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Ectocommensal protozoan infestations of gills of red swamp crawfish, Procambarus clarkii (Girard), from commercial ponds
Aquaculture, 55 (1986) 161-164 Elsevier Science Publishers B.V., Amsterdam
-Printed
in The Netherlands
161
ECTOCOMMENSAL PROTOZOAN INFESTATIONS OF GILLS OF RED SWAMP CRAWFISH, PROCAMBARUS CLARKII (GIRARD), FROM COMMERCIAL PONDS
JANIS
ROBIN
SCOTT’
and RONALD
‘Department of Veterinary Medicine, Louisiana State 2Department of Veterinary Louisiana State University (Accepted
16 April
L. THUNE’,’
Microbiology and Parasitology, School of Veterinary University, Baton Rouge, LA (U.S.A.) Science, Louisiana Agricultural Experiment Station, Agricultural Center, Baton Rouge, LA 70803 (U.S.A.)
1986)
ABSTRACT Scott, J.R. and Thune, red swamp crawfish,
culture,
R.L.,
1986.
Procambarus
Ectocommensal protozoan infestations of gills of clarkii (Girard), from commercial ponds. Aqua-
55: 161-164.
Crawfish, Procambarus clarkii (Girard), collected from commercial ponds were examined microscopically to determine the presence of ectocommensal protozoans on the gills. The relation between the incidence of gill ectocommensal protozoans and pond water quality was examined. Ninety-four percent of crawfish sampled were infested, with sixty-five percent of the infested crawfish carrying more than 100 ectocommensals per gill filament. Protozoans observed were of the genera Epistylis, Acineta, Lagenophrys, and Cothurnia, the latter being the most prevalent. Significant correlations existed between gill ectocommensal incidence and water quality variables indicative of primary productivity.
INTRODUCTION
A variety of ectocommensal protozoans has been described from crawfish, including Epistylis, Cothurnia, Acineta, Zoothamnium and Lagenophrys (Lahser, 19’74; Johnson, 1977); however, these reports are generally for the carapace of wild crawfish and rarely for the gill chamber (Lahser, 1974). Several investigators have reported the presence of ectocommensal protozoans on the gills of pond-raised shrimp (Lightner, 1975; Couch, 1978). Others have reported deaths in pond-raised shrimp from heavy infestations of the shrimp gill surface with the stalked peritrich Zoothamnium, particularly in conjunction with low dissolved oxygen (Lightner, 1975; Fisher, 1977). This study was conducted to determine the incidence of ectocommensal protozoans on the gills of crawfish in five commercial ponds and to examine
0044~3486/86/$03.50
o 1986 Elsevier Science Publishers B.V.
162
the relationship between the presence of gill ectocommensals quality. MATERIALS
and water
AND METHODS
The study ponds, management procedures and water quality analysis methods were as described by Scott and Thune (1986). Samples of ten P. chrkii were dip-netted weekly from each of five ponds from 1 November 1982 through June 1983. Live crawfish were placed in plastic bags, stored on ice and transported to the laboratory for examination, Three podobranchs (anterior, mid and posterior) were removed from each crawfish and ectocommensals were counted in three fields at the tip of the podobranch filaments and three at the podobranch axis using 10X objective, Infestation levels were quantified as the total number of ectocommensal protozoans observed per podobranch, and individual protozoans were indentified using standard keys (Kudo, 1977). RESULTS
Ninety-four percent (1560 of 1660) of the crawfish sampled were infested. Sixty-five percent (1012 of 1560) of the infested crawfish had TABLE 1 Range of mean water quality variables from commercial crawfish ponds from November 1982 to May 1983. Variables with significant and highly significant correlations to ectocommensal protozoan incidence are indicated Variable
Range of mean
Total nitrogen (mg/l as N) Total ammonia nitrogen (mg/l as N) Nitrate-nitrogen (mg/l as N) Nitrate-nitrogen (mgjl as N) PR Chemical oxygen demand (mg/l) Total carbon dioxide (mg/l) Free carbon dioxide (mg/l) Soluble inorganic phosphorus (mg/l as P) Total phosporus (mg/l as P) Total hardness (mg/l as CaCO,) Total alkalinity (mgjl as CaCO,) Biological oxygen demand (mg/l) Chlorophyll Q (pg/l) Turbidity (NTU) Dissolved oxygen concentration (mg/l) Water temperature (“C)
1.7-9.5” O-30-0.27* * 0.07-0.125 0.005-0.050 6.75-7.10 2.1-5.1 lo-60 0.5-3.2* * 0.027-0.32 0.182-0.228* * 56-83 52-89 24-48* 10-31 2-170** 4.2-8.2 9-24
* P > 0.01 but < 0.05.
