Distribution of thirteen species of Brachionus in nine stations from Cochin backwaters was studied

during August 2000-July 2002. Of the 13 species, B. plicatilis and B. rotundiformis were observed

in all the stations. B. rotundiformis was dominant with 85.76%. Detailed observations on the qualitative

and quantitative distribution are presented

Varghese, Molly

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130Journal of the Marine Biological Association of India (2011)Molly VargheseJ. Mar. Biol. Ass. India, 53 (1) :  130 - 134, January - June 2011IntroductionRotifers, especially Brachionus species, areconsidered to be an excellent food for larval stagesof many finfishes and crustaceans. Realising theimportance of Brachionus, Pejler (1977) gave anaccount on the global distribution of the familyBrachionidae.  Koste (1979) reviewed the Australianspecies of Brachionus. The distribution ofBrachionus species in Spanish Mediterraneanwetlands was studied by Miracle et al. (1987). Vasishtand Battish (1971) studied Brachionus species ofnorth India. Sharma (1980a) gave an account on thefamily Brachionidae of Punjab. The distribution ofBrachionus populations in ponds was dealt bySampathkumar (1989). Su et al. (1998) discussedthe distribution of the family Brachionidae inMangolian waters.  Much of the informationavailable from India is concentrated on north India.In southern part of India, except those of Gopakumar(1998) and Anitha (2003), major studies were carriedout in freshwater bodies.The distribution of Brachionus species in manyof the brackishwater habitats in Kerala is not welldocumented. From Cochin backwaters, Molly et al.(2006) gave a systematic account on Brachionusspecies and a preliminary study on the rotifer faunawas made by Molly and Krishnan (2008). Other thanDistribution of Brachionus species (Phylum Rotifera) in Cochin backwaters,Kerala, IndiaMolly VargheseCentral Marine Fisheries Research Institute, P. B. No. 1603, Cochin - 682 018, India.E-mail: mollykandathil@hotmail.comAbstractDistribution of thirteen species of Brachionus in nine stations from Cochin backwaters was studiedduring August 2000-July 2002. Of the 13 species, B. plicatilis and B. rotundiformis were observedin all the stations. B. rotundiformis was dominant with 85.76%. Detailed observations on the qualitativeand quantitative distribution are presented.Keywords:  Brachionus, rotifer, distribution, Cochin backwatersthese two, there is no information available so far onBrachionus species from Cochin backwaters.The present study is aimed to investigate thespatial and seasonal distribution of different speciesof Brachionus both qualitatively and quantitativelyin nine selected centres of Cochin backwaters.Material and MethodsThe Cochin backwaters and certain canalsadjoining the system extending to about 50 km wereselected for the study.  Map showing the location ofsampling stations is the same as given by Molly etal. (2006).  Monthly collections of rotifers were madefrom nine stations viz. Vypeen, Puthuvypu, Narakkal,Cherai, Eloor, Fisheries Harbour, Ernakulam Marketcanal, Mangalavanam and Poothotta during theperiod from August 2000 to July 2002.The rotifer samples were collected from eachstation by filtering 500 litres of water throughplankton net made of bolting silk having a mesh sizeof 40 µ and preserved in 4% formaldehyde. Fromthis, Brachionus species were identified with the helpof a number of publications especially that of Nayar(1968), Koste (1978), Sharma (1983), Battish (1992)and Gopakumar (1998). They were enumerated andexpressed as numbers per m3 of water. For seasonalanalysis, February-May was considered as131Journal of the Marine Biological Association of India (2011)Distribution of Brachionus spp. in Cochin backwaterspremonsoon, June-September as monsoon andOctober-January as postmonsoon season. ANOVAtests were carried out to study the variations ofdifferent species of Brachionus between stations.ResultsQualitative distribution: Thirteen species ofBrachionus under the family Brachionidae wererecorded. The species were Brachionus plicatilis, B.rotundiformis, B. angularis, B. urceolaris, B. rubens,B. forficula, B. caudatus, B. calyciflorus, B.bidentata, B. quadridentatus, B. patulus, B. falcatusand B. mirabilis. The distribution of these species indifferent stations is given in Table 1.Of the 13 species, B. plicatilis and B.rotundiformis, were observed in all the stations.  