Posted on 08/26/2005 9:10:48 AM PDT by cogitator
BIMINI, Bahamas — The bulldozers moved slowly at first. Picking up speed, they pressed forward into a patch of dense mangrove trees that buckled and splintered like twigs. As the machines moved on, the pieces drifted out to sea.
Sitting in a small motorboat a few hundred yards offshore on a mid-July afternoon, Samuel H. Gruber — a University of Miami professor who has devoted more than two decades to studying the lemon sharks that breed here — plunged into despondency. The mangroves being ripped up to build a new resort provide food and protection that the sharks can't get in the open ocean, and Gruber fears the worst.
"At the end of my career, I get to document the destruction of the species I've been documenting for 20 years," he lamented.
Such sentiments have become increasingly common in recent years among a growing number of marine biologists, who find themselves studying species in danger of disappearing. For years, many scientists and regulators believed the oceans were so vast there was little risk of marine species dying out. Now, some suspect the world is on the cusp of what Ellen Pikitch, executive director of the Pew Institute for Ocean Science, calls "a gathering wave of ocean extinctions."
Dozens of biologists believe the seas have reached a tipping point, with scores of species of ocean-dwelling fish, birds and mammals edging toward extinction. In the past 300 years, researchers have documented the global extinction of just 21 marine species — but 16 have occurred since 1972.
Since the 1700s, an additional 112 species have died out in particular regions, and that trend, too, has accelerated since the mid-1960s: Nearly two dozen shark species are close to disappearing, according to the World Conservation Union, an international coalition of government and advocacy groups.
"It's been a slow-motion disaster," said Boris Worm, a professor at Canada's Dalhousie University, whose 2003 study found that 90 percent of the top predator fish have vanished from the oceans. "It's silent and invisible. People don't imagine this. It hasn't captured our imagination, like the rain forest."
Relatively few activists have taken up the cause of marine species. Ocean dwellers are harder to track, and some produce so many offspring they can seem invulnerable. And, in the words of Ocean Conservancy shark-fisheries expert Sonja Fordham, often "they're not very fuzzy."
Although a number of previous extinctions involved birds and marine mammals, it is the fate of many fish that worries experts. The large-scale industrialization of the fishing industry after World War II, a global boom in oceanfront development and a rise in global temperatures are all causing fish populations to plummet.
"Extinctions happen in the ocean; the fossil record shows that marine species have disappeared since life began in the sea," said Elliott Norse, who heads the Marine Conservation Biology Institute in Redmond, Wash. "The question is, are humans a major new force causing marine extinctions? The evidence, and projections scientists are making, suggest that the answer is yes."
Large-scale fishing accounts for more than half the documented fish extinctions in recent years, Nicholas Dulvy, a scientist at Lowestoft Laboratory in England, wrote in 2003. Destruction of habitats in which fish spawn or feed is responsible for another third. Warmer ocean temperatures are another threat, as some fish struggle to adapt to hotter and saltier water that can draw new competitors.
But nothing has pushed marine life to the edge of extinction more than aggressive fishing. Aided by technology — industrial trawlers and factory ships deploy radar and sonar to scour the seas with precision and drag nets the size of jumbo jets along the sea floor — ocean fish catches tripled between 1950 and 1992.
In some cases, fishermen have intentionally exploited species until they died out, such as the New Zealand grayling fish and the Caribbean monk seal; other species have been accidental victims of long lines or nets intended for other catches. Over the past two decades, accidental bycatch alone accounted for an 89 percent decline in hammerhead sharks in the Northeast Atlantic.
Today, sharks, along with sturgeon and sciaenids (known as croakers or drums for the sounds they make undersea), are among the most imperiled of the species that spend most of their lives in the ocean.
Populations of sharks, skates and rays — creatures known as elasmobranchs that evolved 400 million years ago and have skeletons of cartilage, not bone — have difficulty rebounding because they mature slowly and produce few offspring. Shark-fin soup, an Asian delicacy that sells for more than $100 a bowl, has intensified shark hunting in recent years.
Despite the sturgeon's fecundity, overfishing and habitat destruction have caused that population to dive as well. Beluga sturgeon, the source of black caviar, release 360,000 to 7 million eggs in a year, Pikitch noted, but they have declined 90 percent in the past 20 years. Just this month, scientists in Kazakhstan reported that they failed to find a single wild, reproducing beluga female, leaving them with no eggs for hatcheries.