**p < 0.01.
163 TABLE 2 Correlation of Acineta sp., Cothurnia sp., and Epistylis sp. from gills of crawfish, Procambarus clarkii (Girard), with turbidity in commercial ponds Organism -
r
Acineta sp. Cotkurnia sp, Epistylis sp.
-0.2022
**p<
0.8376**
0.4967**
0.01.
more than 100 ectocommensals on the gill surface; however, there was no significant effect of these numbers on crawfish catch. Protozoans observed were of the genera Epktylis, A&eta, Lagenophrys and Cothurnia, the latter being the most prevalent. Lugeaophrys was observed in low numbers and only in late spring. Ranges of mean water quality variables are presented in Table 1 and more detailed analysis of water quality data is presented by Hymel (1984). Turbidity, biological oxygen demand, total ammonia nitrogen and total phosphorus were positively correlated and free carbon dioxide and total nitrogen were negatively correlated with presence of crawfish gill ectocommensals. Turbidity was significantly correlated with the incidence of the peritrichous ciliates, Cothurnia and Epistylis but there was no correlation between turbidity and the suctorian, Acineta (Table 2). DISCUSSION
Ectocommensal protozoans utilize the crustacean cuticular surface as a substrate for attachment and rely on concentrated bacterial populations found in water with high organic loads for nourishment (Fisher, 19’77; Couch, 1983). The water quality variables which significantly correlated with gill ectocommensal incidence in this study are a function of pond productivity, and indicate the presence of elevated levels of organic matter and other nutrients in the pond water (Boyd, 1979). As ponds become more eutrophic and water quality deteriorates, bacterial concentrations increase (Fitzger~d et al,, 1982) and in such conditions, peri~ichous ciliates, such as Cothu~~ia, Ep~styZ~, and Zootha~~iu~, which feed on bacteria, flourish (Johnson, 1977; Fitzgerald et al., 1982). Conversely, the presence of the suctorian, Acineta, which is saprotrophic on ciliated protozoans, suggests that organisms higher in the food web than bacteria are present. In this study, incidence of the peritrichous ciliates, Cothurnia and Epistylis, both bacteriovores, increased with increasing turbidity. In contrast, the suctorian, Acinetu, which is saprotrophic on other protozoans, demonstrated no correlation with turbidity, Mortality due to ectocommensal protozoans in shrimp seems to be due to asphyxiation caused by occlusion of functional
164
respiratory surface by the physical presence of large numbers of protozoans on the gills (Lightner, 1975; Fisher, 1977; Couch, 1978). Ectocommensal infestations of the gills of crawfish examined in this study were common, but no detrimental effect on crawfish yields were indicated. However, during periods of heavy ectocommensal infestation, water quality remained within levels compatible with crawfish production and survival. Should conditions conducive to ectocommensal protozoan proliferation occur in the fall when significant dissolved oxygen depletions are common, infested crawfish would likely be more susceptible, which could affect productivity. ACKNOWLEDGEMENTS
This research was supported through the Organized Research Program of the School of Veterinary Medicine, Louisiana State University. The authors wish to thank Mr. Bill Trimble of the St. Martin Land Company for his cooperation throughout this project.