Themaximum of 9 species was recorded in Station 5.Quantitative distribution: The quantitativedistribution of Brachionus spp. in different stationsis depicted in Fig.1.The maximum abundance of Brachionus wasnoticed at station 2 (1.18 million per m3) followedby station 3 (0.82 million per m3), which may be dueto the favourable conditions prevailing in thosestations. The lowest number of 1053 per m3 wasrecorded at station 6, which is a fishing harbour site.The percentage composition of each species underthe genus Brachionus in different stations is depictedin Fig. 2.Table 1.  Distribution of Brachionus species in different stationsSI. Species Station Station Station Station Station Station Station Station StationNo. 1 2 3 4 5 6 7 8 91 B. plicatilis + + + + + + + + +2 B. rotundiformis + + + + + + + + +3 B. angularis + + + + + + + +4 B. urceolaris + + + + + + + +5 B. rubens + + + + + + + +6 B. forficula + + + + + + +7 B. caudatus +8 B. calyciflorus +9 B. bidentata + + +10 B. quadridentatus + + + +11 B. patulus + +12 B. falcatus + +13 B. mirabilis +Total no. of species 6 6 7 8 9 6 8 5 8+ indicates presence of speciesFig. 2. Percentage composition of Brachionusspecies in the study areaFig. 1. Quantitative distribution of Brachionus spp.in different stations132Journal of the Marine Biological Association of India (2011)Molly VargheseAmong the nine stations, Brachionus plicatilis,B. rotundiformis, B. angularis, B. urceolaris and B.rubens were abundant in station 2. Other speciesshowed abundance beyond station 2. Brachionuscaudatus was observed only at station 3, B.calyciflorus occurred only at station 4 and B.mirabilis only at station 5.B. rotundiformis dominated and contributed85.76% to the total abundance with a range of 45–96 % in different stations. Next in abundance was B.angularis contributing 9.6%. The seasonwisedistribution of different species of Brachionus isgiven in Fig. 3.B. rotundiformis dominated in all the threeseasons, contributing 99%, 56% and 93% duringpremonsoon, monsoon and postmonsoonrespectively. During monsoon season, B. angulariscontributed 32%, while it formed only 3% duringpostmonsoon and less than 1% during premonsoonseason, which perhaps indicates its less tolerance tohigher salinity.The results of ANOVA in relation to Brachionusspecies showed that, out of the 13 species recorded,the numerical abundance of 8 species viz. B. plicatilis,B. rotundiformis, B. angularis, B. urceolaris, B.rubens, B. forficula, B. quadridentatus and B. patulusshowed highly significant variations between stations(p<0.01).DiscussionThe results indicated the availability of 13 speciesof rotifers under the genus Brachionus in the ninestations in Cochin backwaters (central Kerala).  Fromthe southern part of Kerala, 14 species were reportedby Anitha (2003).  Sharma (1983) reported 20 speciesof Brachionus from Indian waters.  The number ofBrachionus spp. recorded all over the world is 55(Segers, 2002).According to Pennak (1957) and Jyoti and Sehgal(1979), more than two species of a rotifer genus donot occur together in a water body. Later, George(1961) recorded occurrence of three species ofBrachionus from the ponds in Delhi. In the presentstudy, the presence of 5 species of Brachionus wererecorded simultaneously in stations 1, 2, 3 and 5.The number of species ranged between 5 and 9 indifferent stations.Nine species of Brachionus viz. B. angularis, B.bidentata, B. calyciflorus, B. caudatus, B. forficula,B. falcatus, B. patulus, B. quadridentatus and B.rubens, recorded in the Cochin backwaters are alsoavailable in freshwater tanks and ponds in and aroundSambalpur, Orissa in eastern part of India (Sharma,1980b). This indicates high salinity tolerance of thesespecies as well as their wide distribution.Sharma (1991) noticed that majority ofBrachionus spp. inhabit freshwater bodies, but B.Fig. 3. Seasonwise distribution of Brachionusspecies in the study areaPremonsoonMonsoonPre onsoonPostmonsoon133Journal of the Marine Biological Association of India (2011)Distribution of Brachionus spp. in Cochin backwatersplicatilis is euryhaline. In the present study, exceptB. rotundiformis and B. plicatilis, the other 11 speciesof Brachionus were not recorded from all the stations,which indicate their restricted distribution, probablyin relation to salinity. These species probably preferlower salinities. It is worthwhile to mention here thatB. rotundiformis was considered as S-strain of B.plicatilis earlier and only recently it is given adifferent species status (Segers, 1995). Of the ninestations studied, the lowest salinity was noticed atstation 5, where salinity did not exceed 4 ppt and