cultivo de Macrobrachium tenellum (Smith) en al laboratorio. An. Inst. Biol. Univ. Nal. Auton. Mexico. 50, Ser. Zool., 1: 127-l 52. Goodwin, H.L. and Hanson, J., 1975. The aquaculture of freshwater prawns (Macrobrachium species). Proceedings of the Workshop on the Culture of Freshwater Prawns, Nov. 1975, St. Petersburg, FL. Martinez-Palacios, C.A. and Ross, L.G., 1986. The effects of temperature, body weight and
RESPIRATORY
REQUIREMENTS
OF MACROBRACHIUMACANTHURUS
197
hypoxia on the oxygen consumption of the Mexican mojarra, Cichlasoma urophthalmus (Gunther). Aquacult. Fish. Manage., 17: 243-248. Martinez-Palacios, C.A., Chavez-Sanchez, Ma.C. and Palomo-Martinez, G., 1980. Avarices sobre el semicultivo del langostino Macrobrachium tenellum (Smith). Memorias 2nd Simposio Latinoamericano de Acuicultura, Vol. 1. UNAM, Mexico, pp. 644-654. Mauro. N.A. and Malecha, S.R., 1984. Intraspecific comparison of haemocyanin oxygen affinity and the effects of hypoxia on oxygen consumption in Macrobrachium rosenbergii (De Man). Comp. Biochem. Physiol., 77A (4): 631-633. Moreira, G.S., McNamara, J.C., Shumway, S.E. and Moreira, P.S., 1983. Osmoregulation and respiratory metabolism in Brazilian Macrobrachium (Decapoda, Palaemonidae). Comp. Biochem. Physiol., 74 ( 1): 57-62. Muller-Feuga, A., Petit, J. and Sabaut, J.J., 1978. The influence of temperature and wet weight on the oxygen demand of rainbow trout (Salmo gairdneri) in freshwater. Aquaculture. 14: 335-363. Nelson, S.G., Armstrong, D.A., Knight, A.W. and Li, H.W., 1977. The effects of temperature and salinity on the metabolic rate of juvenile Macrobrachium rosenbergii (Crustacea: Palaemonidae). Comp. Biochem. Physiol., 56: 533-537. Ross, B. and Ross, L.G., 1983. The respiratory performance of Oreochromis niloticus under adverse environmental conditions. In: G. Yaron and L. Fishelson (Editors), Proceedings of an International Symposium on Tilapia in Aquaculture. Nazareth, Israel, pp. 134- 143. Sacayanan, E.B. and Hirata, H. 1986. Circadian rhythm of feeding and respiration in Kuruma prawn Penaeus japonicus. Mini Rev. Data File Fish. Res. Lab. Kagoshima Univ., 4: 63-76. Stephenson, M.J. and Knight, A.W., 1980. The effect of temperature and salinity on oxygen consumption of post-larvae of Macrobrachium rosenbergii (De Man) (Crustacea: Palaemonidae). Comp. Biochem. Physiol., 67: 699-703. Wheaton, F.W., 1977. Aquaculture Engineering. Wiley, New York, NY, 708 pp.
191
The respiratory requirements of Macrobrachium acanthurus (Weigman) at different temperatures and salinities J.F.E. Gasca-Leyva”, C.A. Martinez-Palacios” and L.G. Rossb “CINVESTAV-IPN, Unidad Merida, Merida. Yucatan, Mexico bInstituteofrlquaculture, Universityof Stirling, Stirling FK9 4L.A, UK (Accepted 28 June 1990)
ABSTRACT Gasca-Leyva, J.F.E., Martinez-Palacios, CA. and Ross, L.C., 199 1. The respiratory requirements of Macrobrachium acanthums ( Weigman) at different temperatures and salinities. Aquaculture. 93: 191-197. The oxygen consumption rate of the freshwater prawn, Macrobrachium acanthurus ( Weigman ), was determined using closed-circuit respirometry at temperatures of 20, 25, 30 and 35°C and salinities of 0, 10 and 20%0, over a weight range of 0.33 to 34.0 g. Oxygen consumption rates ranged from 100 to 9500 mg/kg per h, increased proportionally with temperature and were inversely proportional to body weight. Respiratory rates decreased with increasing salinity, this effect being more marked at lower temperatures and virtually absent at 35°C. The data suggest that M. acanthurus has the ability to osmoregulate. Experiments in which the prawns were allowed to deplete the oxygen concentration showed that this species is an oxygen conformer, with a very limited ability to withstand anoxia.
