Green-lipped Mussel Perna Viridis Research Articles

LIPID CONTENT AND FATTY ACID COMPOSITION IN THE GREEN‐LIPPED MUSSEL PERNA VIRIDIS (L.)

ABSTRACTThe lipid content and fatty acid profile in soft tissue of the green‐lipped mussel Perna viridis, a widely distributed tropical and subtropical bivalve species, were investigated. The total and neutral lipid contents were 6.17 ± 0.71 and 2.71 ± 0.42 mg per 100 mg dw, respectively. The content of docosahexaenoic acid (DHA, C22:6n‐3) was 24.38 ± 2.50 mg/g dw whereas eicosapentaenoic acid (EPA, C20:5n‐3) was present at 12.29 ± 2.12 mg/g dw. These two fatty acids were also at the top high percentage among all the fatty acids, with 38.06 ± 0.86% and 17.89 ± 1.24% (w/w) in total lipids and 34.64 ± 2.74% and 20.33 ± 1.05% (w/w) in neutral lipids, respectively. Therefore, green‐lipped mussel is a rich source of DHA and EPA, the two n‐3 polyunsaturated fatty acids that are beneficial to human health and nutrition.

Heavy metal (Cd, Cu, Pb and Zn) concentrations in the green-lipped mussel Perna viridis (Linnaeus) collected from some wild and aquacultural sites in the west coast of Peninsular Malaysia

The green-lipped mussel Perna viridis (L.), collected from nine (four wild and five aquacultural) sites between 1999 and 2001, off the west coast of Peninsular Malaysia, were analysed for cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn). The concentrations (μg/g dry weight) of these heavy metals ranged from 0.68 to 1.25 for Cd, 7.76 to 20.1 for Cu, 2.51 to 8.76 for Pb and 75.1 to 129 for Zn. These levels should result in no acute toxicities of the metals since they are lower than the permissible limits for human consumption. In addition, these metal concentrations are also considered to be low when compared with regional data using P. viridis as a biomonitoring agent.

Mercury levels in the green-lipped mussel Perna viridis (Linnaeus) from the west coast of peninsular Malaysia.

Mercury levels in the green-lipped mussel Perna viridis (Linnaeus) from the west coast of peninsular Malaysia.

Field depuration and biotransformation of paralytic shellfish toxins in scallop Chlamys nobilis and green-lipped mussel Perna viridis

Under laboratory conditions, the scallop Chlamys nobilis and the mussel Perna viridis were exposed to N-sulfocarbamoyl toxins (C2 toxin), a paralytic shellfish toxin (PST), by feeding a local toxic strain of the dinoflagellate Alexandrium tamarense (ATDP) that produced C2 toxin exclusively. The bivalves were subsequently depurated in the field, and their depuration kinetics, biotransformation and toxin distribution were quantified. Depuration was characterized by a rapid loss within the first day, followed by a secondary slower loss of toxins. In the fast depuration phase, scallops detoxified PSTs more quickly than the mussels (depuration rate constants for scallops and mussels were 1.16 day−1 and 0.87 day−1, respectively). In contrast, the mussels detoxified PSTs more quickly than the scallops in the slow depuration phase, and the calculated depuration rate constants (mean+SE) from day 2 to day 13 were 0.063+0.009 day−1 and 0.040+0.019 day−1 for mussels and scallops, respectively. The differences in the appearances of gonyautoxins, GTX2 and GTX3, and their decarbamoyl derivatives, dcGTX2, dcGTX3 and GTX5, which are all derivatives of C2 toxin, indicated active and species-specific biotransformation of the algal toxins in the two bivalves. In both species of bivalves, the non-viscera tissue contained fewer toxins and lower concentrations than the viscera-containing tissue compartment. In scallops, very little toxin was distributed in the adductor muscle. In mussels, most of the PSTs were found in the digestive gland with significant transport of toxins into the digestive gland from other tissues during the course of depuration. The toxin profiles of scallops and mussels differed from each other and from that of the toxic algae fed. A significant fraction of GTX5 was detected in the mussels but not in the scallops. Our study demonstrates a species specificity in the depuration kinetics, biotransformation and tissue distribution of PSTs among different bivalves.

Can the shell of the green-lipped mussel Perna viridis from the west coast of Peninsular Malaysia be a potential biomonitoring material for Cd, Pb and Zn?

