Reintroduction of endangered fishes to historic habitat has been used as a recovery tool; however, these fish may face competition from other fishes that established in their native habitat since extirpation. This study investigated the physiological response of tidewater goby, Eucyclogobius newberryi, an endangered California fish, when competing for food with threespine stickleback, Gasterost...

We measured total mercury concentrations in water and fish of Lake Managua and Lake Apoyo. Water mercury concentrations were 10-fold higher in Lake Managua than in Lake Apoyo, although differences in mercury concentration in the most common native fish were not significant. One-fourth of the commercially fished tilapia in Lake Managua exceeded maximum recommended mercury levels for consumption ...

Factors including human dispersal, climate change and varied environmental stressors are altering fish species distributions. Range expansions producing new records of freshwater which were rare or previously absent from regional jurisdictions (states, provinces territories). Simultaneously, facing declines local extirpations in some areas their distribution. The Resist-Accept-Direct (RAD) fram...

Empirical studies suggest that most exotic species have fewer parasite species in their introduced range relative to their native range. However, it is less clear how, ecologically, the loss of parasite species translates into a measurable advantage for invaders relative to native species in the new community. We compared parasitism at three levels (species richness, abundance and impact) for a...

Histopathological changes in gills of a native fish Capoeta aculeata, naturally-infected with parasites were studied. The specimens (15.5 to 22.8 cm) were collected from Choghakhor lagoon in West Iran. 35 (11%) of the total 318 studied fishes were infected with gill parasites. Overall, six protozoan and metazoan parasite species were collected from fishes including Ichthyophthirius multifiliis,...

The study of distribution and dispersal invasive fishes is challenging during the early stages invasion. Quantification trace elements incorporated into fish hard parts represents an innovative technique for this task. Otolith chemistry has been used to describe stock structure, migratory behaviour support management several species. We otolith population structure tench (Tinca tinca), invader ...

A novel system combining a trap and pulsed direct current electricity was able to catch up to 75% of tagged invasive sea lamprey Petromyzon marinus in free-flowing streams. Non-target mortality was rare and impacts to non-target migration were minimal; likely because pulsed direct current only needed to be activated at night (7 hours of each day). The system was completely portable and the annu...

An invasive species is one that arrives (oftenwith human assistance) in a habitat it had not previously occupied, then establishes a population and spreads autonomously. Species invasions are one of the main conservation threats today and have caused many species extinctions. The great majority of such invasions are by species introduced from elsewhere, although some native species have become ...

The establishment of exotic game fishes to enhance recreational fisheries through authorized and unauthorized stocking into freshwater systems is a global phenomenon. Stocked fishes are often top predators that either replace native top predators or increase the species richness of top predators. Many direct effects of stocking have been documented, but the ecosystem consequences are seldom qua...

1. Stream fragmentation alters the structure of aquatic communities on a global scale, generally through loss of native species. Among riverscapes in the Great Plains of North America, stream fragmentation and hydrologic alteration (flow regulation and dewatering) are implicated in the decline of native fish diversity. 2. This study documents the spatio–temporal distribution of fish reproductiv...