Short and long-term exposure of marine medaka (Oryzias melastigma) to an aluminum salt and to the cocktail of elements released by galvanic anode cathodic protection (GACP): impact on survival, growth, reproduction and behavior

Abstract

Galvanic Anodes as a Cathodic Protection system (GACP) are massively used to prevent corrosion of metallic materials that are immersed in seawater. The dissolution of these alloys leads to the release of metallic elements, in particular the principal constituent aluminum (Al), that is predicted to increase along with the exponential development of offshore wind farms. A limited number of studies have examined Al toxicity to marine fish, alone or in cocktail. To our knowledge, effects of GACP-released elements on fish remain completely unexplored. The present work evaluated acute and chronic toxicity of aluminum salt and of the cocktail of elements released by a functioning GACP system using marine medaka (Oryzias melastigma) as a model species. Embryo-larval development was monitored in acute exposure settings (phenotypic observations, locomotion) and various traits were analyzed in adults exposed for 150 days to the chemicals: growth, reproductive effort, and 4 behavioral traits (shoaling behavior, spontaneous activity, anxiety, exploratory abilities). Embryonic development of the F1 generation was monitored. Results show no significant adverse effect in developmental or in adult stages with regards to survival, growth, and reproductive output. Nonetheless, significant increase in anxiety level in the novel tank diving test was reported after exposure to Al at high dose (191 µg L^-1 and 333 µg L^-1 for respectively dissolved and total Al concentration). The same trend was observed in the GACP condition together with a tendency to form tighter shoals (291 µg L^-1 and 394 µg L^-1 for respectively dissolved and total Al concentration). Overall, the present data support limited toxicity from GACP systems to a model marine fish species in environmental conditions.