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 ...

BISMARCK — North Dakota Game and Fish fisheries biologists spend a lot of time in fall surveying district lakes and the Missouri River System in North Dakota looking for natural fish reproduction, ...

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 ...

Select an option below to continue reading this premium story. Already a Honolulu Star-Advertiser subscriber? Log in now to continue reading. The queen of egg production is the ocean sunfish ...

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, ...

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 ...

FRENCH RIVER, Minn. - The St. Louis River has a healthy population of adult lake sturgeon, but those fish are not producing the numbers of young fish that biologists had hoped to see. Few adult ...

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 – ...

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 ...