The International Maritime Organization (IMO) will enforce a new abundance-based performance standard for ballast water in September, 2017. Strong oxidants, like chlorine, have been proposed as a method for achieving this standard. However chlorine treatment of ballast water can produce hazardous trihalomethanes. We assessed maximum trihalomethane production from one chlorine dose for three types of ballast water (fresh, brackish and marine) and three levels of total organic carbon (TOC) concentration (natural, filtered, enhanced). While the current standard test considers a five day voyage, there is a high possibility of shorter trips and sudden change of plans that will release treated waters in the environment. Water source and TOC significantly affected trihalomethane production, with the highest amounts generated in brackish waters and enhanced TOC concentration. The concentration of brominated trihalomethanes increased from background levels and was highest in brackish water, followed by marine and fresh water.

Plasticity and variability of morphological and physiological traits are common characteristics that allow invasive species to survive, establish and spread to new environments. In order to study the metabolic response of the invasive mussel Limnoperna fortunei (Dunker) (Mytilidae), which has spread through South America and Asia, oxygen consumption was measured under three different acclimation temperatures (18, 22 and 27°C). After an acclimation period of at least 7 days, oxygen consumption was measured and analysed as functions of length and mass. Biochemical composition was also investigated on specimens collected under natural conditions. Environmental scanning electron microscopy determined that the elemental composition and crystalline structure of the shells were normal as described for L. fortunei previously. Average oxygen consumption per mussel was 1.63 ± 0.12 μmol O2 h−1 for an average ash‐free dry weight (AFDW) of 58.7 ± 3.0 mg. The average standard metabolic rate (SMR) per mussel was 14.94 ± 1.30, 30.04 ± 3.38, and 47.10 ± 3.54 μmol O2 gAFDW−1 h−1, at 18, 22 and 27°C, respectively. Significant higher SMR values were recorded at 27°C than at lower temperatures. This metabolic response allows L. fortunei to survive, reproduce and spread across a wide range of habitats, including tropical and subtropical environments in South America.