INTRODUCTION
Although there are about 100 species of the freshwater prawn, Macrubtachium (Goodwin and Hanson, 1975), very few of these have characteristics appropriate for aquaculture and the principal efforts to date have been with Mucrobruchium rosenbergii. In 1974, Boschi listed 14 American species of Palaemonidae of probable economic value, and Cabrera-Jimenez et al. ( 1979) indicated that M. tenellum and A4. americanurn were suitable species for culture on the Pacific coasts of Mexico and Central and South America, and that M. ucunthurus and M. curcinus had a similar potential on the eastern coasts of the continent. Although M. acanthus is a smaller prawn than ikf. curcinus, it nevertheless has attractive attributes for aquaculture, in that it is tolerant of a range of salinities, has a high fecundity, is relatively resistant to diseases and handling, and has a good market acceptance. It has been successfully grown to market
0044-8486/91
jSO3.50
0 199 1 -
Elsevier Science Publishers
B.V.
192
J.F.E. GASCA-LEYVA ET AL.
size within 6 months in various parts of Mexico and has also been used in polyculture with carp (Cabrera-Jimenez et al., 1979; Martinez-Palacios et al., 1980). A knowledge of the oxygen requirements of aquatic animals is of great importance for aquaculture at all levels of intensity. Such data are critical for the design of systems (Wheaton, 1977) and are also useful in the transportation of live organisms. Respiratory data provide a good basis for the calculation of carrying capacities, particularly of semi-intensive culture systems. The major factors affecting the oxygen requirements of aquatic organisms are body weight, environmental temperature and salinity, and diet. In general, prawns with high tolerances and wide resistance to temperature and salinity variation will have a greater potential for culture in a wider range of conditions. This paper describes experiments to determine the effects of body weight, temperature, salinity and acute hypoxia on the resting oxygen consumption of juvenile and adult M. acanthurus. MATERIALS AND METHODS
Stocks of A4. acanthurus were collected from Laguna de1 Espino, Tabasco, Mexico, using traps and transported to the laboratory where they were maintained in freshwater in circular 70-l libreglass aquaria. These animals were used as broodstock to provide the juveniles and adults for the experiments. Experimental animals were maintained at 25°C and were fed ad libitum on a pelleted 22% protein diet. For the measurement of oxygen consumption rate, a simple closed-circuit respirometer was used, as described by Ross and Ross ( 1983 ) and using the same chambers and experimental protocol as described by Martinez-Palacios and Ross ( 1986). The respirometer chambers were contained in, and supplied from, a water bath and so environmental temperature and salinity could be altered easily by changing the medium in the bath. The oxygen content of the water was measured using a YSI model 57 oxygen meter and probe, and the output was recorded on a Cole-Palmer flat-bed chart recorder. Two brief experiments were conducted in order to define the conditions for the respirometry. Groups of ten animals were placed in 200-l fibreglass tanks at salinities of 0, 10, 20 and 30%0 at a temperature of 25 “C. Mortalities were recorded at hourly intervals over a period of 48 h. Prawns were removed from their stock tanks, starved for 24 h, and placed in the respirometer system under the given environmental conditions. A preliminary series of four experiments, using animals of between 3 and 5 g, was conducted to determine the time required to reach a steady rate of oxygen consumption. The respiratory rate of animals in a weight range from 0.33 to 34.0 g was measured at temperatures of 20, 25, 30 and 35°C and at salinities of 0, 10, and 20%0, these conditions reflecting those likely to be experienced both in
RESPIRATORY REQUIREMENTS OF MACROBRACHIUM
193
ACANTHCJRUS
culture and in the natural environment. Measurements were made approximately 15 h after individual prawns had been introduced to the system, at which time the respirometer was closed and the decrease in dissolved oxygen was recorded over a period of no more than 15 min to avoid any hypoxic effects. For each combination of temperature and salinity, the oxygen consumption of between 35 and 45 animals was recorded and naive prawns were used for each experiment. Eleven prawns in the weight range 4 to 22 g were allowed to slowly deplete the oxygen in the chambers at 25 “C in freshwater. The oxygen content of the system was monitored continuously and the trials were terminated when the animals lost equilibrium and became moribund. RESULTS
All animals survived within the 48-h experimental periods at salinities of 0, 10 and 20%0. At 30%0 there was a 75% mortality after 3 h and 100% after 4 h; before death the animals became blanched and highly stressed. From these results it was decided to conduct experiments at salinities up to 20%. The respiratory rate of animals during the first 24 h after introduction to the respirometers is shown in Fig. 1; the data are shown as a percentage of the mean stable level. Following the initial handling stress, respiratory rate settled to an approximately constant value after 16 h. Based on this information, all further measurements were made after a 16 h acclimation period.
