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Traditional attitudes towards the sea, as something immutable and distant to humanity, are hugely out of date.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.

See on www.economist.com

Advertisements

Leatherback sea turtles gain critical habitat

Published on: July, 06 2011 by Bob Egelko, San Francisco Chronicle – Leatherback sea turtles gain critical habitat.

The Obama administration agreed Tuesday to protect an area of Pacific coastal waters by November as critical habitat for the endangered leatherback sea turtle, settling a lawsuit by conservation groups.

Leatherback sea turtle with head above water (Dermochelys coriacea) imageThe National Marine Fisheries Service had settled an earlier suit by proposing in January 2010 to designate 70,600 square miles of waters off California, Oregon and Washington as a refuge for the huge migrating reptiles and the jellyfish they eat. The California zone would extend from Point Vicente in Los Angeles County to Point Arena in Mendocino County.

The Center for Biological Diversity and other conservation advocates accused the government in a lawsuit filed in April of ignoring a January 2011 deadline under the earlier settlement for a final designation of critical habitat. The agency has not said whether it plans to change the proposed boundaries in the plan that is now due by Nov. 15.

“We believe the critical habitat as proposed is inadequate,” said Teri Shore, program director of Turtle Island Restoration Network, another plaintiff in the suit. Although the zone is a step toward preserving the leatherbacks, she said, it should cover a broader area off the California coast where drift gillnet fishing, a threat to the turtles, is now banned from mid-August to mid-November.

The federal agency has also heard from Pacific Gas & Electric Co., which urged flexibility in the rules to avoid a potential multibillion-dollar cost of a new water-cooling system for the Diablo Canyon nuclear power plant on the San Luis Obispo County coast.

After the government designates critical habitat for an endangered species, sponsors of all projects affecting the zone must consult with the National Marine Fisheries Service and take any needed protective measures.

Leatherbacks are the largest sea turtles, growing up to 8 feet long and weighing as much as a ton. They also have the longest migration, 12,000 miles each summer and fall from nesting grounds in Indonesia to the West Coast of the United States.

They were placed on the endangered species list in 1970, but their numbers have continued to fall because of pollution and accidental deaths caused by commercial fishing, according to government reports. Conservation groups said the Pacific population has plunged by more than 95 percent since 1980.

Like this at Facebook

Pacific Island Countries Step Up Shark Conservation Efforts

Published on: June, 22 2011 – PRNewswire – USNewswire Washington Pacific Island Countries Step Up Shark Conservation Efforts

NOAA agent counting confiscated shark fins imageThe Association of Pacific Island Legislatures (APIL) issued a resolution last week stressing the need for additional actions to protect sharks.

The resolution, reached at APIL’s general assembly conference in Palau, states that the association agrees with “protective legislation in Palau, Hawaii, CNMI [Commonwealth of the Northern Mariana Islands] and Guam.”

The approved language asks “all member legislative assemblies of APIL to adopt similar legislation for a unified regional ban prohibiting the possession, selling, offering for sale, trading or distribution of shark fins, rays and ray parts.”

“Pacific islanders are again taking the global lead in initiatives to safeguard sharks from overfishing,” said Matt Rand, director of Global Shark Conservation for the Pew Environment Group. “The decision reached in Palau, home of the first Pacific shark sanctuary, underscores the growing momentum for conserving these animals across the region and sends another signal to the rest of the world that more needs to be done.”

Trade in shark fins has been banned by APIL members from Hawaii, Guam and the Northern Marianas, and it has been suspended by the Marshall Islands.

“The shark fin ban in the CNMI was the most important legislation I introduced in my 20-year career as a public servant,” said Representative Diego T. Benavente, the commonwealth’s former House speaker and lieutenant governor. “It is imperative that this movement to protect sharks spread from island to island, nation to nation.”

Sharks, which grow slowly, mature late and produce few young during their lifetimes, have difficulty recovering from overfishing and depletion. These apex predators, living at the top of the food web, are key to maintaining the health of ocean ecosystems. Yet up to 73 million are killed every year, primarily for their fins.

“We applaud all members of APIL for responding to the plight of the region’s sharks,” Rand said. “We support their efforts and hope that their leadership continues to inspire other coastal nations to protect these important animals.”

The member states of APIL are the Northern Marianas, Guam, Palau, Yap, Chuuk, Pohnpei, Kosrae, the Marshall Islands, Kiribati, American Samoa, Nauru and Hawaii. The exclusive economic zones of all APIL member nations total an area larger than the land masses of the continental United States and European Union countries combined.

The Pew Environment Group is the conservation arm of The Pew Charitable Trusts, a nongovernmental organization that works globally to establish pragmatic, science-based policies that protect our oceans, preserve our wildlands and promote clean energy. www.PewEnvironment.org/Sharks

Like this at Facebook
%d bloggers like this: