We report the presence of blackchin tilapia, Sarotherodon melanotheron, in the coastal waters of Manila Bay and in the river tributary of Hagonoy, Bulacan, suggesting its possible range expansion. The occurrence of the native Central American Mayan cichlid, Cichlosoma urophthalmus, is also putatively confirmed for the first time in Hagonoy, Bulacan. While morphological features, morphometric characters, and meristic counts of the current populations match those reported elsewhere for these species, further genetic work is required to confirm their identification and possibly provide information on their source. Negative impacts of the existence of the two species due to competitive interactions have already been anecdotally reported, however, no empirical scientific evidence is available to provide verification. Therefore, studies on the potential ecological impacts should be done, especially because the two species were already reported as notoriously invasive.

The invasive crustacean Hemimysis anomala was first discovered in the Republic of Ireland in April 2008. By 2009 it had extended its range to lakes throughout the navigated River Shannon waterway, occasionally occurring in large swarms in shallow waters and in lower densities at deep sites. In this study, a standardised stratified fish survey of Upper Lough Erne in 2013 found H. anomala in the stomach contents of four perch (Perca fluviatilis). These fish were captured at sites located at the northern and southern extremes of the lake, suggesting that invasive H. anomala are distributed throughout this waterbody. This catchment is directly linked to the River Shannon through the Shannon–Erne canal and our data indicates that, as previously predicted, the distribution of H. anomala now includes Northern Irish freshwaters.

While part of a single country, the Indonesian archipelago covers several biogeographic regions, and the high levels of national shipping likely facilitate transfer of non-native organisms between the different regions. Two vessels of a domestic shipping line appear to have served as a transport vector for the Asian green mussel Perna viridis (Linnaeus, 1758) between regions. This species is indigenous in the western but not in the eastern part of the archipelago, separated historically by the Sunda Shelf. The green mussels collected from the hulls of the ferries when in eastern Indonesia showed a significantly lower body condition index than similar-sized individuals from three different western-Indonesian mussel populations. This was presumably due to reduced food supply during the ships’ voyages. Although this transport-induced food shortage may initially limit the invasive potential (through reduced reproductive rate) of the translocated individuals, the risk that the species will extend its distributional range further into eastern Indonesia is high. If the species becomes widely established in eastern Indonesia, there will then be an increased risk of incursions to Australia, where the mussel is listed as a high-priority pest species.

This paper reports the first record of the non-indigenous species Gammarus roeselii Gervais, 1835 in the sub-lacustrine Ticino River basin (Po river floodplain, Northern Italy). Up to now in Italy, this Balkanian amphipod, known as an “exotic species, well established” in Central Europe, had only been reported in the North-Eastern part of the country (Sile River basin). Gammarus roeselii has a low spreading potential, so its presence in other parts of Europe can only be explained by human activities. However, the available data suggests that its presence in the sub-lacustrine Ticino River basin does not currently represent a threat to the population of the native Echinogammarus stammeri, which is still very healthy in this area.

This report updates the geographical distribution of Sardinella gibbosa (Bleeker, 1849): confirming its presence in the Red Sea and documenting its introduction into the Eastern Mediterranean Sea. Both updates are based on overlooked museum voucher specimens, some of which were collected 86 years ago. In addition, a simplified morphological key is provided for identification of the clupeids currently found in the Eastern Mediterranean Basin.