The concern with clams, aside from losing them, is that the actual ingredient found by NMR (as found in Busan 77) is specifically listed as an EPA approved molluscicide. That's not in seawater, but it's a huge warning flag if the indentity were known:
MOLLUSK CONTROL: To control mollusks such as Corbicula species in recirculating or once-through cooling water and industrial systems, add This product at dosage rates of 2 to 20 ppm. Make continuous or intermittent additions at the intake water. Continuous addition is required for noticeably fouled systems. Intermittent feeding is used to maintain control. This product is used to control algae and mollusks such as Corbicula and Dreissena species in potable water treatment systems. Mitigation: Add This product to the raw water at dosage rates of 2 to 5 ppm (2 to 5 ml_ of This product /1000 L of water). For badly fouled systems, treat continuously for up to 21 days, followed by regular control treatments. Control: To avoid fouling of potable water systems by mollusks, treat the raw water at 2 ppm for 60 minutes, repeating this treatment daily or a continuous feed of 0.5 mg/L