Can Encapsulation of the Biocide DCOIT Affect the Anti-Fouling Efficacy and Toxicity on Tropical Bivalves?

The encapsulation of the biocide DCOIT in mesoporous silica nanocapsules (SiNC) has been applied to reduce the leaching rate and the associated environmental impacts of coatings containing this biocide. This research aimed to evaluate the effects of DCOIT in both free and nanostructured forms (DCOIT vs. SiNC-DCOIT, respectively) and the unloaded SiNC on different life stages of the bivalve Perna perna: (a) gametes (fertilization success), (b) embryos (larval development), and (c) juveniles mussels (byssus threads production and air survival after 72 h of aqueous exposure). The effects on fertilization success showed high toxicity of DCOIT (40 min-EC50 = 0.063 μg L−1), followed by SiNC-DCOIT (8.6 μg L−1) and SiNC (161 μg L−1). The estimated 48 h-EC50 of SiNC, DCOIT and SiNC-DCOIT on larval development were 39.8, 12.4 and 6.8 μg L−1, respectively. The estimated 72 h-EC50 for byssus thread production were 96.1 and 305.5 µg L−1, for free DCOIT and SiNC-DCOIT, respectively. Air survival was significantly reduced only for mussels exposed to free DCOIT. Compared to its free form, SiNC-DCOIT presented a balanced alternative between efficacy and toxicity, inhibiting efficiently the development of the target stage (larvae that is prone to settle) and satisfactorily preventing the juvenile attachment.

PENGARUH SIMULASI TRANSPORTASI KAPAL PADA KERENTANAN KERANG HIJAU Perna viridis TERHADAP HYPOSALINITY

Introduced species are species which exceed their natural distribution limits (native range) by a certain mode of introduction (vector). Natural movements are responsible to a limited extent. Introduction of a species could influence the susceptibility of a species to environmental stress no matter if introduced purposely or un purposely. Introduction of species could happen by natural movement i.e. organism can movement influenced by current and some organism can migrate to one area to another area; and human activity either purposely i.e. aquarium trade, aquaculture or un purposely such as accidentally through fouling on ship hulls. However, a dominant vector which has large contribution on species introduction is transported by ship hulls and ballast water tanks. Furthermore, the objective of this experiment is to investigate whether the organism can increase their tolerance during transport. The experimental design to mimicking transport condition in short term lab experiment and compared pre-stress group and non-stress group on the second stress. Afterward, looking forward the survival of the organism. Chosen of Green Mussels (P. viridis) from Muara Kamal, Jakarta Bay, and hyposaline stress. The response variable these experiments are survival and byssus. The results of this study showed that the group of pre-stress and non-stress group was no difference in the simulation of transport for survival. Byssus thread increase when recovery long enough and decrease when getting double stress.