FSP - Microcosm News- Earth Watch Report: Marine biology

Showing posts with label Marine biology. Show all posts

Thursday, March 20, 2014

Oceana Report Exposes Nine of the Dirtiest U.S. Fisheries

Entangled seal pup

Dominique Mosbergen

Oceana Report Sheds Light On Staggering By-Catch Problem In U.S. Fisheries

Posted: 03/20/2014 5:37 pm EDT Updated: 03/20/2014 5:59 pm EDT

That fish dish at your favorite neighborhood bistro may be hiding a gruesome secret.
"When you buy fish at a grocery store or restaurant, you might also be getting a side order of sea turtle or dolphin to go with it," said Dominique Cano-Stocco, Oceana's campaign director of responsible fishing, referring to the large number of dead sea creatures tossed by fishermen each year.
According to a new Oceana report, United States fisheries discard about 17 percent to 22 percent of everything they catch every year. That amounts to a whopping 2 billion pounds of annual by-catch -- injured and dead fish and other marine animals unintentionally caught by fishermen and then thrown overboard. This includes endangered creatures like whales and sharks, as well as commercially viable fish that may have been too young or too damaged to bring to port.
"By-catch is one of the biggest challenges facing the U.S. today," Cano-Stocco said. "It's one of the largest threats to the proper management of our fisheries and to the health of our oceans and marine ecosystems." Due to underreporting, by-catch numbers are probably an underestimate, she explained.
Released Friday, Oceana's report strives to highlight the need to document by-catch numbers and develop better management strategies to prevent the high level of unnecessary slaughter in our oceans.

shark

Bull shark trapped in fishing net

The report identifies nine of the worst by-catch fisheries in the nation. These fisheries -- defined as groups of fishermen that target a certain kind of fish using a particular kind of fishing gear in a specific region -- are reportedly responsible for more than half of all domestic by-catch; however, they're only responsible for about 7 percent of the fish brought to land, the report notes.
Some of these fisheries reportedly discard more fish than they keep; others are said to throw out large amounts of the very fish species they aim to catch. California fishermen who use drift gillnets (walls of netting that drift in the water) to capture swordfish, for example, reportedly throw out about 63 percent of their total catch.
Between 2008 and 2012, about 39,000 common molas, 6,000 sharks, as well as hundreds of seals, sea lions and dolphins, were seriously injured or killed in the California drift gillnet fishery, Oceana notes.

bycatch

Tuesday, October 29, 2013

Toxic Ocean Conditions During Mass Extinction Reveals Insight into Today's Climate

Catherine Griffin

First Posted: Oct 29, 2013 10:56 AM EDT

It turns out that it doesn't take much to turn our planet's ocean waters into something that's toxic to life. Scientists have taken a closer look at a massive extinction event that occurred 93.9 million years ago and have found that it didn't take as much sulfide as previously thought in the ocean waters to cause this major climatic perturbation.
In order to examine this particular extinction, the scientists examined the chemistry of rocks deposited during that time period. This revealed that oxygen-free and hydrogen sulfide-rich waters extended across roughly five percent of the global ocean. That's far more than today modern ocean's at .1 percent, but far less than previously thought.
"These conditions must have impacted nutrient availability in the ocean and ultimately the spatial and temporal distribution of marine life," said Jeremy Owens, one of the researchers, in a news release. "Under low-oxygen environments, many biologically important metals and other nutrients are removed from seawater and deposited in the sediments on the seafloor, making them less available for life to flourish."

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The Daily Galaxy

EcoAlert --Toxic Hydrogen Sulfide-Rich Oceans Led to Major Extinction 93.9 Million Years Ago

“Today, we are facing rising carbon dioxide contents in the atmosphere through human activities, and the amount of oxygen in the ocean may drop correspondingly in the face of rising seawater temperatures,” said said Timothy W. Lyons, a professor of biogeochemistry at University of California (Riverside). “Oxygen is less soluble in warmer water, and there are already suggestions of such decreases. In the face of these concerns, our findings from the warm, oxygen-poor ancient ocean may be a warning shot about yet another possible perturbation to marine ecology in the future.”

Oxygen in the atmosphere and ocean rose dramatically about 600 million years ago, coinciding with the first proliferation of animal life. Since then, numerous short-lived biotic events — typically marked by significant climatic perturbations — took place when oxygen concentrations in the ocean dipped episodically. The most studied and extensive of these events occurred 93.9 million years ago. By looking at the chemistry of rocks deposited during that time period, specifically coupled carbon and sulfur isotope data, a research team led by UCR biogeochemists reports that oxygen-free and hydrogen sulfide-rich waters extended across roughly five percent of the global ocean during this major climatic perturbation — far more than the modern ocean’s 0.1 percent but much less than previous estimates for this event.
The research suggests that previous estimates of oxygen-free and hydrogen sulfide-rich conditions, or “euxinia,” were too high. Nevertheless, the limited and localized euxinia were still sufficiently widespread to have dramatic effect on the entire ocean’s chemistry and thus biological activity.

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