,

Annual Reproductive Cycle of the Saccostrea cucullata (von Born)

P. SUKUMAR' were fixed in alcoholic Bouin's solution. processed, wax M. MOHAN JOSEPH embedded, sectioned at 7 fl-m and stained with Delafield's College of Fisheries. haematoxylin and alcoholic eosin. The classification University of Agricultural Sciences, scheme for gonadal histology provided by Joseph and Mangalore - 575 002, Madhyastha (1982) was followed. The temporal distribution Kamataka. of developmental and regression stages of the gonad of each sex during the study period was analysed. Environmental parameters (water temperature, pH, salinity 'Present address: and dissolved oxygen) were recorded at the sampling site. Fisheries College, Tamil Nadu Agricultural University. Tuticorin - 628 OOB, Tamil Nadu. Results and Discussion The temporal distribution of temperature, salinity, SUKUMAR, P., and JOSEPH, MM., 1988. Annual reproductive cycle 01 the dissolved oxygen and pH is illustrated in Fig. l. The surface rock oyster Saccostrea cucullata (von Born). In: M. Mohan Joseph water temperature varied from 24"C (October) to 32'C (Ed.) The First Indian Fisheries Forum, Proceedings. Asian (May). The lowest and highest salinity values were during Fisheries Society. Indian Branch. Mangalore. pp. 20i - 210. September (29.78%0) and May (35.56%0) which coincided respectively with peaks of monsoon and summer. The Abstract dissolved oxygen values ranged from 5.20 mVl (October) to 7.65 mill (June). The pH of the ambient water ranged fro m The annual reproductive cycle of the rock oyster, 5accostrea cucu/Jata (von Born) inhabiting Someshwar coast. near Mangaiore was investigated. 8.2 to 8.6. The reproductive cycle commences with gametogenic activity during The distribution of gonadal stages of maturity and the January - February, followed by gonadal development and maturation distribution of developing, maturing and spawning during March - May. Spawning is

207 208

The sali nity values during the period of gametogenesis decline in salinity in the present instance is similar to such (January - February) varied between 33.47 and 34.65%. Full earlier reports on Indian bivalves (Panikkar and Aiyar, gonadal maturity in > 60% individuals was recorded 1939; Rao, 1951. Kuriakose. 1973). However, as pointed out during April - May when salinity values were between 35.00 by Joseph and Madyastha ( 1982 and 1984) evidences are and 35 .5 6~"o. Initial spawning coincided with a drop in lacking to establish that salinity per se regulates gonad salinity during early June (33.80%0). differentiation, gametogenesis and nature and degree of The reproductive cycle of 5. cucullata delineated by the spawning in oysters inhabiting the Indian waters. present investigation can be summarised as follows: The Hermaphroditic individuals occasionally appear in gametogenic activity commences during January - strictly gonochoristic (Sastry, 1979). However, true February followed by gonad development and maturation functional hermaphroditism does not occur in oviparous during March - May. Spawning is continuous from June to oysters (Andrews, 1979). Occasional sex changes in various December with two peaks during late June to early species of oviparous oysters inhabiting different regions September and November to December. Though few have been reported (Amemia, 1925; Awati and Rai, 1931; oysters of indeterminate stage were observed, the oyster Roughley, 1933; Burkenroad, 1937; Rao. 1953; Asif 1979b; population does not pass on to an inactive phase. Rogers and Cubas, 1981). Hermaphroditism and sex Hermaphrodites occurred in small quantities during the reversal have been reported in 5. eueullata inhabiting peak of the breeding season. Histological features of the Indian and Karachi coasts (Awati and Rai , 1931; Asif, 1979b). hermaphroditic gonads such as collapsed and disintegrating The direction of sex change from a functional female to nature of the follicles with ova, presence of only a very few fu nctional male observed in the present study is similar to oocytes. absence of primary and secondary oocytes within the report of Awati and Rai (1931). Lack of food due to the collapsed follicles and infiltration of the follicular area parasitization of pea crab resulted in the change of sex in by spermatids indicated that the change of sex in this O. (:5.) eueullata (Awati and Rai , 1931 ). No such parasiti· oyster is from a functional female to a functional male. zation was noted in the present study. Purchon (1968) and Continuous reproduction throughout the year for a Joseph and Madhyastha (1984) suggested that the species may be expected in areas of little seasonal change transition from unisexuality to hermaphroditism or vice such as in deep sea and parts of tropics (Giese and Pearse. versa is possible depending on environmental stress. 1974). Gametogenesis more than once during a breeding season in C. madrasensis (Rae. 1951: Joseph and Acknowledgements

