DEPURATION

DEP 12/1

SIVALINGAM, P.M., ALLAPITCHAY, I., KOJIMA, H. and T. YOSHIDA
PCBs and pesticides content in cultured cockles from the state of Penang, Malaysia.
1983   7 pp
Proc. Symp. Coast. Aqua., Cochin, January 12–18, 1980. Part 2: Mol. cul. Symp. Ser. Mar. Biol. Assoc.
India, no. 6, 636–642

A survey on the PCBs and persistent pesticides content in cultured cockles obtained from 10 different farms in the state of Penang demonstrated values ranging between the region of 160.29–335.31 ppbs for PCBs (Kanechlor 400) and non-detectable levels of p,p DDE in most samples except for cockles obtained from the Batu Maung 1 site demonstrated a value of 9.24 ppb. Based on these results it is concluded that cultured cockles in the state of Penang are acceptable for consumption from the viewpoint of their contamination.

DEP 12/2

DAVIES, I.M. and J.D. PAUL
Accumulation of copper and nickel from anti-fouling compounds during cultivation of scallops (Pecten maximus) and Pacific oyster (Crassostrea gigas).
1986,   10 pp
ICES Council Meeting 1986, ICES, Copenhagen, Denmark, 1986, 10 pp

Scallop (P. maximus) and Pacific oysters (C. gigas) have been grown for 31 weeks in nets treated with copper oxidebased antifouling paint, and on trays constructed from copper-nickel (90:10) alloy mesh. Copper was accumulated by both species in the net enclosure during the initial 6 weeks of cultivation, and over the subsequent 25 weeks copper was gradually lost from the scallops, but retained by the oysters. Both species accumulated high concentrations of copper from the alloy trays (up to 280 mg/kg in scallop digestive gland, and 790 mg/kg in whole oysters). Transfer of the shellfish to untreated enclosure at week 31 resulted in a further loss of copper from scallops, but the oyster maintained their levels for the following 10 weeks. No significant accumulation of nickel occurred in either species.

DEP 12/3 RAY, S.M. and K.S. RAO
Manual on marine toxins in bivalve molluscs and general consideration of shellfish sanitation.
1984   100 pp
CMFRI Spec. Publ., no. 16, CMFRI, Cochin (India), 100 pp

The manual discusses shellfish culture and shellfish poisoning under the following headings: 1) symptoms and treatment of shellfish poisoning; 2) public health and economic significance of shellfish quality; 3) geographic and seasonal distribution of shellfish poisoning; 4) transvectors of shellfish poisons; 5) source and nature of shellfish poisons; 6) prevention and control of shellfish poisons; 7) miscellaneous shellfish poisonings; and 8) general considerations of shellfish sanitation: techniques for monitoring quality and purification of shellfish.

DEP 12/4

ONOUE, Y., NOGACHI, T. and K. HASHIMOTO
Studies on paralytic shellfish poison from the oyster cultured in Senzaki Bay, Yamaguchi Prefecture.
1980   4 pp
Bull. Jap. Soc. Fish./Nissuishi, vol. 46, no. 8, 1031–1034

Attempts were made to search the cause of food poisoning in which 16 persons developed numbness in the mouth by ingesting the oyster Crassostrea gigas from Senzaki Bay, Yamaguchi Prefecture. The midgut glands of the oyster collected from Senzaki Bay, soon after the poisoning (midJan., 1979) were analyzed. Results showed that the fractions contained gonyautaxins-1, 2, 3 and 5, together with saxitoxin and neosaxitoxin. It was concluded that the poisoning was caused by the paralytic shellfish poison which had accumulated in the oyster.

DEP 12/5

RAGELIS, E.P. (Ed)
Historical perspective on paralytic shellfish poison.
1984   12 pp
Seafood toxins. American Che. Soc., Washington, DC,
August 28 - September 2, 1983. Acs. Symp. Ser., no. 262, 99–111

A review is presented of the important historical development leading to the present understanding of the chemical nature of paralytic shellfish poison, including its chemical structure and properties, mechanisms causing death and present means of control making shellfish safer for human consumption.

DEP 12/6

VAUGHN, J.M. and E.F. LANDRY
Public health considerations associated with molluscan aquaculture systems: Human viruses.
1984   16 pp
Aquaculture, vol. 39, nos. 1–4, 299–315

The documentation of several recent outbreaks of human virus diseases with the consumption of shellfish has reiterated the threat posed by these agents to the shellfish industry. This article reviews pertinent outbreaks, identifies principal viral agents involved, and delineates systems which may be at greatest risk. The results of two recent laboratory studies which sought to define environmental factors that contribute to virus accumulation by shellfish are also discussed.

