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Due to its location and geomorphology, Colombia has a great variety of ecosystems and a high biodiversity; this natural wealth is also observed in its drainage basins where, additionally, a considerable number of endemic plants and animals have been reported. Unfortunately, these bodies of water have undergone major changes made by man; such is the case of the Porce River Drainage. In addition to the use of its water for hydroelectric generation, its channel has been altered and affected by the growth of a great city on its banks, causing the populations of fish that live there to suffer great alterations and disappearances. The ecosystem services provided by fish in this ecosystem have not been adequately determined. Based on functional traits such as size, diet, habitat and distribution in the water column of the fish of the Porce River, the ecosystem services provided by these organisms will be characterized, showing their importance and which types of services they provide direct or indirectly to society. This will allow the formulation of a proposal for more integral management of the biodiversity of this heavily impacted drainage. Sixtytwo species of fish were found in this drainage that can provide regulatory ecosystem services such as: biological control (32 species); water quality improvement (30 spp.); genetic resources (54 spp.); provision services such as food (11 spp.) and ornamental fishes (31 spp.); and cultural services as sources of leisure and recreation (15 spp.). Unfortunately, this drainage has been negatively impacted by modifications of its channel, contamination of its waters and introduction of exotic fish species for the provision of food. All these impacts strongly affect this ecosystem and drastically decrease the surviving native fish populations that have been reported for this river, seriously reducing the ecosystem services that the Porce River species can supply, and which are essential for the functioning of the other ecosystems associated with this drainage and for the human well-being of the region. [ABSTRACT FROM AUTHOR]

During the last decades invasive species became a matter of concern all over the world. Established salmonid populations make sport fishery in Patagonia one of the top in the world, but there is increasing evidence that these populations have negative impacts on native ecosystems. Predation rates and feeding preferences of native catfish Hatcheria macraei and invasive trout Oncorhynchus mykiss were compared by exposing three stream benthic invertebrate species with contrasting ecological roles to direct predation. Secondly, feeding and escaping behaviours of the mayfly Meridialaris chiloeensis belonging to either non-naive or naive populations to predators were investigated in the presence of predation chemical cues, i.e. non direct predator access. Total predation by trout was 2–3 times higher than by native catfish. Trout had clear prey preferences while catfish changed its preferences with shifting prey composition. Invertebrate species showed different responses to predation by native and exotic fish due to the different strategies of fish and invertebrates which resulted from the combination of predator efficiency and prey vulnerability. Feeding activity of non-naive nymphs was significantly lower than that of naive nymphs. In addition, mayfly nymphs from both populations showed higher emigration rates in presence of trout chemical cues than in presence of catfish cues or in fishless treatment. Consequently, the reduced feeding activity observed in non-naive mayflies exposed to rainbow trout cues resulted from their inactivity in channels, as both nymph populations had similar emigration rates. Due to high predation rates, prey preferences (i.e. high potential to exploit prey resources) and induced strong predation avoidance behaviour of prey, invasive trout may have a stronger influence on the abundance and species composition of native macroinvertebrates than native catfish. In just about one century, invertebrate species such as the ubiquitous M. chiloeensis show behavioural adaptations to this exotic predator. [ABSTRACT FROM AUTHOR]

While the ecological impact of anthropogenically introduced exotic species is considered a major threat for biodiversity and ecosystems functioning, it is generally not accounted for in the environmental life cycle assessment (LCA) of products. In this article, we propose a framework that includes exotic species introduction in an LCA context. We derived characterization factors for exotic fish species introduction related to the transport of goods across the Rhine-Main-Danube canal. These characterization factors are expressed as the potentially disappeared fraction (PDF) of native freshwater fish species in the rivers Rhine and Danube integrated over space and time per amount of goods transported (PDF.m3.yr.kg-1). Furthermore, we quantified the relative importance of exotic fish species introduction compared to other anthropogenic stressors in the freshwater environment (i.e., eutrophication, ecotoxicity, greenhouse gases, and water consumption) for transport of goods through the Rhine-Main-Danube waterway. We found that the introduction of exotic fish species contributed to 70-85% of the total freshwater ecosystem impact, depending on the distance that goods were transported. Our analysis showed that it is relevant and feasible to include the introduction of exotic species in an LCA framework. The proposed framework can be further extended by including the impacts of other exotic species groups, types of water bodies and pathways for introduction. [ABSTRACT FROM AUTHOR]

ABSTRACT Freshwater ecosystems worldwide are experiencing native fish losses with severe threats to the conservation of freshwater biodiversity and ecosystem functioning, and the debate on whether the cause is biotic or abiotic disturbance is still open., Temporal variation in fish assemblages was analysed over an 18 year period in 14 waterways of the lowland backwaters of the Po River in north-eastern Italy, which are important feeding, spawning and nursery sites for native fish., In 1991, 14 native and eight exotic species were collected. In less than 20 years 10 native species underwent local extinction, three of which - Rutilus pigus, Rutilus aula, and Chondrostoma soetta - were endemic to the Padano-Veneto District in northern Italy., Ordination of the data (MDS, CLUSTER, ANOSIM, SIMPER) showed a clear temporal gradient in fish community structure. After the establishment of the exotic predator Silurus glanis, some native species significantly declined in abundance and biomass (i.e. Alburnus arborella and Scardinius erythrophthalmus) or disappeared (i.e. Rutilus aula and Tinca tinca). Moreover, exotic species Cyprinus carpio, Ameiurus melas, and Carassius auratus from previous introductions, underwent significant changes in their abundance and biomass. No correlation was found between fish community structure and water quality parameters (BIOENV)., The success of exotic species, particularly S. glanis which thrived in this degraded habitat, seems to have led to the decline of native fish fauna in the canals of the lower portion of the Po River basin. Conservation strategies focusing on the containment of exotic species and habitat restoration are recommended., Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Species that invade a new environment often may lead to population declines of endemic species. Here I document the invasions of an African cichlid (genus Oreochromis) in 1988 and the Mexican Astyanax fasciatus (Characidae) in 1996 into Laguna Chichancanab (Yucatan, Mexico), and the impact on an endemic Cyprinodon species flock and the poeciliid Gambusia sexradiata. After the invasion of Astyanax fasciatus, their relative abundances decreased enormously, most likely caused by predation on the fry. One species, Cyprinodon simus, might have even gone extinct or just occurs in extremely reduced numbers. Furthermore, it was observed that the percentage abundance of the detritivorous Cyprinodon beltrani increased significantly, in contrast to all other Cyprinodon species. This study also revealed that infestation by metacercaria (black spots) of an ectoparasitic trematode and of an endoparasitic nematode increased in the Cyprinodon spp. following the introduction of Oreochromis. Whereas the infestation by trematodes decreased after a period of 6 years, the prevalence and intensity of infestation by nematodes stayed at a high level. In contrast, in G. sexradiata the parasite load remained always very low. [ABSTRACT FROM AUTHOR]

This paper is the first record of the exotic cichlid, the redbelly tilapia, Tilapia zillii (Gervais, 1848), from natural freshwater bodies of Iran, which has most likely been deliberately released to enhance fish production. The new records extend the geographical distribution range of this exotic fish. [ABSTRACT FROM AUTHOR]