Sunday, 19 May, 2013

Ecologists are desperate to forestall a devastating invasion of the Lakes. Can electric fences block carp from Lake Michigan, or should canal be closed?

The ocean’s most valuable fish are caught in a vise. Areas known as dead zones are encroaching on their living zones and pinning them closer to the surface, where they are more vulnerable to becoming the day’s catch. The predicament is yet another side effect of climate change.

Fish contamination was rare after the giant oil spill in the Gulf of Mexico in 2010, with levels of dangerous hydrocarbons well below “levels of concern.” But nobody looked systematically at heavy metals, the Gulf still has a lot of oil, and the many different hydrocarbons may have unpredictable impacts.

Most of our planet is ocean, and now we have a better idea of what lives there. Marine creatures are much weirder than those on land. The Census of Marine Life looked at salmon migration, Arctic animals, and the uncountable variety of bacteria in the sea. Want to take a look?

Can we fix rivers? Dams, levees, and locks can harm rivers and wetlands. So can draining rivers dry, or encasing them in concrete. In a few places, conservationists are finding smarter ways to manage rivers and wetlands. Is a win-win solution possible for our wicked water woes?

When chemicals in the water trigger the endocrine system, male fish can start looking and acting female. What happens once chemicals from plastics, drugs and our own endocrine system are flushed down the toilet? Can we prevent them from entering our streams and harming wildlife?

Cleaner fish remove parasites from other fish. Why do males punish females who eat the wrong food from their host? A clue to the evolution of cooperation?

A new study finds a surprising number of fish, birds and mammals in the oceans 100 and 1,000 years ago. Can this information help regulators slow the decline of important marine animals?

Three giant new reserves, extend 50 miles out from shore, will protect coral reefs, fish, clams, and other life forms. But how effective are marine protected areas?

When too much fertilizer reaches the Gulf of Mexico through the Mississippi River, a vast area gets robbed of oxygen. What can be done to reduce the dead zone that appears each summer?

Study shows the wisdom of allowing fish stocks to recover. Production is higher, but costs are lower. What would it take to bring economic and environmental sanity to the fishing industry?

Some people find sea gulls annoying, but they have their uses.

Gills are the equivalent of a mammal’s lungs, says Jeffrey Malison, director of the aquaculture program at University of Wisconsin-Madison. “Their primary purpose is to exchange gases, take oxygen in and release carbon dioxide out of the fish.” Both lungs and gills have a bed of very small blood vessels with thin walls that the [...]

Big sharks eat little sharks and rays, which eat shellfish. So ultimately, hunting big sharks may cause shellfish to disappear.

How’s a hungry fish supposed to make a living in the shallow water below tropical mangrove trees? Hint: Squirt, squirt!