I, 0
8
I6
24
Time
t hours1
32
40
48
Fig. l_ Decrease in respiratory rate of Mucrobrachium acanthurus following introduction respirometers. Vertical bars show standard deviation.
to the
J.F.E. GASCA-LEYVA ETAL.
194
There was an inverse linear relationship between log,O body weight and log,,, respiration rate under all environmental conditions tested. The regression equations for these relationships are summarised in Table 1. As may be expected, oxygen consumption rate increased notably with temperature. The effects of hypoxia on respiratory rate are shown in Fig. 2. As prawns of different body weights were used in these experiments, the data were expressed as percent decrease in rate against dissolved oxygen concentration. It was clear that M. acanthurus is an oxygen conformer and that no attempt is made to regulate oxygen consumption. In general, the effect of these acute TABLE 1 Regression equations of log,, respiratory rate ( Y) on logI body weight ( W) Salinity (960)
Temperature ( “C)
Regression equations
n
ra
20 25 30 35
Y=5.761 I -0.8529W Y=5.4369-0.6935 W Y=5.2043-0.5299W
44 34 44 44
0.9400 0.9373 0.9735 0.8687
10
20 25 30 35
Y=5.1787-0.8019W Y= 5.4598 -0.7683 W Y=5.1078-0.6028W Y=5.1576-0.5798W
41 36 36 45
0.8323 0.9468 0.9592 0.8691
20
20 25 30 35
Y=5.1132-0.7036W
42 44 39 45
0.9520 0.8528 0.8899 0.9658
0
Y=5.5985-0.6752
W
Y=5.1654-0.6735W Y=4.8176-0.5522W Y=5.8550-0.7452W
“All correlation coefficients were significantly different from zero (P-z 0.001).
ok-
-
2
3 Dissolved
4
5 oxygen
7
6 (mg/l
8
I
Fig. 2. The percentage reduction in respiratory rate of Macrobrachium acanthurus under acute hypoxic conditions at 25°C and 0% salinity. The dotted curve was fitted by eye.
RESPIRATORY REQUIREMENTS OF MACROBRACHIUMACANTHURUS
195
hypoxic conditions became evident at dissolved oxygen levels of 4 to 6 mg/l. Below about 4 mg/l there was a progressive decline in oxygen consumption rate and below 1.5 mg/l there was a marked linear reduction in rate, accompanied by strong swimming and ventilatory movements. DISCUSSION
It is widely appreciated that smaller animals have a higher oxygen consumption rate ( QOz) than larger individuals of the same species (Beamish and Mookherjii, 1964; Muller-Feuga et al., 1978) and this relationship was clearly revealed in these experiments. The effects of temperature are self-evident from the regression equations derived from this work. The overall effects of salinity and temperature on QO, of a 3.5-g A4. acanthurus can be seen in Fig. 3. The respiratory costs were maximal in freshwater and were reduced at higher salinities, with the greatest reduction at 1OYoo.This strongly indicates that M. acunthurus is an osmoregulator and that the isosmotic point is close to lOo/oo.These results are in contrast to those of Moreira et al. ( 1983) who suggested that QO, was maximal at the isosmotic point. On the other hand, Nelson et al. ( 1977) showed significant changes in QO, in response to salinity and Stephenson and Knight ( 1980) showed that QOz declined with increasing salinity from freshwater to 28%0 in M. rosenbergii. It is clear that z k P
3.2
1
25 ‘C
20 lc
Salinity
( %I
Fig. 3. The respiratory rate of 3.5-g Macrobrachium acanthurus at different temperatures and salinities.
196
J.F.E. GASCA-LEYVA ET AL.
M. acanthurus is an osmoregulator and that not all Macrobruchium species have the same osmoregulatory capacity and response in QO, to salinity changes. It is also evident that many previous workers have used postlarvae or juveniles in their experiments and that there is probably a strong difference in response depending on developmental stage. The response to acute hypoxia was that of an oxygen conformer. This is in agreement with the data of Mauro and Malecha ( 1984) who showed that VOz decreased with increasing hypoxia in A4. rosenbergii. However, the same authors also showed that scaphognathite beat rate significantly increased as p0, declined suggesting an attempt to regulate oxygen intake. This increased respiratory effort was clearly seen in the present work while it was also notable that M. acunthurus was unable to withstand extreme hypoxia for more than 15 min, in contrast to the more prolonged tolerance times found in some tropical fish (Ross and Ross, 1983; Martinez-Palacios and Ross, 1986). The data derived in this work form a useful basis for the calculation of carrying capacities of semi-intensive and intensive culture systems for M. acanthurus over the range of temperatures and salinities most commonly encountered in the field. In using the data generated here, however, it will be necessary to make some allowance for routine motor activity, and the effects of social interactions which are probably density-dependent. The contribution of specific dynamic action is also very important although this was not measured in this work. Armitage and Wall ( 1982) showed a decrease in V02 during starvation in the crayfish, Oronectes nais. Similarly, Sacayanan and Hirata ( 1986 ) showed an approximate doubling of respiratory rate in Penaeus japonicus after feeding and this factor could reasonably be applied to the data reported here.