REFERENCES Boyd, C.E., 1979. Water Quality in Warm Water Fish Ponds. Auburn University Agricultural Experiment Station, Auburn, AL, 359 pp. Couch, J.A., 1978. Disease, parasites and toxic responses of commercial penaeid shrimps of the Gulf of Mexico and South Atlantic Coasts of North America. Fish. Bull., 76: l-44. Couch, J.A., 1983. Disease caused by protozoa. In: A.J. Provenzano (Editor), The Biology of Crustacea. Vol. 6. Pathobiology. Academic Press, New York, NY, pp. 79-111. Fisher, W.S., 1977. Epibiotic microbial infestations of cultured crustaceans Proc. Annu. Meet. World Maricult. Sot., 8: 673-684. Fitzgerald, M.E.C., Simco, B.A. and Coons, L.B., 1982. Ultrastructure of the peritrich ciliate Ambiphrya ameiuri and its attachment to the gills of the catfish Ictalurw punctatus. J. Protozool., 29: 213-217. Hymel, T., 1984. Water quality dynamics in commercial crawfish ponds and toxicity of selected water quality variables to Procambarus clarkii. Master’s Thesis, Louisiana State University, Baton Rouge, LA, 118 pp. Johnson, S.K., 1977. Crawfish and freshwater shrimp diseases. Texas A & M University Sea Grant College Program. Texas Agricultural Extension Service, Publ. No. TAMUSG-77-605, 19 pp. Kudo, R.R., 1977. Protozoology. Charles C. Thomas, Springfield, IL, 1174 pp. Lahser, C.W., Jr., 1974. Epizooites of crayfish, I. Ectocommensals and parasites of crayfish of Brazos County, Texas. In: Second Annual International Symposium of Freshwater Crayfish, Baton Rouge, LA pp. 276-285. Lightner, D.V., 1975. Some potentially serious disease problems in the culture of penaeid shrimp in North America. In: Proc. Third U.S.-Japan Meeting on Aquaculture, Tokyo, Japan, pp. 75-97. Scott, J.R. and Thune, R.L., 1986. Bacterial flora from the red swamp crawfish, Procambarw clarkii (Girard), from commercial ponds. Aquaculture, in press.
-Printed
in The Netherlands
161
ECTOCOMMENSAL PROTOZOAN INFESTATIONS OF GILLS OF RED SWAMP CRAWFISH, PROCAMBARUS CLARKII (GIRARD), FROM COMMERCIAL PONDS
JANIS
ROBIN
SCOTT’
and RONALD
‘Department of Veterinary Medicine, Louisiana State 2Department of Veterinary Louisiana State University (Accepted
16 April
L. THUNE’,’
Microbiology and Parasitology, School of Veterinary University, Baton Rouge, LA (U.S.A.) Science, Louisiana Agricultural Experiment Station, Agricultural Center, Baton Rouge, LA 70803 (U.S.A.)
1986)
ABSTRACT Scott, J.R. and Thune, red swamp crawfish,
culture,
R.L.,
1986.
Procambarus
Ectocommensal protozoan infestations of gills of clarkii (Girard), from commercial ponds. Aqua-
55: 161-164.
Crawfish, Procambarus clarkii (Girard), collected from commercial ponds were examined microscopically to determine the presence of ectocommensal protozoans on the gills. The relation between the incidence of gill ectocommensal protozoans and pond water quality was examined. Ninety-four percent of crawfish sampled were infested, with sixty-five percent of the infested crawfish carrying more than 100 ectocommensals per gill filament. Protozoans observed were of the genera Epistylis, Acineta, Lagenophrys, and Cothurnia, the latter being the most prevalent. Significant correlations existed between gill ectocommensal incidence and water quality variables indicative of primary productivity.
