The R/V Oceanus completed a 9,789 km, 28 day passage from Woods Hole, Massachusetts, in the Atlantic Ocean, through the Panama Canal to Yaquina Bay, Oregon, in the Pacific Ocean on 21 February 2012. The Oceanus had previously operated in the Mediterranean Sea and Atlantic Ocean (including the Caribbean Sea). We document the sequential acquisition of the barnacles Balanus trigonus and Amphibalanus venustus and the oyster Ostrea equestris on the Oceanus on its high and low latitude transoceanic, intra-oceanic, and interoceanic travels before she was surveyed in Yaquina Bay. The close correspondence between hull fouling accumulations and the detailed two year Oceanus working history reveals B. trigonus settlement occurred in every tropical port visited by the Oceanus, that some populations survived through two of three Woods Hole winters, and that some of these populations passed through the freshwater Panama Canal. These results suggest that marine hull-fouling species are continuously transported globally between most ports of call by most ship passages.

The utility of traits involved in resource exploitation is a central criterion for the adaptive character of radiations. Here, we test for differentiation in morphology, jaw mechanics and nutrition among species and sexes of Lake Matano’s sympatric ‘roundfin’ sailfin silversides. The three incipient fish species differ significant in several candidate traits for adaptation following ecological selection pressure, corresponding to contrasting jaw mechanics and distinct patterns in food resource use. These findings are consistent with functional adaptation and suggest divergence following alternative modes of feeding specialization. Further, intersexual resource partitioning and corresponding adaptation in jaw mechanics is evident in two of the three incipient species, demonstrating that sexual dimorphism contributes to the ecomorphological and trophic diversity of the emerging radiation. This is, to the best of our knowledge, the first study reporting interspecific as well as intersexual adaptation by alternative modes of form and function in an evolving fish species flock.

No abstract

Thermally altered water bodies can function as "hot spots" where non-native species are establishing self-sustaining populations beyond their tropical and subtropical native regions. Whereas many tropical fish species have been found in these habitats, the introduction of non-native parasites often remains undetected. Here, n = 77 convict cichlids (Amatitlania nigrofasciata) were sampled by electro-fishing at two sites from a thermally altered stream in Germany and examined for parasite fauna and feeding ecology. Stomach content analysis suggests an opportunistic feeding strategy of A. nigrofasciata: while plant material dominated the diet at the warm water inlet (∼30 °C), relative contributions of insects, plants, and crustaceans were balanced 3 km downstream (∼27 °C). The most abundant non-native parasite species was the tropical nematode Camallanus cotti with P = 11.90 % and P = 80.00 % at the inlet and further downstream, respectively. Additionally, nematode larvae of Anguillicoloides crassus and one specimen of the subtropical species Bothriocephalus acheilognathi were isolated. A. nigrofasciata was also highly infected with the native parasite Acanthocephalus anguillae, which could be linked to high numbers of the parasite's intermediate host Asellus aquaticus. The aim of this study was to highlight the risk and consequences of the release and establishment of ornamental fish species for the introduction and spread of non-indigenous metazoan parasites using the convict cichlid as a model species. Furthermore, the spread of non-native parasites into adjacent fish communities needs to be addressed in the future as first evidence of Camallanus cotti in native fish species was also found.

12The linkage between behavioural types and dispersal tendency has been suggested to be a 13 widespread phenomenon and understanding its mechanisms has become a pressing issue in light 14 of global change and biological invasions. Here, we investigate whether individuals who colonize 15 new habitats exhibit a certain set of behavioural types that differs from those remaining in the 16 source population. We focussed on a feral population of guppies (Poecilia reticulata) that is 17 assumed to undergo a yearly (re)colonization process. Guppies are among the most widespread 18 invasive species in the world, but in temperate regions these fish can only survive in thermally 19 altered freshwaters due to their tropical origin. The investigated population has sustained in a 20 thermally-altered stream in Germany for over 50 years, where they find year-round suitable water 21 temperatures around a warm-water influx. However, in warm seasons, peripheral parts of the 22 warm-water flume become thermally accessible and may be colonized. We sampled fish from the 23 source population and from a winter-abandoned downstream site in March, June and August. Fish 24 were tested for boldness, sociability and activity involving open field tests as well as interactions 25 with a biomimetic robot as social partner. Guppies differed consistently among each other in all 26 three traits. Behavioural trait expression in the source population differed across seasons, 27 however, we could not detect differences between source and downstream populations. Instead, 28 all sampled populations showed a remarkably stable behavioural syndrome between boldness and 29 activity despite strong changes in water temperatures across seasons. We conclude that random 30 drift (as opposed to a personality-biased dispersal) is a more likely dispersal mode for guppies, at 31 least in the investigated stream system. In the face of highly fluctuating environments, guppies 32 seem to be extremely effective in keeping their behavioural expressions constant, which could help 33 explain their successful invasion and adaptation to disturbed habitats. 34