DEP 12/7

KASSNER, J.
Trace metals in shellfish and growing area designation.
1983   2 pp
J. Shellfish Res., vol. 3, no. 1, 94–95

The level of coliform bacteria, as set forth by the National Shellfish Sanitation Program (NSSP), is the water quality standard used to classify shellfish growing areas. Port Jefferson Harbor, NY, a moderately industrialized embayment of Long Island Sound, and Setauket Harbor, a more urbanized tributary basin of Port Jefferson Harbor, both have areas classified as certified (shellfish permitted) and as uncertified (shellfish prohibited). Sediment analyses of the two harbors suggest that noncoliform pollutants, particularly trace metals, are present. The hard clam Mercenaria mercenaria was sampled for trace metals to determine how trace metal concentrations in the shellfish tissues compared with the level of bacteriological pollution in the growing water and the NSSP classification. The concentration of metals in the shellfish does not appear to be reliably related to the coliform level.

DEP 12/8

SHIOMI, K., TANAKA, E., YAMANAKA, H. and T. HIKUCHI
Accumulation of tetrodotoxin by marine gastropods.
1984   10 pp
Bull. Jap. Soc. Sci. Fish./Nissuishi, vol. 50, no. 7, 1269–1279

The trumpet shell Charonia sauliae and the ivory shell Babylonia japonica being reared with the toxicant muscle of puffer fish Lagocephalus lunaris lunaris were found to accumulate tetrodotoxin (TTX) from the baits. The mid-gut gland exclusively became toxic while the muscle did not. Although the toxicity of the mid-gut gland roughly paralleled the total amount of toxin given, the rates of toxin accumulation differed remarkably from specimen to specimen. Results suggest that TTX accumulated in C. sauliae can be excreted during rearing of more than 4 weeks without feed.

DEP 12/9

THOMSON, J.D.
Short-term changes in metal concentration in the cultivated pacific oyster, Crassostrea gigas Thunberg, and the implications for food standards.
1983   9 pp
Aust. J. Mar. Freshwat. Res., vol. 34, no. 3, 397–405

Two experiments, one of 48 h and one of 100 h duration, were performed with Pacific oysters to ascertain changes in metal concentration after flow-through treatments with seawater, filtered seawater and filtered, diluted seawater. Oysters that were kept in air and had not defaecated were used as controls. The achieve osmotic balance with salinity of 15 × 10 super (-3), the water of lower salinity was taken up by the oysters, thus reducing the wet weight concentrations of the metals. Mean zinc concentration of oysters in the filtered seawater was 1044 mg kg super (-1) compared with 725 mg kg super (-1) filtered diluted seawater in the 48 h experiment and 1122 mg kg super (-1) and 860 mg kg super (-1), respectively, in the 100 h experiment. Iron was the only metal that appeared to be lost in the faeces and pseudofaeces. Particulates adsorbed in the gills may have increased the variability of the metal concentrations, particularly iron. Copper, however, was taken up by oysters in low-salinity water with particulates removed.

DEP 12/10

PILLAI, C.T.
Microbial flora of mussels in the natural beds and farms.
1980   3 pp
Coast. Aq. Mussel Farming, Progress and Prospects, CMFRI Bull., no. 29, CMFRI, Cochin (India), 1980, 41–43

Quantitative estimation of the bacterial load of the brown mussels Perna indicus cultured at Vizhinjam has been shown as 10 super (6). The occurrence of coliforms, Escheria coli, faecal streptococci and coagulate positive staphylococci is reported. Pseudomonas, Vibrio and Micrococcus are seen as normal flora.

DEP 12/11

BUISSON, D.H., FLETCHER, G.C. and C.W. BEGG
Bacterial depuration of the Pacific oyster (Crassostrea gigas) in New Zealand.
1981   10 pp
N. Z. J. Sci., vol. 24, nos. 3–4, 253–262

Optimum parameters for depuration of the New Zealand Pacific oyster (Crassostrea gigas) were found to be a minimum flow of 2 1/2 cycles per hour of sterilised water over the oysters and loading factor of up to 3 oysters per litre of water. Temperature, and the level of the initial contamination (measured as faecal coliforms), were the major factors influencing the success of depuration. Maximum initial contamination levels for a successful depuration at different temperatures within the range 5–23 degree C have been established. For example, maximum initial contamination levels of 560, 3500, and 23000 faecal coliforms/100 g of flesh could be depurated at temperatures of 7, 14, and 21 degree C respectively after 24 hours depuration. Examination of the rates of depuration indicates that the removal of bacteria follows two patterns. Recommendations for the depuration of the Pacific oyster grown under New Zealand conditions are listed.

DEP 12/12

NOODT, W. and S.A. GERLACH (Eds)
Certified areas for mollusk culture.
1977   9 pp
An. Inst. Invest. Mar, Punta de Betin, no. suppl. 1, Inst. Inves. Mar. Punta Betin, Santa Marta (Colombia), 1977, 31–39

The author describes the actions taken by USA and Canada to control the quality of mollusks that entered their markets as a result of epidemics of intestinal disorders. These actions included the establishment of specifications to be met by the areas where the mollusks were collected or cultured, especially in relation to the amount of coliforms present in the water. The importance of the designation and protection of specific areas for mollusk culture and exploitation by each of the producer countries is discussed.