themaximum number of Brachionus species (9) wasrecorded from this station, which indicates thepreference of Brachionus species to low salinities.The number of species increased from station 1 tostation 5. The first station is located at the mouth ofthe estuary and other stations are situatedsubsequently upstream. Eventhough the number ofspecies increases with low salinities, the abundancewas maximum at station 2 followed by station 3,which indicates the influence of other physico-chemical parameters on the abundance ofBrachionus.Thus, different species were found to preferspecific environments and this information may beapplied to select the strain/species of rotifer formaintaining cultures. Since rotifers are consideredto be an excellent and indispensable live feed inaquaculture, long term investigations will be useful.AcknowledgementsThe author is thankful to the Director, C.M.F.R.I.,for providing the facilities to carry out this work.She also expresses her gratitude to Dr. L. Krishnan,Principal Scientist (Retd.) for guidance and supportduring the study.ReferencesAnitha, P. S. 2003. Studies on certain selected live feedorganisms used in aquaculture with special referenceto rotifers (Family: Brachionidae). Ph. D.Thesis,C.I.F.E., Mumbai. 330 pp.Battish, S. K. 1992. Freshwater Zooplankton of India.Oxford & IBH Publishing Co., New Delhi. 233 pp.George, M. G. 1961. Observations on the rotifers fromshallow ponds in Delhi. Curr. Sci., 30: 268-269.Gopakumar, G. 1998. Studies on brackishwater rotifers ofKerala with special reference to B. plicatilis O. F.Muller as live feed for aquaculture. Ph. D. Thesis, Univ.of Kerala. 229 pp.Jyoti, M. K. and H. Sehgal. 1979. Ecology of rotifers ofSurinsar, a subtropical, freshwater lake in Jammu (J andK), India. Hydrobiologia, 65(1): 23-32.Koste, W. 1978. Rotatoria. Die Radertiere Mitteleuropas.2 vols. Gebruder Borntraeger, Berlin, Stuttgart, WestGermany. 673 pp., 234 plates.Koste, W. 1979. New rotifera from the river Murray, southeastern Australia, with a review of the Australianspecies of Brachionus and Keratella. Aust. J. Mar.Fresh. Res., 30: 237-253.Miracle, M. R., M. Serra, E. Vincente and C. Blanco. 1987.Distribution of Brachionus species in SpanishMediterranean wetlands. Hydrobiologia, 147: 75-81.Molly, V. and L. Krishnan. 2008. A preliminary study onrotifer fauna of Cochin backwaters, Kerala. J. Mar.Biol. Ass. India, 50(1): 119-121.Molly, V., L. Krishnan and V. J. Kuttyamma. 2006.Systematic account on rotifers of the genus Brachionusfrom Cochin Backwaters. J. Mar. Biol. Ass. India,48(2): 147-155.Nayar, C. K. G. 1968. Rotifer fauna of Rajasthan, India.Hydrobiologia, 31: 168-185.Pejler, B. 1977. On the global distribution of the familyBrachionidae (Rotatoria). Arch. Hydrobiol. Suppl.,53(2): 255-306.Pennak, R. W. 1957. Species composition of limneticzooplankton communities. Limnol. Oceanogr., 2: 222-232.Sampathkumar, R. 1989. Taxonomic composition anddistribution of Brachionus (Rotatoria : Monogononta)populations in ponds. J. Bombay Nat. Hist. Soc., 88:67-72.Segers, H. 1995. Nomenclatural consequences of somerecent studies on Brachionus plicatilis (Rotifera,Brachionidae). Hydrobiologia, 313-314: 121-122.Segers, H. 2002. The nomenclature of the Rotifera :annotated checklist of valid family and genus-groupnames. J. Nat. Hist., 36: 631-640.134Journal of the Marine Biological Association of India (2011)Molly VargheseSharma, B. K. 1980a. Contributions to the rotifer fauna ofPunjab State, India. I. Family Brachionidae.Hydrobiologia, 76: 249-253.Sharma, B. K. 1980b. Contributions to the rotifer fauna ofOrissa, India. Hydrobiologia, 70: 225-233.Sharma, B. K. 1983. The Indian species of the genusBrachionus (Eurotatoria: Monogononta:Brachionidae). Hydrobiologia, 104: 31-39.Sharma, B. K. 1991. Rotifera. Animal Resources of India(Protozoa to Mammalia). State of the Art ReportZoological Survey of India, Calcutta. p. 69-88.Su, R., H. Segers and H. J. Dumont. 1998. Distribution ofBrachionidae Rotifera, Monogononta) in innerMongolian waters. Int. Rev. Hydrobiol, 83(4): 305-310.Vasisht, H. S. and S. K. Battish. 1971. The rotifer fauna ofnorth India: Brachionus.  Res. Bull. Panjab. Univ.,22(1&2): 179-188.Received : 12/11/10Accepted : 28/02/11Published : 15/06/11

Distribution of Brachionus species (Phylum Rotifera) in Cochin backwaters,

Kerala, India

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Distribution of Brachionus species (Phylum Rotifera) in Cochin backwaters, Kerala, India

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