The distributions of Cd, Pb and Zn in the total soft tissues and total shells of the green-lipped mussel Perna viridis were studied in field collected samples as well as from laboratory experimental samples. The results showed that Cd, Pb and Zn were readily accumulated in the whole shells. In mussels sampled from 12 locations along the west coast of Peninsular Malaysia, the ratios of the shell metals to the soft tissue metals were different at each sampling site. Nevertheless, the Cd and Pb levels in the shells were always higher than those in the soft tissues, while the Zn level was higher in the soft tissues than in the shells. In comparison with soft tissues, the degrees of variability for Pb and Cd concentrations in the shells were lower. The lower degrees of variability and significant ( P<0.05) correlation coefficients of Cd and Pb within the shells support the use of the mussel shell as a suitable biomonitoring material for the two metals rather than the soft tissue since this indicated that there is more precision (lower CV) in the determination of metal concentrations in the shell than in the soft tissue. Experimental work showed that the pattern of depuration in the shell was not similar to that of the soft tissue although their patterns of accumulation were similar. This indicated that the depuration of heavy metals in the shell was not affected by the physiological conditions of the mussels. Although Zn could be regulated by the soft tissue, the incorporated Cd, Pb and Zn remained in the shell matrices. The present results support the use of the total shell of P. viridis as a potential biomonitoring material for long-term contamination of Cd, Pb and Zn.

Allozyme polymorphisms and heavy metal levels in the green-lipped mussel Perna viridis (Linnaeus) collected from contaminated and uncontaminated sites in Malaysia

It has been widely reported that heavy metal contamination in coastal waters can modify the allozyme profiles of marine organisms. Previous studies have recorded elevated metal concentrations in sediments and mussel tissues off Peninsular Malaysia. In the present study, horizontal starch gel electrophoresis was carried out to estimate the levels of allelic variation of the green-lipped mussel, Perna viridis, collected from one contaminated and three relatively uncontaminated sites off Peninsular Malaysia. Fourteen polymorphic loci were observed. In addition, the concentrations of cadmium, copper, lead, mercury and zinc were determined in the sediments and in the soft tissues of the mussels. Mussels from contaminated site, evidenced by high metal pollution indices (MPI) of the sediment and the mussel tissues, showed the highest percentage of polymorphic loci (78.6%), while those collected from the uncontaminated sites had lower MPI of the sediment and mussel tissue, and exhibited lower percentages of polymorphic loci (35.7–57.1%). The population from the contaminated site showed the highest excess of heterozygosity (0.289) when compared to that of the populations from the three uncontaminated sites (0.108–0.149). Allozyme frequencies at the phosphoglucomutase ( PGM; E.C. 2.7.5.1) locus also differed between the contaminated and uncontaminated populations. Previous studies have shown that exposure to heavy metals can select or counter-select for particular alleles at this locus. The present results suggest that allozyme polymorphism in P. viridis is a potential biomonitoring tool for heavy metal contamination but further validation is required.

Toxicities and tolerances of Cd, Cu, Pb and Zn in a primary producer ( Isochrysis galbana) and in a primary consumer ( Perna viridis)

Studies on toxicities and tolerances of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the brown alga Isochrysis galbana and in the green-lipped mussel Perna viridis were conducted by short-term bioassays using endpoints growth production and mortality, respectively. The 5-day EC 50 and 24-h LC 50 of these heavy metals were determined in the brown alga and mussel, respectively. The EC 50 values calculated for the alga were 0.74 mg/l for Cd, 0.91 mg/l for Cu, 1.40 mg/l for Pb and 0.60 mg/l for Zn. The LC 50 values for the mussels were 1.53 mg/l for Cd, 0.25 mg/l for Cu, 4.12 mg/l for Pb and 3.20 mg/l for Zn. These LC 50 values were within the concentration ranges as reported by other authors who used P. viridis as the test organism. Based on these EC 50 and LC 50 values, the alga was most sensitive to Zn, followed by Cd, Cu and Pb while the mussel was most sensitive to Cu, followed by Cd, Zn and Pb. Differences in the trophic levels, metal handling strategies, biology and ecology of the primary producer (brown alga) and the primary consumer (mussel) are believed to be the plausible causes for the different toxicities and tolerances of the metals studied.

Background concentrations of Cd, Cu, Pb and Zn in the green-lipped mussel Perna viridis (Linnaeus) from Peninsular Malaysia

Background concentrations of Cd, Cu, Pb and Zn in the green-lipped mussel Perna viridis (Linnaeus) from Peninsular Malaysia

Can the byssus of green-lipped mussel Perna viridis (Linnaeus) from the west coast of Peninsular Malaysia be a biomonitoring organ for Cd, Pb and Zn? Field and laboratory studies