Croakers' large swim bladders — air-holding sacs that help them maintain buoyancy — account for their imminent demise. Traditional Chinese medicine prizes the bladders, and the sound they make when pressed against vibrating muscles can reveal croakers' location to fishermen through sonar.
"They've been survivors on an evolutionary scale, but they've met their match, and it is us," said Pikitch, who writes about sharks and sturgeon in an upcoming book, "State of the Wild 2006."
Despite scientists' warnings, American and international authorities have been slow to protect marine species. The only U.S. saltwater fish to make the protected list is a ray, the smalltooth sawfish, which was added in 2003.
The National Oceanic and Atmospheric Administration's Fisheries Service is charged with protecting 61 threatened or endangered marine species.
Director Bill Hogarth said his agency focuses on protecting vulnerable populations so they will not have to be listed.
"That's our job — to make sure species don't wind up on the endangered-species list," he said.
But conservationists said NOAA officials are reluctant to classify fish as endangered because doing so conflicts with the agency's mission of promoting commercial fishing.
Michael Hirshfield, chief scientist at the advocacy group Oceana, said he has repeatedly seen government officials provide shifting estimates of how many threatened or endangered sea turtles can acceptably die each year in eastern scallop fisheries.
"You never get an answer to the question how many turtles would have to be killed before you would say, 'That's not OK,' " he said.
On re-reading, one question does occur to me: why were fishermen exploiting the Caribbean monk seal?
Anyone know if lemon sharks are good eating?
They taste like lemon chicken.
"Extinctions happen in the ocean; the fossil record shows that marine species have disappeared since life began in the sea," said Elliott Norse, who heads the Marine Conservation Biology Institute in Redmond, Wash."
The difference is that none of these extinctions was caused my mankind.
I have lived my life on and near the sea, and have many clients that are in the commercail fishing industry. Pushing the oceans over the edge will be disastrous for us all.
Counting fish is a tricky business, especially when some removes their neighborhood.
In order to arrest this decline in marine diversity, intelligent beings must design interventions which counter natural selection, which doesn't seem to "care" about extinction all that much.
You just have to look at what the collapse of the western populations of the Atlantic cod did to coastal commnities in eastern Canada. Its now happening in Europe as well, and communities like my own home community in south Donegal, Ireland are being hurt badly.
I don't think overfishing and pollution can be really be termed natural selective forces.
Whyever not?
People are part of the natural environment, are they not?
What makes a dam built by humans less "natural" than one builty by beavers?
Why is predation by humans less "natural" than predation by other species?
a: how do we know that many of these fish aren't moving further out, and further down to avoid fishers?
b: how many species live in the depths of the middle of the oceans that we haven't even begun to discover yet?
Yes, I can see that argument. However, the pressures we bring to bear are not part of the normal workings of nature - they're much more severe. A beaver dam is temporary and the species that exist along with it are adapted to it - it'll never block the migration of salmon or eels. A factory ship vacuuming up massive shoals of fish is not the same as a school of dolphins taking out a small percentage of the shoal.
Answer to a) fishing practices are too good, the fish can't hide, and though the oceans are vast, the places where fish congregate are much smaller (conditions such as ocean circulation determine where food supplies are high).
Answer to b) there may be a lot of species in the mid-depths, but very few of them are commercially desirable.
It is unfortunate that the leftist liberals have taken over a lot of good conservation programs. They have cried wolf so many time that I don't believe a lot of what they say. The have also had a LOT of mission creep from their original objective.
(b)The deeper down you go, the fewer species there are, as they're dependent on whatever organic matter sinks from the surface (aside from chemosynthetically-based hyrdothermal vent communities). There are undoubtedly lots of deep sea species to be discovered, but they're never going to rival communities closer to and at the surface in terms of numbers and diversity.
So by your definition of natural selective forces, a nuclear bomb would apply?
and Rhino horns, and Bear gall bladders...
I think that it's time to outlaw "traditional Chinese medicine".
How can we be both a part of nature and not? Is human culture distinct from the natural?
"What a piece of work is man! how noble in reason! how infinite in faculty! in form and moving how express and admirable! in action how like an angel! in apprehension how like a god! the beauty of the world, the paragon of animals! "Hamlet, Act II, Scene II.
You don't think we've risen above nature at this point? What other species has existed in the 4.6 billion years of earth's history that wields such power over nature? That's not to say that we're immune from the effects of certain natural phenonemna, but to contend that we're merely just another species existing amongst all the other species of the planet is nonsense.
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