Approaches to the control of golden mussel settlement

M. PÉREZ; M. GARCÍA; R. ROMAGNOLI; M. STUPAK

Río de Janeiro, Brasil

Congreso; 13th International Congress on Marine Corrosion and Fouling; 2006

APPROACHES TO THE CONTROL OF GOLDEN MUSSEL SETTLEMENT 1, 3,4M Pérez, 1,2M García, 1, 3, 4 R Romagnoli, 1,3M StupakM Pérez, 1,2M García, 1, 3, 4 R Romagnoli, 1,3M Stupak 1CIDEPINT – Centro de Investigación y Desarrollo en Tecnología de Pinturas. Calle 52 e/ 121 y 122, (B1900AYB) La Plata, Argentina Calle 52 e/ 121 y 122, (B1900AYB) La Plata, Argentina Calle 52 e/ 121 y 122, (B1900AYB) La Plata, Argentina CIDEPINT – Centro de Investigación y Desarrollo en Tecnología de Pinturas. Calle 52 e/ 121 y 122, (B1900AYB) La Plata, Argentina 2CICPBA- Comisión de Investigaciones CientíficasCICPBA- Comisión de Investigaciones Científicas 3CONICET – Consejo Nacional de Investigaciones Científicas y TécnicasCONICET – Consejo Nacional de Investigaciones Científicas y Técnicas 4UNLP – Universidad Nacional de La Plata e-mail: biofouling@cidepint.gov.ar e-mail: biofouling@cidepint.gov.ar e-mail: biofouling@cidepint.gov.ar UNLP – Universidad Nacional de La Plata e-mail: biofouling@cidepint.gov.arbiofouling@cidepint.gov.ar In Argentina, studies on biofouling control were carried out principally in the marine environment due to heavy fouling colonization and, as a consequence, the great economic impact on submerged man-made structures. However, the introduction of golden mussel, Limnoperna fortunei, into South American freshwaters from Asia, just over fifteen years ago, and their spread through inland waters have resulted in a major economic problem to rawwater- dependent infrastructures, including power generation facilities. Currently, there is great interest in devising new non-toxic methods to control the mussel settlement. In this paper, results obtained by application of cathodic protection currents and the effect of two tannin solutions on Limnoperna fortunei were investigated. The application of a potential difference across an interface generates an electric field and the flow of current. When the interface is cathodically polarized its pH increases as a consequence of hydroxyl generation. Organisms do not resist abrupt pH changes as those that take place in a polarized interface. In this way, cathodic protection is a useful method to control fouling settlement. The main problem is to decide the optimum current density level to avoid fouling settlement. In the particular case of Limnoperna fortunei, it was found that very low cathodic current densities are capable of influencing the behaviour of these mussels; these current densities are too low to protect steel against corrosion. So, cathodic current densities required to protect steel are high enough to avoid Limnoperna fortunei settlement. On the other hand, the probable antifouling effect of two different tannins on Limnoperna fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), On the other hand, the probable antifouling effect of two different tannins on Limnoperna fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), On the other hand, the probable antifouling effect of two different tannins on Limnoperna fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), very low cathodic current densities are capable of influencing the behaviour of these mussels; these current densities are too low to protect steel against corrosion. So, cathodic current densities required to protect steel are high enough to avoid Limnoperna fortunei settlement. On the other hand, the probable antifouling effect of two different tannins on Limnoperna fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), On the other hand, the probable antifouling effect of two different tannins on Limnoperna fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), On the other hand, the probable antifouling effect of two different tannins on Limnoperna fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrations of 1g/L and 0,5 g/L. After 120 minutes exposition they neither had their siphons extended and nor byssal threads were produced. Similar behaviour was observed in experiments carried out with cuprous oxide saturated solution. However, when organisms exposed to test solutions were transferred to freshwater they could recover. In control crystallizing vessels (filtered freshwater only), very low cathodic current densities are capable of influencing the behaviour of these mussels; these current densities are too low to protect steel against corrosion. So, cathodic current densities required to protect steel are high enough to avoid Limnoperna fortunei settlement. On the other hand, the probable antifouling effect of two different tannins on Limnoperna fortunei was studied. Tannins are naturally occurring phenolic compounds with high relative molecular weight (>500) which precipitate proteins. Low concentration solutions of tannins, quillaja and quebracho, were employed in this research and its action compared with that of saturated solutions of cuprous oxide, a common biocide pigment used in antifouling paint formulations. Results obtained showed that mussels close hermetically their valves when they are exposed to quillaja and quebracho tannin solutions, at concentrat