Researchers in Sweden have discovered that traces of many medicines can be found in fish that have been swimming in treated waste water. One such medicine, the hormone levonorgestrel, was found in ...

Every year in September and October, fisheries biologists for the North Dakota Game and Fish Department conduct fall fish reproduction surveys on lakes and rivers in North Dakota. Game and Fish ...

Low oxygen levels in coastal waters interfere with fish reproduction by disrupting the fishes' hormones, a marine scientist has found. Incidents of seasonal low levels of oxygen, known as hypoxia, ...

Seasonal hypoxia, when dissolved oxygen concentrations in water drop below 2 milligrams per liter, is a normal summer occurrence in estuaries. Over the past 20 years, however, pollution has increased ...

Research by Rebecca Asch, a recent graduate of Scripps Institution of Oceanography at UC San Diego, shows a strong correlation between warmer ocean temperatures and changes in the timing of fish ...

WASHINGTON — An all-female freshwater fish species called the Amazon molly that inhabits rivers and creeks along the Texas-Mexico border is living proof that sexual reproduction may be vastly ...

An international study led by biologists from Monash University and the University of Tuscia has revealed how long-term exposure to pharmaceutical pollutants is dramatically altering fish behavior, ...

A DNA probing technique clarifies the mechanism behind clonal reproduction of female dojo loach fish, also providing insight into the ancestral origin of the clonal population. Hokkaido University ...

Several U.S. research teams report reproductive problems in Gulf Coast fish that periodically encounter oxygen at concentrations as low as those in so-called dead zones (SN: 6/5/04, p. 360: Dead ...

A consistent metabolic ratio found across 133 Chinese marine and freshwater fish species provides new evidence in support of the idea that fish become sexually active – and spawn for the first time – ...