INTRODUCTION
A variety of ectocommensal protozoans has been described from crawfish, including Epistylis, Cothurnia, Acineta, Zoothamnium and Lagenophrys (Lahser, 19’74; Johnson, 1977); however, these reports are generally for the carapace of wild crawfish and rarely for the gill chamber (Lahser, 1974). Several investigators have reported the presence of ectocommensal protozoans on the gills of pond-raised shrimp (Lightner, 1975; Couch, 1978). Others have reported deaths in pond-raised shrimp from heavy infestations of the shrimp gill surface with the stalked peritrich Zoothamnium, particularly in conjunction with low dissolved oxygen (Lightner, 1975; Fisher, 1977). This study was conducted to determine the incidence of ectocommensal protozoans on the gills of crawfish in five commercial ponds and to examine
0044~3486/86/$03.50
o 1986 Elsevier Science Publishers B.V.
162
the relationship between the presence of gill ectocommensals quality. MATERIALS
and water
AND METHODS
The study ponds, management procedures and water quality analysis methods were as described by Scott and Thune (1986). Samples of ten P. chrkii were dip-netted weekly from each of five ponds from 1 November 1982 through June 1983. Live crawfish were placed in plastic bags, stored on ice and transported to the laboratory for examination, Three podobranchs (anterior, mid and posterior) were removed from each crawfish and ectocommensals were counted in three fields at the tip of the podobranch filaments and three at the podobranch axis using 10X objective, Infestation levels were quantified as the total number of ectocommensal protozoans observed per podobranch, and individual protozoans were indentified using standard keys (Kudo, 1977). RESULTS
Ninety-four percent (1560 of 1660) of the crawfish sampled were infested. Sixty-five percent (1012 of 1560) of the infested crawfish had TABLE 1 Range of mean water quality variables from commercial crawfish ponds from November 1982 to May 1983. Variables with significant and highly significant correlations to ectocommensal protozoan incidence are indicated Variable
Range of mean
Total nitrogen (mg/l as N) Total ammonia nitrogen (mg/l as N) Nitrate-nitrogen (mg/l as N) Nitrate-nitrogen (mgjl as N) PR Chemical oxygen demand (mg/l) Total carbon dioxide (mg/l) Free carbon dioxide (mg/l) Soluble inorganic phosphorus (mg/l as P) Total phosporus (mg/l as P) Total hardness (mg/l as CaCO,) Total alkalinity (mgjl as CaCO,) Biological oxygen demand (mg/l) Chlorophyll Q (pg/l) Turbidity (NTU) Dissolved oxygen concentration (mg/l) Water temperature (“C)
1.7-9.5” O-30-0.27* * 0.07-0.125 0.005-0.050 6.75-7.10 2.1-5.1 lo-60 0.5-3.2* * 0.027-0.32 0.182-0.228* * 56-83 52-89 24-48* 10-31 2-170** 4.2-8.2 9-24
* P > 0.01 but < 0.05.
**p < 0.01.
163 TABLE 2 Correlation of Acineta sp., Cothurnia sp., and Epistylis sp. from gills of crawfish, Procambarus clarkii (Girard), with turbidity in commercial ponds Organism -
r
Acineta sp. Cotkurnia sp, Epistylis sp.
-0.2022
**p<
0.8376**
0.4967**
0.01.
