An Ocean of Troubles

Overfishing, global warming and pollution threaten to transform the ocean—and perhaps life as we know it.

IN 1998 a rise in sea temperatures caused by El Niño, a periodic eastward surge of warm Pacific water, caused a mass bleaching of the world’s coral reefs, the permanent or temporary home of perhaps a quarter of all marine species. Up to 90% of the Indian Ocean’s technicoloured reefs turned to skeletal wastes, largely devoid of life. Had this happened to rainforests—coral’s terrestrial equivalent—a sea-change in attitudes to the environment could have been expected. But because this change occurred in the sea, the calamity drew remarkably little comment.
Traditional attitudes towards the sea, as something immutable and distant to humanity, are hugely out of date. The temperature change that harmed the corals was not caused by human activity; yet it was a foretaste of what man is now doing to the sea. The effects of overfishing, agricultural pollution and anthropogenic climate change, acting in concert, are devastating marine ecosystems. Though corals are returning to many reefs, there is a fair chance that in just a few decades they will all be destroyed, as ocean temperatures rise owing to global warming. The industrial pollution that is cooking the climate could also cause another problem: carbon dioxide, absorbed by the sea from the atmosphere, turns to carbonic acid, which is a threat to coral, mussels, oysters and any creature with a shell of calcium carbonate.

The enormity of the sea’s troubles, and their implications for mankind, are mind-boggling. Yet it is equally remarkable how little this is recognised by policymakers—let alone the general public. Killer sharks are a more appealing subject than algal blooms; though they are much less deadly. There is also a dearth of good and comprehensive books on a subject that can seem too complicated and depressing for any single tome. Callum Roberts, a conservation biologist, has now provided one.

He starts with a bold claim: that anthropogenic stresses are changing the oceans faster than at almost any time in the planet’s history. That may be putting it too strongly. Yet there is no quibbling with the evidence of marine horrors that Mr Roberts presents.

The Chagos is one of the few marine locations ...

The Chagos is one of the few marine locations in the world where there are almost no ongoing, direct human impacts over almost all of its areas. The marine reserve would serve as a reference site for global scientific research to aid in our understanding of such things as climate change, tropical marine ecosystems and the impacts of commercial fisheries.

Take overfishing. The industrialisation of fishing fleets has massively increased man’s capability to scoop protein from the deep. An estimated area equivalent to half the world’s continental shelves is trawled every year, including by vast factory ships able to put to sea for weeks on end. Yet what they are scraping is the bottom of the barrel: most commercial species have been reduced by over 75% and some, like whitetip sharks and common skate, by 99%. For all the marvellous improvements in technology, British fishermen, mostly using sail-power, caught more than twice as much cod, haddock and plaice in the 1880s as they do today. By one estimate, for every hour of fishing, with electronic sonar fish finders and industrial winches, dredges and nets, they catch 6% of what their forebears caught 120 year ago.

Overfishing is eradicating the primary protein source of one in five people, many of them poor. It also weakens marine ecosystems, making them even more vulnerable to big changes coming downstream.

For example, there is the matter of chemical pollution, mostly from agricultural run-off. This has created over 400 dead-zones, where algal tides turn the sea anoxic for all or part of the year. One of the biggest, at the mouth of the Mississippi Delta in the Gulf of Mexico, covers 20,000 square km (7,700 square miles) of ocean. An annual event, mainly caused by the run-off of agricultural fertilisers from 40% of America’s lower 48 states, it makes the one-off Deepwater Horizon oil-spill look modest by comparison.

Global warming is another problem. Hitherto, the sea has been a buffer against it: because the heat capacity of water is several times that of air, the oceans have sucked up most of the additional heat, sparing the continents further warming. Yet this is now starting to change—faster than almost anyone had dared imagine.

One effect of the warming ocean, for example, is to increase the density difference between the surface and the chilly deep, which in turn decreases mixing of them. That means less oxygen is making it down to the depths, reducing the liveability of the oceans. Off America’s west coast, the upper limit of low-oxygen water is thought to have risen by 100 metres. Where strong winds bring this water nearer to the surface, there are mass die-offs of marine life. Such events will proliferate as the climate warms.

This is a poor lookout for already put-upon fish. “Fish under temperature and oxygen stress will reach smaller sizes, live less long and will have to devote a bigger fraction of their energy to survival at the cost of growth and reproduction,” writes Mr Roberts. And that is before he gets to the effects of ocean acidification, which could be very bad indeed. Without dramatic action to reverse these processes, he predicts a catastrophe comparable to the mass extinctions of the Palaeocene-Eocene Thermal Maximum, when carbon-dioxide levels, temperature and ocean acidity all rocketed. He writes: “Not for 55m years has there been oceanic disruption of comparable severity to the calamity that lies just a hundred years ahead.” That would be hard to prove; it would be better not to try.

So what is to be done? Mr Roberts provides a hundred pages of answers, occupying roughly a third of the book. They range from the obvious—curbing carbon emissions—to technical fixes, like genetic improvements to aquaculture stocks. None is impossible; and Mr Roberts, almost incredibly, describes himself as an optimist. He writes, “We can change. We can turn around our impacts on the biosphere.” We had better do so.

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NOAA steps up effort to address sea turtle mortality, seeks public input

Published on: June, 24 2011NOAA steps up effort to address sea turtle mortality, seeks public input.