Concentrations of cadmium (Cd), lead (Pb) and zinc (Zn) in total soft tissues (ST) and byssus (BYS) of the green-lipped mussel Perna viridis from 11 different geographical locations off the west coast of Peninsular Malaysia were determined. The metal concentrations distributed between the BYS and ST were compared. The results of this study indicated that higher levels of Cd (1.31 μg/g), Pb (38.49 μg/g) and Zn (206.52 μg/g) were accumulated in the BYS than in the total ST (Cd: 0.29 μg/g; Pb: 8.27 μg/g; Zn: 102.6 μg/g). Semi-static and short period controlled laboratory experiments were also conducted for the accumulation and depuration of Cd, Pb and Zn in the total ST and BYS of P. viridis. The ratios (BYS/ST) for Pb and Cd from the laboratory experiments showed that the total ST accumulated more metals than the BYS. Therefore, these laboratory results disagreed with those found for the field samples. However, the laboratory results for the Zn ratio (BYS/ST) agreed with those of the field samples. It was evident that when compared to the ST, the BYS was a more sensitive biomonitoring organ for Zn while it could be a complementary organ for Cd and Pb in the total ST. Since total ST of P. viridis had been reported to have regulative mechanism for Zn, its BYS can be used as a biomonitoring organ for the identification of coastal areas exposed to Zn pollution.

Effects of Total Soft Tissue and Shell Thickness on the Accumulation of Heavy Metals (Cd, Cu, Pb, and Zn) in the Green-Lipped Mussel Perna viridis

The effects of the total soft tissue dry weight and shell thickness and on the accumulation of Cd, Cu, Pb, and Zn were determined in the green-lipped mussel Perna viridis. In agreement with Boyden's formula (1977), our results showed that the plotting of metal concentrations against the total soft tissue dry weight and shell thickness of the mussel on a double logarithmic basis gave negative coefficients especially for Cd, Pb, and Zn. Therefore, the smaller mussels (lower total soft tissue dry weight) had higher concentrations of Cd, Pb, and Zn than the larger ones. Since shell thickness could be considered to estimate of the age of the mussel, it was also found that the younger mussels accumulated more Cd, Pb, and Zn than the older ones. This indicated that P. viridis has a different metabolic strategy for each of the metals studied which may be related to age. However, the accumulation of Cu was hardly affected by the sizes and ages of the mussel. This indicated that the accumulation pathways of Cu and the processes affecting the bioavailability of Cu to the mussel are different from those for Cd, Pb, and Zn.

Accumulation, depuration and distribution of cadmium and zinc in the green-lipped mussel Perna viridis (Linnaeus) under laboratory conditions

Ecotoxicological tests were conducted in the green-lipped mussel Perna viridis under laboratory conditions. Different rates of accumulation and depuration in soft tissues are found and this might be due to different mechanisms of metal binding and regulation. At the end of depuration, Cd levels in soft tissues of P. viridis were 10–30 times higher than before exposure, while Zn levels in soft tissues were almost similar to levels before exposure. These results indicate that P. viridis is a good biomonitoring organism for Cd but Zn levels might be actively regulated. It remains uncertain whether P. viridis is a good biomonitoring organism of environmental Zn contamination. However, the positive patterns, although different rates, of accumulation and depuration for Cd and Zn support the use of P. viridis as a biomonitoring agent for such metals.

Correlations between speciation of Cd, Cu, Pb and Zn in sediment and their concentrations in total soft tissue of green-lipped mussel Perna viridis from the west coast of Peninsular Malaysia

Total concentrations and speciation of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in surface sediment samples were correlated with the respective metal measured in the total soft tissue of the green-lipped mussel Perna viridis, collected from water off the west coast of Peninsular Malaysia. The aim of this study is to relate the possible differences in the accumulation patterns of the heavy metals in P. viridis to those in the surface sediment. The sequential extraction technique was employed to fractionate the sediment into ‘freely leachable and exchangeable’ (EFLE), ‘acid-reducible,’ ‘oxidisable–organic’ and ‘resistant’ fractions. The results showed that significant ( P<.05) correlations were observed between Cd in P. viridis and Cd in the sediment (EFLE fraction and total Cd), Cu in P. viridis and Cu in the sediment (EFLE and ‘acid-reducible’ fractions and total Cu) and Pb in P. viridis and Pb in the sediment (‘oxidisable–organic’ fraction and total Pb). No significant correlation ( P>.05) was found between Zn in P. viridis and all the sediment geochemical fractions of Zn and total Zn in the sediment. This indicated that Zn was possibly regulated from the soft tissue of P. viridis. The present results supported the use of P. viridis as a suitable biomonitoring agent for Cd, Cu and Pb.

