In India, the Central Marine Fisheries Research

Institute, succeeded In developing a viable

technology for pearl culture using Pinctadajiicata

in 1973 and since then research is continuing

to improve the technology. Further, the successful

development of hatchery technology for the

production of pearl oyster spat during 1981 led

to production of pearl oyster seed overcoming the

problem of non-availability of seed from the wild

for pearl culture industr

Daniel, S D

Thiagarajan, R

CMFRI Digital Repository

ISSN 0254-380 X <J^ VEMSOF iGlOOIOUSSEIinCEl , TOTHE / H T I O I ^ MARINE FISHERIES INFORMATION SERVICE 1947-1996 I t • - ^ i ? ^ * " r ^ . •••• '^^S^^lMu, • ^ l ^ ^ ^ •;• i ^ / T TECHNICAL EXTENSION H - ; , ' - - ' ' > ^ -AND SERIES M:"'^.^: •mi^^ ^ - ^ ^ 44*^5^ 4^lR>K4ch1 CENTRAL MARINE FISHERIES a r ^ ^ S T T ^ IFTF^TFT RESEARCH INSTITUTE <=birc<H, ^TTTrT COCHIN, INDIA INDIAN COUNCIL OF AGRICULTURAL RESEARCH 856 INFLUENCE OF SEASONALITY AND LUNAR PERIODICITY ON THE MATURITY PATTERN OF PINCTADA FUCATA FOR NUCLEUS IMPLANTATION IN PEARL CULTURE R. Thiagarajan Mandapam Regional Centre ofCMFRI, Mandapam Camp - 623 520, India S.D. Daniel ORKEYAquaculture, Mandapam- 623 518, India In India, the Central Marine Fisheries Resear-ch Institute, succeeded In developing a viable technology for pearl culture using Pinctadajiica-ta in 1973 and since then research is continuing to improve the technology. Further, the success-ful development of hatchery technology for the production of pearl oyster spat during 1981 led to production of pearl oyster seed overcoming the problem of non-availability of seed from the wild for pearl culture industry. These developments resulted in the establishment of the Tamil Nadu Pearls (Pvt.) Limited at Mandapam and the firm is carrying out pearl culture since 1983. James (Bull. CMFRI. 39:120-122. 1987) has indicated some of the research and development require-ments on pearl culture such as the production of shell bead nuclei indigenously and to improve gross production and quality of cultured pearls. 15 In the commercial operations at Mandapam a large number of mother oysters were found not suitable for nucleus implantation due to the ripe and developing condition of their gonads. An ave-rage of 49 % were only suitable for implantation of nuclei and in some days only 2 % were suita-ble. This problem caused unnecessary stress to oysters. Therefore it was decided to examine the influence of seasonal and lunar periodicity on maturation of the oyster in relation to nuclei implantation. The study was based on the samples brought from the mother oyster farm at Krusadai Island. When the oysters attained suitable size for nucleus implantation operation, they were transported to Tamil Nadu Pearls Implantation Centre at Mandapam. Preconditioning of mother oyster for surgery was done by keeping the oysters in running filtered sea water during the previous night of the surgery date. On every nucleus implantation day, 100 oysters were taken at random for surgery. The visceral mass was found occupied largely by gonad which takes the major nucleus load. The oysters were opened and those found in the inac-tive or 'condition' (other than the ripe and develo-ping) stage, were suitable for implantation of nuclei. The ripe and developing stage oystersh were returned along with other discarded oysters to the oyster farm. Between September '85 and August '86 a total of 21,800 mother oysters were examined in 218 nucleus implantation days. The data on preconditioned oysters for impla-nation were pooled monthwise and the number in the three gonadial classification viz. the ripe, the developing and the inactive are given in Table 1. The monthwise percentage of ripe, developing and inactive oysters are shovra in Fig.l. During October, November and March 1985 and July-August 1986, the inactive oysters constituted more than 50 % of the population. The monthly percentage of ripe oysters ranged from 21 to 61 % and the mean monthly percentage was 36 %. During September, Janua-.TABLE l. Monthwise number of oysters In different gonadial conditions viz. ripe, developing and inactive Month Sept '85 Oct. Nov. Dec. J a n '86 Feb. Mar. Apr. May J u n . Ju l . Aug. Total % Sample No. 300 2,400 2 ,300 2 ,500 2,500 2.300 1,100 1.300 1.600 1,200 2,700 1,600 21.800 100.0 Ripe 166 661 480 935 1,146 1.140 244 681 981 450 6 4 7 344 7,875 36.1 Developing 39 464 326 320 368 291 186 437 160 151 364 231 3,337 15.3 Inactive 95 1,275 1.494 1,245 986 869 670 182 459 599 1.689 1,025 10,588 