Madhyastha, 1982) and once in 5. cucullata The authors are grateful to Prof. H.P.C. Shetty, Director of Instruction (Nagabhushanam and Bidarkar, 1977) have been recorded (Fisheries) for encouragement. The Junior Research fe llowship awarded to in Indian waters. A similar seasonal gametogenic activity the first author by the Indian council of Agricultural Research. New Delhi was observed in the present study. Staggered gametogenesis during the tenure of which the study was carried out is greatetully in 5. eueullata inhabiting Karachi coast (Asit, 1980) may be acknowledged. related to the species' ability to show variations in reproductive responses in different geographical areas References (Giese and Pearse, 1974). Spawning periodicities in I .-\Jagarswami. K.. 1966. Studies of some aspects of biology of the Saccostrea spp inhabiting different regions have been wedge·calm Donax {aba. Gmelin from the Mandapam coast in the recorded by many workers (Awati and Rai. 1931; Ansari and Gulf of Mannar. J. mar. bioI. Ass. India. 8 : 56-iS. 1 Ahmed. 1972: Di namani, 1974; Fatuchri, 1976; Amemiya, I., 1925. Hennaphroditism of the Portuguese Oyster. Nature. 116 Nagabhushanam and Bidarkar, 1977: Asif 1979a and 1980; ,608. Braley. 1982). Unlike in earlier reports from Indian waters Andrews. J.D .. 1979. Pelecypoda : . In : Reproduction of r.,'larine Invertebrates A.C. Giese and J5. Pearse (Editors ) Vol. V., Molluscs : (Awati and Rai. 1931: Nagabhushanam and Bidarkar. 1977) Pelecypods and Lesser classes. Academic Press . ~ew York Jan 5. eueullata in the present study showed spawning during Franci sco London. south·west monsoon and post monsoon (June Ansari. F. and Ahmed, M. , 1972. Seasonal gonadal changes in the oyster December). The influence on the reproductive cycle of Crassostrea glomera ta. Pakistan J. ZooJ.. 4( 1) : 35-43. bivalves by several exogenous and endogenous factors has '-\~il. ~\.. 1979". Reproductive cycle and changes in associated parts of gonads in Crass ostrea (Saccostrea ) gJomerata (Gould ) from been explai ned by Gi ese and Pearse (1974 ). Newell et al. the coast of Karachi. Indian J. Fish., 26 (1 -2): 13·22. (1982). Sastry (1982) an d Mackie ( 1984). Generally, Asif. M.. 19i9h. Hermaphroditism and sex re versal in the four reproductive behaviour in tropical species is not directly common oviparous species of oysters from the coast 01 correlated to temperature variations. Increase in salinity Karachi. Hydrobiologia. 66: 49·55. has been found to initiate gametogenesis in many Indian .-lost! . \1.. 1980. ThE> reproductive cycle in the population Saccostrea cuctll/ata ( Born ) from the coast of Karachi. Hydrobiologia. bivalves (Sastry, 1955; Alagarswami, 1966: Nagabhushananl 68( 1), 73 ·79. and Talikhedkar, 197i: Nagabhushanam and Dhamne, 1977 ; Awati , P. and Ral. H.S .. 19:31. U<;trea cueHl/ata ( I he l5(Jmbay oys ter ). Joseph and Madhyastha. 1982). Initiation of spawning with Indian. Zoo l. Memoir .. 3:l 07 pp. 209