Effects of toxic dinoflagellate Alexandrium tamarense on the energy budgets and growth of two marine bivalves

Harmful algal blooms (HAB) may impose a serious threat to aquatic lives and human health. We determined the effects of a toxic dinoflagellate Alexandrium tamarense (clone ATCI01, isolated from Hong Kong coastal waters) on the energy budget, quantified as scope for growth (SFG), and the growth rate of the manila clam Ruditapes philippinarum and the green-lipped mussel Perna viridis. To quantify the SFG, clams and mussels were dosed with different amounts of toxic A. tamarense for 6 days, resulting in different toxin burdens in the tissues. Clearance rate, absorption efficiency, and respiration rate were subsequently measured in these toxin containing bivalves. Clearance rate significantly declined at the highest toxin burden in the clams only, while there was no significant difference in the clearance rate among different treatments for the mussels. The respiration rate of either bivalve was not significantly affected by toxin accumulation in the tissues. In contrast, the absorption efficiency of both clams and mussels decreased, in a concentration-dependent manner for mussels but not for clams, when the tissue accumulated the toxins. With an increase in paralytic shellfish poisoning (PSP) toxin burden, SFG in both clams and mussels was significantly reduced, primarily because of the decrease of absorption efficiency. The growth rate of juvenile clam R. philippinarum, measured as an increment in tissue dry weight over a 15 d exposure period, was significantly lower during their feeding on toxic dinoflagellate than the growth rate of clams feeding on the diatom Thalassiosira pseudonana. The juvenile mussel P. viridis, however, exhibited similar growth rates after feeding on the toxic dinoflagellates and the nontoxic diatom. This study showed that SFG can provide a sensitive and integrated measure of the effect of HAB on the physiology of bivalves. Clam R. philippinarum may be more sensitive, in terms of their energy budget, to PSP toxin accumulation than the mussel P. viridis.

Responses of the green-lipped mussel Perna viridis (L.) to suspended solids

Laboratory experiments were conducted to investigate the lethal and sublethal effects of suspended solids on the survival and physiological, behavourial and morphological changes of the green-lipped mussel Perna viridis collected from Tolo Harbour, Hong Kong. Results showed that P. viridis survived in all test conditions of suspended solids from 0 to 1200 mg/l over a period of 96 h. Physiological responses of the green-lipped mussel under 14-d exposure of suspended solids from 0 to 600 mg/l, followed by 14-d recovery in natural seawater, revealed no significant changes ( p>0.05) in oxygen consumption and dry gonosomatic index for treatments in different concentrations of suspended solids and exposure time. Changes in clearance rate were only found to be significant ( p<0.001) with exposure time. Responses in behavourial and morphological changes of the green-lipped mussel were also studied under similar experimental treatments and exposure time. Byssus production was significantly ( p<0.001) related to exposure time. Gill damage, however, was significantly greater in treatments ( p<0.001). Present findings suggested that P. viridis could tolerate a high level of suspended solids in the laboratory. There were dose-dependent effects of suspended solids on morphology of gill filaments. Implications of survival and responses of the green-lipped mussel to suspended solids in the marine environment are discussed.

Population dynamics and energy budgets of green-lipped mussel Perna viridis (Linnaeus) in a polluted harbour

The population dynamics of Perna viridis (Linnaeus, 1758) in inner Tolo Harbour, Hong Kong were studied from May 1987 to September 1988. There were two recruitments per year, the first from July to September, the second from November to March. The dry gonosomatic index (DGSI) of a standard animal (70 mm) varied seasonally. The highest value was obtained in January 1988 (0.33), the lowest in September 1987 (0.14). The growth of P. viridis was highly seasonal and major growth was observed from May to November. An annual growth of 49.7 mm was estimated for the first year with a further increase of 24.2 mm in the second year and 9.3 mm in the third year. Mortality was high in summer, especially of large individuals during the post-spawning period. The standing biomass varied from 3.8 MJ·m −2 in July 1988 to 31.3 MJ·m −2 in May 1988. Annual production (May 1987–May 1988) of soma, gonad and shell were 11.67, 6.05 and 14.53 MJ·m −2·year −1, respectively. Respiration accounted for 77% of assimilation.

Ocean disposal and land reclamation problems of Penang, Malaysia

An account is given of the enviromental impact of solid wastes used for reclaiming land in coastal areas of Penang, and of the impact of a major sewage outfall on the Western Channel. Leaching of heavy metals was shown to be one of the main sources of contamination from solid wastes. Heavy metal accumulation by the Green-lipped mussel Perna viridis L. and juveniles of the Finfish, Liza subviridis L., used to monitor the effects of the Penang ocean outfall, indicated contamination by most metals in particular Pb and Zn. The sewage outfall was also monitored for bacterial contamination and its role as a source of parasitic diseases evaluated. Recommendations for the treatment of both types of waste are discussed.