more than 100 ectocommensals on the gill surface; however, there was no significant effect of these numbers on crawfish catch. Protozoans observed were of the genera Epktylis, A&eta, Lagenophrys and Cothurnia, the latter being the most prevalent. Lugeaophrys was observed in low numbers and only in late spring. Ranges of mean water quality variables are presented in Table 1 and more detailed analysis of water quality data is presented by Hymel (1984). Turbidity, biological oxygen demand, total ammonia nitrogen and total phosphorus were positively correlated and free carbon dioxide and total nitrogen were negatively correlated with presence of crawfish gill ectocommensals. Turbidity was significantly correlated with the incidence of the peritrichous ciliates, Cothurnia and Epistylis but there was no correlation between turbidity and the suctorian, Acineta (Table 2). DISCUSSION
Ectocommensal protozoans utilize the crustacean cuticular surface as a substrate for attachment and rely on concentrated bacterial populations found in water with high organic loads for nourishment (Fisher, 19’77; Couch, 1983). The water quality variables which significantly correlated with gill ectocommensal incidence in this study are a function of pond productivity, and indicate the presence of elevated levels of organic matter and other nutrients in the pond water (Boyd, 1979). As ponds become more eutrophic and water quality deteriorates, bacterial concentrations increase (Fitzger~d et al,, 1982) and in such conditions, peri~ichous ciliates, such as Cothu~~ia, Ep~styZ~, and Zootha~~iu~, which feed on bacteria, flourish (Johnson, 1977; Fitzgerald et al., 1982). Conversely, the presence of the suctorian, Acineta, which is saprotrophic on ciliated protozoans, suggests that organisms higher in the food web than bacteria are present. In this study, incidence of the peritrichous ciliates, Cothurnia and Epistylis, both bacteriovores, increased with increasing turbidity. In contrast, the suctorian, Acinetu, which is saprotrophic on other protozoans, demonstrated no correlation with turbidity, Mortality due to ectocommensal protozoans in shrimp seems to be due to asphyxiation caused by occlusion of functional
164
respiratory surface by the physical presence of large numbers of protozoans on the gills (Lightner, 1975; Fisher, 1977; Couch, 1978). Ectocommensal infestations of the gills of crawfish examined in this study were common, but no detrimental effect on crawfish yields were indicated. However, during periods of heavy ectocommensal infestation, water quality remained within levels compatible with crawfish production and survival. Should conditions conducive to ectocommensal protozoan proliferation occur in the fall when significant dissolved oxygen depletions are common, infested crawfish would likely be more susceptible, which could affect productivity. ACKNOWLEDGEMENTS
This research was supported through the Organized Research Program of the School of Veterinary Medicine, Louisiana State University. The authors wish to thank Mr. Bill Trimble of the St. Martin Land Company for his cooperation throughout this project.
REFERENCES Boyd, C.E., 1979. Water Quality in Warm Water Fish Ponds. Auburn University Agricultural Experiment Station, Auburn, AL, 359 pp. Couch, J.A., 1978. Disease, parasites and toxic responses of commercial penaeid shrimps of the Gulf of Mexico and South Atlantic Coasts of North America. Fish. Bull., 76: l-44. Couch, J.A., 1983. Disease caused by protozoa. In: A.J. Provenzano (Editor), The Biology of Crustacea. Vol. 6. Pathobiology. Academic Press, New York, NY, pp. 79-111. Fisher, W.S., 1977. Epibiotic microbial infestations of cultured crustaceans Proc. Annu. Meet. World Maricult. Sot., 8: 673-684. Fitzgerald, M.E.C., Simco, B.A. and Coons, L.B., 1982. Ultrastructure of the peritrich ciliate Ambiphrya ameiuri and its attachment to the gills of the catfish Ictalurw punctatus. J. Protozool., 29: 213-217. Hymel, T., 1984. Water quality dynamics in commercial crawfish ponds and toxicity of selected water quality variables to Procambarus clarkii. Master’s Thesis, Louisiana State University, Baton Rouge, LA, 118 pp. Johnson, S.K., 1977. Crawfish and freshwater shrimp diseases. Texas A & M University Sea Grant College Program. Texas Agricultural Extension Service, Publ. No. TAMUSG-77-605, 19 pp. Kudo, R.R., 1977. Protozoology. Charles C. Thomas, Springfield, IL, 1174 pp. Lahser, C.W., Jr., 1974. Epizooites of crayfish, I. Ectocommensals and parasites of crayfish of Brazos County, Texas. In: Second Annual International Symposium of Freshwater Crayfish, Baton Rouge, LA pp. 276-285. Lightner, D.V., 1975. Some potentially serious disease problems in the culture of penaeid shrimp in North America. In: Proc. Third U.S.-Japan Meeting on Aquaculture, Tokyo, Japan, pp. 75-97. Scott, J.R. and Thune, R.L., 1986. Bacterial flora from the red swamp crawfish, Procambarw clarkii (Girard), from commercial ponds. Aquaculture, in press.