Braley, RD., 19R2. Reproductive periodicity in the indigenous oyster Panikkdf. i\.K. and Aiyar, RG., 1939. Observations on breeding in Saccostrea cucu/Jata in Sasa Bay. Apra Habor, Guam. Mar. brackishwater in Madras. Proc. India Acad. Sci .. 9B BioI.. 69(3 ), 165-173. 343·364. Burkenroad, M.D., 1937. The sex ratio in alternationa! hermaphrodites. Pun'hon. RD .. 196,11. The Bioiog:.· of the Jlolfusca Pergam(ln Press. London with special reference tn the determination of rate of reversal of pp.56(). sexual phase in oviparous oyster. 1. ,\1ar. Res .. 1 : 75 -S-I. Rao. KV. IY51. Ilbser:ations on the probable effects of salinity on the Dinamani. P.. 1974. Reproductive cycle and gonadal changes in the spa"'ning development and selling of the Indian backwater oyster Newzealand rock oyster Crassostrea glomerata. Newzealand J. Mar. Ostrea madrasensis. Pnx. Indian :\cad. Sci., xm ::?31 -::?.56 Freshwater Res .. 8( 1): 39-65. Rao, KV. 1953. Sex chang~ in the O\'iparous Indian backwater oyster Fatuchri, M .. 1976. Stud) on the spawning season of local oyster Ostrea (Cla $-" ()~t rea I madras('f1sis. C11rr. Sci .. n : J 77-JiB. Crassostrea (uculJa(i1 in ban ten Bay. \Iar. Fish. Res. Rep. (l) Rao. KV, 19.16. Seasonal gonadal changes in the adult bat.:kwater oyster 47-46. Oslrea ( Crc1ssostrea l madras('f1sis Preston from Ennur near Giese, A.c. and Pearse. J.5.. 1974. Introduction : General Principles. In Madras. Proc. Indian ..... cad. Sci .. -t--tB : 332-3 .1 6. Reproduction of Marine Invertebrates AC. Giese and J5. Pearse Rao. K.5 .. 197,1. On Mussels and Oysters. In The Commercial \1olluscs of (Editors) Vol.! p.p ; 1-49. Academic Press. New York. India. Bull. Central ~larinl' Fisheries Research Institute. Cochm. Joseph, MM. and Madhyastha. M.N .. 1982. Gametogenesis and somatic India. NO.:!5. versus gonadal growth in the oyster Crassostrea madrasensis. Rogers. p, and Cubas. G,.1. .. 19R1. Gonadi c changes at hist()lo~ical ' lp\'f'1 of Indian. J. Mar. Sci.. 11 (4) : 303-311. Crassostrea \'jrginica (C ;n1Plin 19i 1l in a fluvial iilgoon system Joseph. MM. and Madhyastha, M.N., 1984. Annual reproductive cycle and Pom-Atastasta T erminos lagoon. Campeche. Mexico lMol!usca sexuality of the oyster Crassostrea madrasensis \Prestoll ). Bival\'ia I.--\In. Inst. Lienc. '\lar. Limnol. Lni\' \ac. Aution . .\\ex .. 8( 1): Aquaculture, 40 : 22~-231. 21 -42. Kuriakose, P.5" 1973. Studies on the A~vtilidae of the Indi an coasis. Ph.D. Roughley. T.e.. 193J. The life history of the Australian Oyster ( Ostrea Thesis, Uni versity of Kerala. commerdaJis) Proc. Unn. Soc. ~ew South Wales .. 58 : 279-333 . Ma£kie, GL, 1984, Bivalve. In : The S. Tompa. N.H. Verdonk and Sastry. AX. 19:15. Studies on the biology of some :\'Iollusca. '\lSc. Thesis. JAM. Van Dan Biggellarr (Editors). Vol. 7 Reproduction pp Andhra Cni\' .. \\·altdir. India. 351-402, Academic Press InclNew York. Sastry . ..1..\ .. 19 79. Pelecypoda I (Excluding Ostreidae)!n : Reproduction of Nagabhushanam, R. and Dhamme, K.P .. 1977. Seasonal gonadal changes in Marine lnwrtebrates Xc. Giese and 1S. Pearse (Edi tors 1 \·ol.\" .. the calm Paphia Laterisulca. Aquaculture, 10(2) : 141-152. ~-10 11u scs : Pelecypods and Lesser classes. :l.p I U -292 ;kademic Nagabhushanam, Rand Bidarkar, 0.5" 1977. Reproductive biology of Press. \ew York San Fransisco London Indian rock oyster Cras..'wstrea cucullata. Indian J. Fish., 24 (1&2 ) : Sastry, A.:"I. 198:!. Em'ironmental regulation of molluscan reproductiun. 135-142. Shellfish. Res. ~ . 106. Nagabhushanam, R. and Talikhedkar. P.l\1.. 1977. Reproductive biology of the wedge clam Donax cunealus. Indian J. Mar. Sci., 6(1): 35. Newell. RI.E.. Hilbish. T J. , Koehn. RK. and Newell CJ. 19S2 Environmental and genetic influences on the reprorluclive cyde of the blue mussel. MytiJllS edulis, (L). J. Shellfish. Res. 2 : 105.

"'-----0 o, ~.,;>~ "to O>

,36

," " .;+ ... •0 ~ \/'- ~~ • A \ .- ,.: "~'" 3>!: ,• Z ,. :; '\;- ;!,/\.,< ,.I " y--- '" ./ " ",' ...... M' J' ..J ' ..J' J' "'. "'" 5 ' 5' )<,I' .... D' rI' .)' oJ' ~' ,.. M' ",' A MONTH 5

Fig. I , Temporal distribution of water characteristics during tht' period fi[ .~tu(h· 210

I D o1 001.

H ~ =

FR", =

FR, ===;::::::::::=:::=== ...... ---c===:::::=:::=:::>···-= = ==.n._ F~ I/) w ---==,.--= ...,I/) H" I FJ). (L

FO, ..../

1'1°3

1>'\°2

f M.D -,---r-, f j • r L I j I , T -r'-'I-'-'~I"'--'-I"'TI ""'''Ti-'IC'T'--'-I'i"T1"'T'~-"~'-''''=-----'-''''T'-''TI'''-'I-,-,,'r>''T'~ A" rvt' M ~ J ' J h J ' J" A ' A~ 5' 5" 0 ' 0" N f Nil D' !)" -.\' J M F l F"1t M'M' A' MONTHS

Fig. :1. °ercentage distribution of gonadal stages of maturity of S. cuelll/aia during the period of study.

100 ff) W

..J

A~ M" M'" J" J"I' J' J .... AI' AN 5 ' S .... 0' 0,..... N" N"/ 0;' 0'" J' J# F" F .... M ' M' t( MONTHS

Fig. ~. Perrt>ntag(' distribution oi dt'\"t'lopin!.!. ma t urin~ and spa\\'ning' stages of 5. cucullMa dur in~ the pt'riod of stlld~