48.6 ry, February, April and May, the ripe oysters for-med 55, 46, 50, 52 and 61 % respectively. During November, March, July and August, the ripe oysters formed 21-24 % which is well below the average of 36 %. The monthly mean gonad developing stage was 15 % and was less than the mean during Sep-tember, November-February and May-August. The developing stage oysters were more during October, March and April and formed 19, 17 and 34 % respectively. Fig. 1 Monthwise percentage of ripe, developing anil inactive oysters at Krusadai Island pearl oyster I'arm. 16 The pearl oysters in Tutlcorln harbour farm also showed the inactive, maturing and mature gonads and these stages were represented almost in all the months during 1980-'81 (Chel-1am, Bull. CMFRI. 39 : 13-20, 1987). The percenta-ge of resting/inactive gonad was less during March-May and September-October 1980 among Tuticorin harbour farm oysters. In Krusadai farm oyster, during April-May and September, the inactive oysters were less (14-32 %) than the monthly mean percentage (49 %). The daily percentage of occurrence of inac-tive oysters was plotted against the date of opera-tion and the full moon and new moon days are marked in Fig. 2. In addition to the day of full moon and new moon, 3 days before and after the full moon and the new moon days were taken as lunar periods. The rest of the period between the full moon and new moon was taken as interlunar period. The number of sampling days during the lunar periods and interlunar periods, the date of full moon and new moon and the percentage of occur-rence of inactive, developing and ripe oysters are given in Table 2. A closer examination of the mean values of inactive oysters between interlu-nar and lunar periods (Fig. 2) showed slight increase as well as slight decrease in the percenta-ge. To know whether there is a relationship of per-centage occurrence of inactive oysters during lunar and interlunar periods and to know whe-ther there is a general increase or decrease in the percentage of inactive oysters between the two lunar periods, regression analysis was performed and was found that the mean value of inactive oysters percentage (51) was more during lunar period than the percentage during interlunar period (45) and this showed an increase of inac-tiveoysters during lunar period. From the above analysis of the data for the effect of lunar periods on the daily occurrence of ripe, developing and inactive oysters it was evi-dent that there was not much difference in the MMPN a»MV itwv Fig. 2. Dally percentage occurrence of inactive oysters and the mean values during full moon, new moon and serai-lunar periods during September ' 85 to August '86. structure of the population periods. Contrary to the general belief, the ripe oysters were slightly less during the lunar period and the inactive oysters were slightly more than in the interlunar period. The variation in the percentage occurren-ce of inactive oysters was mainly due to the sea-son. It will be advantageous to make use of the season of inactive oysters to the maximum for pearl culture operations. 17 TABLE 2. The number of sampling days durir\g the full moon (F), semi lunar (S) and new moon (N) periods and the per-centage of inactive, developing and rip^ oysters Date of Full Lunar and New phase Moon Number of sam-pling days Oyster gonad condition Inactive Devel-oping ripe 29.09.'85 14.10.'85 27.10.'85 12.11.'85 27.11.'85 12.12.'85 27.12.'85 10.01.'86 25.01.'86 08.02.'86 24.02.'86 10.03.'86 25.03.'86 09.04.'86 24.G4.'86 08.05.'86 23.05.'86 07.06.'86 21.07.'86 05.08.'86 19.08.'86 21.06.'86 07.07.'86 F S N S F S N S F S N S F S N S F S N S F S N S F S N S F S N S F S N S F S N S F S F S N S 4 7 6 4 6 6 5 6 6 6 6 7 5 5 6 6 6 6 6 8 5 2 -2 6 4 -2 6 5 5 7 2 --6 6 7 5 2 6 2 6 8 6 6 28 47 63 52 58 68 74 56 64 61 48 50 41 29 36 41 43 41 28 26 66 66 60 68 35 4 12 14 12 39 48 37 69 68 61 45 76 55 49 54 54 64 22 22 22 13 13 15 10 16 15 12 12 11 19 7 12 17 19 18 15 U 9 14 27 16 12 53 34 27 12 8 6 20 17 12 15 23 10 21 16 10 11 13 50 31 15 35 29 17 16 28 21 27 40 39 40 64 52 42 38 41 57 63 25 20 13 16 53 43 54 59 76 53 46 43 14 20 24 32 14 24 35 36 35 23 18 

Influence of seasonality and lunar periodicity on the maturity pattern of Pinctada fucata for nucleus implantation in pearl culture

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Influence of seasonality and lunar periodicity on the maturity pattern of Pinctada fucata for nucleus implantation in pearl culture

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