Shrimp trawler imageAs part of stepped-up efforts to address an increase in sea turtle strandings in the Gulf of Mexico, NOAA announced today it will explore new rules to reduce unintended catch and mortality of sea turtles in the southeastern shrimp fishery.

NOAA has documented an increase in sea turtle strandings in the northern Gulf, particularly throughout the Mississippi Sound area. Between January 1, 2011 and June 17, 2011, 379 sea turtle strandings have been reported along the Alabama, Mississippi and Louisiana coastline. The majority of these strandings, 238 turtles, occurred in Mississippi. NOAA leads the National Stranding Network, and is actively monitoring trends and investigating the cause of the strandings.

Results of the necropsies done to date indicate many of the turtles likely drowned. The exact causes of all of the drownings and any contributing factors have yet to be determined.

NOAA has scheduled a series of public scoping meetings in mid-July in Alabama, Mississippi, Louisiana, and North Carolina, to solicit public comments to assist  the  agency in identifying  issues and options for evaluation in a draft Environmental Impact Statement assessing the environmental impacts of  potential regulatory approaches reduce sea turtle mortality.

Turtle Excluder Devices (TEDs), required in most shrimp fisheries, are effective at reducing sea turtle drowning when properly installed and maintained. However, one type of gear, shrimp skimmer trawls, is currently allowed to operate without TEDs, and is instead regulated using tow time limits. The focus of this scoping process is to assess options to reduce sea turtle bycatch in the southeastern shrimp fishery.

In other efforts to increase compliance, NOAA’s Fisheries Service gear experts and enforcement personnel have hosted several turtle excluder device workshops throughout the Gulf states to provide information and assistance to fishermen on federal requirements and proper installation of the devices. These experts have conducted numerous courtesy inspections on the docks and at-sea to improve compliance within the Gulf shrimp fishery.

NOAA is also actively working to improve compliance by conducting numerous enforcement patrols throughout the Gulf. “Violations of turtle excluder device requirements are being documented, and warnings and citations issued,” said Alan Risenhoover, acting director of NOAA Fisheries’ Office of Law Enforcement. “These actions, combined with increased visibility on the water and outreach on the docks, seem to be resulting in increased compliance.”

The shrimp industry has also directly reached out to its members to provide information about turtle excluder device compliance. The Southern Shrimp Alliance scheduled more than a dozen meetings to inform their members that turtle excluder device compliance is a serious issue, stressing the importance of proper installation and maintenance.

Today’s announcement is another step to address a problem recognized by fishing industry leaders. NOAA scientists and managers will continue to work closely with the fishing community and the states to improve compliance, and enhance use of fishing gear and techniques to prevent sea turtles from being caught in fishing nets.

In responding to the increased number of sea turtle deaths in the Gulf region, NOAA is also assessing potential impacts to sea turtles resulting from the Deepwater Horizon spill. Those injury assessment efforts are ongoing.

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Thousands of Gulf Sea Turtles Killed by Shrimp Trawls

Published on: June, 22 2011 – Susan Cohn Rockfeller, Huff Post Green – Thousands of Gulf Sea Turtles Killed by Shrimp Trawls.

Sea turtle Guantanamo imageImagine that you’re going for a swim in the ocean, when suddenly you’re scooped up by an enormous net that drags you under. Scrambling to find an escape, you realize you’re stuck, and you won’t be able to come up for air. There’s no way out.

This is the reality for many sea turtles in the Gulf of Mexico, who have been turning up dead in appalling numbers. Last year more than 600 sea turtles were found either dead or injured in the Gulf, which is more than six times the average over the last two decades. And already in 2011, more than 560 have washed up. And since only a miniscule portion of dead or injured sea turtles wash up on shore, the real number of turtles dying is enormous.

I was shocked to learn that while sea turtles have been undoubtedly affected by the massive oil spill last year, there’s another culprit: Gulf of Mexico shrimp trawls. Not all trawls in the Gulf shrimp fishery are required to use Turtle Excluder Devices (TEDs), which are escape hatches that prevent sea turtles from drowning in trawl nets. Without TEDs, shrimp trawls are essentially sea turtle death traps.

Like you and me, sea turtles are air-breathers; when they get caught in fishing nets they may be unable to come up for air. Each of the six sea turtle species found in U.S. waters is listed as either endangered or threatened under the Endangered Species Act, which means that they may go extinct in the foreseeable future.

But did you know that under the Endangered Species Act, the government authorizes fisheries to injure or kill a specific number of sea turtles? That’s right, and more than 98 percent of all sea turtle interactions authorized to U.S. fisheries are given to the shrimp fishery.

The government assumed that TEDs are 97 percent effective and authorized the shrimp fishery to kill 1,451 loggerhead sea turtles. Oceana recently released evidence that so many shrimp trawls are not using the escape hatches properly that the number of loggerheads killed is likely thousands higher.

Loggerhead nesting populations in the U.S. are struggling — and these shrimp trawls aren’t helping.

The solution, as Oceana and other environmental organizations have pointed out, is simple: the government must require TEDs in all trawls, especially shrimp trawls, and enforce these regulations — or else shut down the Gulf shrimp fishery.

Sea turtles have been swimming in the oceans for millions of years, and now these ancient mariners are being unnecessarily pushed toward extinction. It’s time to give sea turtles a breather.

Susan Rockefeller is on the board of directors of Oceana, the international ocean conservation organization.

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