REFERENCES Armitage, K.B. and Wall, T.J., 1982. The effect of body size, starvation and temperature acclimation on oxygen consumption of the crayfish, Oronectes nais. Comp. Biochem. Physiol., 73A: 63-68. Beamish, F.W.H. and Mookherjii, P.S., 1964. Respiration of fishes with special emphasis on standard oxygen consumption. I. Influence of weight and temperature on respiration of goldfish, Carassiusauratus L. Can. J. Zool., 42: 161-175. Boschi, E.E., 1974. Biologia de 10s crustaceos cutivables en America Latina. FAO Simposio sobre Acuicultura en Carpas de America Latina. Carpas/6/74/SR 7. FAO, Rome. Cabrera-Jimenez, J.A., Chavez, C. and Martinez-Palacios, C.A., 1979. Fecundidad y cultivo de Macrobrachium tenellum (Smith) en al laboratorio. An. Inst. Biol. Univ. Nal. Auton. Mexico. 50, Ser. Zool., 1: 127-l 52. Goodwin, H.L. and Hanson, J., 1975. The aquaculture of freshwater prawns (Macrobrachium species). Proceedings of the Workshop on the Culture of Freshwater Prawns, Nov. 1975, St. Petersburg, FL. Martinez-Palacios, C.A. and Ross, L.G., 1986. The effects of temperature, body weight and
RESPIRATORY
REQUIREMENTS
OF MACROBRACHIUMACANTHURUS
197
hypoxia on the oxygen consumption of the Mexican mojarra, Cichlasoma urophthalmus (Gunther). Aquacult. Fish. Manage., 17: 243-248. Martinez-Palacios, C.A., Chavez-Sanchez, Ma.C. and Palomo-Martinez, G., 1980. Avarices sobre el semicultivo del langostino Macrobrachium tenellum (Smith). Memorias 2nd Simposio Latinoamericano de Acuicultura, Vol. 1. UNAM, Mexico, pp. 644-654. Mauro. N.A. and Malecha, S.R., 1984. Intraspecific comparison of haemocyanin oxygen affinity and the effects of hypoxia on oxygen consumption in Macrobrachium rosenbergii (De Man). Comp. Biochem. Physiol., 77A (4): 631-633. Moreira, G.S., McNamara, J.C., Shumway, S.E. and Moreira, P.S., 1983. Osmoregulation and respiratory metabolism in Brazilian Macrobrachium (Decapoda, Palaemonidae). Comp. Biochem. Physiol., 74 ( 1): 57-62. Muller-Feuga, A., Petit, J. and Sabaut, J.J., 1978. The influence of temperature and wet weight on the oxygen demand of rainbow trout (Salmo gairdneri) in freshwater. Aquaculture. 14: 335-363. Nelson, S.G., Armstrong, D.A., Knight, A.W. and Li, H.W., 1977. The effects of temperature and salinity on the metabolic rate of juvenile Macrobrachium rosenbergii (Crustacea: Palaemonidae). Comp. Biochem. Physiol., 56: 533-537. Ross, B. and Ross, L.G., 1983. The respiratory performance of Oreochromis niloticus under adverse environmental conditions. In: G. Yaron and L. Fishelson (Editors), Proceedings of an International Symposium on Tilapia in Aquaculture. Nazareth, Israel, pp. 134- 143. Sacayanan, E.B. and Hirata, H. 1986. Circadian rhythm of feeding and respiration in Kuruma prawn Penaeus japonicus. Mini Rev. Data File Fish. Res. Lab. Kagoshima Univ., 4: 63-76. Stephenson, M.J. and Knight, A.W., 1980. The effect of temperature and salinity on oxygen consumption of post-larvae of Macrobrachium rosenbergii (De Man) (Crustacea: Palaemonidae). Comp. Biochem. Physiol., 67: 699-703. Wheaton, F.W., 1977. Aquaculture Engineering. Wiley, New York, NY, 708 pp.